Interaction of low-cycle fatigue and creep in nonisothermal loading

Abstract

The elements of thermally stressed structures operating at high temperatures are frequently subjected to the action of cyclic mechanical loads and temperatures changing with time according to complex rules. Since the length of a load cycle may be from several seconds to tens of hours, in many cases alternating-sign elastoplastic deformation is accompanied by temperature-time phenomena and creep. Creep deformations may develop both during hold under load and in steady loading or unloading at a quite low rate. The presence of creep deformations in the cycle has a definite influence on the mechanism of low-cycle failure and the life of the material, and the form of the load cycle and the asymmetry and sign of the stresses on the background of which the creep deformations develop are important factors.