三维四向编织复合材料的弹性性能预测研究

根据三维四向编织复合材料中纤维束的空间几何结构特征,提出了改进的三细胞模型,该模型包含内部单胞、两种表面单胞以及棱角单胞四类结构,考虑了各类单胞中纤维束的空间结构,并引入平均纤维束填充因子来描述各类单胞中纤维束的不同截面形状对材料弹性常数的影响.基于刚度平均化方法建立了相应的刚度预测模型.得到了三维四向编织复合材料的工程弹性常数.与实验结果的对比表明,计算结果的预测精度较好.最后讨论了编织角和纤维体积分数对材料等效弹性性能的影响.

Evaluation of elastic properties of 3-D 4-direction braided composites

An improved three-cell model,which includes interior cells,two kinds of surface cells and corner cells,was proposed based on the geometrical characteristic of the yarns for 3-D 4-directional braided composite.The variation of characteristics for the yarns in the cells was considered in the present model.The average yarn packing factor was proposed to distinguish the different cross-sectional variations of the yarns in different cells.Based on this model,the stiffness prediction model was established with the method of stiffness averaging.By comparing with the available experimental data,it shows the applicability of the present model.At last,the influence of the braiding angle and the fiber volume fraction is discussed.