Modeling continuous grain crushing in granular media: A hybrid peridynamics and physics engine approach

Numerical modeling of crushable granular materials is a challenging but important topic across many disciplines of science and engineering. Commonly adopted modeling techniques, such as those based on discrete element method, often over-simplify the complex physical processes of particle breakage and remain a far cry from being adequately rigorous and efficient. In this paper we propose a novel, hybrid computational framework combining peridynamics with a physics engine to simulate crushable granular materials under mechanical loadings. Within such framework, the breakage of individual particles is analyzed and simulated by peridynamics, whilst the rigid body motion of particles and inter-particle interactions are modeled by the physics engine based on a non-smooth contact dynamics approach. The hybrid framework enables rigorous modeling of particle breakage and allows reasonable simulation of irregular particle shapes during the continuous breakage process, overcoming a glorious drawback/challenge faced by many existing methods. We further demonstrate the predictive capability of the proposed method by a simulation of one-dimensional compression on crushable sand, where Weibull statistical distribution on the particle strength is implemented. The simulation results exhibit reasonable agreement with experimental observations with respect to normal compression line, particle size distribution, fractal dimension, as well as particle morphology. The presented work provides a rigorous and efficient way to study the complex process of particle breakage in granular media, and offers future opportunities to examine micro-structural behaviors of crushable granular materials. (C) 2019 Elsevier B.V. All rights reserved.