Simulating shearing behavior of realistic granular soils using physics engine

The discrete element method (DEM) has become a preeminent numerical tool for investigating the mechanical behavior of granular soils. However, traditional DEM uses sphere clusters to approximate soil particles, which is not efficient in simulating realistic particles. This paper demonstrates the potential of using a physics engine technique to address limitations of the DEM method. Physics engines are originally developed for video games for simulating physical and mechanical processes that occur in the real world to create an immersive and realistic gaming experience. Physics engines use triangular face tesselations to represent objectives, which provides higher accuracy for modeling realistic particle geometries. This paper has three objectives. First, this paper introduces the physics engine technique to the geotechnical community. Second, this paper develops a series of pre-processing, servo-controlling, and post-processing functions embedded into physics engine to generate soil specimens with designed packing densities, perform direct shear tests, and output simulation results including stress–strain relations, fabrics, and force chains. Third, this paper develops a miniature direct shear test that can be scanned by X-ray computed tomography (X-ray CT) for evaluating the simulation accuracy of the physics engine. The numerical results agree well with experimental results. This study provides DEM modelers with physics engine as one more option for simulating realistic particles.