计及界面损伤的割口正交叠层板的拉伸破坏

TENSILE FAILURE OF NOTCHED CROSS-PLY LAMINATES TAKING INTO ACCOUNT THE INTERFACIAL DAMAGE

基于剪滞理论,建立了一种计及界面损伤的分层剪滞模型,分析了含割口的正交叠层板在拉伸荷载作用下的应力重新分布问题,据此可求得界面损伤区长度和割口前缘完整纤维的应力集中因子。在此基础上,采用细观统计破坏理论,研究了割口正交叠层板的拉伸破坏机理和强度,定量获得了残余拉伸强度与界面剪切强度的关系,所得结果与现有实验吻合较好。结果表明,应力集中和强度与割口长度及界面剪切强度有关;适宜的界面黏结,具有较高的残余拉伸强度。

Based on the shear-lag theory, a layering shear-lag model taking into account the interracial damage was proposed and the stress redistributions for notched cross-ply laminates under tension were analyzed, from which both the length of the interracial damage area and stress concentration factors in intact fibers at root of the notch were obtained. On the basis of the knowledge of these stress redistrihutions, the tensile failure mechanism and strengths of notched ernss-ply laminates were studied by using a micro-statistical fracture theory. Consequently, the relation between residual tensile strength and interracial shear strength was obtained quantitatively. The present resuhs are in good agreement with the existing experiment and show that hoth the stress concentration and strength are related to the interfacial shear strength and the residual tensile strength is relatively high when the interracial cohesion is appropriate.