三维四向编织复合材料有效性能的预报

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, 建立了比较合理的三胞模型。模型中考虑了3种单胞各自纤维束的空间结构和弯曲, 同时引入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。基于刚度体平均方法, 建立了相应的刚度预报模型, 得到了三维四向编织复合材料的工程弹性常数。用细观力学方法分析了工艺参数和尺寸效应对材料有效性能的影响规律。不同尺寸试件的数值预报结果和实验结果吻合较好。

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

A relatively reasonable three-cell model for 3D 4-directional braided composites is proposed based on the geometrical characteristic of the yarns. The variation of bending characteristics for the yarns in a three-cell was considered in the present model. The fill factor was proposed to distinguish the different cross-sectional variations of the yarns in the three cells. The model to predict stiffness was then established based on the stiffness volume average method. The elasticity constants of the material were obtained. The effects of the processing parameters and the dimension of the structure on the effective elastic properties of the composite were also studied by the meso-mechanical method. The numerical examples of the structure with different dimensions calculated by the model show that the theoretical predictions compare well with experimental results.