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Johansson, Andreas
Publications (10 of 10) Show all publications
Ericson, L., Johansson, A., Ölvander, J. & Palmberg, J.-O. (2009). Optimisation of Structure Borne Noise and Fluid Borne Noise from Fluid Power Pumps and Motors. In: Proc. of the 11th Scandinavian Fluid Power Conference. Paper presented at The 11th Scandinavian Fluid Power Conference, June 2-4, Linköping, Sweden.
Open this publication in new window or tab >>Optimisation of Structure Borne Noise and Fluid Borne Noise from Fluid Power Pumps and Motors
2009 (English)In: Proc. of the 11th Scandinavian Fluid Power Conference, 2009Conference paper, Published paper (Other academic)
Abstract [en]

Structure borne noise in a machine rises from piston force and bending moments among others. This noise arises directly from the pump shell. In this study, a transfer function methodology is employed for mapping simulated internal pump dynamics, such as piston forces and bending moments, on to structure borne noise. Using these transfer functions, it is possible to predict how, for instance, changed valve plate timing affects simulated piston forces and bending moments and in turn how that will affect audible noise. Hence, it is possible to design an objective function that directly reflects audible noise. The transfer functions are experimentally obtained and are valid for a specific machine shell and to some minor extent the room’s acoustical properties. Also, fluid borne noise is important to consider when designing a quiet machine. Fluid borne noise arises mainly from flow pulsation created inside the machine.

Simulation of the internal pump dynamics, and optimisations, are carried out using a pump model developed in the simulation tool HOPSAN. The design application is a hydraulic machine of bent axis type with seven pistons. The theory outlined and the method proposed in the paper can also be applied to other types of hydraulic machines. The paper shows how both structure borne noise and fluid borne noise can be considered using multi-objective optimisation. The paper shows how different noise reduction features affect the sound pressure level and the flow pulsation. The paper also compare the pump and motor case.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-73977 (URN)
Conference
The 11th Scandinavian Fluid Power Conference, June 2-4, Linköping, Sweden
Available from: 2012-01-18 Created: 2012-01-18 Last updated: 2017-12-20Bibliographically approved
Johansson, A., Ölvander, J. & Palmberg, J.-O. (2007). Experimental verification of cross-angle for noise reduction in hydraulic piston pumps. Proceedings of the Institution of mechanical engineers. Part I, journal of systems and control engineering, 221(3), 321-330
Open this publication in new window or tab >>Experimental verification of cross-angle for noise reduction in hydraulic piston pumps
2007 (English)In: Proceedings of the Institution of mechanical engineers. Part I, journal of systems and control engineering, ISSN 0959-6518, E-ISSN 2041-3041, Vol. 221, no 3, p. 321-330Article in journal (Refereed) Published
Abstract [en]

One of the most important drawbacks with hydraulic systems is noise and vibration, which mainly originate from the hydrostatic pump. A great number of noise-reducing design features have been developed, but they are all, to a greater or lesser extent, sensitive to variations in operational conditions. The present paper is concerned with optimal design and experimental verification of the cross-angle in an axial piston pump. The cross-angle is a small fixed incline of the swash plate in the direction that is perpendicular to the traditional displacement direction. It enables effective noise reduction throughout the whole range of displacement angles.

Simulation-based optimization is used to design a pump with optimal cross-angle and a matching valve plate. The design is manufactured and experimentally evaluated. Source flow measurements using the two-microphone method show good agreement between simulation and experiments, which verifies the applicability of the simulation model used. The benefits from using the cross-angle are then verified by comparing it with a pump with a traditional swash plate design, i.e. without the cross-angle. Both source flow measurements and sound level measurements in an anechoic chamber show good improvements from using the cross-angle.

Keywords
Cross-angle, Noise, Optimization, Simulation, Source flow
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-49333 (URN)10.1243/09596518JSCE208 (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12
Johansson, A. (2005). Design principles for noise reduction in hydraulic piston pumps: simulation, optimisation and experimental verification. (Doctoral dissertation). Linköping: Linköpings universitet
Open this publication in new window or tab >>Design principles for noise reduction in hydraulic piston pumps: simulation, optimisation and experimental verification
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Noise reduction in hydmulic systems has been an important research topic for several decades. In recent years, industry's interest in the area has grown dramatically. The reason is new national and international requirements and legislation governing working conditions. As a consequence of this, considerable reduction of noise from machinery in general has been achieved. The reduction of noise in hydraulic systems, however, has not gained from the same considerable progress, which implies that hydraulic noise has become perceptible through the surrounding machinery noise. Not only has noise reduction of hydraulic systems become increasingly important, it has also become more difficult because of the ever-increasing working pressure level, which is highly correlated to noise and vibration.

Noise in hydraulic systems is created mainly by the hydrostatic pump and motor, working with large pressure differences in the suction and delivery ports. Being exclusively of displacement type, the hydrostatic machine creates substantial flow pulsations in both the discharge and suction ports. The flow pulsations give rise to system pressure pulsations, which in turn transform into vibration and audible noise. Excessive pulsating piston forces and bending moments due to the large pressure difference between the machine's discharge and suction ports also contribute to noise and vibration.

To obtain satisfactory noise reduction, there is a need for effective and reliable design tools and design methods. This thesis concerns simulation, optimisation and experimental verification of axial piston pump design for noise reduction. Much of the work relates to the different origins of noise and how to formulate objective functions that simultaneously reflects different aspects of noise reduction. New and conventional design features are examined both theoretically and experimentally. One novel and promising design feature thoroughly investigated in this thesis is the so-called crossangle that aims to provide low noise in variable displacement machines. Different measurement approaches are employed for experimental verification. It is shown that conventional methods are often inadequate for measuring source flow in variable displacement units due to the complex outlet channel. A new method, referred to as the Source admittance method, is proposed.

Place, publisher, year, edition, pages
Linköping: Linköpings universitet, 2005. p. 164
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 965
Keywords
hydraulic piston pumps
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-31420 (URN)17198 (Local ID)91-85457-15-9 (ISBN)17198 (Archive number)17198 (OAI)
Public defence
2005-10-14, Nobel, Hus B, Campus Valla, Linköpings Universitet, Linköping, 10:15 (English)
Opponent
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2012-12-05Bibliographically approved
Johansson, A. & Palmberg, J.-O. (2005). The importance of suction port timing in axial piston pumps. In: Palmberg, Jan-Ove (Ed.), Proc. of the 9th Scandinavian International Conference on Fluid Power, (SICFP '05). Paper presented at The 9th International Conference on Fluid Powers, SICFP'05, July 1-3, Linköping, Sweden (pp. 32). Linköping: Linköping Universitet, Institute of Technology
Open this publication in new window or tab >>The importance of suction port timing in axial piston pumps
2005 (English)In: Proc. of the 9th Scandinavian International Conference on Fluid Power, (SICFP '05) / [ed] Palmberg, Jan-Ove, Linköping: Linköping Universitet, Institute of Technology , 2005, p. 32-Conference paper, Published paper (Refereed)
Abstract [en]

Hydraulic pumps give rise to flow ripples in both discharge and suction lines. The flow pulsations transform into pressure ripples which in turn create vibration and audible noise. With a careful design of the valve plate timing, flow ripple can be minimised. Much research is dedicated to the design of discharge port commutation, i.e. the pre-compression dynamics. This work, however, focuses on the suction port timing.

Besides controlling flow ripple in the tank line, suction port timing influences fluid air-release which in turn has substantial impact on the effective system bulk modulus. lncreased air-release implies reduced cylinder filling performance, reduced volumetric efficiency and increased flow pulsations. In addition, the cylinder decompression at suction port commutation directly affects the resulting piston force profile and internal bending moments which largely contributes to pump housing vibration and noise emissions. Thus. the design of the suction port timing is crucial for flow ripples, air-release, pump housing vibrations and direct noise emissions from the pump. Also. the risk for cavitation is controlled.

This paper also investigates the efficiency of an Air Drain Groove, ADC, as an alternative to conventional pressure relief grooves at suction port commutation. Correctly designed, the ADG reduces the cylinder pressure at piston top dead centre by bleeding off a very small amount of cylinder fluid to the housing drain. The air-release hereby obtained is directed into the pump casing instead of into the suction port and should thereby give rise to a higher system bulk modulus. Experiments reveal, however, that the efficiency of the ADC is not preferable to a conventional pressure relief groove, neither regarding air-release, nor noise emissions.

Place, publisher, year, edition, pages
Linköping: Linköping Universitet, Institute of Technology, 2005
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-31417 (URN)17195 (Local ID)9185457965 (ISBN)9789185457960 (ISBN)17195 (Archive number)17195 (OAI)
Conference
The 9th International Conference on Fluid Powers, SICFP'05, July 1-3, Linköping, Sweden
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2012-12-05
Johansson, A. (2004). Reduktion av pulsationer vid pumpkonstruktion. In: Hydraulikdagarna,2003. Linköping, Sweden: Linköpings universitet
Open this publication in new window or tab >>Reduktion av pulsationer vid pumpkonstruktion
2004 (Swedish)In: Hydraulikdagarna,2003, Linköping, Sweden: Linköpings universitet , 2004Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Linköping, Sweden: Linköpings universitet, 2004
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-36399 (URN)31247 (Local ID)31247 (Archive number)31247 (OAI)
Available from: 2009-10-10 Created: 2009-10-10
Johansson, A., Andersson, J. & Palmberg, J.-O. (2003). Influence from the cross-angle on piston forces and bending moments in variable hydraulic piston pumps.
Open this publication in new window or tab >>Influence from the cross-angle on piston forces and bending moments in variable hydraulic piston pumps
2003 (English)Report (Other academic)
Abstract [en]

By implementing an additional incline (cross-angle) of the swash plate of an axial piston pump, in the direction perpendicular to the traditional displacement direction, the piston dead-centre points will move as the displacement angle varies. The cross-angle is fixed and normally very small (1-4°). If designed correctly, the movement of the dead-centre points achieved by using a cross-angle coincides with the dead centres desired for optimal cylinder pre-compression and decompression for all displacement angles. It has in earlier works been described how the cross-angle enables minimisation of discharge and inlet peak-to-peak flow ripple for all displacement angles simultaneously. In this paper, it is also investigated how the piston forces and the bending moments are influenced.

The cross-angle is designed using simulation-based multi-objective optimisation. It is investigated how objective functions can be made up from peak-to-peak values as well as from frequency spectrum of signals. The trade-offs between the conflicting objectives considered are elucidated by using the concept of Pareto optimality. The result from such a Pareto optimisation is not one optimal solution, but a set of optimal solutions. With the technique presented, it is thus possible to investigate an optimal value for the cross-angle that the most beneficial impact on all factors that influence the noise level of the pump.

Series
LITH-IKP-R, ISSN 0281-5001 ; 1391
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-85981 (URN)
Available from: 2012-12-05 Created: 2012-12-05 Last updated: 2012-12-05
Johansson, A. (2002). Noise reduction of hydraulic systems: design considerations and methods. (Licentiate dissertation). Linköping: Linköpings universitet
Open this publication in new window or tab >>Noise reduction of hydraulic systems: design considerations and methods
2002 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

AS A CONSEQUENCE OF increased requirements concerning pleasant working conditions, the system designer of today is facing challenges besides the traditional performance related ones. Subjects such as cleanliness, low sound and vibration levels etc. play important roles in modern system development. The requirements have resulted in considerable improvements on machineries in general, but still the noise often reaches unacceptable levels. In many applications of today, the noise emitted by the hydraulics can be identified through the totally emitted noise, and the trend towards increasing working pressure, which is directly correlated to noise and vibrations, seems to last. Therefore, studies regarding noise from hydraulic systems are still highly relevant.

The primary noise source in a hydraulic system is the hydrostatic machine, working with large pressure differences. Being exclusively of displacement type, the hydrostatic machine divides the flow into separate volumes, which are pressureized or de-pressurized. This working principle will cause phenomena such as pressure peaks, flow ripple and internal force and torque ripple, all contributing to noise and vibrations. However, when considering the complete system it becomes evident that noise is normally created by joint effort from different origins and their interaction with external hydraulic and mechanical systems. It is therefore difficult to point out one origin solely.

This thesis aims to survey and summarize work accomplished in the area of noise and vibrations in hydraulic systems. In the work, effort has been concentrated to the internal workings of the axial piston machine, mainly the pump. To map the couplings between geometric design and dynamic behaviour, simulation technique is frequently used. The most common design features are de­ scribed and discussed. A rating system, grading the different noise reducing devices mutually, which gives the designer the ability to chose the most beneficial design feature regarding to high reduction of flow ripple in relation to implementation cost, is presented.

 

Place, publisher, year, edition, pages
Linköping: Linköpings universitet, 2002. p. 131
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 953
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:liu:diva-146013 (URN)LiU-Tek-Lic-2002:26 (Local ID)9173733652 (ISBN)LiU-Tek-Lic-2002:26 (Archive number)LiU-Tek-Lic-2002:26 (OAI)
Available from: 2018-03-27 Created: 2018-03-27 Last updated: 2019-08-06Bibliographically approved
Johansson, A., Andersson, J. & Palmberg, J.-O. (2002). Optimal design of the cross-angle for pulsation reduction in variable displacement pumps. In: Burrows, C. R. and Edge, K. A (Ed.), Power Transmission and Motion Control: PTMC 2002. Paper presented at Bath Workshop on Power Transmission and Motion Control (PTMC 2002), September 2002, Bath, UK (pp. 319-333). Wiley-Blackwell
Open this publication in new window or tab >>Optimal design of the cross-angle for pulsation reduction in variable displacement pumps
2002 (English)In: Power Transmission and Motion Control: PTMC 2002 / [ed] Burrows, C. R. and Edge, K. A, Wiley-Blackwell, 2002, p. 319-333Conference paper, Published paper (Refereed)
Abstract [en]

The cross-angle, illustrated in this paper, is a fixed displacement angle around the axis perpendicular to the normal trunnion axis. With the cross-angle, the traditional piston dead centres will change as the normal displacement angle is varied. The result is a behaviour similar to thal of the revolving valve plate technique. but without any movable parts. When the cross-angle is used in a constant pressure system with a variable pump, the desired dead centre for optimal pro-compression coincides with the obtained dead centre for a wide range of displacement angles. This implies that when the cross-angle is used, the flow ripple becomes less sensitive to changes in displacement angles. The cross-angle does not constitute an alternative to the different design features developed, but rather as complement for preserved effective flow ripple reduction over a wide range of displacement angles.

ln this study. simulation-based optimisations, employing non-gradient optimisation techniques such as genetic algorithms and the Complex method, are used in order to find the optimal cross-angle for a variable displacement pump. Furthermore. with the help of optimisation, the trade-offs between attributes such as low flow ripples, avoidance of large cylinder pressure-peaks, and cavitation have been studied. Increased insight is thereby gained into what possibilities the cross-angle offers regarding reduction of pump ripple for a variable displacement pump.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2002
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-36697 (URN)32178 (Local ID)1860583792 (ISBN)978-1860583797 (ISBN)32178 (Archive number)32178 (OAI)
Conference
Bath Workshop on Power Transmission and Motion Control (PTMC 2002), September 2002, Bath, UK
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2012-12-05
Werndin, R., Johansson, A. & Palmberg, J.-O. (2001). A General Model of a Multi Displacement Machine using TLM SICFP' 01. In: Scandinavian International Conference on Fluid Power,2001.
Open this publication in new window or tab >>A General Model of a Multi Displacement Machine using TLM SICFP' 01
2001 (English)In: Scandinavian International Conference on Fluid Power,2001, 2001Conference paper, Published paper (Other academic)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-35585 (URN)27811 (Local ID)27811 (Archive number)27811 (OAI)
Available from: 2009-10-10 Created: 2009-10-10
Johansson, A. & Blackman, B. (2000). Prediction of Pump Dynamics Utilizing Computer Simulation Model - with Special Reference to Noise Reduction. In: SAE International Off Highway Conference,2000.
Open this publication in new window or tab >>Prediction of Pump Dynamics Utilizing Computer Simulation Model - with Special Reference to Noise Reduction
2000 (English)In: SAE International Off Highway Conference,2000, 2000Conference paper, Published paper (Other academic)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-35274 (URN)26050 (Local ID)26050 (Archive number)26050 (OAI)
Available from: 2009-10-10 Created: 2009-10-10
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