A Rate-Dependent Damage Mechanics Model on Plasticity and Ductile Fracture Prediction of Automotive Steel Sheets

In this work, tensile tests were performed on H340 and DP1000 steel sheets at various strain rates and temperatures. The displacement, deformation and local strain fields of the specimens were measured using digital image correlation (DIC) techniques. Meanwhile, the temperature fields of specimen gauge section were measured with a high-speed thermal camera in the uniaxial tensile tests at different strain rates. Experimental results show that the strain rate and adiabatic temperature have significant effects on the deformation and fracture behavior of the investigated steels. Therefore, a user-defined plasticity and damage mechanics model was developed and calibrated based on the comprehensive effects of stress state, strain rate and temperature. The proposed rate-dependent model has been proven to be successful in predicting the deformation and fracture behavior of the investigated steel sheets at both laboratory and structure scales.