Numerical prediction of thermal aging and cyclic loading effects on fracture toughness of cast stainless steel CF8A: Experimental and numerical study

Abstract

This paper presents a FE simulation method to predict the thermal aging effect on fracture behavior of cast stainless steel CF8A under monotonic and very low-cyclic fatigue loading conditions. A multi-axial fracture strain energy damage model is determined from tensile and C(T) test data of un-aged CF8A under the monotonic loading condition. To simulate fracture behavior of aged CF8A, the multi-axial fracture strain energy of aged CF8A is obtained by multiplying the thermal aging constant determined from tensile test data by the multi-axial fracture strain energy of the unaged CF8A. The model is then extended to predict fracture behaviours of unaged and aged CF8A under fully-reversed cyclic loading. For the damage model, the model determined for the monotonic loading is applied to simulate fracture behavior under cyclic loa ding, based on the assumption that fracture energy is not dependent on the loading mode. It is shown that simulation results can capture the thermal aging effect on fracture behavior under monotonic and cyclic loading well.