Abstract We present a thermal–mechanical–chemical-phase field model that captures the multi-physical coupling effects of precipitation creeping, crystal plasticity, anisotropic fracture, and crack healing in polycrystalline rock at various temperature and strain-rate regimes. This model is solved via a fast Fourier transfer solver with an operator-split algorithm to update displacement, temperature and phase field, and chemical concentration incrementally. In nuclear waste disposal in salt formation, brine inside the crystal salt may migrate along the grain boundary and cracks due to the gradient of interfacial energy and pressure. This migration has a significant implication on the permeability evolution, creep deformation, and crack healing within rock salt but is difficult to incorporate implicitly via effective medium theories compared with computational homogenization. As such, we introduce a thermodynamic framework and a corresponding computational implementation that explicitly captures the brine diffusion along the grain boundary and crack at the grain scale. Meanwhile, the anisotropic fracture and healing are captured via a high-order phase field that represents the regularized crack region in which a newly derived non-monotonic driving force is used to capture the fracture and healing due to the solution–precipitation. Numerical examples are presented to demonstrate the capacity of the thermodynamic framework to capture the multiphysics material behaviors of rock salt.

中文翻译：

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结晶岩的计算热力学。第二部分：强各向异性多晶的化学损伤可塑性和愈合

摘要 我们提出了一种热-机械-化学相场模型，该模型捕捉了多晶岩在不同温度和应变率状态下的沉淀蠕变、晶体塑性、各向异性断裂和裂缝愈合的多物理耦合效应。该模型是通过快速傅立叶传递求解器求解的，该求解器采用算子分裂算法以递增方式更新位移、温度和相场以及化学浓度。在成盐核废料处理中，结晶盐中的卤水可能由于界面能和压力的梯度沿晶界和裂缝迁移。这种迁移对渗透率演化、蠕变变形、和岩盐中的裂缝愈合，但与计算均质化相比，很难通过有效的介质理论隐含地合并。因此，我们引入了一个热力学框架和相应的计算实现，它们明确地捕获了沿晶界的盐水扩散和晶粒尺度上的裂纹。同时，各向异性断裂和愈合是通过代表正则化裂纹区域的高阶相场来捕获的，其中使用新导出的非单调驱动力来捕获由于溶液-沉淀引起的断裂和愈合。数值例子展示了热力学框架捕捉岩盐多物理场材料行为的能力。我们引入了一个热力学框架和一个相应的计算实现，它明确地捕获了沿晶界的盐水扩散和晶粒尺度上的裂纹。同时，各向异性断裂和愈合是通过代表正则化裂纹区域的高阶相场来捕获的，其中使用新导出的非单调驱动力来捕获由于溶液-沉淀引起的断裂和愈合。数值例子展示了热力学框架捕捉岩盐多物理场材料行为的能力。我们引入了一个热力学框架和一个相应的计算实现，它明确地捕获了沿晶界的盐水扩散和晶粒尺度上的裂纹。同时，各向异性断裂和愈合是通过代表正则化裂纹区域的高阶相场来捕获的，其中使用新导出的非单调驱动力来捕获由于溶液-沉淀引起的断裂和愈合。数值例子展示了热力学框架捕捉岩盐多物理场材料行为的能力。各向异性断裂和愈合是通过代表正则化裂纹区域的高阶相场捕获的，其中使用新导出的非单调驱动力来捕获由于溶液-沉淀引起的断裂和愈合。数值例子展示了热力学框架捕捉岩盐多物理场材料行为的能力。各向异性断裂和愈合是通过代表正则化裂纹区域的高阶相场捕获的，其中使用新导出的非单调驱动力来捕获由于溶液-沉淀引起的断裂和愈合。数值例子展示了热力学框架捕捉岩盐多物理场材料行为的能力。