Effects of Thickness on Fracture Toughness of Carbon/Polyester Composite

The aim of this paper is to evaluate interlaminar fracture toughness and non dimensional stress intensity factors of woven Carbon-Polyester composite based on numerical and experimental methods. A modified version of Arcan specimen was employed to conduct a mixed-mode fracture test using a special loading device. By changing the loading angle, a, from 0 degrees to 90 degrees, mode-I, modeII and all mixed-mode data were created. The finite element analysis was performed with Abaqus software. The interaction j-integral was used to separate the mixed mode stress intensity factors and energy release rate at the crack tip under different loading conditions and different thickness of specimens. The results of fracture toughness tests revealed that the interlaminar fracture of composite is strong under the shearing-mode loading but weaker to the opening- mode loading. It can be seen that by increasing the thickness of the composite specimen, non dimensional stress intensity factors for pure mode I (alpha=0 degrees) and pure mode II (alpha=90 degrees) loading conditions were decreased.