Ratcheting and fatigue behavior of Eurofer97 at high temperature, part 2: modeling

Abstract

A constitutive model is proposed for Reduced-Activation Ferritic-Martensitic (RAFM) steel Eurofer97 at high temperatures by combining formulae from previous modeling approaches to describe and predict mechanical behaviors under various cyclic loading conditions. Two failure modes, fatigue fracture and over-accumulated strain (ratcheting) are able to be simulated by the combined constitutive model. Cyclic softening and the effect of magnitude, symmetry and rate of external loading on ratcheting behavior are also able to be described by the new model. Parameter values are fitted based on strain-controlled and stress-controlled isothermal uniaxial experiments on Eurofer97 batch two at 450°C and 550°C. The simulated results are presented to compare with corresponding experimental data, to show the performance of the new constitutive model.