The Resistance of X-Shaped Re-Entrant Auxetic Sandwich Beams to Localized Impulsive Loading

This study introduces an improved X-shaped re-entrant auxetic structure designed to enhance mechanical performance by incorporating diamond-shaped elements into the re-entrant hexagonal configuration. Using a validated numerical model, the resistance of sandwich beams with the proposed core under localized impulsive loading is explored. The results reveal that local compression and global shear deformation dominate the response. The study further examines the effects of cell arrangement, geometric parameter, inclined gradient distribution, and cell construction on structural behavior. The X-direction arrangement of cells significantly enhances deformation control, improving deflection by dissipating impact energy. Increasing the angle α enhances mechanical properties and reduces residual deflection. Various inclined gradient distribution designs notably affect performance: positive gradients improve energy absorption, while negative gradients alter deformation mode. Under the same conditions, the proposed sandwich beam outperforms the conventional re-entrant hexagonal sandwich beam in terms of impact resistance. This research offers valuable insights for the design of explosion-resistant metamaterial sandwich structures.