Fatigue behavior of filament wound E-glass/epoxy composite tubes damaged by low velocity impact

In this paper, filament wound glass fiber reinforced plastic (GRP) tubes were studied. Impact tests were realized at 5 J and 10 J energy levels. Force–time and force–displacement curves were obtained and damage zones were also examined. The burst strengths of tubes were found in accordance with ASTM-D 1599 before and after impact. For fatigue tests, PLC controlled hydraulic inner-pressure fatigue test rig was set up. Damaged and non-damaged tubes were subjected to the fatigue test in accordance with ASTM-D 2992. The samples were exposed to five different stress levels; 30%, 35%, 40%, 50%, 60% of the burst strength. Number of cycles occurred up to the final failure was recorded and S–N diagrams were plotted. The burst strength and the fatigue life of the damaged GRP pipes were decreased as the impact energy increased. Also the decrease in the fatigue life was greater than that of the burst strength.