The Effect of Pre-stress on Impact Response of Concave and Convex Composite Laminates

Curved composite laminates are used in many applications while in the majority of the studies present in literature, flat laminates are investigated. Therefore in this paper, the influence of the curvature type (convex or concave) and preloading on impact response of curved laminates is considered. For this aim, a specific fixture and specimen were designed. The impact tests were performed at four different impact energies with the specimens fixed only in their straight sides. The results show that the effect of preloading on damaged area of concave laminates is lower than for convex ones. For considering the damage mechanism in different situations some optical pictures are also presented.