低能冲击下复合材料蜂窝夹芯结构表面损伤分析

Surface Damage Analysis of Composite Honeycomb Sandwich Structures Under Low Energy Impact

基于低能量冲击探究复合材料蜂窝夹芯结构表面的损伤模式,分析低能量冲击对结构表面环氧树脂膜的裂纹扩展模式、损伤面积、裂纹长度和数量的影响,通过三点弯曲试验研究了低能冲击后碳纤维增强复合材料层合板的弯曲性能以及损伤极限值。研究结果表明,冲击能量会影响表面环氧树脂膜的损伤扩展模式,裂纹均以冲击落点为中心,向周围不规则地扩展,所形成的损伤面积随冲击能量递增,裂纹扩展长度与冲击能量成正相关,层合板的层间损伤模式以分层和纤维弯曲为主;低能量冲击试验证明了表面环氧树脂膜的裂纹扩展模式、损伤面积等与夹芯结构层合板内部的冲击损伤程度之间具备特定的联系,因此可为设计一种新的无损检测方法用于快速表征结构内部的冲击损伤提供可能性。

Carbon fiber reinforced epoxy resin composite honeycomb sandwich structure is prone to various unpredict⁃able impact damage and damage in engineering applications,and is very sensitive to impact loads,especially after low-speed impact,although there is no obvious damage on the surface,the internal structure may be seriously dam⁃aged,and the failure mechanism and failure mode of the composite sandwich structure are very complex.In this study,the damage mode of the composite honeycomb sandwich structure surface was investigated based on low ener⁃gy impact,and the influence of low energy impact on the crack growth mode,damage area,crack length and number of epoxy resin film on the structure surface was analyzed.The bending properties and damage limits of carbon fiber reinforced composite laminates after low-energy impact were studied by three-point bending test.The results show that impact energy affects the damage expansion mode of epoxy resin film on the surface.The cracks are centered on the impact point and spread irregularly around,and the damage area formed increases with the impact energy.The crack propagation length is positively correlated with the impact energy,and the damage modes of laminates are domi⁃nated by delamination and fiber bending.Moreover,low energy impact tests have proved that there is a specific rela⁃tionship between the crack propagation mode and damage area of the surface epoxy resin film and the impact damage degree inside the sandwich structure laminates,so it can provide a possibility for forming a new non-destructive test⁃ing method to quickly characterize the impact damage inside the structure.