Study on Local High-Velocity-Impact Characteristics of Carbon Fiber Composite Laminates Based on Experimental Image Sequences

For the complex operating environment of rail vehicles impacted by foreign objects, this study carried out experiments on carbon fiber composite laminates impacted by projectiles of three different materials in the gas gun apparatus. High-speed photography was used to capture the impact dynamic process, with subsequent analysis of image sequences enabling the quantification of both projectile energy characteristics and laminate mechanical responses. The key findings reveal that (1) the impact force demonstrates a nonlinear relationship with the energy input, exhibiting diminishing growth rates at higher energy levels, while deformable aluminum projectiles yield significantly lower average impact forces; (2) crack propagation follows a characteristic pattern of initial expansion with the impact energy reaching maxima of 88.40 mm (concrete), 41.48 mm (steel), and 80.35 mm (aluminum), and then decreasing, followed by stabilization post-perforation; (3) the penetration depth showed an accelerating nonlinear growth trend with progressively higher rates of increases as the impact energy rose, and its variation trend exhibited a correlation with the crack length. The results provide quantitative insights into carbon fiber laminates' damage mechanisms, which offer practical implications for the composite structure design in transportation systems subjected to foreign object impacts.