Abstract: This research focuses on exploring the relationship between process parameters and the performance of carbon/carbon composite materials during the needle-punched process, employing a central composite design method to plan the experimental scheme. Using the response surface method to analyze the experimental data, a quadratic response model was established that correlates the bending strength of the product with needle-punched process parameters, including needling depth, needling density, and carbon fiber surface density. Based on this model, the process parameters were optimized and an analysis was conducted on the influence patterns of individual process parameters and their combined effects on the bending strength. The research findings indicate that the best parameters were a needling depth of 12 mm, a needling density of 17.81 needles/cm², and a carbon fiber surface density of 400 g/m². The study also reveals that the carbon fiber surface density had the most significant impact on bending strength, followed by the needling depth, while the effect of needling density is relatively minor. Furthermore, the study uncovers that the coupling effects between needling depth and carbon fiber surface density, as well as between needling depth and needling density, significantly influenced the bending strength. Through delving into the interactive effects of the process parameters, it is determined that the bending performance of the product is optimal when the needling depth is between 12~16 mm, the needling density is between 15~25 needles/cm², and the carbon fiber surface density is between 380~400 g/m², with the strength exceeding 100 MPa. These findings expand the needle punching forming process window for carbon/carbon composite materials, which helps to improve their forming efficiency and product quality.

Key words: C/C composite material, needle-punched, bending strength, response surface method, process parameter optimization