Interlaminar shear of woven fabric Kevlar-epoxy composites in three-point loading

The interlaminar shear behaviour of woven fabric Kevlar-epoxy composites in three-point loading has been studied for various span-to-depth ratios and explained. A detailed analysis of the failure modes has been carried out for various span-to-depth ratios and the observed transition from tensile to shear mode of failure explained. The explanation is based on the elastic-plastic model for Kevlar composite beams. The apparent interlaminar shear strength obtained from short beam tests is shown to increase more than the predicted values for a decrease in span-to-depth ratio. The true interlaminar shear strengths of the different woven fabric Kevlar-epoxy composites were obtained from their apparent values. The effect of thickness on the interlaminar shear strength has been looked into and reported. A detailed failure analysis involving methods and scanning electron microscopic examination of the fracture features has been carried out and reported.