Microvoid Damage Model with Material Dilation for Ductile Fracture

Abstract

A constitutive model that incorporates material dilation and the concept of continuum damage mechanics is developed to predict ductile fracture of steel under monotonic quasi-static loading due to microvoids. In this model, damage is assumed to be isotropic and is a function of the state of stress and the plastic strain increment. Material dilation is assumed to vary with the state of damage. Fracture occurs when the damage limit is reached. Parameters for the model are calibrated using data obtained from tension coupon tests. The constitutive model and the process used to determine its parameters are described. Analyses have been carried out to illustrate the effect of incorporating material dilation. The model is able to closely predict the load versus deformation curve of the tension test. Additional test data required for verifying the model have also been outlined.