Effect of Low-Cycle Fatigue and Hydrothermal Aging on Tensile Properties of Open-Hole Glass Fiber/Polycarbonate and Glass Fiber/Polyamide 6 Composites

In the application of glass fiber reinforced thermoplastic composites, an open hole is used for connecting, and the durability of composites is one of the major concerns. In this study, glass fiber/polycarbonate (GF/PC) and glass fiber/polyamide 6 (GF/PA6) with glass fiber contents of 20 wt.% and 40 wt.% were manufactured by injection molding. The effects of an open hole on the tensile properties of the composites and the influence of low-cycle fatigue (LCF) and hydrothermal aging on the open-hole composites were investigated. The results showed with the same fiber mass faction, notched and unnotched GF/PA6 showed better tensile properties while GF/PA6 was more sensitive to the open hole than GF/PC. LCF test at 55% the maximum load with 30 cycles did not have an obvious influence on all of the four kinds of composites. Among these samples, the LCF test had the greatest influence on GF/PA6-40. After LCF tests at 70% and 85% of the maximum load with 30 cycles, the decrease rate of the strength of GF/PA6-40 was over 10%. In hydrothermal aging experiments, after exposure for 1600 h, the results indicated that the tensile strength decreased over 15% for GF/PC and over 30% for GF/PA6 due to the hydrolysis of the matrix.