Impact crack quantification analyses in 3-D angle-interlock woven composite using image segmentation method

Abstract

Crack distribution quantifications are key to predict residual strength of composite materials after impact. Here we report impact crack distribution quantifications of 3-D angle-interlock woven composites (3-DAWCs) which were observed with micro-computed tomography (micro-CT), and also characterized with finite element analyses (FEA). A fast and accurate image segmentation algorithm has been employed to identify the inside crack distributions. A damage variable has been adopted to quantify the crack propagation. We found that the weft yarn with straight arrangement is conducive to stress propagation, and is the main load carrier. The large deflection and buckling structure of warp yarns inhibit the stress propagation on the back face. It is shown that the cohesive damages locate at the interlacing points and the interface between resin and surface warp yarns after the first three successive impacts. The FEA model has been verified with the test data for predicting the damage initiation, evolution and failure mode of materials under impact, which is of great significance for the 3-D woven composite material design.