Plastic and damage behaviour of a high strength X100 pipeline steel: Experiments and modelling

The purpose of this work is to develop a constitutive model integrating anisotropic behaviour and ductile damage for a X100 pipeline steel. The model is based on a set of experiments on various smooth, notched and cracked specimens and on a careful fractographic examination of the damage mechanisms. The model is based on an extension of the Gurson–Tvergaard–Needleman model which includes plastic anisotropy. Provided brittle delamination is not triggered, the developed model can accurately describe the plastic and damage behaviour of the material. The model is then used as a numerical tool to investigate the effect of plastic anisotropy and delamination on ductile crack extension. It is shown in particular that it is not possible to obtain a unified description of rupture properties for notched and cracked specimens tested along different directions without accounting for plastic anisotropy.