Low velocity impact and compression after impact of thin and thick laminated carbon fiber composite panels

This study explores the impact behavior of thin and thick composite panels, yielding insights into their behavior under increasing impact energies. Thin composite specimens demonstrated limited surface damage tolerance, while thicker panels remained visually intact but suffered internal damage, adversely affecting their compressive load capacity. The study shows a robust correlation between impact energy and key measurements, including dent depth, bottom surface matrix splitting, and internal delaminations. Moreover, the research identified a consistent pattern in damage initiation, showing that the onset of matrix splitting and delamination remained relatively constant regardless of increasing impact energy, emphasizing the predictability of damage initiation. Compression after impact study showed distinctive responses between thin and thick composites. Thin composites exhibited global buckling before final failure, with a gradual reduction in peak load-carrying capability as damage escalated. In contrast, thick composites suffered substantial damage and delamination at higher impact energies, leading to significant losses, up to 60%, in residual compressive load capacity. The study introduces a simplified quasi-static model to capture delamination effects on panel responses to lowvelocity impacts. This study contributes significantly to understanding composite materials' impact behavior, providing essential knowledge for practical applications and future research endeavors.