Preparation and Characterization of Carbon Fiber Spread Tow/Carbon Felt Needled Fabrics

ABSTRACT Carbon fiber needled fabric reinforced composites have been widely used in aerospace, defense, and rail transportation. However, carbon fiber spread tow/carbon felt needled fabrics are still in the preliminary exploration stage, and the influence of the needling process on their structure and performance remains unclear. This study conducted research on the preparation, structural characterization, and performance study of carbon fiber spread tow/carbon felt needled fabrics. It investigated the structural characteristics of these fabrics, the influence of needling density and needling path on their mechanical properties, as well as the coupled effects of total needling density and the number of unit layers needled per pass. The results indicated that needling caused significant damage to the fibers of the carbon fiber spread tow. With a needling density of 5 needles/cm ² , the tensile strength decreased by 23%. At 15 needles/cm ² , it showed a sharp decline of 61%. Within the range of 30–60 needles/cm ² , the decrease reached 67%–75%, though the rate of reduction began to slow. In contrast, the interlaminar peel strength showed a uniform increasing trend with increasing needling density, exhibiting an approximately proportional relationship. Compared to offset needling, in situ needling yielded higher residual in‐plane tensile strength and interlaminar peel strength. When the total needling density exceeded 40 needles/cm ² , adopting the “single‐pass needling with two unit layers” process resulted in better overall mechanical properties of the fabric.