低速多次冲击下碳纤维/环氧树脂基复合材料层合板失效机制及剩余强度评估

Failure mechanism and assessment of residual strength of carbon fiber/epoxy resin matrix composite laminates under multiple impacts at low velocities

  • 摘要: 碳纤维(Carbon fiber,CF)增强环氧树脂(Epoxy resin,EP)基复合材料因其优异的抗冲击性而被广泛应用在飞机结构件。考虑到飞机在飞行过程中部分结构会遭受多次冲击的工况,设计CF/EP复合材料层合板的多次冲击及冲击后压缩试验。通过对多次冲击的力学响应曲线分析及内部损伤图观测,得到不同冲击载荷对复合材料多次冲击的力学性能影响及多次冲击过程中的主要损伤机制和损伤传播模式。在此基础上,对冲击后的剩余压缩强度及失效形貌进行了分析,得到了CF/EP复合材料层合板在冲击后的损伤容限及失效模式。结果表明:冲击次数的提高将导致复合材料的吸能性下降,抗冲击性下降。在多次冲击过程中,复合材料层合板的损伤模式为自下而上。此外,随冲击能级变化,复合材料在冲击后压缩过程中的主要损伤模式有所变化。

     

    Abstract: Carbon fiber (CF) reinforced epoxy resin (EP) matrix composites were widely used in aircraft structural components due to their excellent impact resistance. Considering that some of the structures of aircraft were subjected to multiple impacts during flight, the CF/EP composite laminates were designed for multiple impacts and compression after impact tests. The mechanical response curves and internal damage diagrams of the multiple impacts were analyzed to obtain the effects of different impact loads on the mechanical properties of the composites during multiple impacts, as well as the main damage mechanisms and damage propagation modes during the multiple impacts. On this basis, the residual compression strength and failure morphology after impact were analyzed to obtain the damage tolerance and failure mode of CF/EP composite laminates after impact. The results show that an increase in the number of impacts will lead to a decrease in the energy absorption and impact resistance of the composites. During multiple impacts, the damage pattern of the composites is bottom-up. In addition, the main damage modes of the composites during compression after impact vary with the impact energy level.

     

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