带表面防护层复合材料层板的低速冲击及冲击后压缩性能试验研究

对增加了表面防护层的国产碳纤维/增韧环氧树脂CCF300/5228A层板的低速冲击及冲击后压缩性能进行了试验研究。通过落锤式低速冲击试验，得到了各组层板的冲击接触力历程、凹坑深度和内部分层面积等特征，而冲击后压缩试验结果可用来对各组层板的损伤容限性能进行评估。结果表明，同裸板相比，加了表面防护层的层板其分层起始载荷变化不大，但形成同样的1.0 mm凹坑所需的冲击能量增大了24%~46%。而对于内部分层，在一定的冲击能量范围下，加表面防护层的层板的C扫分层面积比裸板减小了20%~50%，而在同样凹坑深度的情况下，层板在加了表面防护层之后分层面积变化不大。冲击后压缩性能与内部分层情况具有较大的关联性，同样冲击能量下分层面积较小的各组带表面防护层板，其冲击后压缩强度和破坏应变相对于裸板的提高在15%~50%之间，而在凹坑深度相同的情况下，二者的冲击后压缩强度和破坏应变相差不大。

Experimental study on the low-velocity impact and compression after impact performances of composite laminates with a surface protection layer

The low-velocity impact and compression after impact performances of composite laminates with a surface protection layer was experimentally investigated. Through drop-weight low-velocity impact tests, impact force histories, indentation depths and delamination areas inside the laminates were obtained. The damage tolerance performances for the groups of laminates can be evaluated through compression after impact tests. The test results show that the delamination initiation loads for the laminates with a surface protection layer are nearly the same with the bare laminates, while the impact energies required to generate an indentation with a depth of 1.0 mm are 24%-46% larger. Under the same impact energy, the C-scan delamination areas of the laminates with a surface protection layer are around 20%-50% smaller than the bare laminates. However, at the same indentation depth, the C-scan delamination areas do not change much when adding the surface protection layer to the laminates. The compression after impact (CAI) performances are in close relation to the delamination inside the laminates. Under the same impact energy, the CAI strength and failure strain are 15%-50% greater for the laminates with a surface protection layer which have smaller delamination areas compared with the bare laminates. At the same indentation depth, the CAI strength and failure strain do not appear to be much different for both the bare laminates and those with a surface protection layer.