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  • 1.
    Aevan, Nadjib Danial
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    MDO Framework for Design of Human PoweredPropellers using Multi-Objective Genetic Algorithm2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis showcases the challenges, downsides and advantages to building a MultiDisciplinary Optimization (MDO) framework to automate the generation of an efficientpropeller design built for lightly loaded operation, more specifically for humanpowered aircrafts. Two years ago, a human powered aircraft project was initiatedat Linköping University. With the help of several courses, various students performedconceptional design, calculated and finally manufactured a propeller bymeans of various materials and manufacturing techniques. The performance ofthe current propeller is utilized for benchmarking and comparing results obtainedby the MDO process.The developed MDO framework is constructed as a modeFRONITER project wereseveral Computer Aided Engineering softwares (CAE) such as MATLAB, CATIAand XFOIL are connected to perform multiple consequent optimization subprocesses.The user is presented with several design constraints such as blade quantity,required input power, segment-wise airfoil thickness, desired lift coefficientetc. Also, 6 global search optimization algorithms are investigated to determinethe one which generate most efficient result according to several set standards.The optimization process is thereafter initialized by identifying the most efficientchord distribution with a help of an initial blade cross-section which has been previouslyused in other human powered propellers, the findings are thereafter usedto determine the flow conditions at different propeller stations. Two different aerodynamicoptimized shapes are generated with the help of consecutively performedsubprocesses. The optimized propeller requires 7.5 W less input power to generatenearly equivalent thrust as the original propeller with a total efficiency exceedingthe 90 % mark (90.25 %). Moreover, the MDO framework include an automationprocess to generate a CAD design of the optimized propeller. The generatedCAD file illustrates a individual surface blade decrease of 12.5 % compared tothe original design, the lightweight design and lower input power yield an overallpropulsion system which is less tedious to operate.

  • 2.
    Amadori, Kristian
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Melin, Tomas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Staack, Ingo
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Multidisciplinary Optimization of Wing Structure Using Parametric Models2013Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Aircraft design is an inherently multidisciplinary activity that requires integrating different models and tools to reach a well-balanced and optimized product. At Linköping University a design framework is being developed to support the initial design space exploration and the conceptual design phase. Main characteristics of the framework are its flexible database in XML format, together with close integration of automated CAD and other tools, which allows the developed geometry to be directly used in the subsequent preliminary design phase. In particular, the aim of the proposed work is to test the framework by designing, optimizing and studying a transport aircraft wing with respect to aerodynamic, geometry, structural and accessability constraints. The project will provide an initial assessment of the capability of the framework, both in terms of processing speed and accuracy of the results.

  • 3.
    Andersson Granberg, Tobias
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Polishchuk, Tatiana
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Polishchuk, Tatiana
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Schmidt, Christiane
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    A framework for integrated terminal airspace design2019Inngår i: Aeronautical Journal, ISSN 0001-9240, Vol. 123, nr 1263, s. 567-585Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Route planning and airspace sectorisation are two central tasks in air traffic management. Traditionally, the routing and sectorisation problems were considered separately, with aircraft trajectories serving as input to the sectorisation problem and, reciprocally, sectors being part of the input to the path finding algorithms. In this paper we propose a simultaneous design of routes and sectors for a transition airspace. We compare two approaches for this integrated design: one based on mixed integer programming, and one Voronoi-based model that separates potential "hotspots" of controller activity resulting from the terminal routes. We apply our two approaches to the design of Stockholm Terminal Maneuvering Area.

  • 4.
    Andersson, Henric
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Herzog, Erik
    Saab Aeronautics, Linköping, Sweden.
    Ölvander, Johan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Experience from Model and Software Reuse in Aircraft Simulator Product Line Engineering2013Inngår i: Information and Software Technology, ISSN 0950-5849, E-ISSN 1873-6025, Vol. 55, nr 3, s. 595-606Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Context: "Reuse" and "Model Based Development" are two prominent trends for improving industrial development efficiency. Product lines are used to reduce the time to create product variants by reusing components. The model based approach provides the opportunity to enhance knowledge capture for a system in the early stages in order to be reused throughout its lifecycle. This paper describes how these two trends are combined to support development and support of a simulator product line for the SAAB 39 Gripen fighter aircraft.

    Objective: The work aims at improving the support (in terms of efficiency and quality) when creating simulation model configurations. The objective is to increase the level of reuse when combining and customizing models for usage in a range of development and training simulators.

    Method: The research has been conducted with an interactive approach using prototyping and demonstrations, and the evaluation is based on an iterative and a retrospective method.

    Results: A product line of simulator models for the SAAB 39 Gripen aircraft has been analyzed and defined in a Product Variant Master. A configurator system has been implemented for creation, integration, and customization of stringent simulator model configurations. The system is currently under incorporation in the standard development process at SAAB Aeronautics.

    Conclusion: The explicit and visual description of products and their variability through a configurator system enables better insights and a common understanding so that collaboration on possible product configurations improves and the potential of software reuse increases. The combination of application fields imposes constraints on how traditional tools and methods may be utilized. Solutions for Design Automation and Knowledge Based Engineering are available, but their application has limitations for Software Product Line engineering and the reuse of simulation models.

  • 5.
    Andersson, Tobias
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    The flight perturbation problem: operational aircraft rescheduling2001Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    When there is a perturbation in a carefully planned flight schedule, e.g. an aircraft breakdown, it is important to minimize the negative consequences of this disturbance. In this thesis, a model and a number of solution strategies for the Flight Perturbation Problem is presented. Based on a connection network, a mixed integer multicommodity flow model with side constraints is developed. Cancellations, delays and aircraft swaps, both within the same fleet and between different aircraft types, are used to take care of the perturbation. The model also assures that the schedule returns to normal within a certain time.

    Six different solution strategies arc used to solve the model; the first based on a Lagrangian relaxation of the mixed integer multicommodity flow model. Four strategies are based on Dantzig-Wolfe decomposition and in two of them all feasible points are generated by a tree search algorithm before the master problem is solved, while the other two are column generation based. The last strategy is based on the metaheuristic tabu search.

    The computational tests with real problem data show that the Dantzig-Wolfe based strategies and the tabu search strategy arc very promising, and especially the tabu search strategies could be used in a real problem application that could provide airlines with solutions to complex perturbation problems.

  • 6.
    Arjoni, D. H.
    et al.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campo, Brazil.
    Rocha, G. C.
    Konatus, São José dos Campo, Brazil.
    Moreira, A. H.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campo, Brazil.
    Nicola, R. M.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campo, Brazil.
    Oliveira, W. R.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campo, Brazil.
    Silva, A. V. S.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campo, Brazil.
    Natal, G. S.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campo, Brazil.
    Silveira, L.
    NAC, São José dos Campo, Brazil.
    Thomas, E.
    Embraer, São José dos Campo, Brazil.
    Villani, E.
    TA Instituto Tecnológico de Aeronáutica, São José dos Camp, Brazil.
    Trabasso, Luís Gonzaga
    TA Instituto Tecnológico de Aeronáutica, São José dos Camp, Brazil.
    Experimental Evaluation of the Human Performance on a RoboticFlight Simulator based on FOQA Parameters2016Inngår i: Proceedings of the Aerospace Technology Congress / [ed] Kaj Lundahl, Roland Karlsson, Björn Jonsson and Knut Övrebö, Stockholm, 2016, Vol. 1, s. 1-11Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The SIVOR project, currently being developed by ITA and Embraer, consists of designing andimplementing a high fidelity flight simulator based on the use of COTS industrial robots. The aim of theproject is to provide a cost-efficient and flexible platform that can be used along the design phases of theaircraft. One of the advantages of an industrial robot over the traditional Stewart platform is theavailability of a large workspace, which provides more flexibility for defining the washout filter. Thisfilter converts the aircraft dynamics into robot movements, which has a limited workspace. The mainpurpose of the flight simulator is to provide a motion feeling similar to the one imposed by the aircraftmovements in a real flight. The representativeness of the motion cue is usually evaluated in a qualitativeway by the pilots that fly the simulator. Quantitative methods to evaluate the entire range of actuation of asimulator are complex, inducing tests in fractions of the flight to increase performance. In this work, wediscuss the use of FOQA (Flight Operational Quality Assurance) as an additional quantitative tool for theevaluation of the motion cue in the SIVOR flight simulator. FOQA is a voluntary safety program fromFAA, detailed in AC-120-82. It proposes a set of parameters that can be used by airliners to analyse flightsafety and increase operational efficiency. The verification of FOQA parameters checks whether or notthe pilot complies with the standard operational procedures defined by the airliners and aircraftmanufacturers. The purpose of this work is to analyse whether or not, and to what extent, the FOQAparameters can be used to evaluate the quality of the motion cue of flight simulators. For this purpose, wedefine an experimental procedure that compares flights performed by pilots under different motionmodes. It then calculates a set of behavioural parameters that has been proposed in order to quantify howthe motion affects the inputs of the pilot. The results are submitted to ANOVA statistical analysis thatverifies the relevance of the motion factor. Finally, we discuss the capability of a FOQA basedexperiment to estimate the contribution of the motion to the realism of the flight simulation.

  • 7.
    Arustei, Adrian
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Development of a System Identification Tool for Subscale Flight Testing2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Aircraft system identification has been widely used to this day in applications like control law design, building simulators or extending flight envelopes. It can also be utilized for determining flight-mechanical characteristics in the preliminary design phase of a flight vehicle. In this thesis, three common time-domain methods were implemented in MATLAB for determining the aerodynamic derivatives of a subscale aircraft. For parameter estimation, the equation-error method is quick, robust and can provide good parameter estimates on its own. The output-error method is computationally intensive but keeps account of the aircraft's evolution in time, being more suitable for fine-tuning predictive models. A new model structure is identified using multivariate orthogonal functions with a predicted squared error stopping criteria. This method is based on linear regression (equation-error).

    The code written is flexible and can also be used for other aircraft and with other aerodynamic models. Simulations are compared with experimental data from a previous flight test campaign for validation. In the future, this tool may help taking decisions in conceptual design after a prototype is tested.

  • 8.
    Baer, Katharina
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Simulation-Based Optimization of a Series Hydraulic Hybrid Vehicle2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Hybrid transmissions are characterized by their utilization of more than one form of energy storage. They have the potential to help reduce overall fuel consumption and vehicle emissions by providing the possibility of brake energy recuperation and prime mover operation management. Electric hybrids and electric vehicle drives are nowadays ubiquitous, and mechanical energy storage in flywheel has been investigated in the past. The use of fluid power technology with a combustion engine has also been investigated since the late 1970s, and is frequently revisited.

    Hydraulic hybridization is especially attractive for heavy vehicles with frequent braking and acceleration which benefit most from fluid power components’ high power density, typically busses, delivery or refuse vehicles, and vehicles with existing hydraulic circuits and transmissions, such as forest and construction machinery, but have been considered for smaller vehicles as well.

    Due to the characteristic discharge profile of hydraulic energy storage, special attention needs to be paid to control aspects in the design process to guarantee drivability of the vehicle. In this respect, simulation models can be of use in early design process stages for cheaper and faster evaluation of concepts and designs than physical experiments and prototyping, and to generate better understanding of the system studied. Engineering optimization aids in the systematic exploration of a given design space, to determine limits and potentials, evaluate trade-offs and potentially find unexpected solutions. In the optimization of a hydraulic hybrid transmission, the integration of component and controller design is of importance, and different strategies (sequential, iterative, bi-level and simultaneous approaches) are conceivable, with varying consequences for the implementation.

    This thesis establishes a simulation-based optimization framework for a hydraulic hybrid transmission with series architecture. Component and control parameter optimization are addressed simultaneously, using a rule-based supervisory control strategy. The forward-facing dynamic simulation model at the centre of the framework is built in Hopsan, a multi-disciplinary open-source tool developed at Linköping University. The optimization is set up and conducted for an example application of an on-road light-duty truck over standard drive cycles. Both results from these experiments as well as the framework itself are studied and evaluated. Relevant design aspects, such as explicit design relations to be considered and performance requirements for more robust design, are identified and addressed, and the optimization problem is analysed with regard to algorithm performance and problem formulation. The final result is an optimization framework that can be adjusted for further in-depth studies, for example through the inclusion of additional components or optimization objectives, and extendable for comparative analysis of different topologies, applications and problem formulations.  

    Delarbeid
    1. System Parameter Study for a Light-Weight Series Hydraulic Hybrid Vehicle
    Åpne denne publikasjonen i ny fane eller vindu >>System Parameter Study for a Light-Weight Series Hydraulic Hybrid Vehicle
    2014 (engelsk)Inngår i: PROCEEDINGS OF THE 8TH FPNI PH.D SYMPOSIUM ON FLUID POWER, 2014, ASME Press, 2014, s. V001T03A004-Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Amongst the hybrid vehicle propulsion solutions aiming to improve fuel efficiency, hybrid electric solutions currently receive most attention, especially on the market. However, hydraulic hybrids are an interesting alternative, especially for heavier vehicles due to higher power density which is beneficial if higher masses are moved. As a step towards a comprehensive design framework to compare several possible hydraulic hybrid architectures for a specified application and usage profile, the model of a series hydraulic hybrid vehicle was previously introduced and initially studied concerning component sizing for an exemplary light-duty vehicle in urban traffic. The vehicle is modeled in the Hopsan simulation tool. A comparably straight-forward engine management is used for the vehicle control; both pump and engine controls are based on the hydraulic accumulator’s state-of-charge. The model is developed further with respect to the accumulator component model. Based on that, the influence of several system and component parameters, such as maximum system pressure and engine characteristics, as well as controller parameters on the vehicle’s performance is analyzed. The goal is to allow for more understanding of the system’s characteristics to facilitate future optimization of the system.

    sted, utgiver, år, opplag, sider
    ASME Press, 2014
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-114212 (URN)10.1115/FPNI2014-7840 (DOI)000359389400029 ()978-0-7918-4582-0 (ISBN)
    Konferanse
    8th FPNI Ph.D Symposium on Fluid Power, Lappeenranta, Finland, June 11–13, 2014
    Tilgjengelig fra: 2015-02-13 Laget: 2015-02-13 Sist oppdatert: 2018-03-09
    2. Design Study and Parameter Optimization for a Light-Weight Series Hydraulic Hybrid Vehicle
    Åpne denne publikasjonen i ny fane eller vindu >>Design Study and Parameter Optimization for a Light-Weight Series Hydraulic Hybrid Vehicle
    2015 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Hydraulic hybrid drives are one potential way of improving the fuel efficiency of vehicles, including the possi-bility of recuperating braking energy in a hydraulic accumulator. The high power density of fluid power is mainly advantageous for heavy vehicles, or duty cycles characterized with frequent braking and acceleration. For smaller vehicles, hydraulic hybrid drives are thus most interesting under urban and suburban driving conditions. Amongst the existing architectures, the series hydraulic hybrid offers the advantage of operating the internal combustion engine independently of the vehicle speed, at the cost of a less efficient transmission path than a purely mechanical one. Previously, a series hydraulics hybrid light-duty vehicle was modelled in the transmission-line modelling (TLM)-based simulation software Hopsan from the division of Fluid and Mechatronic Systems (Flumes) at Linköping University. This paper studies through simulation-based optimi-zation how the fuel-optimal vehicle design is affected by various mixes of urban and suburban driving requirements. Both the system’s hardware and the parameters of a basic control strategy are considered. The results show quite similar designs for most performance requirements combinations, and can be the base for further studies addressing additional requirements, conditions and objectives.

    Serie
    Scandinavian International Conference on Fluid Power (SICFP), ISSN 2342-2726
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-122004 (URN)
    Konferanse
    14th Scandinavian International Conference on Fluid Power (SICFP'15), Tampere, Finland
    Tilgjengelig fra: 2015-10-14 Laget: 2015-10-14 Sist oppdatert: 2018-03-09
    3. Aspects of Parameter Sensitivity for Series Hydraulic Hybrid Light-Weight Duty Vehicle Design
    Åpne denne publikasjonen i ny fane eller vindu >>Aspects of Parameter Sensitivity for Series Hydraulic Hybrid Light-Weight Duty Vehicle Design
    2016 (engelsk)Inngår i: Proceedings of the 9th FPNI Ph.D. Symposium on Fluid Power (FPNI2016), American Society of Mechanical Engineers , 2016, artikkel-id V001T01A041Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Hybridization of a vehicle’s drivetrain can in principle help to improve its energy efficiency by allowing for recuperation of kinetic energy and modulating the engine’s load. How well this can be realized depends on appropriate sizing and control of the additional components. The system is typically designed sequentially, with the hardware setup preceding the development and tuning of advanced controller architectures. Taking an alternative approach, component sizing and controller tuning can be addressed simultaneously through simulation-based optimization.

    The results of such optimizations, especially with standard algorithms with continuous design variable ranges, can however be difficult to realize, considering for example limitations in available components. Furthermore, drive-cycle based optimizations are prone to cycle-beating. This paper examines the results of such simulation-based optimization for a series hydraulic hybrid vehicle in terms of sensitivity to variations in design parameters, system parameters and drive cycle variations. Additional relevant aspects concerning the definition of the optimization problem are pointed out.

    sted, utgiver, år, opplag, sider
    American Society of Mechanical Engineers, 2016
    Emneord
    Weight (Mass), Automotive design, Cycles, Optimization, Control equipment, Simulation, Design, Hybrid electric vehicles, Hardware, Stress
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-135737 (URN)10.1115/FPNI2016-1567 (DOI)978-0-7918-5047-3 (ISBN)
    Konferanse
    9th FPNI Ph.D. Symposium on Fluid Power, Florianópolis, SC, Brazil, October 26–28, 2016
    Tilgjengelig fra: 2017-03-17 Laget: 2017-03-17 Sist oppdatert: 2018-03-09
    4. Framework for simulation-based simultaneous system optimization for a series hydraulic hybrid vehicle
    Åpne denne publikasjonen i ny fane eller vindu >>Framework for simulation-based simultaneous system optimization for a series hydraulic hybrid vehicle
    2018 (engelsk)Inngår i: International Journal of Fluid Power, ISSN 1439-9776Artikkel i tidsskrift (Fagfellevurdert) Epub ahead of print
    Abstract [en]

    Hybridisation of hydraulic drivetrains offers the potential of efficiency improvement for on – and off-road applications. To realise the advantages, a carefully designed system and corresponding control strategy are required, which are commonly obtained through a sequential design process. Addressing component selection and control parameterisation simultaneously through simulation-based optimisation allows for exploration of a large design space as well as design relations and trade-offs, and their evaluation in dynamic conditions which exist in real driving scenarios. In this paper, the optimisation framework for a hydraulic hybrid vehicle is introduced, including the simulation model for a series hybrid architecture and component scaling considerations impacting the system’s performance. A number of optimisation experiments for an on-road light-duty vehicle, focused on standard-drive-cycle-performance, illustrate the impact of the problem formulation on the final design and thus the complexity of the design problem. The designs found demonstrate both the potential of energy storage in series hybrids, via an energy balance diagram, as well as some challenges. The framework presented here provides a base for systematic evaluation of design alternatives and problem formulation aspects.

    sted, utgiver, år, opplag, sider
    Taylor & Francis, 2018
    Emneord
    Simulation-based optimization, hydraulic hybrid vehicle, series hybrid, simultaneous design and control optimization, Hopsan
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-152353 (URN)10.1080/14399776.2018.1527122 (DOI)2-s2.0-85055674140 (Scopus ID)
    Tilgjengelig fra: 2018-10-29 Laget: 2018-10-29 Sist oppdatert: 2018-11-23bibliografisk kontrollert
    5. Robustness and performance evaluations for simulation-based control and component parameter optimization for a series hydraulic hybrid vehicle
    Åpne denne publikasjonen i ny fane eller vindu >>Robustness and performance evaluations for simulation-based control and component parameter optimization for a series hydraulic hybrid vehicle
    2019 (engelsk)Inngår i: Engineering optimization (Print), ISSN 0305-215X, E-ISSN 1029-0273, s. 1-19Artikkel i tidsskrift (Fagfellevurdert) Epub ahead of print
    Abstract [en]

    Simulation-based optimization is a useful tool in the design of complex engineering products. Simulation models are used to capture numerous aspects of the design problem for the objective function. Optimization results obtained can be assessed from various perspectives. In this study, component and control optimization of a series hydraulic hybrid vehicle is used as an application, and different robustness and performance aspects are evaluated. Owing to relatively high computational loads, efficient optimization algorithms are important to provide sufficient quality of results at reasonable computational costs. To estimate problem complexity and evaluate optimization algorithm performance, the definitions for information entropy and the related performance index are extended. The insights gained from various simulation-based optimization experiments and their subsequent analysis help characterize the efficiency of the optimization problem formulation and parameterization, as well as optimization algorithm selection with respect to parallel computation capabilities for further development of the model and optimization framework.

    sted, utgiver, år, opplag, sider
    Taylor & Francis, 2019
    Emneord
    Simulation-based optimization, information entropy-rate-based performance index, robustness analysis, direct search optimization, hydraulic hybrid vehicle
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-156185 (URN)10.1080/0305215X.2019.1590566 (DOI)
    Tilgjengelig fra: 2019-04-08 Laget: 2019-04-08 Sist oppdatert: 2019-04-15bibliografisk kontrollert
  • 9.
    Björnsson, Andreas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell Produktion. Linköpings universitet, Tekniska fakulteten.
    Automated layup and forming of prepreg laminates2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Composite materials like carbon fiber-reinforced polymers (CFRPs) present highly appealing material properties, as they can combine high strength with low weight. In aerospace applications, these properties help to realize lightweight designs that can reduce fuel consumption. Within the aerospace industry, the use of these types of materials has increased drastically with the introduction of a new generation of commercial aircraft. This increased use of CFRP drives a need to develop more rational manufacturing methods.

    For aerospace applications, CFRP products are commonly manufactured from a material called prepreg, which consists of carbon fibers impregnated with uncured polymer resin. There are two dominant manufacturing technologies for automated manufacturing using prepreg, automated tape layup and automated fiber placement. These two technologies are not suitable for all types of products, either due to technical limitations or a combination of high investment costs and low productivity. Automation alternatives to the two dominant technologies have been attempted, but have so far had limited impact. Due to the lack of automation alternatives, manual manufacturing methods are commonly employed for the manufacturing of complex-shaped products in low to medium manufacturing volumes.

    The research presented in this thesis aims to explore how automated manufacturing systems for the manufacturing of complex CFRP products made from prepreg can be designed so that they meet the needs and requirements of the aerospace industry, and are suitable for low to medium production volumes. In order to explore the area, a demonstrator-centered research approach has been employed. A number of demonstrators, in the form of automated manufacturing cells, have been designed and tested with industrial and research partners. The demonstrators have been used to identify key methods and technologies that enable this type of manufacturing, and to analyze some of these methods and technologies in detail. The demonstrators have also been used to map challenges that affect the development of enabling methods and technologies.

    Automated manufacturing of products with complex shapes can be simplified by dividing the process into two steps. Thin layers of prepreg are laid up on top of each other to form flat laminates that are formed to the desired shape in subsequent forming operations. The key methods and technologies required to automate such a system are methods and technologies for automated prepreg layup, the automated removal of backing paper and the forming of complex shapes. The main challenges are the low structural rigidity and tacky nature of prepreg materials, the extensive quality requirements in the aerospace industry and the need for the systems to handle a wide array of prepreg shapes.

    The demonstrators show that it is possible to automate the manufacturing of complexshaped products using automated layup and forming of prepreg laminates. Tests using the demonstrators indicate that it is possible to meet the quality requirements that apply to manual manufacturing of similar products.

    Delarbeid
    1. Composite Manufacturing: How Improvement Work Might Lead to Renewed Product Validation
    Åpne denne publikasjonen i ny fane eller vindu >>Composite Manufacturing: How Improvement Work Might Lead to Renewed Product Validation
    2012 (engelsk)Inngår i: Proceedings of the 5th International Swedish Production Symposium / [ed] Mats Björkman, 2012, s. 505-513Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    High-performance polymer composites are mainly used in applications where the benefits of high strength and low weight justify the high material and manufacturing costs. Many of these applications are found today in the aerospace, space and defense industries. Most of today’s commonly used manufacturing methods within this area are highly labor intensive. Furthermore, the quality requirements from the customers require a high level of process control. The purpose of this paper is to explore how changes that are introduced in order to improve productivity in a manufacturing system are managed, particularly with regard to who takes the decision to implement a change and how a change is validated. The study is based on qualitative interviews performed at several companies that manufacture composite components for the aerospace, space and defense sectors. The findings show that the responsibility for deciding to implement a change and the need for validating it are based on many diverse and interconnected factors. Therefore, it is difficult to construct guidelines for early assessment of the scope and cost of a proposed change. Hence each individual change request must be evaluated on its own. The study also shows that the validation process can be adapted to a level that is based on the type of change. In addition, it highlights that control over process parameters in manufacturing is essential.

    Emneord
    composite manufacturing, validation, change request management
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-85268 (URN)978-91-7519-752-4 (ISBN)
    Konferanse
    5th International Swedish Production Symposium (SPS 2012), 6-8 November 2012, Linköping, Sweden
    Tilgjengelig fra: 2012-11-14 Laget: 2012-11-14 Sist oppdatert: 2017-05-17
    2. Automated Removal of Prepreg Backing Paper - A Sticky Problem
    Åpne denne publikasjonen i ny fane eller vindu >>Automated Removal of Prepreg Backing Paper - A Sticky Problem
    2013 (engelsk)Inngår i: Proceedings of the SAE 2013, Aerotech Congress and Exhibition, 24th-26th September 2013, Montreal,Canada, 2013Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Automated solutions for manufacturing composite products based on prepreg often imply Automatic Fiber Placement or Automatic Tape Laying. These systems are generally associated with huge investments. For certain manufacturing applications it is interesting to investigate alternatives to find simpler and less costly automation. One example of an automated system could be the use of a standard industrial robot to pick single prepreg plies from an automated cutting machine and stack them to form a plane laminate. This paper is based on a case illustrating a product from the aircraft manufacturing industry. The case will demonstrate a pick and place concept on a general level and illustrate challenges that must be solved. The challenge selected to be the main focus for this paper is an automated process for backing paper removal. A literature review of different gripping technologies reveals several interesting technologies, and the most promising are tested for backing paper removal. The tests show that an automated removal process can be designed by using standard vacuum grippers in combination with mechanical clamping grippers. In order to lift the backing paper with a vacuum gripper an initial separation between the backing paper and prepreg is needed. This separation is most easily mechanically induced by bending the material. The proposed solution for automatic backing paper removal can be integrated in a manufacturing cell for manufacturing of the studied product.

    Emneord
    composite manufacturing, automation, prepreg, gripping technology
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-99344 (URN)10.4271/2013-01-2289 (DOI)
    Konferanse
    SAE 2013 Aerotech Congress and Exhibition, September 24-26, 2013, Montréal, Quebec, Canada
    Merknad

    SAE Technical Paper 2013-01-2289

    Tilgjengelig fra: 2013-10-16 Laget: 2013-10-16 Sist oppdatert: 2017-05-17bibliografisk kontrollert
    3. Automation of Composite Manufacturing Using Off-the-shelf Solutions, Three Cases from the Aerospace Industry
    Åpne denne publikasjonen i ny fane eller vindu >>Automation of Composite Manufacturing Using Off-the-shelf Solutions, Three Cases from the Aerospace Industry
    2015 (engelsk)Inngår i: Proceedings of the 20th International Conference on Composite Materials, 2015Konferansepaper, Publicerat paper (Annet vitenskapelig)
    Abstract [en]

    With an increased use of composite materials follows a need for rational, cost-efficient manufacturing processes. This paper explores how off-the-shelf solutions, developed for other purposes than composite manufacturing, can be used to build systems for automated composite manufacturing. Three demonstrators, each of them dealing with a specific type of material and all of them representing different manufacturing technologies for automated composite manufacturing, are presented and analyzed to find aspects that affect the ability to use off-the-shelf solutions. The three demonstrators target low to medium manufacturing volumes of complex products and they have been developed in collaboration with industrial partners within the aerospace industry. The conclusions drawn from the development of the demonstrators are that it is technically feasible to use off-the-shelf solutions in the three cases while adhering to the high quality standards of the industry. Furthermore three groups of aspects, quality aspects, product aspects and system aspects, which affect the ability to use off-the-shelf solutions for automated composite manufacturing, are identified.

    Emneord
    composite manufacturing, automation, off-the-shelf, aerospace
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-120300 (URN)
    Konferanse
    ICCM20 - The 20th International Conference on Composite Materials, 19-24th July 2015, Copenhagen Denmark
    Tilgjengelig fra: 2015-07-27 Laget: 2015-07-27 Sist oppdatert: 2017-05-17
    4. Low-cost Automation for Prepreg Handling - Two Cases from the Aerospace Industry
    Åpne denne publikasjonen i ny fane eller vindu >>Low-cost Automation for Prepreg Handling - Two Cases from the Aerospace Industry
    2016 (engelsk)Inngår i: SAE International Journal of Materials & Manufacturing, ISSN 1946-3979, E-ISSN 1946-3987, Vol. 9, nr 1, s. 68-74Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    With an increased use of composite materials within the aerospace industry follows a need for rational and cost-effective methods forcomposite manufacturing. Manual operations are still common for low to medium manufacturing volumes and complex products.Manual operations can for example be found in material handling, when picking prepreg plies from a cutter table and stacking them toform a plane laminate in preparation for a subsequent forming operation. Stacking operations of this kind often involves a greatnumber of different ply geometries and removal of backing paper and other protecting materials like plastic. In this paper two differentdemonstrator cells for automated picking of prepreg plies and stacking of plane laminates are presented. One demonstrator is utilizinga standard industrial robot and an advanced end-effector to handle the ply variants. The other demonstrator is using a dual arm robotwhich allow for simpler end-effector design. In combination with a previously developed system for automated removal of backingpapers both systems have shown to be capable of automatically picking prepreg plies from a plane surface and stack them to generate aflat multistack laminate. The dual arm approach has shown advantageous since it result in simpler end-effector design and a successivelay down sequence that result in good adhesion between the plies in the laminate.

    sted, utgiver, år, opplag, sider
    Warrendale, USA: SAE International, 2016
    Emneord
    Composite, Manufacturing, Automation, Low-cost, Prepreg
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-121602 (URN)10.4271/2015-01-2606 (DOI)000386445700008 ()
    Tilgjengelig fra: 2015-09-28 Laget: 2015-09-28 Sist oppdatert: 2018-02-02bibliografisk kontrollert
    5. Robot-Forming of Prepreg Stacks ‐ Development of Equipment and Methods
    Åpne denne publikasjonen i ny fane eller vindu >>Robot-Forming of Prepreg Stacks ‐ Development of Equipment and Methods
    Vise andre…
    2016 (engelsk)Inngår i: Proceedings of the 17th European Conference on Composite Materials (ECCM17), 2016Konferansepaper, Publicerat paper (Annet vitenskapelig)
    Abstract [en]

    Within the aerospace industry the manufacturing of composite components with complex shapes, such as spars, ribs and beams are often manufactured using manual layup and forming of prepreg material. Automated processes for prepreg layup and efficient forming techniques like vacuum forming are sometimes difficult to employ to these type of products due to technical limitations. This paper describes the development of tools and the forming sequence needed to automate sequential forming of a complex shape using an industrial robot. Plane prepreg stacks are formed to the final shape using a dual-arm industrial robot equipped with rolling tools. Tests show that the developed tools and the employed sequence can be used to form stacks to the desired shape with acceptable quality.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-129925 (URN)
    Konferanse
    ECCM17 - 17th European Conference on Composite Materials 26-30th June 2016, Munich, Germany
    Tilgjengelig fra: 2016-07-01 Laget: 2016-07-01 Sist oppdatert: 2017-05-17bibliografisk kontrollert
  • 10.
    Bradley, Andreas
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan.
    Gårdhagen, Roland
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan.
    Karlsson, Matts
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan.
    Bird-Like Wing Conguration for Pitch Control of a Tailless Aircraft2012Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    A numerical study of a small bird-like aircraft has been performed. The aim of the study was to investigate how a swing wing (actualized through a constant span morphing wing) can be used for pitch control of a tailless aircraft. The results show that a swing wing can be successfully used, and that the aircraft can be maintained in a trimmed state by only small adjustments of part of the wing. A comparison was also made with a Vortex lattice method, but these results significantly deviated from those obtained with CFD. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.

  • 11.
    Colombi, Raffaele
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära.
    CFD Investigation of Aerodynamic Drag Reduction for an Unloaded Timber Truck2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The road transport industry is facing a strong need for fuel consumption reduction, driven by the necessity of decreasing polluting emissions, such as CO2 and NOX, as well as coping with strict regulations and increasing fuel costs. For road vehicles the aerodynamic drag constitutes a major source of energy consumption, and for this reason improving the aerodynamic performance of the vehicle is an established approach for reducing fuel consumption and greenhouse gases emissions.

    In this Thesis work, Computational Fluid Dynamics (CFD) investigations have been carried out in order to investigate and improve the aerodynamic performance of an unloaded timber truck. The work has been divided in two parts. In a first phase, a preliminary study was carried out on a simplified tractor-trailer model in order to establish a suitable computational grid and turbulence model. The hexcore-mesh showed a better performance over the tet- and poly-mesh types. Among the selected RANS turbulence models, the Realizable kε with Enhanced Wall Treatment (EWT) and y+ > 30 showed the highest reliability of results in

    comparison with experimental data and existing CFD investigations.

    In a second phase, the flow field around the baseline unloaded timber truck was analysed in order to highlight potential regions for drag reduction. The truck cabin-bulkhead gap, bunks, the exposed wheels and the stakes were found make key contribution to the drag build-up. The analysis confirmed the 5-yaw case to be the most representative for the wind-averaged drag coefficient.

    Geometry modifications were implemented in order to improve the aerodynamic performance in the selected areas, and subsequently combined into aero-kits in order to enhance the performance, analysed for the 5-yaw case. The combination of extended side skirts, bulkhead shield and collapsed stakes yielded a remarkable result of more than 30% decrease in the wind-averaged drag coefficient, achieved by reducing the flow separation on the cabin leeward A-pillar, and by shielding areas of high stagnation pressure from the side wind.

    Furthermore, a parallel study was conducted on the development of a procedure for the automatic post-processing of results. The outcome was a set of Python scripts to be used with Kitaware Paraview in order to automatically obtain figures of surface variables distributions, iso-surfaces, velocity profiles, drag build-up and total pressure contours. The procedure was finally extended to include the case comparison.

  • 12.
    Dahlberg, Joen
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Andersson Granberg, Tobias
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Polishchuk, Tatiana
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Schmidt, Christiane
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Sedov, Leonid
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Capacity-Driven Automatic Design of Dynamic Aircraft Arrival Routes2018Inngår i: 2018 IEEE/AIAA 37TH DIGITAL AVIONICS SYSTEMS CONFERENCE (DASC), IEEE , 2018, s. 1194-1202Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present a Mixed-Integer Programming framework for the design of aircraft arrival routes in a Terminal Maneuvering Area (TMA) that guarantee temporal separation of aircraft. The output routes constitute operationally feasible merge trees, and guarantee that the overall traffic pattern in the TMA can be monitored by air traffic controllers; in particular, we ensure that all aircraft on the arrival routes are separated in time and all merge points are spatially separated. We present a proof of concept of our approach, and demonstrate its feasibility by experiments for arrival routes during one hour at Stockholm TMA.

  • 13.
    Devadurgam, Hemanth
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Rajagopal, Soorya
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Munjulury, Raghu Chaitanya
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Modeling and Sizing of Conventional and Electrical Environmental Control Systems2019Rapport (Fagfellevurdert)
    Abstract [en]

    Environmental control system holds vital importance as it is responsible for passenger’s ventilation and comfort. This paper presents modelling and sizing of the parameterized model of environmental control systems. Knowledge based engineering application serves as the base for designing and methodology for the environmental control systems. Flexibility in the model enables user to control the size and positioning of the system and also sub-systems  associated with it. Number of passengers serves as the driving input for the environmental control system. A 3-d model gives the exact representation with respect to volume occupied and dependencies on the number of passengers. It also provides a faster method to alter the system to user needs with respect to number of air supply pipes, number of ducts and pipe length. Knowledge based engineering gives the freedom to visualize various options in the conceptual design process.

  • 14.
    Diaz Puebla, Alejandro
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Munjulury, Raghu Chaitanya
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Sizing of actuators for flight control systems and flaps integration in RAPID2015Rapport (Annet vitenskapelig)
    Abstract [en]

    The architecture of the flight control system, essentialfor all flight operations, has significantlychanged throughout the years. The first part ofthe work consists of a preliminary sizing modelof an EHA and an EMA. The second part of thework consists of the development of parametricCAD models of different types of flaps and theirintegration in RAPID. This thesis addresses theactuation system architecture of what it is namedas more electric aircraft with electrically poweredactuators. This consists of the development offlexible parametric models of flight control surfaces,being able to adapt to any wing geometryand their automatic integration in RAPID. Furthermore,it represents a first step in the developmentof an automatic tool that allows the user tochoose any possible wing control surface configuration.

  • 15.
    Eek, Magnus
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska fakulteten.
    On Credibility Assessment in Aircraft System Simulation2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The aeronautical industry is becoming increasingly reliant on Modeling and Simulation (M&S) for use throughout all system development phases, for system verification, and end-user training. To justify and to utilize the full potential of today’s model-based approach, the development of efficient and industrially applicable methods for credibility assessment of M&S efforts is a key challenge.

    This work addresses methods facilitating credibility assessment of simulation models and simulator applications used in aircraft system development. For models of individual aircraft subsystems, an uncertainty aggregation method is proposed that facilitates early model validation through approximate uncertainty quantification. The central idea is to integrate information obtained during component level validation directly into the component equations, and to utilize this information in model level uncertainty quantification.

    In addition to methods intended for models of individual subsystems, this work also proposes a method and an associated tool for credibility assessment of large-scale simulator applications. As a complement to traditional document-centric approaches, static and dynamic credibility information is here presented to end-users directly during simulation. This implies a support for detecting test plan deficiencies, or that a simulator configuration is not a suitable platform for the execution of a particular test. The credibility assessment tool has been implemented and evaluated in two large-scale system simulators for the Saab Gripen fighter aircraft. The work presented herein also includes an industrially applicable workflow for development, validation, and export of simulation models.

    Delarbeid
    1. Methodology for Development and Validation of Multipurpose Simulation Models
    Åpne denne publikasjonen i ny fane eller vindu >>Methodology for Development and Validation of Multipurpose Simulation Models
    2012 (engelsk)Inngår i: 50th AIAA Aerospace Sciences Meeting Online Proceedings including the New Horizons Forum and Aerospace Exposition (2012), AIAA , 2012Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    This paper describes a framework for development and validation of multipurpose simulation models. The presented methodology enables reuse of models in different applications with different purposes. The scope is simulation models representing physical environment, physical aircraft systems or subsystems, avionics equipment, and electronic hardware. The methodology has been developed by a small interdisciplinary team, with experience from Modeling and Simulation (M&S) of vehicle systems as well as development of simulators for verification and training. Special care has been taken to ensure usability of the workflow and method descriptions, mainly by means of 1) a user friendly format, easy to overview and update, 2) keeping the amount of text down, and 3) providing relevant examples, templates, and checklists. A simulation model of the Environmental Control System (ECS) of a military fighter aircraft, the Saab Gripen, is used as an example to guide the reader through the workflow of developing and validating multipurpose simulation models. The methods described in the paper can be used in both military and civil applications, and are not limited to the aircraft industry.

    sted, utgiver, år, opplag, sider
    AIAA, 2012
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-74716 (URN)10.2514/6.2012-877 (DOI)
    Konferanse
    50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, 9–12 January, 2012, Gaylord Opryland Resort & Convention Center, 9-12 January, Nashville, Tennessee
    Tilgjengelig fra: 2012-02-06 Laget: 2012-02-06 Sist oppdatert: 2016-04-25
    2. Study of Industrially Applied Methods for Verification, Validation & Uncertainty Quantification of Simulator Models
    Åpne denne publikasjonen i ny fane eller vindu >>Study of Industrially Applied Methods for Verification, Validation & Uncertainty Quantification of Simulator Models
    2015 (engelsk)Inngår i: International Journal of Modeling, Simulation, and Scientific Computing, ISSN 1793-9623, E-ISSN 1793-9615, Vol. 6, nr 2, artikkel-id 1550014Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    To better utilize the potential of system simulation models and simulators, industrially applicable methods for Verification, Validation and Uncertainty Quantification(VV&UQ) are crucial. This paper presents an exploratory case study of VV&UQ techniquesapplied on models integrated in aircraft system simulators at Saab Aeronauticsand in driving simulators at the Swedish National Road and Transport Research Institute(VTI). Results show that a large number of Verification and Validation (V&V)techniques are applied, some of which are promising for further development and use insimulator credibility assessment. Regarding the application of UQ, a large gap betweenacademia and this part of industry has been identified, and simplified methods areneeded. The applicability of the NASA Credibility Assessment Scale (CAS) at the studied organizations is also evaluated and it can be concluded that the CAS is consideredto be a usable tool for achieving a uniform level of V&V for all models included in asimulator, although its implementation at the studied organizations requires tailoringand coordination.

    sted, utgiver, år, opplag, sider
    World Scientific, 2015
    Emneord
    Simulator credibility; simulation model; verification; validation; uncertainty quantification; V&V; VV&UQ; NASA Credibility Assessment Scale
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-115105 (URN)10.1142/S1793962315500142 (DOI)000365772300005 ()
    Prosjekter
    NFFP6 2013-01211
    Forskningsfinansiär
    VINNOVA, NFFP6 2013-01211
    Tilgjengelig fra: 2015-03-09 Laget: 2015-03-09 Sist oppdatert: 2017-12-04
    3. Enabling Uncertainty Quantification of Large Aircraft System Simulation Models
    Åpne denne publikasjonen i ny fane eller vindu >>Enabling Uncertainty Quantification of Large Aircraft System Simulation Models
    2013 (engelsk)Inngår i: 4:th CEAS conference, 2013 / [ed] Tomas Melin, Petter Krus, Emil Vinterhav, Knut Övrebo, Linköping University Electronic Press , 2013Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    A common viewpoint in both academia and industry is that that Verification, Validation and Uncertainty Quantification (VV&UQ) of simulation models are vital activities for a successful deployment of model-based system engineering. In the literature, there is no lack of advice regarding methods for VV&UQ. However, for industrial applications available methods for Uncertainty Quantification (UQ) often seem too detailed or tedious to even try. The consequence is that no UQ is performed, resulting in simulation models not being used to their full potential.

    In this paper, the effort required for UQ of a detailed aircraft vehicle system model is estimated. A number of methodological steps that aim to achieve a more feasible UQ are proposed. The paper is focused on 1‑D dynamic simulation models of physical systems with or without control software, typically described by Ordinary Differential Equations (ODEs) or Differential Algebraic Equations (DAEs). An application example of an aircraft vehicle system model is used for method evaluation.

    sted, utgiver, år, opplag, sider
    Linköping University Electronic Press, 2013
    Emneord
    Model validation, uncertainty analysis, uncertainty quantification
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-99838 (URN)978-91-7519-519-3 (ISBN)
    Konferanse
    CEAS 2013 - International Conference of the European Aerospace Societies, 16-19 September 2013, Linköping, Sweden
    Tilgjengelig fra: 2013-10-21 Laget: 2013-10-21 Sist oppdatert: 2016-04-25bibliografisk kontrollert
    4. A Framework for Early and Approximate Uncertainty Quantification of Large System Simulation Models
    Åpne denne publikasjonen i ny fane eller vindu >>A Framework for Early and Approximate Uncertainty Quantification of Large System Simulation Models
    2015 (engelsk)Inngår i: Proceedings of the 56th Conference on Simulation and Modelling (SIMS 56), October, 7-9, 2015, Linköping University, Sweden, Linköping: Linköping University Electronic Press, 2015, s. 91-104Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Uncertainty Quantification (UQ) is vital to ensure credibility in simulation results and to justify model-based design decisions – especially in early development phases when system level measurement data for traditional model validation purposes are scarce. Central UQ challenges in industrial applications are computational cost and availability of information and resources for uncertainty characterization. In an attempt to meet these challenges, this paper proposes a framework for early and approximate UQ intended for large simulation models of dynamical systems. A Modelica simulation model of an aircraft environmental control system including a liquid cooling circuit is used to evaluate the industrial applicability of the proposed framework.

    sted, utgiver, år, opplag, sider
    Linköping: Linköping University Electronic Press, 2015
    Serie
    Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 119
    Emneord
    Uncertainty quantification; aleatory uncertainty; epistemic uncertainty; model validation; aircraft system simulation models; Modelica
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-122480 (URN)10.3384/ecp1511991 (DOI)9789176859001 (ISBN)
    Konferanse
    The 56th Conference on Simulation and Modelling (SIMS 56) 7-9 October 2015
    Forskningsfinansiär
    VINNOVA, NFFP6 2013-01211
    Tilgjengelig fra: 2015-11-04 Laget: 2015-11-04 Sist oppdatert: 2018-01-25bibliografisk kontrollert
  • 16.
    Eek, Magnus
    et al.
    Saab Aeronautics, Linköping, Sweden.
    Karlén, Johan
    Saab Aeronautics, Linköping, Sweden.
    Ölvander, Johan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska fakulteten.
    A Framework for Early and Approximate Uncertainty Quantification of Large System Simulation Models2015Inngår i: Proceedings of the 56th Conference on Simulation and Modelling (SIMS 56), October, 7-9, 2015, Linköping University, Sweden, Linköping: Linköping University Electronic Press, 2015, s. 91-104Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Uncertainty Quantification (UQ) is vital to ensure credibility in simulation results and to justify model-based design decisions – especially in early development phases when system level measurement data for traditional model validation purposes are scarce. Central UQ challenges in industrial applications are computational cost and availability of information and resources for uncertainty characterization. In an attempt to meet these challenges, this paper proposes a framework for early and approximate UQ intended for large simulation models of dynamical systems. A Modelica simulation model of an aircraft environmental control system including a liquid cooling circuit is used to evaluate the industrial applicability of the proposed framework.

  • 17.
    Eklund, Adam
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion.
    Karner, Jesper
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion.
    Development of a Framework for Concept Selection and Design Automation: Utilizing hybrid modeling for indirect parametric control of subdivision surfaces2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Saab Aeronautics’ section Overall Design and Survivability develops early aircraft concepts and utilizes Computer Aided Design (CAD) to ensure the feasibility of principal- and critical characteristics. Saab has over the years developed several start models of aircrafts in CAD from pre-defined aircraft configurations, which are to some extent non-generic. When new configurations are to be explored, manual- and repetitive work is required if the new configuration cannot be attained solely through parametric modifications of a start model. The complexity of these CAD models also demands great knowledge of how aircraft components interact with each other to ensure compatibility. The project covered in this thesis was thus carried out to develop a more effective way for Saab to create and explore a larger design space. This by creating a framework that consists of a product configurator coupled with a library of generic CAD models.

    The product configurator that was created is the Saab Tradespace Analyzer & Reconfigurator (STAR), which takes compatibility relationships into consideration to facilitate concept selection. The STAR also provides a dynamic design space calculation to indicate how close the user is to a final concept selection. Two generic CAD models were created, a fuselage model and an air inlet model. A skeleton model was also created in order to reduce model dependencies and to control the main geometry of the aircraft product. In addition to these, an already existing wing model was implemented to form the library of generic CAD models. The framework coupling the STAR with the CAD library utilizes design automation to allow automatic CAD model generation of a concept that has been selected within the STAR.

    It was concluded through extrapolation that the created framework would allow Saab to create and explore a larger design space in a more effective way than what is done today, provided the library of CAD models were to contain the same number of components as today’s start models.

  • 18.
    Ericson, Liselott
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Forssell, Jonas
    Volvo Car Corp, Sweden.
    A NOVEL AXIAL PISTON PUMP/MOTOR PRINCIPLE WITH FLOATING PISTONS DESIGN AND TESTING2018Inngår i: PROCEEDINGS OF THE BATH/ASME SYMPOSIUM ON FLUID POWER AND MOTION CONTROL, 2018, AMER SOC MECHANICAL ENGINEERS , 2018, artikkel-id V001T01A067Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents the first prototype of a novel axial piston pump/motor of slipper type. The pistons are floating in the cylinders and hence the name floating piston pump. The novel pump design fills a gap in the traditional pump design. The pump is made to fit the automobile requirements to use fluid power in a more prominent manner. One of the expected benefits of this design is its simplicity and therefore the machine does not require high manufacturing capabilities. The production cost is expected to be low. The machine is designed with high number of pistons, which leads to a pump/motor with low noise level. The displacement angle is small, 8 degrees, which leads to low piston speeds with its benefits. The main challenge in the design is the piston seal configuration. The seals will both, deform (ovality) and move in a circle relative to the pistons. The paper discusses design considerations and proposes a design. The efficiency measurement of the first prototype is in level of a series produced slipper type machine at its sweet spot.

  • 19.
    Escolano Andrés, Inés
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Knowledge-Based Flight Control System Integration in RAPID2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis work presents a parametrized integration of the flight control system within RAPID by means of the automation in CATIA V5, using Knowledge Pattern.

    Nowadays aircraft’s design and development processes are not only time-consuming but also incur high economic cost. In addition, system integration is highly a multi-disciplinary design process which often involves a large number of different discipline teams working at the same time and space. The main objective of this thesis is to investigate how CAD (Computer Aided Design) software can be used in the early design stages to define the flight control system integration. The purpose of this work to improve the functionality of an in house produced aircraft conceptual design tool carried out at the Division of Fluid and Mechatronic Systems, Linköping University.

    The work consists of preliminary integration of the RAPID flight control system and the hydraulics associated to it. By defining several reusable templates, the automatic definition of a flight control system within the RAPID aircraft has been achieved.

    Moreover it is a parametrical model which allows the user to modify a high number of features as desired to enhance the design process. For this, a user interface in Microsoft Excel connected to CATIA has also been attained.

  • 20. Escolano Andrés, Inés
    et al.
    Chaitanya Munjulury, Raghu
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Knowledge-Based Flight Control System Integration in RAPID2015Rapport (Annet vitenskapelig)
    Abstract [en]

    Nowadays, aircraft’s design and development processes are not only time-consuming but also incur high economic cost. In addition, system integration is highly a multi-disciplinary design process, which involves a large number of different discipline teams working at the same time and space. The main objective of this work is to investigate in the early design stages to define and integrate flight control system. The purpose is to improve the functionality of an in house produced aircraft conceptual design tool RAPID carried out at the Division of Fluid and Mechatronic Systems, Linköping University.

  • 21.
    Gagiu, Răzvan-Florin-Rainer
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion.
    Abin, Kakkattil Paulose
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion.
    Modeling and Simulation of novel Environmental Control System for a combat aircraft2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The present thesis deals with the analysis of Environmental Control System (ECS) as a part of the aircraft conceptual design. The research focuses on developing methods for modelling, simulation and optimization of current and future cooling technologies suitable for aircraft applications. The work started with a pre-study in order to establish the suitability of different cooling technologies for ECS application. Therefore, five technologies namely, Bootstrap (BS), Reverse-Bootstrap (RBS), vapour cycle system (VCS), magnetic cooling (MC) and thermo-electric cooling (EC), were assessed from a theoretical point of view by the method of benchmarking. This resulted into the selection of three most suitable technologies that were further modelled and simulated in Dymola. In order to compare the optimum designs for each technology, the models were optimized using the modeFRONTIER software. The comparison was performed based on the optimum ratio of maximum power of cooling and minimum fuel penalty. The results showed that VCS has the “best” performances compared to BS and RBS. In addition to the active technologies, passive cooling methods such as liquid cooling by means of jet-fuel and poly-alpha-olefin were considered to address high heat transfer rates. In order to apply the cooling technologies in the ECS, concept system architectures were formulated using the functional analysis. This led to the identification of basic functions, components and sub-systems interaction. Based on the comparison carried out previously and the functional analysis, two ECS architectures were developed. Design optimization procedure was applied further in order to assess each concept and also to study the differences between the two concept architectures. The results depict the complex interaction of different key parameters of the architectures and their influence on the outcome. The study culminated with a proposed methodology for formulation of systems architecture using information from the optimization results and a robust functional analysis method. To sum up, the thesis proposes a simulation-based optimization method that allows inclusion of ECS system in aircraft conceptual design phase. The study also proves the complexity of the conceptual design stage for ECS architectures which highly influences the design of the combat aircraft.

  • 22.
    Gangadharan, Venkata Krishnan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Conceptual Design Tool for Aircraft Electrical System2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The conceptual design stage of an aircraft involves many uncertainties with regard to prediction of weight of systems. The current trend is that electrical systems increasingly replace hydraulic and pneumatic systems in an aircraft. This leads to greater uncertainty in weight, size and power requirement prediction.

    This work is an attempt at developing a sizing tool that will allow users to estimate the power requirements and weight of electrical systems for a given size of an aircraft specified either by passenger capacity or by aircraft operating empty weight or by maximum take-off weight.

    As with all predictive tools, the results of this work are based on currently available data, i.e., the specification of existing aircraft. This collection of specification of existing aircrafts would constitute the data library. The accuracy of the result of this work depends greatly on the variety of aircrafts and the level of detail for which the data is available.

    The tool is made in Microsoft Excel with some codes made in VBA to perform Excel calculations.

  • 23.
    Gavel, Hampus
    Linköpings universitet, Institutionen för konstruktions- och produktionsteknik. Linköpings universitet, Tekniska högskolan.
    On aircraft fuel system design: concept evaluation and system modeling2004Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    THE LARGEST AND most important fluid system in an aircraft is the fuel system. Obviously, future aircraft projects involve the design of fuel system to some degree. In this project design methodologies for aircraft fuel systems are studied, with the aim to shortening the system development time.

    This is done by means of illustrative examples of how optimization and the use of matrix methods have been developed and implemented at Saab Aerospace in the conceptual design of ale fuel systems. The methods introduces automation early in the development process and increase understanding of how top requirements on the ale level impact low-level engineering parameters such as pipe diameter, pump size, etc.

    The thesis also discusses a systematic approach when building a large simulation model of a fluid system where the objective is to minimize the development time by applying a strategy that enables parallel development and collaborative engineering, and also by building the model to the correct level of detail. By correct level of detail is meant the level that yields a simulation outcome that meets the stakeholders' expectations. The experienced gained at Saab in building a simulation model, mainly from the Gripen fuel system, but also the accumulated experience from other system models, is condensed and fitted into an overall process.

  • 24.
    Hällqvist, Robert
    et al.
    Systems Simulation and Concept Design, Saab Aeronautics, Linköping, Sweden.
    Braun, Robert
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Early Insights on FMI-based Co-Simulation of Aircraft Vehicle Systems2017Inngår i: Proceedings of 15:th Scandinavian International Conference on Fluid Power, June 7-9, 2017, Linköping, Sweden / [ed] Petter Krus, Liselott Eriksson and Magnus Sethson, Linköping: Linköping University Electronic Press, 2017, Vol. 144, s. 262-270Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Modelling and Simulation is extensively used for aircraft vehicle system development at Saab Aeronautics in Linköping, Sweden. There is an increased desire to simulate interacting sub-systems together in order to reveal, and get an understanding of, the present cross-coupling effects early on in the development cycle of aircraft vehicle systems. The co-simulation methods implemented at Saab require a significant amount of manual effort, resulting in scarcely updated simulation models, and challenges associated with simulation model scalability, etc. The Functional Mock-up Interface (FMI) standard is identified as a possible enabler for efficient and standardized export and co-simulation of simulation models developed in a wide variety of tools. However, the ability to export industrially relevant models in a standardized way is merely the first step in simulating the targeted coupled sub-systems. Selecting a platform for efficient simulation of the system under investigation is the next step. Here, a strategy for adapting coupled Modelica models of aircraft vehicle systems to TLM-based simulation is presented. An industry-grade application example is developed, implementing this strategy, to be used for preliminary investigation and evaluation of a cosimulation framework supporting the Transmission Line element Method (TLM). This application example comprises a prototype of a small-scale aircraft vehicle systems simulator. Examples of aircraft vehicle systems are environmental control systems, fuel systems, and hydraulic systems. The tightly coupled models included in the application example are developed in Dymola, OpenModelica, and Matlab/Simulink. The application example is implemented in the commercial modelling tool Dymola to provide a reference for a TLM-based master simulation tool, supporting both FMI and TLM. The TLM-based master simulation tool TLMSimulator is investigated in terms of model import according to the FMI standard with respect to a specified set of industrial needs and requirements.

  • 25.
    Hällqvist, Robert
    et al.
    Saab Aeronautics, Linköping, Sweden.
    Eek, Magnus
    Saab Aeronautics, Linköping, Sweden.
    Braun, Robert
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    METHODS FOR AUTOMATING MODEL VALIDATION: STEADY-STATE IDENTIFICATION APPLIED ON GRIPEN FIGHTER ENVIRONMENTAL CONTROL SYSTEM MEASUREMENTS2016Inngår i: Proceedings of the 30th congress of the International Council  of the Aeronautical Sciences, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Model Validation and Verification (V&V) has historically often been considered a final step in the model development process. However, to justify model-based design decisions throughout the entire system development process, a methodology for continuous model V&V is essential. That is, model V&V activities should be fast and easy to reiterate as new information becomes available. Using a high fidelity simulation model of the Environmental Control System (ECS) in the Saab Gripen fighter aircraft as a guiding example, this paper further extends to an existing semiautomatic framework for model steady-state validation developed during ECS model validation efforts. Generic methods for identification of steady-state operation are a prerequisite for steady-state validation of industry grade physics based models against insitu measurements. Four different established methods for steady-state identification are investigated and compared: steady-state conditions on the standard deviation estimated from in-situ measurements, conditions on the variation coefficient, t-test on the slope of a simple regression line, and comparison of differently estimated variances. The methods’ applicability, on ECS measurements in particular, is evaluated utilizing steady-state identification needs defined during Gripen ECS model validation activities.

    Model Validation and Verification (V&V) has historically often been considered a final step in the model development process. However, to justify model-based design decisions throughout the entire system development process, a methodology for continuous model V&V is essential. That is, model V&V activities should be fast and easy to reiterate as new information becomes available.

    Using a high fidelity simulation model of the Environmental Control System (ECS) in the Saab Gripen fighter aircraft as a guiding example, this paper further extends to an existing semi-automatic framework for model steady-state validation developed during ECS model validation efforts. Generic methods for identification of steady-state operation are a prerequisite for steady-state validation of industry grade physics based models against in-situ measurements. Four different established methods for steady-state identification are investigated and compared: steady-state conditions on the standard deviation estimated from in-situ measurements, conditions on the variation coefficient, t-test on the slope of a simple regression line, and comparison of differently estimated variances. The methods’ applicability, on ECS measurements in particular, is evaluated utilizing steady-state identification needs defined during Gripen ECS model validation activities.

  • 26.
    Hällqvist, Robert
    et al.
    Saab Aeronautics, Linköping, Sweden.
    Eek, Magnus
    Saab Aeronautics, Linköping, Sweden.
    Lind, Ingela
    Saab Aeronautics, Linköping, Sweden.
    Gavel, Hampus
    Saab Aeronautics, Linköping, Sweden.
    Validation Techniques Applied on the Saab Gripen FighterEnvironmental Control System Model2015Inngår i: Proceedings of the 56th SIMS / [ed] Lena Buffoni, Adrian Pop, and Bernhard Thiele, Linköping, 2015, s. 199-210, artikkel-id ecp15119199Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Environmental Control System (ECS) of the Saab Gripen fighter provides a number of vital functions, such as provision of coolant air to the avionics, comfort air to the cockpit, and pressurization of the aircraft fuel system. To support system design, a detailed simulation model has been developed in the Modelica-based tool Dymola. The model needs to be a “good system representation”, during both steady-state operation and relevant dynamic events, if reliable predictions are to be made regarding cooling performance, static loads in terms of pressure and temperature, and various other types of system analyses. A framework for semi-automatic validation of the ECS model against measurements is developed and described in this paper. The framework extends a proposed formal methodology of semi-automaticmodel validation against in-situ measurements to the model development process implemented at Saab.Applied methods for validating the model in steady-state operation and during relevant dynamic events are presented in detail. The developed framework includes automatic filtering of measurement points defined as steady-state operation and visualization techniques applied on validation experiments conducted in the previously mentioned points. The proposed framework both simplify continuous validation throughout the system development process and enables a smooth transition towards a more independent verification and validation process.

  • 27.
    Jouannet, Christopher
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Lundström, David
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Melin, Tomas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Berry, Patrick
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Design and Flight Testing of a Solar Powered Aircraft, a Student Challenge2013Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The presented work considers designing, building and flight testing a solar poweraircraft as a student project. The goal is to allow student to participate in an aircraft projectfrom design to flight test in order to acquire aircraft design knowledge from theoretical andpractical means. A first theoretical part consists of creating a sizing program for studyingdifferent concepts. Then the gathered knowledge will result in the realization of a flyingdemonstrator. This was realized during a student project over a 5 month period

  • 28.
    Kapidzic, Zlatan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanik och hållfasthetslära. Linköpings universitet, Tekniska fakulteten.
    Static and Fatigue Failure of Bolted Joints in Hybrid Composite-Aluminium Aircraft Structures2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The use of fibre composites in the design of load carrying aircraft structures has been increasing over the last few decades. At the same time, aluminium alloys are still present in many structural parts, which has led to an increase of the number of hybrid composite-aluminium structures. Often, these materials are joined at their interface by bolted connections. Due to their different response to thermal, mechanical and environmental impact, the composite and the aluminium alloy parts are subject to different design and certification practices and are therefore considered separately.The current methodologies used in the aircraft industry lack well-developed methods to account for the effects of the mismatch of material properties at the interface.One such effect is the thermally induced load which arises at elevated temperature due to the different thermal expansion properties of the constituent materials. With a growing number of hybrid structures, these matters need to be addressed. 

    The rapid growth of computational power and development of simulation tools in recent years have made it possible to evaluate the material and structural response of hybrid structures without having to entirely rely on complex and expensive testing procedures.However, as the failure process of composite materials is not entirely understood, further research efforts are needed in order to develop reliable material models for the existing simulation tools.

    The work presented in this dissertation involves modelling and testing of bolted joints in hybrid composite-aluminium structures.The main focus is directed towards understanding the failure behaviour of the composite material under static and fatigue loading, and how to include this behaviour in large scale models of a typical bolted airframe structure in an efficient way. In addition to that, the influence of thermally induced loads on the strength and fatigue life is evaluated in order to establish a design strategy that can be used in the industrial context.

    The dissertation is divided into two parts. In the first one, the background and the theory are presented while the second one consists of five scientific papers.

    Delarbeid
    1. Conceptual studies of a composite-aluminum hybrid wing box demonstrator
    Åpne denne publikasjonen i ny fane eller vindu >>Conceptual studies of a composite-aluminum hybrid wing box demonstrator
    2014 (engelsk)Inngår i: Aerospace Science and Technology, ISSN 1270-9638, E-ISSN 1626-3219, Vol. 32, nr 1, s. 42-50Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    This paper presents a study of two different hybrid composite-aluminum concepts applied to a winglike structure which is exposed to mechanical  and thermal load. The aim of the study is to determine the most suitable  hybrid concept to later on be used in structural fatigue and static testing. In both concepts, the mass is optimized with respect to two different sets of requirements, one of which is currently in use in the fighter aircraft industry and one which is a modified version of the current requirement set. The issues considered in the study are mass, thermal behavior, buckling, bolted joints, failure criteria and fatigue damage, and they are examined in the frame of both requirement sets. The results clearly indicate the order of criticality between the different criteria in the different parts of each concept. Also, the comparison of two requirement sets gives an idea of the degree of influence of the modified criteria on the hybrid concepts and their mass. Based on the mass and the structural behavior in a thermal-mechanical loading one of the hybrid concepts is chosen for further studies and testing.

    sted, utgiver, år, opplag, sider
    Elsevier, 2014
    Emneord
    Hybrid structure, Wing structure, Composite-aluminum, Thermal load, Conceptual study
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-91892 (URN)10.1016/j.ast.2013.11.002 (DOI)000331921900006 ()
    Tilgjengelig fra: 2013-05-03 Laget: 2013-05-03 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    2. Finite element modeling of mechanically fastened composite-aluminum joints in aircraft structures
    Åpne denne publikasjonen i ny fane eller vindu >>Finite element modeling of mechanically fastened composite-aluminum joints in aircraft structures
    2014 (engelsk)Inngår i: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 109, s. 198-210Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    A three-dimensional, solid finite element model of a composite-aluminum single-lap bolted joint with a countersunk titanium fastener is developed. The model includes progressive damage behavior of the composite and a plasticity model for the metals. The response to static loading is compared to experimental results from the literature. It is shown that the model predicts the initiation and the development of the damage well, up to failure load. The model is used to evaluate the local force-displacement responses of a number of single-lap joints installed in a hybrid composite-aluminum wing-like structure. A structural model is made where the fasteners are represented by two-node connector elements which are assigned the force-displacement characteristics determined by local models. The behavior of the wing box is simulated for bending and twisting loads applied together with an increased temperature and the distribution of fastener forces and the progressive fastener failure is studied. It is shown that the fastener forces caused by the temperature difference are of significant magnitude and should be taken into account in the design of hybrid aircraft structures. It is concluded that, the account of the non-linear response of the joints results in a less conservative load distribution at ultimate failure load.

    sted, utgiver, år, opplag, sider
    Elsevier, 2014
    Emneord
    Bolted joints, Composite-aluminum, Finite element modeling, Hybrid wing structures
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-91893 (URN)10.1016/j.compstruct.2013.10.056 (DOI)000331671700020 ()
    Tilgjengelig fra: 2013-05-03 Laget: 2013-05-03 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    3. Quasi-static bearing failure of CFRP composite in biaxially loaded bolted joints
    Åpne denne publikasjonen i ny fane eller vindu >>Quasi-static bearing failure of CFRP composite in biaxially loaded bolted joints
    2015 (engelsk)Inngår i: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 125, s. 60-71Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Hybrid composite-aluminium bolted joints develop internal loads at elevated temperatures, due to the difference in thermal expansion properties of their constituent materials. In aircraft joints, the thermally induced bolt loads are commonly directed perpendicular to the mechanical loads, inducing a biaxial bearing load state. In this work, carbon-epoxy laminate specimens were tested in uniaxial and biaxial quasi-static bearing failure experiments in a specially designed test rig, at elevated temperature. A microscopy study of a failed specimen revealed that the failure process was mainly driven by fibre kinking, although extensive matrix cracking and delaminations were also found. The experiments were simulated by three-dimensional, explicit, finite element analyses, which included intralaminar damage and delamination. The experimental and simulated bearing failure loads differed by 1.7% in the uniaxial case and 2.1% in the biaxial case. It was suggested that the load-displacement response is influenced by the interaction of all damage mechanisms. Delamination modelling was, however, not essential for the prediction of the maximal bearing strength. The same effective bearing strengths were obtained for the biaxially loaded specimens as for the uniaxially loaded ones, but the damage accumulation process and the resulting damage distributions were different. (C) 2015 Elsevier Ltd. All rights reserved.

    sted, utgiver, år, opplag, sider
    Elsevier, 2015
    Emneord
    Hybrid joint; Carbon-epoxy; Thermally induced load; Bearing failure; Finite element analysis
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-118234 (URN)10.1016/j.compstruct.2015.01.038 (DOI)000353177600008 ()
    Merknad

    Funding Agencies|Swedish Armed Forces; Swedish Defence Materiel Administration; Swedish Governmental Agency

    Tilgjengelig fra: 2015-05-22 Laget: 2015-05-22 Sist oppdatert: 2017-12-04
    4. Fatigue bearing failure of CFRP composite in biaxially loaded bolted joints at elevated temperature
    Åpne denne publikasjonen i ny fane eller vindu >>Fatigue bearing failure of CFRP composite in biaxially loaded bolted joints at elevated temperature
    2015 (engelsk)Inngår i: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 127, s. 298-307Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Hybrid composite-aluminium structures develop internal loads when exposed to elevated temperatures, due to the different thermal expansion properties of the constituent materials. In aircraft structures with long rows of bolted joints, the mechanical and the thermally induced bolt loads are oriented in different directions, creating a biaxial bearing load state. In this study, the bearing fatigue failure process and the influence of the biaxial load state on the failure are investigated. An experimental set-up was designed, where both the mechanical and the thermally induced bolt loads were applied by means of mechanical load actuators. Two-bolt, double-lap joints with quasi-isotropic carbon-epoxy composite specimens were subjected to uniaxial and biaxial cyclic loading at 90 degrees C. A microscopy study of the bearing plane revealed that the main fatigue driving mechanisms were matrix cracking and fibre-matrix debonding. Motivated by these findings, a fatigue prediction model based on the kinetic theory of fracture for polymer matrices was run in a finite element code and the results showed a satisfactory correlation to the experimental results. The biaxial loading resulted in a longer fatigue life than the uniaxial loading, for the same peak resultant force, which was explained by the smaller effective stress range in the biaxial case.

    sted, utgiver, år, opplag, sider
    Elsevier, 2015
    Emneord
    Hybrid bolted joint; Carbon-epoxy; Thermally induced load; Fatigue bearing failure
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-118835 (URN)10.1016/j.compstruct.2015.03.031 (DOI)000354139800028 ()
    Merknad

    Funding Agencies|Swedish Armed Forces, Swedish Defence Materiel Administration; Swedish Governmental Agency for Innovation Systems

    Tilgjengelig fra: 2015-06-08 Laget: 2015-06-04 Sist oppdatert: 2017-12-04
    5. Fatigue bearing failure of CFRP composite in bolted joints exposed to biaxial variable amplitude loading at elevated temperature
    Åpne denne publikasjonen i ny fane eller vindu >>Fatigue bearing failure of CFRP composite in bolted joints exposed to biaxial variable amplitude loading at elevated temperature
    2016 (engelsk)Inngår i: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 142, s. 71-77Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Hybrid structures than contain composite-aluminium interfaces tend to develop internal loads at elevated temperatures. In long bolted joints, the thermally induced bolt loads are superimposed onto the mechanically applied load and can induce a biaxial bearing load state. This paper presents an experimental and numerical study of the bearing fatigue failure of carbon-epoxy laminate specimens, exposed to uniaxial and biaxial variable amplitude loading at 90C. A specifically designed experimental rig was used, where both the mechanical and the thermally induced bolt loads were applied by means of mechanical load actuators. A fatigue model based on the kinetic theory of fracture for polymers, which was previously implemented for constant amplitude loading, is expanded to account for the variable amplitude load history. The results suggest that the biaxial loading gives a longer fatigue life than the uniaxial loading for the same maximum peak resultant force. This result can be utilized as a conservative dimensioning strategy by designing biaxially loaded joints in terms of maximum peak resultant bearing load using uniaxial fatigue data.

    sted, utgiver, år, opplag, sider
    Elsevier, 2016
    Emneord
    Carbon-epoxy, Thermally induced load, Fatigue bearing failure, Variable amplitude loading
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-122420 (URN)10.1016/j.compstruct.2016.01.064 (DOI)000372691300008 ()
    Merknad

    Vid tiden för disputation förelåg publikationen som manuskript

    Funding agencies:  Swedish Armed Forces; Swedish Defence Materiel Administration; Swedish Governmental Agency for Innovation Systems

    Tilgjengelig fra: 2015-11-02 Laget: 2015-11-02 Sist oppdatert: 2017-12-01bibliografisk kontrollert
  • 29.
    Kapidzic, Zlatan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Hållfasthetslära. Linköpings universitet, Tekniska högskolan.
    Strength analysis and modeling of hybrid composite-aluminum aircraft structures2013Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The current trend in aircraft design is to increase the proportion of fiber composites in the structures. Since many primary parts also are constructed using metals, the number of hybrid metal-composite structures is increasing. Such structures have traditionally often been avoided as an option because of the lack of methodology to handle the mismatch between the material properties. Composite and metal properties differ with respect to: thermal expansion, failure mechanisms, plasticity, sensitivity to load type, fatigue accumulation and scatter, impact resistance and residual strength, anisotropy, environmental sensitivity, density etc. Based on these differences, the materials are subject to different design and certification requirements. The issues that arise in certification of hybrid structures are: thermally induced loads, multiplicity of failure modes, damage tolerance, buckling and permanent deformations, material property scatter, significant load states etc. From the design point of view, it is a challenge to construct a weight optimal hybrid structure with the right material in the right place. With a growing number of hybrid structures, these problems need to be addressed. The purpose of the current research is to assess the strength, durability and thermo-mechanical behavior of a hybrid composite-aluminum wing structure by testing and analysis. The work performed in this thesis focuses on the analysis part of the research and is divided into two parts. In the first part, the theoretical framework and the background are outlined.Significant material properties, aircraft certification aspects and the modeling framework are discussed.In the second part, two papers are appended. In the first paper, the interaction of composite and aluminum, and their requirements profiles,is examined in conceptual studies of the wing structure. The influence of the hybrid structure constitution and requirement profiles on the mass, strength, fatigue durability, stability and thermo-mechanical behavior is considered. Based on the conceptual studies, a hybrid concept to be used in the subsequent structural testing is chosen. The second paper focuses on the virtual testing of the wing structure. In particular, the local behavior of hybrid fastener joints is modeled in detail usingthe finite element method, and the result is then incorporated into a global model using line elements. Damage accumulation and failure behavior of the composite material are given special attention. Computations of progressive fastener failure in the experimental setup are performed. The analysis results indicate the critical features of the hybrid wing structure from static, fatigue, damage tolerance and thermo-mechanical points of view.

    Delarbeid
    1. Conceptual studies of a composite-aluminum hybrid wing box demonstrator
    Åpne denne publikasjonen i ny fane eller vindu >>Conceptual studies of a composite-aluminum hybrid wing box demonstrator
    2014 (engelsk)Inngår i: Aerospace Science and Technology, ISSN 1270-9638, E-ISSN 1626-3219, Vol. 32, nr 1, s. 42-50Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    This paper presents a study of two different hybrid composite-aluminum concepts applied to a winglike structure which is exposed to mechanical  and thermal load. The aim of the study is to determine the most suitable  hybrid concept to later on be used in structural fatigue and static testing. In both concepts, the mass is optimized with respect to two different sets of requirements, one of which is currently in use in the fighter aircraft industry and one which is a modified version of the current requirement set. The issues considered in the study are mass, thermal behavior, buckling, bolted joints, failure criteria and fatigue damage, and they are examined in the frame of both requirement sets. The results clearly indicate the order of criticality between the different criteria in the different parts of each concept. Also, the comparison of two requirement sets gives an idea of the degree of influence of the modified criteria on the hybrid concepts and their mass. Based on the mass and the structural behavior in a thermal-mechanical loading one of the hybrid concepts is chosen for further studies and testing.

    sted, utgiver, år, opplag, sider
    Elsevier, 2014
    Emneord
    Hybrid structure, Wing structure, Composite-aluminum, Thermal load, Conceptual study
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-91892 (URN)10.1016/j.ast.2013.11.002 (DOI)000331921900006 ()
    Tilgjengelig fra: 2013-05-03 Laget: 2013-05-03 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    2. Finite element modeling of mechanically fastened composite-aluminum joints in aircraft structures
    Åpne denne publikasjonen i ny fane eller vindu >>Finite element modeling of mechanically fastened composite-aluminum joints in aircraft structures
    2014 (engelsk)Inngår i: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 109, s. 198-210Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    A three-dimensional, solid finite element model of a composite-aluminum single-lap bolted joint with a countersunk titanium fastener is developed. The model includes progressive damage behavior of the composite and a plasticity model for the metals. The response to static loading is compared to experimental results from the literature. It is shown that the model predicts the initiation and the development of the damage well, up to failure load. The model is used to evaluate the local force-displacement responses of a number of single-lap joints installed in a hybrid composite-aluminum wing-like structure. A structural model is made where the fasteners are represented by two-node connector elements which are assigned the force-displacement characteristics determined by local models. The behavior of the wing box is simulated for bending and twisting loads applied together with an increased temperature and the distribution of fastener forces and the progressive fastener failure is studied. It is shown that the fastener forces caused by the temperature difference are of significant magnitude and should be taken into account in the design of hybrid aircraft structures. It is concluded that, the account of the non-linear response of the joints results in a less conservative load distribution at ultimate failure load.

    sted, utgiver, år, opplag, sider
    Elsevier, 2014
    Emneord
    Bolted joints, Composite-aluminum, Finite element modeling, Hybrid wing structures
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-91893 (URN)10.1016/j.compstruct.2013.10.056 (DOI)000331671700020 ()
    Tilgjengelig fra: 2013-05-03 Laget: 2013-05-03 Sist oppdatert: 2017-12-06bibliografisk kontrollert
  • 30.
    Kapidzic, Zlatan
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Hållfasthetslära. Linköpings universitet, Tekniska högskolan.
    Nilsson, Larsgunnar
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Hållfasthetslära. Linköpings universitet, Tekniska högskolan.
    Ansell, Hans
    Saab AB, Linköping, Sweden.
    Conceptual studies of a composite-aluminum hybrid wing box demonstrator2014Inngår i: Aerospace Science and Technology, ISSN 1270-9638, E-ISSN 1626-3219, Vol. 32, nr 1, s. 42-50Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a study of two different hybrid composite-aluminum concepts applied to a winglike structure which is exposed to mechanical  and thermal load. The aim of the study is to determine the most suitable  hybrid concept to later on be used in structural fatigue and static testing. In both concepts, the mass is optimized with respect to two different sets of requirements, one of which is currently in use in the fighter aircraft industry and one which is a modified version of the current requirement set. The issues considered in the study are mass, thermal behavior, buckling, bolted joints, failure criteria and fatigue damage, and they are examined in the frame of both requirement sets. The results clearly indicate the order of criticality between the different criteria in the different parts of each concept. Also, the comparison of two requirement sets gives an idea of the degree of influence of the modified criteria on the hybrid concepts and their mass. Based on the mass and the structural behavior in a thermal-mechanical loading one of the hybrid concepts is chosen for further studies and testing.

  • 31.
    Kapidzic, Zlatan
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Hållfasthetslära. Linköpings universitet, Tekniska högskolan.
    Nilsson, Larsgunnar
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Hållfasthetslära. Linköpings universitet, Tekniska högskolan.
    Ansell, Hans
    Saab AB, Linköping, Sweden.
    Finite element modeling of mechanically fastened composite-aluminum joints in aircraft structures2014Inngår i: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 109, s. 198-210Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A three-dimensional, solid finite element model of a composite-aluminum single-lap bolted joint with a countersunk titanium fastener is developed. The model includes progressive damage behavior of the composite and a plasticity model for the metals. The response to static loading is compared to experimental results from the literature. It is shown that the model predicts the initiation and the development of the damage well, up to failure load. The model is used to evaluate the local force-displacement responses of a number of single-lap joints installed in a hybrid composite-aluminum wing-like structure. A structural model is made where the fasteners are represented by two-node connector elements which are assigned the force-displacement characteristics determined by local models. The behavior of the wing box is simulated for bending and twisting loads applied together with an increased temperature and the distribution of fastener forces and the progressive fastener failure is studied. It is shown that the fastener forces caused by the temperature difference are of significant magnitude and should be taken into account in the design of hybrid aircraft structures. It is concluded that, the account of the non-linear response of the joints results in a less conservative load distribution at ultimate failure load.

  • 32.
    Kihlman, Henrik
    Linköpings universitet, Institutionen för konstruktions- och produktionsteknik. Linköpings universitet, Tekniska högskolan.
    Affordable automation for airframe assembly: developing of key enabling technologies2005Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Building aircraft is a challenging field. An aircraft has a life expectancy of 40 years, compared to just 10 years for a car. Given the vibrations of flying at close to Mach one at an altitude of 10,000 meters, these machines must function flawlessly in a tough environment. This demands high quality in the assembly processes. The typical part joining process in the automotive industry is welding, whereas in the aircraft industry, assembly is made through drilling, followed by fastening. The typical tolerances for part location in aircraft assembly, as well as for hole drilling, is +/- 0.2 mm.

    This dissertation discusses the use of industrial robots, widely used for welding and pick-and-place operation for automotive industry, in the automation of the aircraft industry, and specifically for the drilling of holes in the assembly process of airframe parts. The dissertation presents how a new drilling technology called orbital drilling is incorporated with and industrial robot. Orbital drilling reduces the cutting forces up to ten times compared to conventional drilling using a spiral cutter.

    The robot is also utilized for performing changeovers between different airframe structure types. A novel jointed reconfigurable tooling system called Affordable Reconfigurable Tooling (ART) is presented, which uses the robot to reconfigure flexible fixture modules. The ART system can also be rebuilt, which means that the tool is dismantled and reused for a completely different product family (e.g. wings, fins or fuselage sections). This is made possible through a modular framework, i.e. not welded as with conventional tooling, but rather jointed by screws.

    Robots, originally developed for the automotive industry, have an accuracy which is ten times less accurate than that required for aerospace applications. To help meet this limitation in the use of robots in aircraft assembly, an additional metrology system, used in the aircraft industry for calibrating assembly tooling, is integrated into the robot controller. The feedback loop enables the robot to be positioned to ±0.05 mm absolute accuracy. This integration is made possible by existing embedded software packages for the robot and the metrology system.

    The processes in the system are programmed in a software package with an intuitive user interface in a 3D-environment, normally used for the offline-programming of robots in automotive industry. The planning is intuitive, and an approach towards a process planning abstraction level is presented where processes are defined directly on the coordinate frames constituting the robot trajectories and manual operations. Tolerance on accuracy requirements are dynamically programmed in the same environment. The metrology system, working online with the robot controller, eliminates most of the calibration work required in traditional robot programming. Changes in the operation planning take less than a minute to run physically with the best tolerance.

    Delarbeid
    1. Reconfigurable tooling for airframe assembly: a state-of-the-art review of the related literature and a short presentation of a new tooling concept
    Åpne denne publikasjonen i ny fane eller vindu >>Reconfigurable tooling for airframe assembly: a state-of-the-art review of the related literature and a short presentation of a new tooling concept
    2001 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    From the early days of aircraft manufacturing Dedicated Tooling has been used in the assembly process to ensure the attainment of assembly tolerances and product quality. Dedicated Tooling clamps the aircraft parts to be assembled into the jig to enable assembly by riveting. However, increased competition in the aircraft industry has driven the need to improve quality while reducing cost and in turn the need for innovative solutions to accomplish this.

    In this review paper the possibility of using metrology to increase the position accuracy in robotics will be examined. This is necessary to be able to use robotics in assembly of aircraft parts with the appropriate accuracy. Also, because of the small product volumes in the aircraft industry, the jigs must be flexible in order to assemble more than one structure in each jig. Solving these two problems could be the break through for starting to use robotics in aircraft assembly at a higher rate, and doing so in a cost-effective way.

    By then reviewing literature of today's flexible tooling technology in the aircraft industry, the conclusion indicates that there is a gap to fill in aircraft assembly tooling. Modular Tools is one solution where standard aluminium profiles are used to manufacture jigs with some degree of flexibility. Another way is pogo fixturing, which uses sticks to hold airframe parts together in the assembly process. The sticks can only be reconfigured in a limited range, and are not cost-effective. By using Affordable Reconfigurable Tooling, the jigs will not only have greater ability to be reconfigured, but by using robotics for the reconfiguration task as well as for drilling, riveting and other material handling tasks, the system will also be cost effective.

    sted, utgiver, år, opplag, sider
    Ann Arbor, Michigan, USA: University of Michigan, 2001
    Emneord
    Reconfigurable, Airframe, Assembly, Tooling, Flexibility, Affordable
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-73297 (URN)
    Konferanse
    CIRP 1st International Conference on Agile, Reconfigurable Manufacturing, Ann Arbor, Michigan, USA, 21-22 May
    Tilgjengelig fra: 2012-01-13 Laget: 2012-01-02 Sist oppdatert: 2012-11-29bibliografisk kontrollert
    2. Reconfigurable aircraft assembly: using industrial robots and new tooling to meet future production scenarios
    Åpne denne publikasjonen i ny fane eller vindu >>Reconfigurable aircraft assembly: using industrial robots and new tooling to meet future production scenarios
    2002 (engelsk)Inngår i: Proceedings of the 33rd ISR (International Symposium on Robotics), 2002Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    This paper presents the development of a new concept for aircraft airframe assembly tooling. While conventional aircraft assembly tooling relics on rigid steel frames this novel approach can be re-con figured for different products by the help of an accurate laser tracker guided industrial robot. Through this, aircraft manufacturers can better cope with an increased number of variants and smaller volumes which will increase the already high tooling costs. So far in the project a tooling concept has been conceptually designed and economically evaluated. The early technical results of the concepntal work indicate that the concept will work provided that enough mechanical stiffness can be obtained. The economical analysis shows that despite a much higher investment cost, a reconfigurable tool can be economical if it will replace 4-5 conventional tools. In certain future production scenarios reconfigurable tooling can play a very important role to keep the tooling costs down.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-85838 (URN)
    Konferanse
    33rd International Symposium on Robotics in Stockholm, October 8-10
    Tilgjengelig fra: 2012-11-29 Laget: 2012-11-29 Sist oppdatert: 2012-11-29
    3. Affordable reconfigurable tooling
    Åpne denne publikasjonen i ny fane eller vindu >>Affordable reconfigurable tooling
    2002 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Since the early days of aircraft assembly, welded steel structures called Conventional Tooling has been used for positioning and holding parts in place during assembly. This paper presents a new tooling concept called Affordable Reconfigurable Tooling, where a robot is not only used for drilling and riveting but also for reconfiguring the tool itself. The concept consists of modular units that can either be reconfigured between products of the same family of assembly or rebuilt between product families. The research is part of an ongoing EU-founded aircraft industry project - ADFAST*.

    sted, utgiver, år, opplag, sider
    Society of Automotive Engineers, 2002
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-73299 (URN)10.4271/2002-01-2645 (DOI)0-7680-1285-6 (ISBN)
    Konferanse
    2002 SAE Automated Fastening Conference & Exhibition, 1 October 2002, Chester, United Kingdom
    Prosjekter
    ADFAST
    Tilgjengelig fra: 2012-01-13 Laget: 2012-01-02 Sist oppdatert: 2012-11-29bibliografisk kontrollert
    4. Robotic orbital drilling of structures for aerospace applications
    Åpne denne publikasjonen i ny fane eller vindu >>Robotic orbital drilling of structures for aerospace applications
    2002 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    This paper describes ongoing research into orbital drilling using standard industrial robots. The research is a part of an ongoing EU funded aircraft industry project - ADFAST*. Generally it is difficult to use standard industrial robots to automate drilling in the aerospace industry. The stiffness of the standard robotic device is not sufficient to resist the deflections caused by the cutting forces from the drilling process, therefore it is difficult to achieve the tight hole tolerance requirements. Orbital drilling creates lower axial cutting forces compared to conventional drilling and therefore allows the use of low-cost standard industrial robots for drilling holes within the required hole tolerances. This paper presents results from a study where forces, moments and dislocations produced during orbital- and conventional drilling have been measured.

    sted, utgiver, år, opplag, sider
    Chester, United Kingdom: Society of Automotive Engineers, 2002
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-73377 (URN)10.4271/2002-01-2636 (DOI)
    Konferanse
    SAE Automated Fastening Conference & Exhibition, Oktober 1, 2002, Chester, United Kingdom
    Tilgjengelig fra: 2012-01-13 Laget: 2012-01-02 Sist oppdatert: 2012-11-29bibliografisk kontrollert
    5. 6DOF metrology-integrated robot control
    Åpne denne publikasjonen i ny fane eller vindu >>6DOF metrology-integrated robot control
    2003 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    This paper describes ongoing research into Metrology-integrated robot control. The research is a part of an ongoing EU funded aircraft industry project – ADFAST*. The ADFAST project tries to implement the use of industrial robots in low-volume production, high-demand-on-accuracy operations and for dynamic force compensation. To detect and compensate deflection in industrial robots during a process, the robot uses a metrology system. The metrology system supervises the tool center point of the robot as it executes its processes. Leica has recently released a new metrology system; the LTD800, which measures distances with laser interferometry and can simultaneously measure orientation of targets, through photogrammetry, using an additional camera on top of the measuring unit. This paper will describe theory and results from tests performed on integrating the LTD800 with the robot.

    sted, utgiver, år, opplag, sider
    Montreal, QC, Canada: Society of Automotive Engineers, 2003
    Emneord
    Aircraft Assembly
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-73378 (URN)10.4271/2003-01-2961 (DOI)
    Konferanse
    Automated Fastening Conference & Exposition, September 8, 2003, Montreal, Canada
    Tilgjengelig fra: 2012-01-13 Laget: 2012-01-02 Sist oppdatert: 2012-11-29bibliografisk kontrollert
    6. Metrology-integrated industrial robots: calibration, implementation and testing
    Åpne denne publikasjonen i ny fane eller vindu >>Metrology-integrated industrial robots: calibration, implementation and testing
    Vise andre…
    2004 (engelsk)Inngår i: Proceedings of the 35th ISR (International Symposium on Robotics), 2004Konferansepaper, Publicerat paper (Annet vitenskapelig)
    Abstract [en]

    This paper presents integration of a metrology system and an industrial robot. The metrology system consists of a laser tracker that measures the distance to a prism with high accuracy and a camera that through photogrammetry measures the orientation of a reflector. Both laser prism and camera reflector is integrated to a 6D-Reflector that is attached close to the TCP of an industrial robot. Tracker and robot is connected to a PC on a TCP/IP network. The PC takes measurements with the tracker, and thereby compensates the robot to reach high absolute accuracy in the robot positioning (+/-50 μm). The 6D-Reflector has multi-functionality and simplifies calibration procedures. This paper explains the architecture of the system and the methods for calibration.

    Emneord
    Metrology, laser, photogrammetry, robot, online control, calibration
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-73380 (URN)
    Konferanse
    35th ISR International Symposium on Robotics, 23-26 March, Paris, France
    Tilgjengelig fra: 2012-01-09 Laget: 2012-01-02 Sist oppdatert: 2012-11-29bibliografisk kontrollert
    7. Low-cost automation for aircraft assembly
    Åpne denne publikasjonen i ny fane eller vindu >>Low-cost automation for aircraft assembly
    2004 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    In this paper solution for low-cost automation of aircraft assembly is presented. The concept of this development is closely related to "Lean Automation", which in this case concerns the use of modern standard equipment such as standard robots, PC-computers and a newlydeveloped spatial sensor system for prec1s1on measurements of positions. The robot is used to perform reconfiguration of tooling modules that arepossible to be configured/reconfigured in six degrees of freedom. A prototype developed as the result of an EU-project called ADFAST* has been evaluated at Linköping University in Sweden. Technical functionality is reported where the robot manages to configure the flexible tooling modules to a total error bellow 50 μm. This paper presents the resu~s on the portion of the project addressing robot, metrology system and tooling.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-22547 (URN)10.4271/2004-01-2830 (DOI)1810 (Lokal ID)1810 (Arkivnummer)1810 (OAI)
    Konferanse
    SAE 2004 Aerospace Manufacturing & Automated Fastening Conference & Exhibition, September 21th 2004, St Louis, Missouri, United States
    Tilgjengelig fra: 2009-10-07 Laget: 2009-10-07 Sist oppdatert: 2012-11-29
    8. Orbital drilling: implementation and evaluation
    Åpne denne publikasjonen i ny fane eller vindu >>Orbital drilling: implementation and evaluation
    2004 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    This paper deals with issues about Orbital drilling implementation and evaluation. The paper summarizes and includes the so far written papers about Orbital drilling.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-22549 (URN)10.4271/2004-01-2814 (DOI)1812 (Lokal ID)1812 (Arkivnummer)1812 (OAI)
    Konferanse
    SAE 2004 Aerospace Manufacturing & Automated Fastening Conference & Exhibition, September 21th 2004, St Louis, Missouri, United States
    Tilgjengelig fra: 2009-10-07 Laget: 2009-10-07 Sist oppdatert: 2012-11-29
  • 33.
    Kihlman, Henrik
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Monteringsteknik. Linköpings universitet, Tekniska högskolan.
    Brogårdh, Torgny
    ABB Robotics.
    Haage, Mathias
    Lund University.
    Nilsson, Klas
    Lund University.
    Olsson, Tomas
    Lund University.
    On the Use of Force Feedback for Cost Efficient Robotic Drilling2007Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Drilling is one of the most costly and labour-intensive operations in aircraft assembly. Rather than automating with expensive fixtures and precise machinery, our approach is to make use of standard low-cost robot equipment in combination with sensor feedback. The focus is to eliminate the sliding movement of the end-effector during the clamp-up, called the skating effect, and to keep the end-effector orthogonal to the surface, thus avoiding holes that are not perpendicular. To that end, force feedback is used for building up pressure to clamp up an end-effector to the work-piece surface prior to drilling. The system, including the planning of force parameters for each hole to be drilled, was programmed in DELMIA. The drilling was accomplished with the aid of an extension to the ABB Rapid language called ExtRapid, which is an XML-like code that is interpreted by the force feedback controller downstream in the process. Although experimental results are from drilling, the conceptual idea is believed to be useful in many other applications requiring external sensor feedback control of industrial robots.

  • 34.
    Kihlman, Henrik
    et al.
    Linköpings universitet, Institutionen för konstruktions- och produktionsteknik. Linköpings universitet, Tekniska högskolan.
    Engström, Magnus
    Commercial Programs, Saab AB, Linköping, Sweden.
    Affordable reconfigurable tooling2002Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Since the early days of aircraft assembly, welded steel structures called Conventional Tooling has been used for positioning and holding parts in place during assembly. This paper presents a new tooling concept called Affordable Reconfigurable Tooling, where a robot is not only used for drilling and riveting but also for reconfiguring the tool itself. The concept consists of modular units that can either be reconfigured between products of the same family of assembly or rebuilt between product families. The research is part of an ongoing EU-founded aircraft industry project - ADFAST*.

  • 35.
    Kihlman, Henrik
    et al.
    DELFOi.
    Engström, Magnus
    Saab Aeronautics.
    Flexapods - Flexible Tooling at SAAB for Building the NEURON Aircraft2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Building prototype aircrafts is costly in tooling especially since only one aircraft is being built. Today's most common tooling strategy is to weld together a beam framework. Welded framework solutions have long lead times both in design and manufacturing and once the aircraft is assembled the tool becomes obsolete. Flexible tooling strategy uses non-welded tooling thus it can be changed and re-used for future products. Early version of a new aircraft model is always hampered by frequent changes in its design, which is cumbersome to handle in a welded framework solution. This paper presents a flexible assembly tooling solutions based on Flexapods and BoxJoint. The Flexapods are commercialized reconfigurable tooling units that are manually adjusted injunction with a laser tracker to a final positional accuracy of +/? 0,05 mm absolute accuracy. An operator software program called the Flexapod control panel collect metrology data in real-time and an operator screen show graphics on how to manually jog the Flexapod joints to reach the final Cartesian 3D-coordinate. The Flexapods are installed in a modular steel based framework solution called BoxJoint. A complete PLM package has been developed for the solution where the Flexapods are configured in CATIA using an add-on package to CATIA called the Flexapod configurator. All CATIA data is stored in ENOVIA. Once the Flexapod fixture is designed in CATIA a file, containing all Cartesian coordinates of the Flexapods, is exported and loaded into the Flexapod control panel on the workshop floor. A previous paper on the Flexapod as an early concept and a paper on BoxJoint have been presented at SAE Aerofast. This paper follows up on these results and presents a case study at SAAB Aeronautics for implementing the first industrial solution of Flexapods to build the military unmanned aerial vehicle - nEURON.

  • 36.
    Kihlman, Henrik
    et al.
    Linköpings universitet, Institutionen för konstruktions- och produktionsteknik. Linköpings universitet, Tekniska högskolan.
    Loser, Raimund
    Leica Geosystems AG.
    6DOF metrology-integrated robot control2003Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes ongoing research into Metrology-integrated robot control. The research is a part of an ongoing EU funded aircraft industry project – ADFAST*. The ADFAST project tries to implement the use of industrial robots in low-volume production, high-demand-on-accuracy operations and for dynamic force compensation. To detect and compensate deflection in industrial robots during a process, the robot uses a metrology system. The metrology system supervises the tool center point of the robot as it executes its processes. Leica has recently released a new metrology system; the LTD800, which measures distances with laser interferometry and can simultaneously measure orientation of targets, through photogrammetry, using an additional camera on top of the measuring unit. This paper will describe theory and results from tests performed on integrating the LTD800 with the robot.

  • 37.
    Lovaco, Jorge Luis
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Verication of a Modelica Helicopter Rotor Model Using Blade Element Theory2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 38.
    Lundström, David
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Sobron, Alejandro
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Jouannet, Christopher
    Saab Aeronautics, Linköping, Sweden.
    da Silva, Roberto Gil Annes
    Instituto Tecnológico de Aeronáutica (ITA), Brazil.
    Subscale Flight Testing of a Generic Fighter Aircraft2016Inngår i: Proceedings of the 30th Congress of the International Council of the Aeronautical Sciences (ICAS) / [ed] The International Council of the Aeronautical Sciences, Bohn, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Recent technological advances in mechatronics enhance the possibilities of utilizing subscale flight testing as a tool in the development of aircraft. This paper reports the current status of a joint Swedish-Brazilian research project aiming at exploring these possibilities. A 13\% scale fighter aircraft is used as a test bench for developing methods and procedures for data acquisition. The aircraft is equipped with an instrumentation system assembled from off the shelf components as well as open source hardware and software.

  • 39.
    Marchiori, Rodolfo Henrique
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Framework Design for System of Systems: A Bottom Up Approach Applied to Search and Rescue Missions2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis addresses the complexities in the design of System of Systems, by providing a flexible, case independent method to analyse and rank the alternatives that are capable of performing the desired missions or operations assigned by decision makers. Although its methods involve only low-fidelity models, these proved to be the best choice as the design space created and, consequently, the number of analysis grow explosively with the increase of available options to perform the required tasks. This is due to the combinatory approach used in the generation of the design space. Another goal is to provide a demonstration of possible improvements with the addition of ontologies to the early stages of design, especially when complex solutions are expected. This also diminishes the probability of human error by decreasing the amount of work demanded when adding alternatives or changing their characteristics, displaying again the feasible application of knowledge based and automated solutions to the engineering design process. With these advantages, the flexibility of altering the set of inputs is enhanced, adding to the resilience of the framework, as it can be attached to any available compatible ontology and perform in that specific domain without hindrance. Due to the lack of techniques and the probable cost of these once made available, the evaluation of emergence is not considered in this work, and is not reccomended to be directly done once ready for use, at least not on the full result array. Moreover, the modular implementation of the framework makes the exchange of functions a rather simple task, enabling users to adapt it to their own needs. Some immediate implementations are mentioned to greatly improve the general performance and relevance of results provided.

  • 40.
    Marcus, Carina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. Saab AB, SE-58188 Linkoping, Sweden.
    Andersson, Kent
    Swedish Def University, Sweden; National Def University, Finland.
    Åkerlind, Christina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Swedish Def Research Agency, Sweden.
    Balancing the radar and long wavelength infrared signature properties in concept analysis of combat aircraft - A proof of concept2017Inngår i: Aerospace Science and Technology, ISSN 1270-9638, E-ISSN 1626-3219, Vol. 71, s. 733-741Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Designing combat aircraft with high military effectiveness, affordability and military suitability requires balancing the efforts of many engineering disciplines during all phases of the development. One particular challenge is aircraft survivability, the aircrafts ability to avoid or withstand hostile actions. Signature management is one way of increasing the survivability by improving the ability to avoid detection. Here, the long-wave infrared and radar signatures are studied simultaneously in a mission context. By establishing a system of systems approach at mission system level, the risk of sub optimization at a technical level is greatly reduced. A relevant scenario is presented where the aim is to incapacitate an air-defense system using three different tactics: A low-altitude cruise missile option, a low and medium altitude combat aircraft option. The technical sub-models, i.e. the properties of the signatures, the weapons and the sensors are modeled to a level suitable for early concept development. The results from the scenario simulations are useful for a relative comparison of properties. Depending on the situation, first detection is made by either radar or infrared sensors. Although the modeling is basic, the complexity of the infrared signature and detection chain is demonstrated and possible pivot points for the balancing of radar and IR signature requirements are identified. The evaluation methodology can be used for qualitative evaluation of aircraft concepts at different design phases, provided that the technical models are adapted to a suitable level of detail. (C) 2017 Elsevier Masson SAS. All rights reserved.

  • 41.
    Martinsson, Fredrik
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell Produktion.
    Development of Robust Automated Handling of pre-impregnated Carbon Fibre2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Prepreg is a fibre reinforced polymer composite material often used by the aeronautical industry. The material supplier has pre-impregnated the fibre often with an epoxy resin and cured it to a semi-viscous B-stage where the material is tacky (adhesive). Manual layup of prepreg components is still common because there are only a few automated layup techniques which has limited geometric capability and high investment cost.

    Swerea SICOMP is a research institute which have in collaboration with partners developed a manufacturing demonstrator for automated layup of carbon fibre prepreg components based on robotic handling. The manufacturing demonstrator is able to; feed out prepreg from a spool onto a cutting table, cut the prepreg into plies, pick the plies from the cutting table and place them on a layup table, consolidate the prepreg plies on the layup table and remove the backing paper that covers one side of the prepreg.

    Three robustness problems has been identified and these forms the bulk of this master’s thesis. The first problem is that the robot is unable to place the plies on the cutting table with sufficient accuracy due to fluctuating position of the prepreg on the cutting table. The second problem is that the end effector used for the pick and place operation sometimes fails to pick the adhesive plies from the cutting table. The problem originates in limited holding force by the end effectors suction cups and limited capability to perform a peeling motion when picking due to the design of the end effector. The third problem is that process variables like temperature is believed to effect the robustness of the demonstrator but has not been further studied.

    The first problem was solved by implementing a probing routine which measures the position of the prepreg on the cutting table with an array sensor mounted to the robot. The measurement values are used to reprogram subsequent operations.

    The second problem seems to be solved by designing and implementing a new pick and place end effector. The new end effector has higher holding force and better capability to perform a peeling motion while picking and placing the tacky prepreg plies. Tests with the new end effector has been promising, the pick and placeoperation performs robustly, but all ply geometries was not tested and some minor adjustment is needed to further improve the placing accuracy.

    The third problem has not been solved but studied. A literature study reviled that temperature, relative humidity and prepreg out of freezer age is likely to effect the prepreg adhesive properties which in turn is known to effect the robustness. A test procedure has been devised to test how these variables effect the robustnessof the demonstrator. The tests should be conducted when all process steps in the demonstrator is up and running.

  • 42.
    Melin, Tomas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Parametric Airfoil Catalog Part I, Archer A18 to Göttingen 655: An Aerodynamic and Geometric Comparison Between Parametrized and Point Cloud Airfoils2013 (oppl. 1)Bok (Annet vitenskapelig)
    Abstract [en]

    A fundamental part of aircraft design involves wing airfoiloptimization, establishing an outer shape of the wing which has good aerodynamic performance for the design mission, good internal volume distribution for fuel and systems and which also serves as an efficient structural member supporting the load of the weight of the aircraft. The underlying idea with this parametrization is to couple an appropriate number of parameters, balancing the need of geometric accuracy with the necessity of few airfoil parameters in order to facilitate en expedient optimisation, with the intrinsic value of having parameters that makes sense for a human; such as thickness, camber and trailing edge thickness. Several approaches to parametrization of wing proles can be found in the literature. Airfoils can be described by point clouds as done in most airfoil libraries. The number of parameters is twice as large as the number of points used (x and y coordinates) and in the case of aerodynamic optimization this parametrization will most certainly be not well behaved, since no smoothing function is included and must therefore be employed. Other problems may arise for the fact that the airfoils sometimes are defined with too few coordinate points and/or too few decimals, a problem occurring especially with old airfoils. On the other hand, the design space that this kind of parametrization allows representing is extremely large, as any and all shapes can be reproduced, even degenerate ones. Airfoils can also be represented by mathematical functions. Among the most common representatives of thiscategory are indeed the NACA 4-, 5- and 6-digits formulations. Compared to point clouds, they could be said to represent the opposite case: they are very well behaving parametrizations, but they cannot cover avery large design space, since they only provide four to six parameters respectively to be tuned. The NACA 4digit series is particularly interesting as the parametersare a part of the name of the airfoil. In the case of the 5- and 6 digit series, the name is instead constructed from the airfoils aerodynamic characteristic and geometry. Another known set of theoretically defined airfoils are the Joukowski profiles [4]. Using the conformal mapping method, airfoils with a round nose and sharp trailing edge can be represented. Sadly the method is not to recommend for trying to match known airfoils and the design space it describes is quite confined to airfoils with often poor performances.

  • 43.
    Melin, Tomas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Parametric Airfoil Catalog, Part II: Göttingen 673 to YS930: An Aerodynamic and Geometric Comparison Between Parametrized and Point Cloud Airfoils2013Bok (Annet vitenskapelig)
    Abstract [en]

    A fundamental part of aircraft design involves wing airfoiloptimization, establishing an outer shape of the wing which has good aerodynamic performance for the design mission, good internal volume distribution for fuel and systems and which also serves as an efficient structural member supporting the load of the weight of the aircraft. The underlying idea with this parametrization is to couple an appropriate number of parameters, balancing the need of geometric accuracy with the necessity of few airfoil parameters in order to facilitate en expedient optimisation, with the intrinsic value of having parameters that makes sense for a human; such as thickness, camber and trailing edge thickness. Several approaches to parametrization of wing proles can be found in the literature. Airfoils can be described by point clouds as done in most airfoil libraries. The number of parameters is twice as large as the number of points used (x and y coordinates) and in the case of aerodynamic optimization this parametrization will most certainly be not well behaved, since no smoothing function is included and must therefore be employed. Other problems may arise for the fact that the airfoils sometimes are defined with too few coordinate points and/or too few decimals, a problem occurring especially with old airfoils. On the other hand, the design space that this kind of parametrization allows representing is extremely large, as any and all shapes can be reproduced, even degenerate ones. Airfoils can also be represented by mathematical functions. Among the most common representatives of thiscategory are indeed the NACA 4-, 5- and 6-digits formulations. Compared to point clouds, they could be said to represent the opposite case: they are very well behaving parametrizations, but they cannot cover avery large design space, since they only provide four to six parameters respectively to be tuned. The NACA 4digit series is particularly interesting as the parametersare a part of the name of the airfoil. In the case of the 5- and 6 digit series, the name is instead constructed from the airfoils aerodynamic characteristic and geometry. Another known set of theoretically defined airfoils are the Joukowski profiles [4]. Using the conformal mapping method, airfoils with a round nose and sharp trailing edge can be represented. Sadly the method is not to recommend for trying to match known airfoils and the design space it describes is quite confined to airfoils with often poor performances.

  • 44.
    Melin, Tomas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Validation of a numerical simulation tool for aircraft formation flight2013Inngår i: Proceedings of the 4:th CEAS Conference in Linköping 2013 / [ed] Tomas Melin, Petter Krus, Emil Vinterhav, Knut Övrebö, 2013, s. 623-629Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The use of formation flight for increased fuel efficiency has received a lot of attention in the last couple of years.This paper covers a numerical simulation of a NASA test flight utilizing a formation of two F18A Hornet aircraft. The numerical simulation was made using an adapted version of the vortex lattice method TORNADO, allowing for several aircraft to be simulated in a trimmed condition. The numerical results showed good agreement with the flight test data. Some discrepancies due to the numerical model not covering viscous diffusion was found as expected but not quantified or analyzed.

  • 45.
    Melin, Tomas
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Amadori, Kristian
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Parametric wing profile description for conceptual design2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A fundamental part of aircraft design involves the wing airfoil optimization, establishing an outer shape of the wing which has good aerodynamic performance, good internal volume distribution for fuel and systems and which also serves as an efficient structural member supporting the weight of the aircraft. As for all optimization tasks, the complexity of the problem is directly coupled to the parameterization of the geometry. Of highest relevance are the number of parameters and the number of additional constraints that are required to ensure valid modeling.This paper proposes a parameterization method for two dimensional airfoils, aimed at providing a wide design space, while at the same time keeping the number of parameters low. With 15 parameters defining the wing profile, many of the existing airfoils can be modeled with close tolerance.

  • 46.
    Melin, Tomas
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Jouannet, Christopher
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Wing profile performance variations influenced by manufacturing tolerances2013Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The sensitivity of wing profile performance metrics as a function of manufacturing tolerances and operational environment influence was studied using a numerical simulation. By employing a Monte-Carlo approach of varying the geometrical properties of a set of wing profiles, the sensitivity and statistical response was found, which in turn gives an indication towards both the most critical geometrical features and to which airfoil is the most robust with respect to constructions errors and operational fouling.

  • 47.
    Melin, Tomas
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Amadori, Kristian
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Parametric wing profile description for conceptual design2011Inngår i: CEAS 2011 Proceedings, 2011Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    A fundamental part of aircraft design involves the wing airfoil optimization, establishing an outer shape of the wing which has good aerodynamic performance, good internal volume distribution for fuel and systems and which also serves as an efficient structural member supporting the weight of the aircraft. As for all optimization tasks, the complexity of the problem is directly coupled to the parameterization of the geometry. Of highest relevance are the number of parameters and the number of additional constraints that are required to ensure valid modeling.This paper proposes a parameterization method for two dimensional airfoils, aimed at providing a wide design space, while at the same time keeping the number of parameters low. With 15 parameters defining the wing profile, many of the existing airfoils can be modeled with close tolerance.Several approaches to parameterization of wing profiles can be found in the literature. Airfoils can be described by point clouds as done in most airfoil libraries [1]. The number of parameters is twice as large as the number of points used (x and y coordinates) and in the case of aerodynamic optimization this parameterization will most certainly be not well behaved, since no smoothing function is included and must therefore be added. Other problems may arise for the fact that the airfoils sometimes are defined with too few coordinate points and/or too few decimals, a problem occurring especially with old airfoils. On the other hand, the design space that this kind of parameterization allows representing is extremely large, as any and all shapes can be reproduced, even degenerate ones.

  • 48.
    Melin, Tomas
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Krus, PetterLinköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.Vinterhav, EmilSSC ECAPS.Övrebö, KnutSAAB AB, Sweden.
    PROCEEDINGS of the 4:th CEAS conference in Linköping, 20132013Konferanseproceedings (Fagfellevurdert)
    Abstract [en]

    Europe has a strong and proud tradition in aerospace and astronautics, which indeed is a very important area for Europe. It represents a substantial business domain, but maybe equally important, it is also a driver for technology development and innovation that benefits the society as a whole. One of Europe’s greatest challenges is about independence, in order to keep and maintain capabilities within the complete set of technologies needed as a foundation for a sustainable aerospace industry in Europe. This is important when Europe has to look at the next generation of Air Power. It is also fundamental for Europe to be an attractive partner in international projects conducted with global collaboration.

    CEAS – Council of European Aerospace Societies – is an organisation bringing European national aerospace organisations together for increased international strength. Today, CEAS comprises sixteen member organisations with roughly 35,000 individual members. CEAS hosts biennial conferences on aeronautics in Europe where CEAS 2013 in Linköping is the fourth after Venice 2011, Manchester 2009 and Berlin 2007.

  • 49.
    Millar, Alison
    et al.
    Airbus Operations Ltd.
    Kihlman, Henrik
    DELFOi.
    Reconfigurable Flexible Tooling for Aerospace Wing Assembly2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Traditionally, in the civil aerospace industry, assembly fixtures are large, bespoke, permanent structures that are costly to both design and manufacture. Additionally, the time to design, manufacture and install a large fixture can be significant with lead times in excess of 24 months.

    Within Airbus Operations Ltd there is a requirement to reduce non-recurring costs, reduce the time to market and improve the capacity and flexibility of equipment. This means that while the costs and lead times must be reduced, the utilisation of the tooling should be increased.

    Flexible and reconfigurable fixtures have not yet been deployed within Airbus Operations Ltd due to the assembly sizes and complex component configurations. However, they offer the potential for reducing costs by utilising off the shelf components. Using standard parts and implementing design tools can reduce the design time. The reconfigurable and flexible nature of the fixture will also enable embodiment of late component design changes with minimal time and cost impact.

    This paper presents the design, manufacture and installation of a reconfigurable fixture to assemble a wing box section in a research environment. This tooling demonstrator is then being used to evaluate the technical and industrial benefits of reconfigurable fixtures for aircraft wing sub assemblies and assemblies at Airbus.

  • 50.
    Moreira, A. H.
    et al.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campos, Brazil / Centro Universitário do Instituto Mauá de Tecnologia, São Caetano do Sul, Brazi.
    Arjoni, D. H.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campos, Brazil.
    Nicola, R. M.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campos, Brazil.
    Silva, E. T.
    Embraer, São José dos Campos, Brazil.
    Villani, E.
    TA Instituto Tecnológico de Aeronáutica, São José dos Campos, Brazil.
    Trabasso, Luís Gonzaga
    TA Instituto Tecnológico de Aeronáutica, São José dos Campos, Brazil.
    Experimental evaluation of the contribution of adding a motion system to an EDS2016Inngår i: Proceedings of the Aerospace Technology Congress / [ed] Kaj Lundahl, Roland Karlsson, Björn Jonsson and Knut Övrebö, Stockholm, 2016, Vol. 1, s. 1-10Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The use of flight simulators in pilot training campaigns has become a cheaper and saferalternative to the use of a real aircraft, as simulators will not cause any kind of humaninjury or vehicular damages. However, the degree of fidelity of the simulation is of theutmost importance for this application, thus it has become the subject of discussion inseveral studies.It is understood as a flight simulator with a high degree of fidelity, all kind of simulatorsthat are capable of providing motion cues that are sufficiently similar to those obtainedduring an actual flight, so much so that a human would be incapable of noticing anydifference (Giordano et al., 2010). Many argue that the only way to obtain such a highquality of simulation is by using a motion platform, which makes the cost of thisequipment the same order of magnitude of a real aircraft.Several recent studies have contributed in this topic of discussion, the influence of themotion platform is still unclear (McCauley, 2006), (Proctor, Bauer and Lucario, 2007),(McDaniel, Scott and Browning, 1983). Bürki-cohen, Sparko and Bellman (2011) madea thorough review of the need of motion platforms in aircraft simulators while discussesthe need of motion platforms in military helicopter simulators, butThe objective of this work is to analyze the contribution of adding a motion system to anEDS (Engineering Development System), yielding a flexible and reconfigurablesimulator, available as soon as the official aerodynamic databank is made available. Theadvantage (if any) of creating an EDS with motion platform is that it brings to the aircraftdevelopment cycle, the opportunity of anticipating the knowledge acquired in thelearning-by-using approach, by means of a simulation environment that resembles thebehavior of the final product, especially in the early development phases.

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