通过对平纹织物复合材料的横向拉压试验,分析了产生各种破坏现象的微观机理。横向压缩过程中,在与水平面成45°方向剪切破坏的同时还出现层间裂纹。由于两个方向上纱线的弯曲程度不同,破坏形式有很大差异,不同自由边处的纱线界面存在不同程度的剪切破坏,并表现出不同的边缘效应。借助显微镜观察和基于代表体积单元的数值模拟对这些现象进行了分析,发现高度不均匀的内部波纹纱线结构在横向压缩下产生的层间剪切应力是出现横向裂纹的主要原因。
The breakage micro-mechanism of plain-woven fiber reinforced composite materials was studied by means of transverse compressive and tensile experiments. It is observed that the shear damage along 45° with the fill strand occurs together with interlaminar cracks during the process of transverse compression. The damage forms of warp strand and fill strand are different because of the curve diversity, and the strand interfaces and laminar interfaces at free-edges show different shear failures. The differences among failure models are due to the different bending shapes of strands. These phenomena were analysed through microscope observation and numerical simulation. Some possible reasons were given to explain these failure forms. The main reason may be that the interlaminar shear stress is induced by highly anomalous strand structure under transverse compression.