Low velocity impact response of composites and fiber metal laminates with open holes

Abstract

Low-velocity impact response of glass/epoxy composite plates and fiber metal laminates with and without holes is investigated. The critical parameters that affect the delamination characteristics of laminates are impact energy, holes separation distance, type and directionality of fibers. An experimental investigation has been conducted to evaluate the effect of the presence of holes and the incorporation of aluminum layers in the extent of delamination. The extent of damage introduced during the impact event was observed on images obtained from C-scan non-destructive ultrasonic technique. Results indicate that fiber metal laminate made with aluminum layers exhibits an improved dynamic response in comparison with that of conventional laminates. The beneficial effect of using aluminum layers to reduce the extent of delamination produced by impact loading especially on laminates with holes is demonstrated. Furthermore, fiber metal laminates show better load carrying capability than conventional composite plates. The better response of fiber metal laminate with multidirectional fabric in comparison with fiber metal laminate with woven fabric is also examined. These results may be useful to better design the location of holes in composite structures.