基于定点握持弯曲疲劳的高性能纤维弯曲疲劳性能表征

Evaluation of bending fatigue properties of high performance fibers based on fixed-point bending fatigue test

介绍了一种能够测量柔性材料弯曲疲劳性能的定点弯曲疲劳测试装置,利用该仪器测试了Kevlar 49,Kevlar 129,PBO,高强聚乙烯和Nomex共5种高性能纤维的弯曲疲劳性能,获得了它们的弯曲疲劳破坏断裂端形态.从它们的弯曲疲劳破坏形态可以看出Kevlar 49,Kevlar 129和PBO这3种纤维表现为原纤劈裂破坏,高强聚乙烯纤维表现为塑性积累破坏,而No-mex纤维为撕裂破坏;发现纤维的弯曲疲劳断裂次数不同,纤维的破坏形态也有一定区别.

The main aim of this paper is to introduce a bending fatigue testing apparatus and a new fatigue testing method, which can be used to characterize the bending fatigue behavior of flexible materials. The Kevlar 49, Kevlar 129, PBO, Nomex and UHMW-PE fibers are chosen to analyze the bending fatigue properties by the new apparatus. The bending fatigue fracture ends of these high per- formances fibers were obtained. It is evident that The Kevlar 49, Kevlar 129, PBO fibers are always broken due to the fibrillation or axial split. It can be found that the fracture ends of Nomex fiber have no apparent separation and splitting of the micro-fiber, which shows a long tongue fracture end and tearing-type fracture end. It can be also seen that the fracture ends of the UI-IMW-PE fiber have slightly fibrillation and the insignificant fibrillar splitting and the fatigue fracture caused by the obvious accumulated plastic deformation.