STUDY ON THE INFLUENCING FACTORS OF LOW-SPEED IMPACT DAMAGE ON COMPOSITE LAMINATE PANELS

Accidental impacts from falling tools, ground service equipment, and other foreign objects on civil aircraft structures can cause damage to the composite materials, which poses a significant safety threat. With the drop hammer testing, low-speed impact tests were conducted on composite laminate panels to investigate the dynamic mechanical properties and damage behavior. The influence of factors such as laminate thickness, impact energy, and punch material on the damage modes and impact loads of the laminates was analyzed. The results indicate that as laminate thickness increases, the failure mode shifts from predominantly shear plug failure to fiber tensile failure. For low-energy impacts, delamination is the primary damage mode, while higher impact energies result in concurrent delamination and fiber tensile and shear failure. Furthermore, under the same impact energy, soft impacts yield higher peak loads, whereas rigid impacts lead to more severe fiber fractures and laminate damage.