Fabrication, properties and failure of 3D stitched carbon/epoxy composites with no stitching fibers damage

Three-dimensional (3D) stitched carbon/epoxy composites with no stitching fibers damage were fabricated successfully. The fracture toughness, high-temperature flexural response and failure mechanism of 3D stitched composites are reported. The results show fabricated 3D stitched composites with no stitching fibers damage have excellent Model II interlaminar fracture toughness and flexural properties. The temperature is an important parameter affecting the properties of composites and the measured flexural performance decreases with increasing the temperature. The composite exhibits brittle fracture feature, and the destruction is originates from matrix cracking, and a gradual process from compression and tension surface to the interior layers, while the stitching fibers can effectively prevent and change the cracks' propagation paths. Fiber/matrix interface debonding caused by elevated temperature is the main mechanism for material failure.