The effects of stitched density on low-velocity impact damage of cross-woven carbon fiber reinforced silicon carbide composites

Two dimensional carbon fiber reinforced silicon carbide composites (2D C/SiCs) subjected to low-velocity impact (LVI) damage were investigated, in order to evaluate the efficiency of stitching as a reinforcing mechanism able to improve the delamination resistance of 2D C/SiCs. The damage microstructures of the specimens at different stitched density (SD) were observed by infrared thermography and industrial computed tomography scanners. While the damage depth of specimens with the SD of 10 mm/needle was greater than that of specimens with SD of 5 or 15 mm/needle, the residual tensile strength of the specimens with the SD of 10 mm/needle was the highest. With the decreasing of SD, the real damage radius of 2D C/SiCs measured by thermography increased whereas the residual tensile strength did not appear the same phenomenon. The 2D C/SiCs with the SD of 5, 10, and 15 mm/needle had good damage resistance after the LVI, with the tensile strength still retaining 72.43%, 95.20%, and 91.49%, respectively.