A damage coupled elasto-plastic constitutive model of marine high-strength steels under low cycle fatigue loadings

To investigate the low cycle fatigue (LCF) performance and damage behaviours of marine high strength steels (HSSs), experimental analysis and constitutive modelling are carried out in this study. Basic mechanical properties are obtained by the monotonic tensile tests. Cyclic loading tests with different loading protocols are conducted to examine the cyclic stress-strain response. Based on the experimental data, the evolutions of peak stress, yield surface radius, backstress and LCF damage are discussed. The Ramberg-Osgood model and MansonCoffin equation are fitted to characterize the cyclic stress-strain relation and LCF damage behaviours, respectively. Based on the continuum damage mechanics, a damage coupled cyclic elasto-plastic constitutive model is proposed to describe the hysteresis behaviours of marine HSSs. The model parameters are calibrated, and the model accuracy for stress-strain response and fatigue damage prediction is then verified by experimental data.