Energy-tracking impulse method for particle-discretized rigid-body simulations with frictional contact

Simulations of multi-body dynamics for computer graphics, 3D game engines, or engineering simulations often involve contact and articulated connections to produce plausible results. Multi-body dynamics simulations generally require accurate contact detection and induce high computational costs because of tiny time increments. As higher accuracy and robustness are continually being sought for engineering purposes, we propose an improved multi-body dynamics simulator based on an impulse method, specifically an energy-tracking impulse (ETI) algorithm that has been modified to handle particle-discretized rigid-body simulations. In order to decrease the computational costs of the simulations, in the current work, we assume a fixed moderate time increment, allowing multiple-point contacts within a single time increment. In addition to that, we distinguish the treatment between point-to-point and multiple-point contacts, which include edge-to-surface and surface-to-surface contacts, through an additional sub-cycling iterations. The improved ETI method was verified with analytical solutions of examples with single-body contact, a frictional slip, and a rolling contact. Moreover, the method was also validated with an experimental test of a line of dominoes with multiple-point contacts. Finally, a demonstration simulation with bodies of complicated shape subjected to a large number of constraints is given to show the optimum performance of the formulation.