Morin, Claire (2008) Thermomechanical fatigue of Shape Memory Alloys PFE - Project Graduation, ENSTA.
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Shape Memory Alloys are increasingly used in a wide range of state-of the art technologies. That is why a detailed knowledge of their behaviour and a good prediction of their fatigue behaviour are needed. The papers on this topic mainly concern the modelling of different phenomena (pseudo-elasticity, simple way shape memory, superthermal effect, martensite orientation...), and suggest many constitutive laws. Some articles regard the cyclic thermomechanical behaviour but there is no reliable 3D low cycle fatigue criterion. Moumni et al. () began to introduce a low cycle fatigue criterion for SMA subjected to pseudo-elastic tension-compression by taking into account the dissipated energy in the stabilized hysteresis loop (). We worked to extend this criterion to torsion loading and to introduce the influence of hydrostatic pressure as in Dang Van criterion. In order to obtain the value of the dissipated energy in torsion loading we had to code entirely the mechanical problem with the pseudo-elastic constitutive law from the unified model of Zaki-Moumni (). The numerical program of the constitutive law in Castem involved the setting up of an incremental solving strategy (as in plasticity). However working with a bimaterial and having many internal variables complicated both the algorithm and the solving. This work opens some prospects for future work that are detailed at the end of the report.
|Thesis (PFE - Project Graduation)
|Materials Science, Mechanics and Mechanical Engineering
|17 avr. 2009 02:20
|16 mai 2014 14:17
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