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  • 1.
    Norman, Viktor
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Calmunger, Mattias
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    On the micro- and macroscopic elastoplastic deformation behaviour of cast iron when subjected to cyclic loading2019In: International journal of plasticity, ISSN 0749-6419, E-ISSN 1879-2154, Vol. 115, p. 200-215Article in journal (Refereed)
    Abstract [en]

    The complicated constitutive behaviour of cast iron, involving a non-linear elastic regime, tension-compression stress asymmetry, varying elastic modulus and an inflection in the tension-to-compression hardening curve, is investigated using a micromechanical modelling approach. In this way, it is demonstrated that the abnormalities observed in the constitutive behaviour are qualitatively and quantitatively explained by the interaction behaviour between the matrix and graphite constituents. In initial tension, the absence of linearity is rationalised by the successive loss in load-carrying capacity of the graphite phase due to debonding, which in subsequent cycling, results in the opening and re-contact of the matrix-graphite interface. This effect is demonstrated to result in tension-compression asymmetry in stress and elastic modulus, as well as the inflection in tension-to-compression loading. The given model of explanation is validated by comparison to the experimentally acquired microscopic strain field in EN-GJV-400 at locations where stress concentrations are generated due to the matrix-graphite debonding, using high-resolution digital image correlation of scanning electron images.

  • 2.
    Gigan, Gael
    et al.
    Chalmers Univ Technol, Sweden.
    Norman, Viktor
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Ahlström, Johan
    Chalmers Univ Technol, Sweden.
    Vernersson, Tore
    Chalmers Univ Technol, Sweden; AF Ind AB, Sweden.
    Thermomechanical fatigue of grey cast iron brake discs for heavy vehicles2019In: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering, ISSN 0954-4070, E-ISSN 2041-2991, Vol. 233, no 2, p. 453-467Article, review/survey (Refereed)
    Abstract [en]

    The development of fatigue life assessment models for vehicle components exposed to thermomechanical fatigue supports the establishing of adequate maintenance intervals that neither cause unnecessary vehicle downtime, nor jeopardize the function of the components. In modern automotive applications, braking is closely related to safety and is commonly performed with disc brakes. Failure here may result in structural damage or even breakdown and loss of lives. In the present work, the cyclic response of grey cast iron is analysed and the fatigue life of brake discs made from this material is studied by use of four different fatigue life assessment models: the Smith-Watson-Topper model, the Coffin-Manson model and two mechanism-based damage models. Results from isothermal and thermomechanical experiments on uniaxially loaded specimens are used for calibration of the models. Finally, the models are used to assess the life of a brake disc for a simulated brake dynamometer experiment. It is found that the fatigue model parameters that are calibrated using different sets of isothermal uniaxial test data show a substantial spread. A comparison with results from full-scale brake rig experiments shows that predictions by any of the models that have been calibrated using data from a well-designed thermomechanical test are in reasonable agreement with the estimated crack initiation phase for actual brake disc lives. It can be concluded that it is not sufficient to calibrate the studied fatigue life models using isothermal uniaxial tests for predictions of thermomechanical fatigue lives.

  • 3.
    Norman, Viktor
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Fatigue of Heavy-Vehicle Engine Materials: Damage Mechanisms, Laboratory Experiments and Life Estimation2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Due to increasing demands on sustainability exerted by end-costumers and policy makers, heavyvehicle manufacturers are urged to increase the engine efficiency in order to reduce the exhaust gas emission. However, increasing the efficiency is also associated with an elevated fatigue rate of the materials constituting the engine parts, which consequently reduces the engine service life. The aim of the present thesis is therefore to confront the expected increase by studying the fatigue behaviour and damage mechanisms of the materials typically employed in heavy-vehicle diesel engines. With this knowledge, this work seeks to guide the development of new heavy-vehicle engine materials, as well as to develop improved life estimation methods designated to assist the mechanical design of durable heavy-vehicle engines.

    In essence, a large set of thermo-mechanical fatigue (TMF) and combined thermomechanical and high-cycle fatigue (TMF-HCF) tests is conducted at engine load conditions on laboratory specimens of lamellar, compacted and spheroidal graphite iron. In this way, the fatigue performance and associated damage mechanisms are investigated. In particular, a new fatigue property is identified, the TMF-HCF threshold, which quantifies how resistant a material is to superimposed high-cycle fatigue.

    The damage mechanism at low temperatures (≲500°C) is confirmed to consist of the initiation, propagation and coalescence of numerous microcracks. Based on this, a successful fatigue life estimation model is formulated, allowing accurate estimations of TMF and TMF-HCF tests on smooth specimens, and TMF tests on notched specimens. In the latter case, the microcrack growth behaviour in non-uniform cyclic stress fields and its implications for life estimation are clarified. At elevated temperatures (≳500°C), surface oxidation is shown to govern the fatigue performance of cast iron grades intended for exhaust manifolds. It is observed that oxide intrusions are induced, from which surface fatigue cracks are initiated. Consequently, an optimal material at these conditions should have a low oxide growth rate and few casting defects at the surface, as these factors are found to stimulate the growth of intrusion.  

    List of papers
    1. Damage evolution in compacted graphite iron during thermomechanical fatigue testing
    Open this publication in new window or tab >>Damage evolution in compacted graphite iron during thermomechanical fatigue testing
    2016 (English)In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 29, no 1-2, p. 26-33Article in journal (Refereed) Published
    Abstract [en]

    Thermomechanical fatigue properties of a compacted graphite iron in an out of phase configuration are investigated for different maximum temperatures and mechanical strain ranges. Furthermore, the stressï¿œstrain hysteresis loops are analysed, and, in particular, the unloading modulus, i.e. the elastic modulus measured during specimen unloading, is obtained from each cycle. This material parameter has earlier been explicitly related to the amount of microcracking in cast irons. The results show that the unloading modulus linearly declines with the numbers of cycles in all tests performed. In addition, the rate of change of the unloading modulus is closely related to the number of cycles to failure. Accordingly, it is concluded that microcracks are independently propagated by fatigue until a point of rapid crack linking resulting in ultimate failure. This is supported by microstructural analyses consisting of optical microscope images taken at different stages throughout the life of a specimen.

    Place, publisher, year, edition, pages
    Taylor & Francis, 2016
    Keywords
    Thermomechanical fatigue, Out-of-phase loading, Compacted graphite iron, Microcracking
    National Category
    Other Materials Engineering
    Identifiers
    urn:nbn:se:liu:diva-121028 (URN)10.1179/1743133615Y.0000000019 (DOI)000377468800005 ()
    Funder
    VINNOVA, FFI-2012-03625Swedish Foundation for Strategic Research , SM12-0014
    Note

    Funding agencies: Scania CV AB; Strategic Faculty Grant AFM (SFO-MAT-LiU) at Linkoping University [2009-00971]

    Available from: 2015-09-03 Created: 2015-09-03 Last updated: 2018-02-13Bibliographically approved
    2. Thermo-mechanical and superimposed high-cycle fatigue interactions in compacted graphite iron
    Open this publication in new window or tab >>Thermo-mechanical and superimposed high-cycle fatigue interactions in compacted graphite iron
    2015 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 80, p. 381-390Article in journal (Refereed) Published
    Abstract [en]

    The effect of adding a superimposed high-frequent strain load, denoted as a high-cycle fatigue strain component, upon a strain-controlled thermo-mechanical fatigue test has been studied on a compacted graphite iron EN-GJV-400 for different thermo-mechanical fatigue cycles and high-cycle fatigue strain ranges. It is demonstrated that the successive application of an high-cycle fatigue load has a consistent effect on the fatigue life, namely the existence of a constant high-cycle fatigue strain range threshold below which the fatigue life is unaffected but severely reduced when above. This effect on the fatigue life is predicted assuming that microstructurally small cracks are propagated and accelerated according to a Paris law incorporating an experimentally estimated crack opening level.

    Place, publisher, year, edition, pages
    Elsevier, 2015
    Keywords
    Cast iron, Thermo-mechanical fatigue, High-cycle fatigue, Fatigue crack growth, Life prediction
    National Category
    Other Engineering and Technologies Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-121029 (URN)10.1016/j.ijfatigue.2015.06.005 (DOI)000360596500040 ()
    Available from: 2015-09-03 Created: 2015-09-03 Last updated: 2018-02-13Bibliographically approved
    3. The effect of superimposed high-cycle fatigue on thermo-mechanical fatigue in cast iron
    Open this publication in new window or tab >>The effect of superimposed high-cycle fatigue on thermo-mechanical fatigue in cast iron
    2016 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 88, p. 121-131Article in journal (Refereed) Published
    Abstract [en]

    The eect of superimposing a high-cycle fatigue strain load on an out-ofphase thermo-mechanical fatigue test of a lamellar, compacted and spheroidal graphite iron, has been investigated. In particular, dierent total mechanical strain ranges, maximum temperatures and high-cycle fatigue strain ranges have been studied. From this, a new property has been identied, measured and compared, namely the thermo-mechanical and high-cycle fatigue threshold, dened as the high-cycle fatigue strain range at which the life is reduced to half. Using a model developed earlier, the lifetimes and the threshold have been successfully estimated for the lamellar and compacted graphite iron, however underestimated for the spheroidal graphite iron. Nevertheless, an expression of the threshold was deduced from the model, which possibly can estimate its value in other cast irons and its high-cycle fatigue frequency dependence.

    Place, publisher, year, edition, pages
    Elsevier, 2016
    Keywords
    Cast iron, Thermo-mechanical fatigue, High-cycle fatigue, Fatigue crack growth, Life prediction
    National Category
    Mechanical Engineering Other Engineering and Technologies
    Identifiers
    urn:nbn:se:liu:diva-121030 (URN)10.1016/j.ijfatigue.2016.03.020 (DOI)000375817000013 ()
    Note

    Funding agencies: Scania CV AB; Swedish Governmental Agency for Innovation Systems [FFI - 2012 - 03625]; Swedish Foundation for Strategic Research [SM12 - 0014]; Linkoping University [2009 - 00971]

    Vid tiden för disputation förelåg publikationen endast som manuskript

    Available from: 2015-09-03 Created: 2015-09-03 Last updated: 2018-02-13Bibliographically approved
    4. Damage Mechanisms in Silicon-Molybdenum Cast Irons Subjected to Thermo-mechanical Fatigue
    Open this publication in new window or tab >>Damage Mechanisms in Silicon-Molybdenum Cast Irons Subjected to Thermo-mechanical Fatigue
    2017 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 99, no 2, p. 258-265Article in journal (Refereed) Published
    Abstract [en]

    The damage mechanisms active in silicon-molybdenum cast irons, namely EN-GJS-SiMo5-1 and SiMo1000, under thermo-mechanical fatigue and combined thermo-mechanical and high-cycle fatigue conditions have been investigated. The studied load conditions are those experienced at critical locations in exhaust manifolds of heavy-vehicle diesel engines, namely a temperature cycle of 300–750 °C with varied total mechanical and high-cycle fatigue strain ranges. It is established that oxide intrusions are formed in the early life from which macroscopic fatigue cracks are initiated close to the end-of-life. However, when high-cycle fatigue loading is superimposed, small cracks are preferentially initiated at graphite nodules within the bulk. In addition, it is found that both the oxidation growth rate and casting defects located near the surface affect the intrusion growth.

    Place, publisher, year, edition, pages
    Elsevier, 2017
    Keywords
    Cast iron, Thermo-mechanical fatigue, High-cycle fatigue, Enviromental assisted fatigue, Fatigue crack growth
    National Category
    Materials Engineering
    Identifiers
    urn:nbn:se:liu:diva-137287 (URN)10.1016/j.ijfatigue.2017.01.014 (DOI)000400718300007 ()2-s2.0-85017123996 (Scopus ID)
    Note

    Funding agencies: Scania CV AB; Swedish Governmental Agency for Innovation Systems [FFI-2012-03625]; Swedish Foundation for Strategic Research [SM12-0014]; Strategic Faculty Grant AFM (SFO-MAT-LiU) at Linkoping University [2009-00971]

    Available from: 2017-05-10 Created: 2017-05-10 Last updated: 2018-02-13Bibliographically approved
    5. The Transition from Micro- to Macrocrack Growth in Compacted Graphite Iron Subjected to Thermo-Mechanical Fatigue
    Open this publication in new window or tab >>The Transition from Micro- to Macrocrack Growth in Compacted Graphite Iron Subjected to Thermo-Mechanical Fatigue
    2017 (English)In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, no 186, p. 268-282Article in journal (Refereed) Published
    Abstract [en]

    The complete fatigue process involving the growth of microstructurally small fatigue cracks prior to macrocrack initiation and the subsequent large crack propagation in notched compacted graphite iron, EN-GJV-400, specimens subjected to thermo-mechanical fatigue has been investigated. It is shown that microcracks are initiated at graphite tips within an extended volume at the notch which eventually leads to an abrupt microcrack coalescence event. As a macrocrack is generated in this way, the crack growth switches to conventional characteristics which is assessed in terms of elasto-plastic fracture mechanics parameters. Consequently, two important implications regarding lifetime assessment are identified; possible underestimation due to (i) how the stress is evaluated in view of the spacial distribution of microcracking and (ii) the crack retardation effect associated with the crack growth transition.

    Place, publisher, year, edition, pages
    Elsevier, 2017
    Keywords
    Cast iron, notches, delta J, crack tip opening displacement
    National Category
    Materials Engineering
    Identifiers
    urn:nbn:se:liu:diva-143691 (URN)10.1016/j.engfracmech.2017.10.017 (DOI)000418056700017 ()
    Available from: 2017-12-14 Created: 2017-12-14 Last updated: 2018-05-04
  • 4.
    Norman, Viktor
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Skoglund, Peter
    Scania CV AB, Materials Technology, Södertälje.
    Leidermark, Daniel
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    Moverare, Johan
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Damage Mechanisms in Silicon-Molybdenum Cast Irons Subjected to Thermo-mechanical Fatigue2017In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 99, no 2, p. 258-265Article in journal (Refereed)
    Abstract [en]

    The damage mechanisms active in silicon-molybdenum cast irons, namely EN-GJS-SiMo5-1 and SiMo1000, under thermo-mechanical fatigue and combined thermo-mechanical and high-cycle fatigue conditions have been investigated. The studied load conditions are those experienced at critical locations in exhaust manifolds of heavy-vehicle diesel engines, namely a temperature cycle of 300–750 °C with varied total mechanical and high-cycle fatigue strain ranges. It is established that oxide intrusions are formed in the early life from which macroscopic fatigue cracks are initiated close to the end-of-life. However, when high-cycle fatigue loading is superimposed, small cracks are preferentially initiated at graphite nodules within the bulk. In addition, it is found that both the oxidation growth rate and casting defects located near the surface affect the intrusion growth.

  • 5.
    Norman, Viktor
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Skoglund, Peter
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering. Scania CV AB, Materials Technology, Södertälje, Sweden.
    Leidermark, Daniel
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    Moverare, Johan
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    The Transition from Micro- to Macrocrack Growth in Compacted Graphite Iron Subjected to Thermo-Mechanical Fatigue2017In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, no 186, p. 268-282Article in journal (Refereed)
    Abstract [en]

    The complete fatigue process involving the growth of microstructurally small fatigue cracks prior to macrocrack initiation and the subsequent large crack propagation in notched compacted graphite iron, EN-GJV-400, specimens subjected to thermo-mechanical fatigue has been investigated. It is shown that microcracks are initiated at graphite tips within an extended volume at the notch which eventually leads to an abrupt microcrack coalescence event. As a macrocrack is generated in this way, the crack growth switches to conventional characteristics which is assessed in terms of elasto-plastic fracture mechanics parameters. Consequently, two important implications regarding lifetime assessment are identified; possible underestimation due to (i) how the stress is evaluated in view of the spacial distribution of microcracking and (ii) the crack retardation effect associated with the crack growth transition.

  • 6.
    Norman, Viktor
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Skoglund, Peter
    Scania CV AB, Materials Technology, Södertälje, Sweden.
    Moverare, Johan
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Damage evolution in compacted graphite iron during thermomechanical fatigue testing2016In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 29, no 1-2, p. 26-33Article in journal (Refereed)
    Abstract [en]

    Thermomechanical fatigue properties of a compacted graphite iron in an out of phase configuration are investigated for different maximum temperatures and mechanical strain ranges. Furthermore, the stressï¿œstrain hysteresis loops are analysed, and, in particular, the unloading modulus, i.e. the elastic modulus measured during specimen unloading, is obtained from each cycle. This material parameter has earlier been explicitly related to the amount of microcracking in cast irons. The results show that the unloading modulus linearly declines with the numbers of cycles in all tests performed. In addition, the rate of change of the unloading modulus is closely related to the number of cycles to failure. Accordingly, it is concluded that microcracks are independently propagated by fatigue until a point of rapid crack linking resulting in ultimate failure. This is supported by microstructural analyses consisting of optical microscope images taken at different stages throughout the life of a specimen.

  • 7.
    Norman, Viktor
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Skoglund, Peter
    Scania CV AB, Materials Technology, Södertälje, Sweden.
    Leidermark, Daniel
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    Moverare, Johan
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    The effect of superimposed high-cycle fatigue on thermo-mechanical fatigue in cast iron2016In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 88, p. 121-131Article in journal (Refereed)
    Abstract [en]

    The eect of superimposing a high-cycle fatigue strain load on an out-ofphase thermo-mechanical fatigue test of a lamellar, compacted and spheroidal graphite iron, has been investigated. In particular, dierent total mechanical strain ranges, maximum temperatures and high-cycle fatigue strain ranges have been studied. From this, a new property has been identied, measured and compared, namely the thermo-mechanical and high-cycle fatigue threshold, dened as the high-cycle fatigue strain range at which the life is reduced to half. Using a model developed earlier, the lifetimes and the threshold have been successfully estimated for the lamellar and compacted graphite iron, however underestimated for the spheroidal graphite iron. Nevertheless, an expression of the threshold was deduced from the model, which possibly can estimate its value in other cast irons and its high-cycle fatigue frequency dependence.

  • 8.
    Norman, Viktor
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Fatigue of Heavy-Vehicle Engine Materials: Experimental Analysis and Life Estimation2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The heavy-vehicle automotive industry is constantly subjected to higher demands. In particular, new European emission standards are formulated with the intention of improving the environmental friendliness of newly-produced vehicles through reduced exhaust emission. In one way or another, this implies a successive improvement of the engine efficiency, which in turn, inevitably will require a higher combustion pressure and temperature. This is a respectable challenge for future engine constructions, but also for the engineering materials used to embody them. As higher thermal and mechanical loads must be sustained, there is a higher rate of wear, and consequently, a negative effect on the extent of the engine lifetime.

    The aim of the present thesis is to confront the expected increase in rate of wear, henceforth referred to as fatigue, by studying the effect on materials typically employed in heavy-vehicle engines, namely cast irons. Foremost, the intention has been to improve the understanding of the physical mechanisms of fatigue in these materials, in order to develop a lifetime estimation method designated to assist the mechanical design of heavy-vehicle engines.

    In essence, a large set of thermo-mechanical fatigue (TMF) and combined thermo-mechanical and high-cycle fatigue (TMF-HCF) tests has been conducted at engine load conditions on laboratory specimens of lamellar, compacted and spheroidal graphite irons. In this way, these three different material groups have been experimentally compared and the associated fatigue mechanism has been studied. In particular, a new property related to TMF-HCF conditions has been identified and measured, . Regarding the fatigue mechanism, it has been affirmed to consist of the initiation, propagation and coalescence of numerous microcracks. Based on this, a successful lifetime assessment model was formulated, allowing good estimations of the fatigue life of laboratory specimens subjected to both TMF and TMF-HCF conditions.

    List of papers
    1. Damage evolution in compacted graphite iron during thermomechanical fatigue testing
    Open this publication in new window or tab >>Damage evolution in compacted graphite iron during thermomechanical fatigue testing
    2016 (English)In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 29, no 1-2, p. 26-33Article in journal (Refereed) Published
    Abstract [en]

    Thermomechanical fatigue properties of a compacted graphite iron in an out of phase configuration are investigated for different maximum temperatures and mechanical strain ranges. Furthermore, the stressï¿œstrain hysteresis loops are analysed, and, in particular, the unloading modulus, i.e. the elastic modulus measured during specimen unloading, is obtained from each cycle. This material parameter has earlier been explicitly related to the amount of microcracking in cast irons. The results show that the unloading modulus linearly declines with the numbers of cycles in all tests performed. In addition, the rate of change of the unloading modulus is closely related to the number of cycles to failure. Accordingly, it is concluded that microcracks are independently propagated by fatigue until a point of rapid crack linking resulting in ultimate failure. This is supported by microstructural analyses consisting of optical microscope images taken at different stages throughout the life of a specimen.

    Place, publisher, year, edition, pages
    Taylor & Francis, 2016
    Keywords
    Thermomechanical fatigue, Out-of-phase loading, Compacted graphite iron, Microcracking
    National Category
    Other Materials Engineering
    Identifiers
    urn:nbn:se:liu:diva-121028 (URN)10.1179/1743133615Y.0000000019 (DOI)000377468800005 ()
    Funder
    VINNOVA, FFI-2012-03625Swedish Foundation for Strategic Research , SM12-0014
    Note

    Funding agencies: Scania CV AB; Strategic Faculty Grant AFM (SFO-MAT-LiU) at Linkoping University [2009-00971]

    Available from: 2015-09-03 Created: 2015-09-03 Last updated: 2018-02-13Bibliographically approved
    2. Thermo-mechanical and superimposed high-cycle fatigue interactions in compacted graphite iron
    Open this publication in new window or tab >>Thermo-mechanical and superimposed high-cycle fatigue interactions in compacted graphite iron
    2015 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 80, p. 381-390Article in journal (Refereed) Published
    Abstract [en]

    The effect of adding a superimposed high-frequent strain load, denoted as a high-cycle fatigue strain component, upon a strain-controlled thermo-mechanical fatigue test has been studied on a compacted graphite iron EN-GJV-400 for different thermo-mechanical fatigue cycles and high-cycle fatigue strain ranges. It is demonstrated that the successive application of an high-cycle fatigue load has a consistent effect on the fatigue life, namely the existence of a constant high-cycle fatigue strain range threshold below which the fatigue life is unaffected but severely reduced when above. This effect on the fatigue life is predicted assuming that microstructurally small cracks are propagated and accelerated according to a Paris law incorporating an experimentally estimated crack opening level.

    Place, publisher, year, edition, pages
    Elsevier, 2015
    Keywords
    Cast iron, Thermo-mechanical fatigue, High-cycle fatigue, Fatigue crack growth, Life prediction
    National Category
    Other Engineering and Technologies Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-121029 (URN)10.1016/j.ijfatigue.2015.06.005 (DOI)000360596500040 ()
    Available from: 2015-09-03 Created: 2015-09-03 Last updated: 2018-02-13Bibliographically approved
    3. The effect of superimposed high-cycle fatigue on thermo-mechanical fatigue in cast iron
    Open this publication in new window or tab >>The effect of superimposed high-cycle fatigue on thermo-mechanical fatigue in cast iron
    2016 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 88, p. 121-131Article in journal (Refereed) Published
    Abstract [en]

    The eect of superimposing a high-cycle fatigue strain load on an out-ofphase thermo-mechanical fatigue test of a lamellar, compacted and spheroidal graphite iron, has been investigated. In particular, dierent total mechanical strain ranges, maximum temperatures and high-cycle fatigue strain ranges have been studied. From this, a new property has been identied, measured and compared, namely the thermo-mechanical and high-cycle fatigue threshold, dened as the high-cycle fatigue strain range at which the life is reduced to half. Using a model developed earlier, the lifetimes and the threshold have been successfully estimated for the lamellar and compacted graphite iron, however underestimated for the spheroidal graphite iron. Nevertheless, an expression of the threshold was deduced from the model, which possibly can estimate its value in other cast irons and its high-cycle fatigue frequency dependence.

    Place, publisher, year, edition, pages
    Elsevier, 2016
    Keywords
    Cast iron, Thermo-mechanical fatigue, High-cycle fatigue, Fatigue crack growth, Life prediction
    National Category
    Mechanical Engineering Other Engineering and Technologies
    Identifiers
    urn:nbn:se:liu:diva-121030 (URN)10.1016/j.ijfatigue.2016.03.020 (DOI)000375817000013 ()
    Note

    Funding agencies: Scania CV AB; Swedish Governmental Agency for Innovation Systems [FFI - 2012 - 03625]; Swedish Foundation for Strategic Research [SM12 - 0014]; Linkoping University [2009 - 00971]

    Vid tiden för disputation förelåg publikationen endast som manuskript

    Available from: 2015-09-03 Created: 2015-09-03 Last updated: 2018-02-13Bibliographically approved
  • 9.
    Segersäll, Mikael
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, The Institute of Technology.
    Calmunger, Mattias
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, The Institute of Technology.
    Norman, Viktor
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, The Institute of Technology.
    Fredriksson, Claes
    Student Reactions to CES EduPack in an Undergraduate Materials Selection Course2015Conference paper (Refereed)
  • 10.
    Norman, Viktor
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Skoglund, Peter
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering. Scania CV AB, Materials Technology, Södertälje, Sweden.
    Leidermark, Daniel
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    Moverare, Johan
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Thermo-mechanical and superimposed high-cycle fatigue interactions in compacted graphite iron2015In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 80, p. 381-390Article in journal (Refereed)
    Abstract [en]

    The effect of adding a superimposed high-frequent strain load, denoted as a high-cycle fatigue strain component, upon a strain-controlled thermo-mechanical fatigue test has been studied on a compacted graphite iron EN-GJV-400 for different thermo-mechanical fatigue cycles and high-cycle fatigue strain ranges. It is demonstrated that the successive application of an high-cycle fatigue load has a consistent effect on the fatigue life, namely the existence of a constant high-cycle fatigue strain range threshold below which the fatigue life is unaffected but severely reduced when above. This effect on the fatigue life is predicted assuming that microstructurally small cracks are propagated and accelerated according to a Paris law incorporating an experimentally estimated crack opening level.

  • 11.
    Norman, Viktor
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, The Institute of Technology.
    Skoglund, Peter
    Moverare, Johan
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, The Institute of Technology.
    Damage Evolution in Compacted Graphite Iron during Thermo-Mechaical Fatigue Testing2014Conference paper (Refereed)
1 - 11 of 11
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