纺织复合材料细观力学分析的一般性周期性边界条件及其有限元实现

摘要

针对纺织复合材料细观有限元分析中单胞网格的快速生成与顺利施加周期性边界条件之间的矛盾,提出了非周期性网格划分条件下,一般性周期性边界条件的数学表达形式.基于ABAQUS有限元软件平台,通过在单胞模型的相对面、相对边及相对角点施加多点约束(MPC)方程,实现了一般性周期性边界条件的施加.结合三维四向编织复合材料单胞模型,对比分析了周期性网格划分和非周期性网格划分情况下,单胞模型受载下的变形状态、应力分布及弹性性能的预测结果,验证了一般性周期性边界条件的正确性和有效性.研究表明:一般性周期性边界条件可以实现复杂细观结构单胞模型的自由网格划分,降低网格划分的难度,提高网格生成的质量.%In order to resolve the conflict between the quick mesh generation of a unit-cell and the successful application of the periodic boundary conditions,a more general method is developed in the micromechanical finite element analysis of textile composites with an aperiodic mesh.The application of the general periodic boundary conditions is realized by enforcing multi-point constraints (MPC) on the corresponding nodes on paired faces,edges and corners of the unit-cell on the platform of ABAQUS software.The deformation,stress distribution and the predicted mechanical properties of 3D four-directional braided composites are compared between the unit-cell models with periodic and aperiodic mesh,thus verifying the validity and applicability of the proposed boundary conditions.The results show that the general periodic boundary conditions can achieve the free meshing of unit-cells with complicated microstructures,reduce the difficulty of meshing and improve the quality of mesh generation.