Experiments and numerical simulation of damage and fracture of the X0-specimen under non-proportional loading paths

Abstract

The paper deals with new non-proportional biaxial experiments and corresponding numerical simulations to analyze the load-history dependence on damage and fracture behavior of ductile metals. The numerical simulations are based on a phenomenological, thermodynamically consistent anisotropic continuum damage model considering the effect of stress triaxiality and Lode parameter on damage behavior. The model as well as the corresponding material parameter identification is discussed and a full set of material parameters is given. The new biaxial experiments take into account non-proportional and corresponding proportional loading paths with special focus on stress states changes from shear to tension dominated cases. The corresponding strain fields of critical regions of the X0-specimen have been analyzed by digital image correlation technique and indicate good accordance with the numerically predicted ones. The evolution of the calculated plastic and damage fields elucidate the relevance of both independent mechanisms. The results are supported by scanning electron microscopy images of the fracture surfaces. This experimental–numerical technique applied to the non-proportional biaxial experiments provides new insights of the stress and load-history dependent damage and fracture processes.