Non-isothermal low-cycle fatigue analysis of elasto-viscoplastic materials

A non-isothermal elasto-viscoplastic model, developed within the framework of continuum damage mechanics, is proposed to investigate the influence of thermomechanical coupling on fatigue life of metallic materials. The numerical simulation of constant-amplitude low-cycle fatigue testing of a 316L stainless steel at room temperature shows that the hypothesis of isothermal processes may be inadequate when cyclic inelastic deformations are involved. The results show that the specific heat can decrease when the fatigue damage is high, causing a localized increase of the temperature even if the amount of heat generated is not so high and, hence, promoting a reduction in lifetime.