Desiccation cracking of soil-like materials is a common phenomenon in natural dry environment, however, it remains a challenge to model and simulate complicated multi-physical processes inside the porous structure. With the goal of tracking such physical evolution accurately, we propose an MPM based method to simulate volumetric shrinkage and crack during moisture diffusion. At the physical level, we introduce Richards equations to evolve the dynamic moisture field to model evaporation and diffusion in unsaturated soils, with which a elastoplastic model is established to simulate strength changes and volumetric shrinkage via a novel saturation-based hardening strategy during plastic treatment. At the algorithmic level, we develop an MPM-fashion numerical solver for the proposed physical model and achieve stable yet efficient simulation towards delicate deformation and fracture. At the geometric level, we propose a correlating stretching criteria and a saturation-aware extrapolation scheme to extend existing surface reconstruction for MPM, producing visual compelling soil appearance. Finally, we manifest realistic simulation results based on the proposed method with several challenging scenarios, which demonstrates usability and efficiency of our method.

中文翻译：

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非饱和土壤中 MPM 驱动的动态干燥开裂和卷曲

类土材料的干燥开裂是自然干燥环境中的普遍现象，然而，对多孔结构内部复杂的多物理过程进行建模和模拟仍然是一个挑战。为了准确跟踪这种物理演变，我们提出了一种基于 MPM 的方法来模拟水分扩散过程中的体积收缩和裂纹。在物理层面，我们引入理查兹方程来演化动态水分场来模拟非饱和土壤中的蒸发和扩散，并建立弹塑性模型，通过塑性处理过程中一种新的基于饱和度的硬化策略来模拟强度变化和体积收缩。在算法层面，我们为所提出的物理模型开发了一个 MPM-fashion 数值求解器，并实现了对微妙变形和断裂的稳定而有效的模拟。在几何层面，我们提出了一个相关的拉伸标准和一个饱和度感知外推方案来扩展 MPM 的现有表面重建，产生视觉上引人注目的土壤外观。最后，我们基于所提出的方法在几个具有挑战性的场景中展示了真实的模拟结果，这证明了我们方法的可用性和效率。