Biaxial experiments and numerical analyses on damage prediction in metal forming processes

Abstract

The paper discusses an anisotropic continuum damage and failure model for ductile metals. The phenomenological approach is based on kinematic definition of damage tensors and takes into account the effect of stress state on damage conditions and damage strain evolution laws. Different branches of these criteria based on experimental studies and numerical simulations are considered corresponding to various microscopic damage and fracture mechanisms depending on stress intensity, stress triaxiality and the Lode parameter. Experiments with biaxially loaded specimens and corresponding numerical simulations have been performed showing that they cover a wide range of stress states in combined tension, shear and compression regimes. Digital image correlation technique has been used to analyze current strain states in critical regions of the specimens. Damage behavior for shear-compression loading conditions appearing in metal forming processes is discussed in detail.