Morphology-driven Impact Resistance Mechanism of Desert Scorpion Tergum and Performance Validation of Biomimetic Ballistic Protector

Modern ballistic protection equipment demands a critical balance between high impact resistance and lightweight, a challenge unresolved by conventional approaches. Biological systems achieve such synergy through evolutionarily optimized structures, offering promising biomimetic solutions, yet a limited understanding of impact-resistance mechanisms hinders their full potential. This study employed a multi-technique approach combining ultra-depth-of-field microscopy, SEM, EDS, FTIR, nanoindentation, and impact testing to investigate the convex hull of Lq (desert scorpion) tergum and the locally thickened regions at the hulls relative to the inter-hull gaps. Convex hulls deflect and disperse impact loads, while local thickening guides cracks and dissipates energy, balances impact resistance, and lightweighting. Hp tergum (rainforest scorpion) served as a control, confirming this convex hull–local thickening dual mechanism as a key adaptation of desert scorpions to particle impacts. Finite element models of the central (BM₁) and lateral (BM₂) convex hull arrangements were subjected to particle impacts. The lateral (BM₂) configuration exhibited superior stress regulation and damage mitigation. Guided by this lateral prototype, bio-inspired ceramic-fiber protectors were designed and fabricated. Ballistic tests (7.62 mm armor-piercing incendiary projectiles, 800–815 m/s) showed a 24.9% reduction in BFS compared with conventional flat composites of equal areal density, lowering potential human impact. Its impact-resistance mechanism, which involves projectile deflection combined with stress homogenization and crack guidance, closely replicates the desert scorpion tergum’s biological mechanism. This work provides a mechanism-driven design paradigm for lightweight composite armor.