Significance of Creep-Fatigue Interactions in Strctural Integrity Assessment

Creep-fatigue interaction is a special phenomena that have a detrimental effect on the performance of metal parts of components operating at elevated temperatures. This paper deals with the simultaneous interactions between creep and fatigue. The effect of hold time, hold position, temperature and creep ductility on creep-fatigue interaction life and damage modes of several high temperature alloys are presented in detail. The inherent deficiencies and potentially serious consequences of over-or under- design by using the classical Linear Time and Cycle-Fraction rule for predicting structural durability under high temperature creep-fatigue conditions are presented. The potential of a strain based approach in accurately predicting creep-fatigue life for ensuring
structural integrity is outlined.