Geometry-dependency and plasticity are considered in the contact force models for the discrete element method simulations of elastic and elastoplastic fiber assemblies subject to uniaxial compression. It is observed that the contact force models have a significant impact on compressive loads. A simplified normal contact force model leads to smaller loads at large solid volume fractions compared to the experimental results, while the present geometry-dependent models give better predictions. Simulations with a simple Coulombic tangential contact force model (considering sliding friction only) significantly underestimate the loads, while a Mindlin tangential force model that considers static friction improves the predictions. For the modeling of the fibers that undergo large plastic deformations, plasticity should be considered for both the fiber bending and fiber–fiber normal contact in order to obtain correct simulation results. Elastic models for fiber–fiber contact and fiber bending deformation remarkably overpredict the loads for the plastic fibers.

中文翻译：

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弹性和弹塑性纤维组件的离散元方法模型

在接触力模型中考虑了几何相关性和塑性，用于对受单轴压缩的弹性和弹塑性纤维组件进行离散元方法模拟。据观察，接触力模型对压缩载荷有显着影响。与实验结果相比，简化的法向接触力模型在较大的固体体积分数下导致较小的载荷，而目前的几何相关模型给出了更好的预测。使用简单的库仑切向接触力模型（仅考虑滑动摩擦）进行的模拟显着低估了载荷，而考虑静摩擦的 Mindlin 切向力模型改进了预测。对于经历大塑性变形的纤维的建模，为了获得正确的模拟结果，纤维弯曲和纤维 - 纤维法向接触都应考虑塑性。纤维-纤维接触和纤维弯曲变形的弹性模型显着高估了塑料纤维的载荷。