Time-space damage analysis of the short fiber reinforced thermoplastics during creep and fatigue loading

有效地设计和制造工程应用塑料的能力需要大量的材料长期性能知识。疲劳寿命是一种典型的长期特性，在经历循环载荷的部件和结构中应该加以表征。人们对塑料疲劳产生的基本机理进行了大量的研究，但对许多塑料疲劳产生的机理仍没有明确的认识。采用声发射（AE）、超声测量和光学显微镜（OM）技术对玻璃纤维增强尼龙66的疲劳断裂机理进行了研究。试件边缘声速随循环加载而减小。这种行为与试样边缘的基体裂纹和纤维断裂有关。

The ability to effectively design and manufacture plastics for engineering applications requires a large body of knowledge on long-term performance of the materials. The fatigue life is a typical long-term property that should be characterized in components and structures where cyclic loads are experienced. There has been considerable research into the basic mechanism that cause fatigue of plastics, but still there is not a clear understanding of the mechanism in many plastics. In this study, the mechanism of the fatigue fracture of glass fiber reinforced nylon66 has been identified using acoustic emission (AE), ultrasonic measurement and optical microscopy (OM) techniques. The acoustic velocity of the edge of specimens decreased by the cyclic loading. This behavior was correlated to matrix cracks and fiber breakages at the edge of the specimens.