压缩载荷下UHMWPE纤维复合材料层合板的力学性能与失效分析

Mechanical Properties and Failure Analysis of UHMWPE Fiber Composite Laminates under Compressive Loading

为获得超高分子量聚乙烯(ultra-high molecular weight polyethylene,UHMWPE)纤维复合材料层合板在静、动态压缩载荷下的力学性能与失效模式,采用万能材料试验机和分离式霍普金森压杆对材料进行面外方向的压缩实验,获得了不同应变率下材料的应力-应变关系。通过扫描电子显微镜观察材料微观失效形貌,分析了材料的失效模式。结果表明,UHMWPE纤维复合材料层合板在应变率较低(6.7×10^(-3)-6.7×10^(−2)s^(−1))且相差较小时,无应变率效应;在高应变率(2.05×10^(3)~5.27×10^(3)s^(−1))下,材料具有明显的应变率效应。压缩强度随应变率的增加而增大,动态增强因子逐渐增大,具有明显的应变率强化效应。静态压缩载荷下,材料的主要破坏模式为纤维的拉伸、断裂;动态压缩载荷下,材料的主要破坏模式为纵向位错分层。

To determine the mechanical properties and failure modes of ultra-high molecular weight polyethylene(UHMWPE)fiber composite laminates under static and dynamic compressive loading,a universal material testing machine(UTM)and a split Hopkinson pressure bar(SHPB)experimental system were used to obtain the stress-strain relationships of UHMWPE subjected to out-of-plane compression at different strain rate loading.After experiments,the microscopic failure morphology of the material was observed through scanning electron microscopy(SEM),then the failure mode of the material was analyzed.The results show that the UHMWPE fiber composite laminates performs a rate-independent behavior at low strain rates(6.7×10^(−3)s^(−1)to 6.7×10^(−2)s^(−1));while a rate-dependent at high strain rates(2.05×10^(−3)s^(−1)to 5.27×10^(−3)s^(−1)).The compression strength increases with the rising strain rate,and the dynamic enhancement factor gradually increases,with an obvious strain rate strengthening effect.Under static compression,the main damage mode of UHMWPE is the stretching and fracture of the fibers,while at dynamic situation,the main damage mode of the material is the longitudinal dislocation delamination.