Z-pins对层合复合材料非对称分层增韧作用参数分析——Ⅰ型层间韧性

Parametric analysis of enhancement of Z-pins on asymmetric delamination of Z-pinned laminated composites——Mode Ⅰ delamination toughness

假设纤维Z-pins的桥联力与嵌入厚度成正比,建立适于非对称分层(分层位于层合板厚度方向上的任意位置)的Z-pin细观力学模型并构造相应的Z-pin单元,结合考虑一阶剪切变形的梁单元,建立了用于分析含浅部分层采用Z-pins增韧的双悬臂梁(Double cantilever beam,DCB)有限元模型,并在分层裂纹面上引入接触单元以防止分析过程中2个分层子梁在分层前缘处的相互嵌入。通过数值算例分析了Z-pins对含非对称分层的DCB试件Ⅰ型层间韧性的增强作用。参数分析表明,当分层位置靠近层合板的表面时,Z-pins的增韧作用明显下降,其较薄分层子层的厚度是决定Z-pins对Ⅰ型层间韧性增强效果的关键参数。

The bridging forces provided by the fiber Z-pins were assumed to be proportional to their length embedded in the laminates.Based on the currently available Z-pin micro-model,a Z-pin element was developed and a beam element model was proposed in this paper to study the effect of Z-pins on mode Ⅰ delamination toughness of Z-pinned double cantilever beam（DCB） specimens.A contact element was also introduced to the proposed model to avoid the unrealistic penetration of the two substrate beams at the delamination crack tip.The numerical results show that the Z-pins can significantly improve the mode Ⅰ delamination toughness of the Z-pinned laminated DCB specimens.However,less enhancement on mode Ⅰ delamination toughness is obtained when the delamination is close to the surface of DCB.