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中文核心期刊

基于各向异性断裂相场模型的自适应多尺度有限元方法

ADAPTIVE MULTISCALE FINITE ELEMENT METHOD BASED ON ANISOTROPIC FRACTURE PHASE FIELD MODEL

  • 摘要: 纤维增强复合材料具有复杂的断裂模式, 各向异性断裂相场模型可以自动捕捉裂纹的萌生和演化, 适于模拟纤维增强复合材料的断裂失效行为, 但其计算成本较高. 为了提高相场模型的计算效率, 基于自适应网格算法和扩展的多尺度有限元方法, 本文提出了一种针对各向异性断裂相场模型的自适应多尺度有限元方法. 自适应网格算法会根据每一步迭代结束后网格节点上的相场变量及其增量确定裂纹路径, 并自动细化裂纹路径附近的网格. 断裂相场模型通过交错迭代算法进行求解, 在更新位移场时, 被细化的网格使用传统的有限元方法, 未细化的网格使用考虑了振荡边界条件的扩展的多尺度有限元方法. 更新相场时, 均使用传统的有限元单元. 在粗细两种单元的界面上, 利用多尺度有限元方法的数值基函数对界面上的节点进行约束. 利用建立的模型分别对在拉伸载荷下不同铺层角以及变刚度的纤维增强复合材料单层板的断裂行为进行分析. 数值结果表明: 本文提出的模型能够准确地捕捉裂纹路径, 并且得到的数值结果与现有文献和试验结果吻合良好, 与传统有限元相场模型相比, 在保证计算精度的同时, 能够显著减少计算时间.

     

    Abstract: The fiber reinforced composites have complex fracture modes. The anisotropic fracture phase field model can automatically capture the initiation and evolution of cracks, which is suitable for simulating the failure behavior of fiber reinforced composite materials. However, it is computationally expensive. In order to improve the computational efficiency of the anisotropic fracture phase field model, an adaptive multiscale finite element method for the anisotropic fracture phase field model is proposed in this paper. The adaptive mesh algorithm and the extended multiscale finite element method are adopted in the proposed model. Based on the calculational results at the end of each iteration step, the adaptive mesh algorithm determines the crack paths according to the phase field variables and their increments at the mesh nodes. Meanwhile, the algorithm can automatically refine the mesh near the crack path. The fracture phase field model is solved by a staggered iteration algorithm. When updating the displacement field, the refined meshes use the traditional finite element method, while the non-refined meshes use a multiscale finite element method by considering the oscillating boundary conditions. When updating the phase field, all meshes use the traditional finite element method. At the interface between the coarse and fine elements, the numerical basis functions obtained from the multiscale finite element method are employed to constrain the nodes at the interface. The proposed model is applied to analyze the fracture failure behavior of fiber reinforced composite plates with different lay-up angles and variable stiffness under tensile loading. Numerical results demonstrate that the proposed model can accurately capture the crack paths. In addition, the numerical results obtained by the proposed model are in good agreement with the existing models and experimental results. Compared to the traditional finite element phase field model, the computational time of this model is reduced obviously with the same computational accuracy.

     

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