超高分子量聚乙烯纤维增强复合材料层合板层间断裂韧性

Interlaminar fracture toughness of ultra-high molecular weight polyethylene fiber reinforced composite laminates

作为装甲解决方案的一组重要材料,超高分子量聚乙烯(UHMWPE)纤维增强复合材料在冲击作用下主要的破坏模式之一是分层脱粘。针对UHMWPE复合材料层合板提出一种改进的双悬臂梁(DCB)试件,研究了其Ⅰ型层间断裂韧性(GIC)和失效特性,分析了DCB试件厚度及纤维铺层方向对GIC的影响,讨论了层间断裂破坏机制及结构塑性对裂纹扩展过程的影响,评估了现有试验标准中层间断裂韧性计算方法的适用性。结果表明:较小厚度的DCB试件呈现明显的塑性行为,由此测得的层间断裂韧性受结构塑性的影响显著,适当增加试件厚度可有效避免塑性的影响。本文结果为UHMWPE复合材料进一步的动态层间性能及其理论模型的研究提供实验参考和数据支撑,对复合材料防护结构设计具有重要的工程意义。

Ultra-high molecular weight polyethylene(UHMWPE)fiber reinforced composites are considered as state-of-the-art materials for armor solutions,and interlaminar delamination is one of the main failure mechanisms for the composites under impact loadings.For UHMWPE composite laminates,an improved double cantilever beam(DCB)specimen was proposed.The interlaminar fracture toughness(GIC)and failure characteristics were then studied.Analysis were conducted regarding the influence of the specimen thickness and fiber layups on the GIC.The failure mechanism of interlaminar fracture and the effect of structural plasticity on the crack propagation process were further discussed.Evaluation was also implemented on the applicability of the existing test standards for the calculation of the interlaminar fracture toughness.Results show that the DCB specimen with small thickness exhibits obvious plastic behavior,and the measured interlaminar fracture toughness is significantly affected by structural plasticity.Increasing the thickness of the specimen can effectively avoid the influence of plasticity.Conclusively,the results presented in this paper provide experimental reference and data support for the study of dynamic interlaminar properties and theoretical models of UHMWPE composites,that have important engineering significance for the design of composite protective structures.