Experimental investigation on response and failure modes of 2D and 3D woven composites under low velocity impact

In this study, the behavior of 2D and 3D woven composites is compared under low velocity impact. Several 2D and 3D specimens were tested using a dropweight tower, and their performance was compared using extracted data such as damage threshold load, damage initiation time, absorbed energy and maximum deflection. Besides, their damage modes and delamination areas were examined by stereomicroscope and C-scan technique, respectively. The results showed that the 3D woven composites absorbed more impact energy than 2D ones while their maximum deflection was lower. Moreover, the delamination and damage areas were much smaller in the 3D composites than the 2D ones of similar thickness. A new parameter is presented for comparing damage severity of the 2D and 3D composites. Unlike conventional parameters, the presented one shows potential for being applicable to laminated composites, regardless of their areal densities, layer numbers and weave structures.