The temperature effect on the inter-laminar shear properties and failure mechanism of 3D orthogonal woven composites

Recent increases in the use of carbon fiber reinforced plastics, especially for high-temperature applications, has induced new challenges in evaluating their mechanical properties. The effects of temperature on the shear performance of 3-dimensional orthogonal and 2-dimensional plain woven composites were compared in this study through double-notch shear tests. A scanning electron microscope was employed to investigate the fiber/matrix interface properties to reveal the failure characteristics. The results showed that temperature had a visible impact on the inter-laminar shear strength (ILSS), deformation modes, and failure mechanism. The ILSS decreased as temperature increased, which was caused by the degradation of the matrix properties and fiber/matrix interface properties at high temperature. A finite element model was established to analyze the transient deformation process and the damage mechanism of the 3D orthogonal woven composite. This indicated that Z-binder yarns could improve the delamination resistance of 3D orthogonal woven composites, especially under high temperatures. The changes in failure modes of the 3D orthogonal woven composites was put down to thermal softening of the epoxy resin caused by high temperature and the undulation of the yarns.