【摘要】 基于三维五向编织复合材料细观单胞模型,将材料内部、表面、棱角区域内具有相同走向的纤维束简化为单向复合材料,利用桥联模型,确定了单向复合材料的柔度矩阵,将具有不同材料主向的单向复合材料的刚度通过体积进行平均,得到了三维五向编织复合材料的总体刚度矩阵,进一步计算得到材料的工程弹性常数;以单向复合材料为基础,宏观上基于等应变假设,结合桥联模型,确定出材料内各组分(纤维束和基体)的细观应力分布,对纤维束采用Hoffman失效准则,基体采用Mises失效准则,预报了三维五向编织复合材料的拉伸强度。结果表明,三维五向编织复合材料的刚度和强度的预测值与实验值吻合较好,验证了本文分析模型的有效性。更多还原

【Abstract】 Based on unit cell model,the 3D five-directional braided composites can be simplified as unidirectional composites with differential local axial coordinate system and the flexibility matrix of unidirectional composites can be defined utilizing the bridge model.The total stiffness matrix of braided composites can be obtained by the volume averaged stiffness of unidirectional composites with differential local axial coordinate system and the engineering elastic constants of braided composites were computed further.Based on the iso-strain assumption and the bridge model,the stress distribution of fiber bundle and matrix of different unidirectional composites can be determined and the tensile strength of 3D five-directional braided composites were predicted based on the failure criterion of Hoffman for the fiber bundle and Mises for the matrix.The results show that the theoretical predictions of the stiffness and strength of 3D five-directional braided composites fit well with the experiment data,which demonstrates the validity of this model.更多还原