Static and dynamic crushing responses of CFRP sandwich panels filled with different reinforced materials

This study aims to investigate the crashworthiness of carbon fiber reinforced plastic (CFRP) sandwich panels filled with different reinforced materials under quasi-static compression and low velocity impact loading. Four lightweight filler materials (namely EPP foam, aluminum honeycomb, rubber foam balls and plastic hollow balls) were chosen and a series of static and dynamic tests were carried out to explore the damage mechanism, load bearing capacity, energy absorption and cushioning properties of these different sandwich panels. The complete core crushing contributed to the loading resistance and energy absorption under the static compression leaving the top and bottom CFRP facesheet intact. Three distinct load-displacement categories, classified as no rebound (unfilled), incomplete rebound (filled with aluminum honeycomb and plastic balls) and complete rebound (filled with EPP and rubber balls) were observed in the impact tests; the localized facesheet rupture and core crushing were dedicated to significant energy absorption during impact. The specimens filled with aluminum honeycomb and plastic hollow balls exhibited superior energy absorption capabilities (2.8 and 4.8 J/g, respectively) in the static compression testes, while the specimens filled with aluminum honeycomb and EPP foam exhibited superior capability of energy absorption (0.8 and 0.9 J/g, respectively) in the impact tests.