碳纤维增强环氧树脂基复合材料轴管的低速冲击失效机制及剩余压缩性能

Failure mechanisms and residual compression performance of carbon fiber reinforced epoxy composite shaft tubes subjected to low velocity impact

采用落锤冲击试验模拟低速冲击过程,对碳纤维增强环氧树脂基复合材料传动轴的轴管在不同能级冲击下的损伤行为以及冲击后的剩余压缩性能进行了研究;通过ABQUAS有限元分析软件和X射线断层扫描技术(CT)相结合的方法观察了复合材料轴管在受到低速冲击时的损伤形式,研究其内部损伤规律。结果表明,复合材料轴管的抗冲击形变能力随着冲击能量的增加先增强后减弱,在冲击能量为10~20 J之间出现最大值。CT无损检测结果显示复合材料轴管的失效形式包括分层损伤、树脂开裂和纤维破裂(断裂)。在低能量冲击时,复合材料轴管主要产生分层损伤和树脂的开裂,而纤维断裂损伤只出现在冲击位置,且随着冲击能量的增加纤维断裂现象愈加显著。有限元仿真结果显示复合材料轴管中的碳纤维在拉伸方向的失效明显小于压缩失效,压缩失效沿纤维排布方向扩散,拉伸失效沿轴向和横向呈十字扩散,轴向失效的程度大于横向失效的程度;而树脂的压缩失效沿轴向从冲击位置向横向扩散,扩散形状近似圆形,越靠近圆心失效越明显,拉伸失效范围呈十字,整体失效沿十字边缘扩散。

Drop hammer impact test was used to study the failure mechanism and the compression after impact(CAI)of carbon fiber reinforced epoxy composite shaft tubes when subjected to different impact energy levels to simulate the low-velocity impact(LVI)process.ABQUAS finite element analysis technology and X-ray tomography(CT)techniques were used to investigate the internal failure mechanisms.Results show that,with the increase of impact energy,the deformation resistance of the composite tubes first increases and then decreases,and reaches a maximum value when the impact energy falls between 10 J and 20 J.The accuracy of the test results is confirmed by the fact that the energy absorption rates of the shaft tube with different energy levels differ little.CT results show that the composite shaft tube after LVI mainly fails in forms of delamination and resin cracking.Fiber fracture mainly occurs at the impact location,and the fiber fracture becomes more and more significant with the increase of impact energy.The finite element simulation results show that the fiber failure of composite shaft tube in the tensile direction is significantly less than the compression failure.The compression failure mainly diffuses along the fiber layout direction.The tensile failure mainly spreads along the axial direction and transverse direction,and the axial failure degree is greater than the transverse failure degree.The compression failure of the resin mainly diffuses from the impact position to the transverse along the axial direction.The diffusion shape is nearly round,the closer to the center,the failure is more obvious.The stretching failure range is a cross;the overall failure diffuses along the cross edge.