Z-pin植入对二维机织复合材料层合板力学性能影响的数值模拟

Numerical simulation of the Z-pin inserting effect on mechanical properties of 2D woven composite laminate

  • 摘要: 针对植入Z-pin后的碳纤维增强平纹机织复合材料的微观结构,建立了含Z-pin机织复合材料单层板和层合板的单胞模型。预测了Z-pin直径、分布间隔对单层板的面内纵向拉伸力学性能的影响,发现含有Z-pin的机织复合材料单胞在受面内拉伸时,会在Z-pin附近出现应力集中,单胞首先会在应力集中区域发生失效而导致强度降低。通过三维单胞模型模拟了Z-pin在层合板中拉出脱离的过程,得出了不同Z-pin直径、不同分离层厚度下的拉拔力-位移曲线。建立了用非线性弹簧模拟Z-pin的双悬臂梁(DCB)模型,结合虚拟裂纹闭合技术(VCCT),模拟了含有Z-pin复合材料层合板的Ⅰ型裂纹扩展,结果表明:Z-pin直径越大,分布越密,层合板的等效Ⅰ型应变能释放率 GIC越大,且直径越大,GIC 随裂纹扩展的波动幅度越大,分布越密,GIC 波动的波长越小。

     

    Abstract: The Z-pinned woven composite unit cell models of lamina and laminate were developed based on the plain woven composite micro-structure with carbon fiber reinforced after Z-pin inserted. The influence of Z-pin diameter and distribution interval on the in-plane longitudinal tensile mechanical properties was predicted. The stress concentration around Z-pin in the Z-pinned woven composite unit cell model was recognized. The strength would be reduced after unit cell been failed due to the stress concentration. The process of Z-pin pulled out from laminated plates was simulated. The pull-out force versus displacement curves with different Z-pin diameters and thicknesses of separate sub layer were obtained. The double cantilever beam (DCB) with nonlinear spring element and virtual crack closure technique (VCCT) was developed. The mode I crack propagation of Z-pinned laminate was simulated. It was concluded that equivalent mode I energy release rate G IC of the laminate and its waviness amplitude were larger caused by larger Z-pin diameter. Moreover, the denser the Z-pin distribution was, the larger GICwas and the smaller its wavelength was.

     

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