三维六向编织复合材料渐进损伤模拟及强度预测

基于三维六向编织复合材料的细观结构,假设第六向纱线的截面形状为菱形,建立了三维六向编织复合材料的渐进损伤有限元模型。采用Linde等提出的失效准则,引入周期性位移边界条件,对三维六向编织复合材料的纵向拉伸应力-应变行为进行了渐进损伤数值模拟,讨论了单胞模型在纵向拉伸载荷作用下的细观损伤起始、扩展和最终失效的演化过程,并预测了材料的拉伸强度。在此基础上,进一步研究了编织角、纤维体积分数和编织纱水平取向角等参数对材料纵向拉伸力学性能的影响规律。研究结果表明,三维六向编织复合材料的轴向纱线拉伸断裂是导致其破坏的最主要因素。所得数值结果与现有试验值吻合较好,验证了该模型的有效性,为更深入研究此类材料的力学性能奠定了基础。

Progressive damage simulation and strength prediction of three-dimensional and six-directional braided composites

Based on the meso-structure of three-dimensional and six-directional braided composites and assuming that the cross-section of weft yarn on the sixth direction was diamond, a representative volume element (RVE)-based micromechanical damage model was presented to predict the damage propagation and strength of three-dimensional and six-directional braided composites. The stress-strain relation of three-dimensional and six-directional braided composites was simulated by using failure criteria proposed by Linde and the periodicity boundary condition. The progressive damage of three-dimensional and six-directional braided composites was studied subjected to longitudinal tensile loading, and ultimate strength of the sample was obtained. Furthermore, the changing characteristics of mechanical properties with the material parameters of braided composites were discussed. The results show that the main factor to break the three-dimensional and six-directional braided composites is longitudinal tensile breakage of axial yarns, and the FEM results are in a good agreement with experimental data, which confirms the effectiveness of the model and provides a basis for the analysis of mechanical properties.