A generic energy‐conserving linear normal contact model for concave particles in the discrete element method (DEM) is presented in this article. It is derived based on a recently enhanced general energy‐conserving contact theory for arbitrarily shaped particles. A set of more effective evaluation schemes required in the model are also given, which shows that only the intersection boundary between two contact shapes, instead of their contact region or surfaces, is required to be explicitly obtained, thereby substantially improving both efficiency and applicability of the proposed contact model over the previous version. A surface triangular mesh is used to represent any 3D concave particle. The computational issues associated with the contact of two surface triangulated 3D shapes, including the contact detection, the determination of intersection boundary segments, the computation of contact features and parallelization, critical time step, and friction and damping treatment for multiple contacts are described in detail. Two sets of numerical examples involving various concave 3D shapes with a large number of surface triangles are presented to demonstrate either the superb energy‐conserving property of the proposed model model, or its effectiveness, robustness, and universal nature for wider and more complex problems.

中文翻译：

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表面三角形网格代表的凹形颗粒的通用节能离散元建模策略

本文介绍了一种离散粒子方法（DEM）中的一般的凹形颗粒能量守恒线性法线接触模型。它是基于最近增强的任意形状颗粒的通用节能接触理论得出的。还给出了模型中需要的一组更有效的评估方案，该方案表明，仅需要明确获得两个接触形状之间的交点边界，而不是它们的接触区域或表面，从而显着提高了效率和适用性。与先前版本相比建议的联系模型。表面三角形网格用于表示任何3D凹面粒子。与两个表面三角3D形状的接触相关的计算问题，包括接触检测，详细描述了相交边界段的确定，接触特征和并行度的计算，关键时间步长以及多个接触的摩擦和阻尼处理。给出了两组涉及各种具有大量表面三角形的凹面3D形状的数值示例，以说明所提议模型模型的出色节能特性，或其有效性，鲁棒性和更广泛，更复杂问题的通用性。