Influence of simple shear and void clustering on void coalescence
University of New Brunswick
The fracture of porous ductile materials subjected to simple shear loading is numerically investigated using three-dimensional unit cells containing voids of various shapes and lengths of the inter-void ligament. In shear loading, the porosity reduction is limited while the void rotates and elongates within the shear band. The strain at coalescence was revealed to be strongly related to the initial void spacing and void shape. Initially prolate voids are particularly prone to shear coalescence while initially oblate voids are most resistant to shear failure. To investigate the localization effect within three-void clusters during void coalescence, tensile tests and finite element simulations of drilled hole samples are performed by varying cluster orientations with respect to applied loading and hole spacing ratios. The experimental and numerical results revealed that material ductility is significantly decreased with increasing hole spacing ratios for certain cluster orientation. The existing coalescence models over estimate the coalescence strains for the considered three-void cluster.