含孔隙缺陷三维五向编织复合材料偏轴拉伸力学性能分析

针对孔隙缺陷对材料力学性能的重要影响，在材料细观模型中引入随机分布的孔隙缺陷，研究了含孔隙缺陷三维五向编织复合材料的偏轴拉伸力学性能。基于2种典型编织角试件，讨论了孔隙率对材料正轴力学性能的影响，通过与实验数据对比，确定了材料的孔隙率。结合周期性边界条件施加偏轴拉伸载荷，获取了不同偏轴角度下材料的应力-应变曲线，并预测了材料的强度性能。模拟了典型偏轴角度下材料的细观损伤起始、演化过程，分析了材料的失效机理，为其他复合材料结构孔隙缺陷问题及偏轴载荷问题数值分析提供了一定的参考。 

Off-axis tensile mechanical properties of 3D five-directional braided composites with void defects

In view of the important influence of void defects on the mechanical properties of materials, the off-axis tensile mechanical properties of 3D five-directional braided composites with voids are studied by introducing randomly distributed void defects into the meso-scale model of material. For two specimens with typical braided angles, the effect of void contents on the on-axis mechanical properties was discussed and the appropriate void contents were determined by comparing with the available experimental data. Based on the periodic boundary conditions, the off-axis load was applied to obtain the stress-strain curves of the material under different off-axis angles and the strength properties were thus predicted. The meso-scale damage initiation and evolution processes of the composites under typical off-axis angles were simulated and the failure mechanism was analyzed in detail, which provides a proper reference for the numerical analysis of void defects and off-axis loading problems of other composite structures.