Damage evolution around shear loaded intervoid ligaments in plane strain and plane stress

Abstract

Damage evolution in two types of shear-dominant quasi-statically loaded specimens, with a single spherical pore embedded at their mid-gauge section, is analysed numerically. The evolving damage in those geometrically identical specimens is characterized using the Gurson-Tvergaard-Needleman (GTN) model accounting for nucleation and growth of porosity, and its extension for shear deformations following Nahshon and Hutchinson . We show that under shear-compression (SCS), the dominant damage mechanism in the pore surroundings consists of voids nucleation, followed by high shear deformations that increase the NH damage component. On the other hand, in the case of shear-tension (STS), damage accumulation by shear deformations (i.e. NH extension) appears to be negligible compared to the mechanism of void growth. A correlation is shown between the fracture surface of a test specimen and the numerical results shown here. It is suggested that the shear-compression-specimen (SCS) might be a good candidate for the calibration of the Nahshon-Hutchinson term as it was found to dominate over the growth component.