Peridynamics Modeling of a Shock Wave Perturbation Decay Experiment in Granular Materials with Intra-granular Fracture

The shock wave perturbation decay experiment is a technique in which the evolution of a perturbation in a shock wave front is monitored as it propagates through a material field. This tool has recently been explored to probe the high-rate shear response of granular materials. This dynamic behavior is complicated due to inter- and intra-granular phenomena involved. Mesoscale modeling can give insight into this complexity by explicitly resolving the interactions and deformation of individual grains. The peridynamic theory, which is a nonlocal continuum theory, provides a suitable framework for modeling dynamic problems involving fracture. Prior research has focused mostly on the continuum, bulk response, neglecting any localized material failure, of granular materials. A systematic investigation of the effects of grain fracture and frictional contact forces between grains on the continuum behavior of granular materials is carried out by peridynamic simulations of a shock wave perturbation decay experiment. A sensitivity assessment of dominant factors indicates that grain fracture, a phenomenon ignored in most computational investigations of granular materials, plays a large role in the bulk dynamic response. Our results show that the wave propagates faster with an increase in the toughness of the material and the inter-particle friction. Also, the shock amplitude is shown to decay faster in tougher materials. It is further confirmed that under strong compression self-contact among fractured grain sub-particles cannot be neglected.