Experimental Study on Low‐Velocity Impact Damage of Aluminum Honeycomb‐Basalt Fiber Composite Sandwich Panels

To meet the urgent need for lightweight impact‐resistant structures in new energy vehicles battery protection, an aluminum‐honeycomb/basalt‐fiber composite panel is proposed as a novel protective underbody, offering lightweight design, high specific strength and energy absorption. Drop‐weight impact testing was conducted to characterize the dynamic mechanical response, and high‐speed three‐dimensional digital image correlation (3D‐DIC) was used to quantify the influence of the thickness of the aluminum facesheet, basalt fiber ply count, core density of the aluminum honeycomb, and impact energy on the impact resistance. The peak impact force increased by factors of 3.60, 3.98, and 4.85 relative to the aluminum baseline. The dominant failure modes were penetration, tearing, and buckling. The ultimate load‐carrying capacity of the panels with aluminum honeycomb core increases by factors of 4.54, 5.62, and 6.71 relative to aluminum. Local indentation and honeycomb crushing are the prevailing deformation modes, and no perforations occur. The aluminum honeycomb significantly enhances the panel stiffness and impact resistance. With increasing impact energy, the delaminationand tearing is delayed by crack bridging in the basalt fiber plies and interlaminar constraint, while progressive core crushing combined with face‐sheet plasticity established multiple energy‐dissipation pathways.