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

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。

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

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 modeⅠdelamination 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 modeⅠdelamination toughness of the Z-pinned laminated DCB specimens. However，less enhancement on modeⅠdelamination toughness is obtained when the delamination is close to the surface of DCB.