Ductile tearing of pipeline-steel wide plates: II. Modeling of in-plane crack propagation

Abstract The purpose of this work is to develop a finite element simulation of static ductile tearing tests carried out on pipeline-steel wide plates. Experiments have been presented in a companion paper (Part I [1] ). The simulation is based on an extension of the Gurson–Tvergaard–Needleman model which includes plastic anisotropy and viscoplasticity effects. The parameters of the model are fitted using tensile specimens (smooth and notched bars). Simulated tests are used to evaluate macroscopic fracture parameters which were experimentally measured: the energy dissipation rate R and the thickness reduction Z. The simulation tool is then used to numerically investigate the effect of plate thickness, plastic anisotropy and through-thickness hardness gradients on the crack growth resistance. It is shown that with increasing thickness, the energy dissipation rate first increases and then decreases. A through-thickness hardness gradient is beneficial when the surface is harder than the bulk. Plastic anisotropy can be either detrimental or beneficial depending on the loading direction. These effects are explained in terms of plastic localization inducing necking along the crack path and in terms of stress distribution.