Abstract: To investigate the damage characteristics and impact resistance of polyimide (PI) fiber three-dimensional woven composites under high-speed impact, this study conducted 14 sets of ballistic impact tests, with projectile velocities ranging from 130 m/s to 300 m/s. High-speed photography and digital image correlation (DIC) technology were used for analyzing the displacement of target plates, and comparisons were made with carbon fiber three-dimensional woven composites.The test results showed that the ballistic limit of the polyimide fiber composite target plate was 293 m/s, with a maximum energy absorption of 836 J, demonstrating excellent anti-penetration ability. The main damage mechanisms included tensile fracture of fiber bundles, brittle cracking of the matrix, and local bulging. DIC data indicated that the maximum back deformation of the target plate under critical penetration, rebound, and penetration conditions was 16.2 mm, 8.3 mm, and 4.95 mm, respectively. Comparisons with carbon fiber three-dimensional woven composites revealed that the energy absorption of polyimide fiber composites was 70.6% higher than that of carbon fiber composites. Polyimide fiber composites primarily undergo ductile failure, absorbing energy through large-scale plastic deformation, while carbon fiber composites are dominated by brittle fracture and prone to sudden brittle failure. The study indicated that polyimide fiber three-dimensional woven composites possess excellent high-speed impact resistance and energy absorption capacity, and have the potential to be applied in impact-resistant structures such as aero-engine containment casing.

Key words: polyimide fiber, composite materials, plate impact, damage characteristics, deformation