Impact performance and energy absorption of sandwich panels with STF-filled honeycomb cores and various skin materials under low-velocity impact conditions

Sandwich panels with honeycomb cores are widely used for structural applications due to their lightweight and impact-resistant properties. However, improving the energy absorption and crashworthiness of these panels remains a significant challenge, particularly when optimizing core materials and skin configurations. This study examines how different core materials, STF-filled honeycomb, water, resin, and semi-rigid foam, affect the impact performance of sandwich panels at low velocities. Additionally, the influence of different skin materials such as aluminum, epoxy-glass composites, and STF-impregnated fabric is analyzed. The panels were fabricated by filling the honeycomb cores with different materials and applying the skins to the cores. Low-velocity impact tests were conducted at drop heights of 100 mm and 500 mm to evaluate energy absorption, mean crushing force, and specific energy absorption. The results demonstrate that STF-filled cores significantly improve energy absorption and impact resistance compared to traditional core materials. Furthermore, STF-impregnated fabric skins enhance overall panel performance, making STF-filled sandwich panels a promising solution for lightweight, high-strength structures in industries such as automotive and aerospace.