复合材料中纱束的几何形态

在预测三维机织复合材料力学性能时, 将纱线特别是纬纱横截面假设成何种形状一直众说纷纭。本文中假设纬纱截面形状分别为圆形、 跑道形、 凸透镜形、 矩形, 经纱横截面形状为矩形, 采用刚度平均法和等应变力学模型计算了4种角联锁结构复合材料的弹性模量, 经与复合材料的数字图像对比分析和实验验证表明, 圆形纬纱截面形状假设与数字图像相差较大, 与其它截面形状假设的弹性模量预测结果相差也较大, 跑道形、 凸透镜形、 矩形等纬纱截面形状假设彼此间弹性模量预测结果的差异很小, 与实验数据也具有较好的一致性。

Geometry configuration of yarn in composite materials

The suppositions of the cross-section shape of yarns, especially weft yarns, in composite materials are different when predicting mechanical properties of three dimensional woven reinforced composite materials. The roundness, raceway, convex and rectangle shapes were assumed as the cross-section of weft yarns while the rectangle shape was assumed as the cross-section of warp yarns. In this paper, the elastic modulus was predicted for four different angle-interlock structural composite materials using the stiffness averaging method and the iso-strain mechanical model. Contrasting with digital photos of the composite materials and with experimental results of the elastic modulus, the result shows that the roundness assumption of weft yarn cross-sections is far inaccurate and the predicting result of elastic modulus under the condition of the roundness assumption is much smaller. There is little difference in the predicting results of elastic modulus between raceway, convex and rectangle cross-sections of the weft yam assumptions and the predicting results are in better agreement with the experiment results of the elastic modulus.