Short crack growth based procedures to assess fatigue life of components subjected to thermal cyclic loading.

The results of three different fatigue lifetime assessment procedures are compared for the study case of a thick-walled pipe made of stainless austenitic steel (German stabilized austenite 1.4550) and subjected to thermal cyclic loading. In detail, calculated fatigue lifetime according to the damage parameters D_TMF [1] and P_J [2] on one hand and code conforming fatigue analysis using ASME Section III, Division 1, NB 3000 [3] on the other hand are contrasted. Herein, the damage parameter D_TMF is a generalization of the D_CF parameter according to Riedel. It is a measure of the damaging effect of an arbitrary non-isothermal loading cycle. Like the damage parameter P_J it uses an approximation formula for the determination of the effective cyclic J-integral. D_TMF and P_J are used to describe the fatigue process in terms of short crack growth