层间颗粒增韧复合材料层压板的损伤阻抗特性

DAMAGE RESISTANCE OF THE COMPOSITE LAMINATES WITH INTERLAYER THERMOPLASTIC PARTICLES

采用热塑性颗粒对HT7/5228、HT3/NY9200G和HT3/5224三种高温固化环氧基体复合材料层压板进行层间增韧。为了提高冲击后压缩强度(CAI)和考察损伤阻抗, 测试了平均分层起始能量eⅡc以及接触力凹坑深度关系。试验结果表明, 增韧颗粒和基体树脂形成的层间区域能有效地吸收断裂能量并抑制分层的发生, eⅡc显著提高。在静压痕力下, 层间增韧复合材料层压板具有较深的凹坑深度和较小的损伤面积。层间增韧的几何效应、裂纹传播路径控制、颗粒桥联以及裂尖屏蔽是主要的增韧机理, 颗粒的塑性变形和最终失效也耗散了大量断裂能量。

Three types of carbon-fibre epoxy composites, HT7/5228, HT3/NY9200G and HT3/5224, were interlayer toughened with thermoplastic particles. In order to improve compression strength after impacting (CAI) and evaluate damage resistance, a quasi-static indentation (QSI) test was conducted. The experimental results indicate that the interlayer zones formed by particles and epoxy can significantly suppress delamination and crack propagation. Average delamination onset energy eIIc is significantly improved. The relation between indent depth and contact force shows that the interleaved specimen achieves a smaller damage area at the expense of greater indent depth in the local region. The toughening mechanism is chiefly as follows: geometrical effect of interlayers, crack path kinking and deflection, and crack tip shielding. A large amount of fracture energy is absorbed by ductile deformation and ultimate failure of the particles.