Failure of woven fiber glass epoxy composite under charpy impact loading

Woven glass fiber reinforced epoxy composite at 55 vol% fiber content was fabricated using conventional hand lay-up method. The impact strength of the prepared samples were measured under Charpy impact test at +50oC and - 50oC temperature. The fractured surface of composite samples were investigated using scanning electron microscope. The impact energy for samples fractured at +50oC was at 380 KJm-2 whereas the low temperature of - 50oC showed impact energy of 178 KJm-2. The high plastic deformation from the sample tested at +50oC is the evidence from the high amount of absorbed energy compared to -50oC which revealed lower deformation. At this subzero temperature, the increased brittleness produced extensive matrix cracking and fiber splitting. However, scanning electron fractograph at +50oC showed mixed failure mode of large delaminations, fiber splitting and matrix cracking. The impact values of 380 KJm-2 and 178 KJm-2 tested at +50oC and -50oC respectively would suggest that this composite is suitable to replace steel for impact applications and is safe to be used at both high and low environmental temperatures.