Coupling analysis of pattern formation in desiccation cracks
Coupling analysis of pattern formation in desiccation cracks
复制标题
DOI：
10.1016/j.cma.2016.04.029
复制
发表时间：
2016-08
影响因子：
7.2
通讯作者：
S. Hirobe;K. Oguni
中科院分区：
文献类型：
--
作者：
S. Hirobe;K. Oguni
干燥裂缝是粉末与水混合物在干燥过程中普遍存在的现象。这些裂缝具有网状结构，并将干燥表面细分为典型尺寸的多边形细胞。无论材料的选择和干燥过程中的微小细节如何，尽管可以观察到一些变化，但细胞的基本拓扑结构（即网状结构和多边形细胞）始终是保守的。这种稳定的、共同的干裂形态特征有力地说明了其背后存在着共同的调控机制。本文认为，干燥裂纹模式的形成是(1)由于干燥引起的体积分数变化，(2)不均匀体积收缩对应的变形场平衡，(3)裂纹形成三者耦合作用的结果。在此基础上，提出了一种干燥、变形和断裂的耦合模型，用于干燥裂纹模式的数值分析。本文采用有限元法（用扩散方程描述）和粒子离散化有限元法（PDS-FEM）对无缝变形和断裂进行了耦合分析。数值分析结果与实验观测结果在单元的基本拓扑结构和裂纹扩展的层次顺序上吻合较好。这些结果表明，所提出的方法抓住了干燥裂纹现象模式形成的基本控制机制。
Desiccation cracks are widely observed as a result of the drying process of the mixture of powder and water. These cracks have a net-like structure and tessellate the dry-out surface area into polygonal cells with typical size. Regardless of the choice of the materials and the minor details in the drying process, while some varieties can be observed, the basic topology of the cells (i.e., net-like structure and the polygonal cells) is persistently conserved. This stable and common feature in the desiccation crack patterns strongly suggests the existence of the common governing mechanism behind. In this paper, the pattern formation of desiccation cracks is regarded as the result of the coupling among (i) the change in water volume fraction due to desiccation, (ii) the equilibrium of deformation field corresponding to the inhomogeneous volume shrinkage, and (iii) the crack formation. Based on this assumption, a coupling model of desiccation, deformation, and fracture is proposed for the numerical analysis of the desiccation crack patterns. We perform the coupled analysis by using finite element method for the desiccation (described by the diffusion equation) and particle discretization scheme finite element method (PDS-FEM) for the seamless analysis of deformation and fracture. The results of the numerical analysis show satisfactory agreement with the experimental observation in terms of the basic topology of the cells and the hierarchical sequence of the crack propagation. These results indicate that the proposed approach captures the fundamental governing mechanism of the pattern formation of the desiccation crack phenomenon.