Low cycle fatigue analysis of ferrite-martensite dual-phase steel using advanced cyclic plasticity models

Abstract

A computational model has been developed to predict the low cycle fatigue (LCF) characteristics of ferrite-martensite dual phase (DP) steel. LCF results of DP steel performed at strain amplitudes varying from 0.3% to 1.5% show initial cyclic hardening followed by cyclic softening behavior. Finite element simulation employing Chaboche model fails to capture the initial cyclic hardening behavior specifically at lower strain amplitudes. To predict the observed cyclic hardening and softening characteristics of DP steel with a progressive number of cycles, Ohno-Wang cyclic plasticity model has been modified by altering the yield function, which is formulated by incorporating a memory stress function. All the material parameters have been calibrated considering hysteresis loop of the first cycle of LCF result of ± 1.5% uniaxial strain. The developed material model has been integrated with ABAQUS 6.14 finite element package to perform the LCF simulation. A comparison between simulation and experimental results for all strain amplitudes reveals that the proposed model has the better capability to predict the overall LCF characteristics of DP steel.