Failure mechanisms of 2‐D and 3‐D woven fiber reinforced polymer composites

Abstract A simple lab‐scale weaving method was used to produce multidirectional fiber preforms to improve the delamination resistance and damage tolerance of composites. Mechanical properties measured in this study included short‐beam shear strength and damage tolerance of 2‐D and 3‐D woven composites. The constituents of fiber and matrix in these composites are Kevlar‐29 (Du Pont) and Epon 828 (Shell Chemical Co.) epoxy. Attention was directed to the differentiation of deformation and failure mechanisms in these composites as a function of material parameters and loading conditions. The sequence of failure mechanisms differ between 2‐D and 3‐D composites. Results indicated that 3‐D woven composites exhibited higher shear strength than 2‐D woven composites. Also, 3‐D composites absorbed more impact energy than 2‐D composites. Failure mechanisms of composites subjected to repeated impacts were observed intermittently by using scanning electron microscopy and light microscopy. The failure of 2‐D composites was due to a combination of shear and tensile mode, but in 3‐D composites the failure was dominated by tensile mode.