Soft particle materials such as some pharmaceutical and food products are composed of particles that can undergo large deformations under low confining pressures without rupture. The rheological and textural properties of these materials are thus governed by both particle rearrangements and particle shape changes. For the simulation of soft particle materials, we present a numerical technique based on the material point method, allowing for large elasto-plastic particle deformations. Coupling the latter with the contact dynamics method makes it possible to deal with contact interactions between particles. We investigate the compaction of assemblies of elastic and plastic particles. For plastic deformations, it is observed that the applied stress needed to achieve high packing fraction is lower when plastic hardening is small. Moreover, predictive models, relating stress and packing fraction, are proposed for the compaction of elastic and plastic particles. These models fit well our simulation results. Furthermore, it is found that the evolution of the coordination number follows a power law as a function of the packing fraction beyond jamming point of hard particle packings.

软颗粒材料（例如某些药品和食品）由可在低围压下发生大变形而不会破裂的颗粒组成。因此，这些材料的流变学和质地特性受颗粒重排和颗粒形状变化的支配。对于软颗粒材料的模拟，我们提出了一种基于材料点方法的数值技术，该方法允许较大的弹塑性颗粒变形。后者与接触动力学方法的耦合使处理粒子之间的接触相互作用成为可能。我们研究了弹性和塑料颗粒组件的压实。对于塑性变形，观察到，当塑性硬化较小时，实现高填充率所需的外加应力较低。而且，提出了有关应力和堆积率的预测模型，用于压缩弹性和塑料颗粒。这些模型非常适合我们的仿真结果。此外，发现配位数的演变遵循幂定律，作为超过硬质颗粒堆积物的堵塞点的堆积率的函数。