Micromechanical finite element modelling of thermo-mechanical fatigue for P91 steels
Li, Dong-Feng and Barrett, Richard A. and O’Donoghue, Padraic E. and Hyde, Chris J. and O’Dowd, Noel P. and Leen, Sean B. (2016) Micromechanical finite element modelling of thermo-mechanical fatigue for P91 steels. International Journal of Fatigue, 87 . pp. 192-202. ISSN 0142-1123
In this paper, the cyclic plasticity and fatigue crack initiation behaviour of a tempered martensite ferritic steel under thermo-mechanical fatigue conditions is examined by means of micromechanical finite element modelling. The crystal plasticity-based model explicitly reflects the microstructure of the material, measured by electronic backscatter diffraction. The predicted cyclic thermo-mechanical response agrees well with experiments under both in-phase and out-of-phase conditions. A thermo-mechanical fatigue indicator parameter, with stress triaxiality and temperature taken into account, is developed to predict fatigue crack initiation. In the fatigue crack initiation simulation, the out-of-phase thermo-mechanical response is identified to be more dangerous than in-phase response, which is consistent with experimental failure data. It is shown that the behaviour of thermo-mechanical fatigue can be effectively predicted at the microstructural level and this can lead to a more accurate assessment procedure for power plant components.
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