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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。
Based on the mesostructure of the three-dimensional six-directional braided composites, the progressive damage model of three-dimensional six-directional braided composites was established assuming that the cross-sectional shape of the sixth direction yarn was rhombus. By using the failure criteria proposed by Linde et al., The periodic displacement boundary conditions are introduced to simulate the progressive damage of the longitudinal tensile stress-strain behavior of three-dimensional six-directional braided composites. The effects of the unit cell model under longitudinal tensile load The evolution of mesoscopic damage initiation, propagation and eventual failure was predicted and the tensile strength of the material was predicted. On this basis, further study of the impact of braid angle, fiber volume fraction and the horizontal orientation angle of braided yarn on the longitudinal tensile mechanical properties of the material. The results show that the three-dimensional six-directional braided composite axial tensile fracture is the most important factor leading to its destruction. The obtained numerical results are in good agreement with the existing experimental values, which verify the validity of the model and lay a foundation for further study on the mechanical properties of such materials.