EXPERIMENTAL AND FINITE ELEMENT ANALYSIS OF MODE I INTERLAMINAR FRACTURE ENERGY IN CARBON/EPOXY WOVEN LAMINATES

Composite materials have been widely applied because they have advantages including high stiffness, strength and weight ratio. Composites also have the disadvantage of resistance to impact loads due to different damage modes compared to metallic materials. Delamination damage mode is the separation between layers causing a drastic decrease in properties to trigger catastrophic failure. One of the parameters to measure delamination resistance is fracture energy with the Double Cantilever Beam (DCB) test. This study aims to conduct experiments and simulations of DCB tests on twill weave woven carbon composite fibers made by Vacuum Assisted Resin Infusion (VARI) method. Quasi-isotropic, orthotropic and asymmetric fiber direction arrangements were tested to determine the effect of response and fracture energy values. Numerical modeling with Cohesive Zone Model (CZM) with 2D and 3D cohesive contact model provides an understanding of both models. The results show that the variation of stacking direction gives higher force response and lower fracture energy values. The higher bending stiffness leads to faster crack propagation. The orthotropic model provides higher stiffness so that the decrease in fracture energy value is quite significant. In the asymmetric model, the decrease in fracture energy due to the difference in stiffness of the adherent causes a slight decrease in the fracture energy value.