Effect of stacking sequence on the mechanical properties of glass-carbon hybrid composites before and after impact

Hybrid composites are susceptible to accidental low energy impacts from hazards such as tools dropping during maintenance, transportation debris and hailstones. These impacts can cause significant strength reduction and localized damage which is potentially a source of mechanical weakness especially for graphite composites. The effect of stacking sequence on mechanical properties of stitched composites is studied for low velocity impact damages. Tests were performed for the same volume fraction (V_f) with different hybrid sequence and ply angle. The incorporation of glass fibers in carbon reinforced structures improved impact properties and increased the strain to failure. The addition of carbon fibers to the surface of glass-reinforced composites increases the flexural modulus for undamaged samples. Tensile failure mechanism of damaged plies seems to be affected by the interaction of reinforcement property, hybrid order and ply angle.