Contact models that simulate rotational resistance at particle contacts have been proposed as a means to capture the effect of shape in DEM simulations. This contribution critically explores some key issues related to the implementation of rotational resistance models; these include the need for physically meaningful model parameters, the impact of the model on the overall numerical stability/critical time increment for the DEM model, model validation, and the assessment of model performance relative to real physical materials. The discussion is centred around a rotational resistance model that captures the resistance provided by interlocking asperities on the particle surface. An expression for the maximum permissible integration time step to ensure numerical stability is derived for DEM simulations when rotational resistance is incorporated. Analytical solutions for some single-contact scenarios are derived for model validation. The ability of this type of model to provide additional fundamental insight into granular material behaviour is demonstrated using particle-scale analysis of triaxial compression simulations to examine the roles that contact rolling and sliding have on the stability of strong force chains.

已经提出了模拟粒子接触处的旋转阻力的接触模型，作为在DEM模拟中捕获形状影响的一种方法。这一贡献批判性地探索了与旋转阻力模型的实施有关的一些关键问题；其中包括对物理上有意义的模型参数的需求，模型对DEM模型的整体数值稳定性/关键时间增量的影响，模型验证以及相对于实际物理材料的模型性能评估。讨论围绕旋转阻力模型进行，该模型捕获了由粒子表面上的凹凸不平互锁提供的阻力。当结合了旋转阻力时，可为DEM仿真得出最大允许积分时间步长的表达式，以确保数值稳定性。推导了一些单接触方案的分析解决方案，以进行模型验证。通过使用三轴压缩模拟的粒子尺度分析来检验接触滚动和滑动对强力链的稳定性所起的作用，证明了这种类型的模型能够提供有关颗粒材料行为的其他基本信息的能力。