Effects of hostile solutions on the static and dynamic behavior of carbon/epoxy composites

Fiber-reinforced laminated composite is often used in harsh environments that may affect their static stability and long-term durability as well as residual strength. In this study, the effect of heavy chemical environments such as acid and alkaline and retaining time for these environments on flexural strength and flexural fatigue behavior of carbon/epoxy laminated composites were investigated. In this context, carbon/epoxy was retained into an acidic and alkaline solution having 5%, 15%, and 25% concentration by weight for 1-4 months. Fatigue behavior of carbon/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 carbon/epoxy laminated composites, which were not retained into any environments (unretained). The test results showed that the solution type, solution concentration, and retaining time caused noticeable changes in the static and dynamic strengths of carbon/epoxy laminated composites.