The effect of different environmental condition on flexural strength and fatigue behavior of e-glass/epoxy composites

Abstract

The composite materials exposed to dynamic loads may suffer damage at strength value, which is under own yield strengths. Also, improper environmental conditions accelerate the damage process. In this study, the effect of heavy chemical environments such as acid and alkaline and retaining time for these environments on flexural strength and fatigue behavior of E-glass/epoxy laminated composites was investigated. In this content, glass/epoxy (G(8)) having eight layers was produced by using the hand lay-up method. The produced composite materials were retained into acidic and alkali solution having 5%, 15%, and 25% concentration a period of 1, 2, 3, and 4 months. A computer-controlled fixed-end type fatigue test machine capable of tilting 10 test samples at the same time was designed and manufactured to determine the fatigue behavior of composite samples. Fatigue behavior of glass/epoxy was determined under dynamic flexural load which corresponds to 80%, 70%, 60%, 50%, and 40% of static three-point bending strength of the test sample. SEM image of damaged specimens was taken to describe the failure mechanism of damage which occurs after fatigue. Also, to better understand environmental condition on the fatigue life, results were compared with results of glass/epoxy laminated composites, which were not retained into any environments (0%).