含缺陷C/SiC平纹机织复合材料拉伸力学行为数值模拟

采用APDL语言实现ANSYS的二次开发,建立含预制缺陷的纤维束截面卵圆形多尺度单胞模型。首先计算纤维束单胞的初始模量,强度以及最大应变;随后利用扫描电镜图中的缺陷建立单胞模型,并引入周期性边界条件,预测材料的初始各向材料常数。同时利用Linde提出的逐渐损伤准则,进行单轴拉伸力学行为的数值模拟,并阐述该平纹机织复合材料单胞模型在经向拉伸载荷作用下其纤维束的损伤及演化过程。该模型计算得到的最大拉应度为0.65%,强度为256.46 MPa。结果表明,该模型给出的数值模拟结果与实验数据吻合较好,证明了模型的有效性,为该类材料的优化设计及其力学性能分析提供了一种有效方法。

Numerical Simulation of C/SiC Plain Weave Composites withDefects under Unidirectional Tension

The second time develop of the ANSYS was realized by using APDL language, and an ovoid sectional multi-scale unit cell model for fiber bundle section with pre-made defects was established.At first the initial modulus, the strength and the ultimate strain of fiber bundle were calculated.Then the unit cell model of C/SiC woven composites was established according to the SEM photographs.By introducing the periodic boundary conditions, the initial anisotropic constants of C/SiC woven composites were predicted.The failure criteria proposed by Linde was utilized to set up the progressive damage mode,and the C/SiC plain weave composites with defects under unidirectional tension was simulated.So,the damage evolution process of the fiber bundle could be interpreted, when the unit cell of C/SiC plain weave composites was under the unidirection load.The numerical results show that the proposed model accurately captures the data from the experiments, which demonstrates the validity of the present analytical model.Furthermore, the numerical model provides an alternate way to design and predict the mechanical properties of plain weave composites.