Materials and architected structures for underbody blast mitigation in armoured fighting vehicles: From conventional protection systems to additively manufactured metallic lattices

Armoured Fighting Vehicles (AFVs) must survive distinct but interacting threat classes, including kinetic-energy and armour-piercing projectiles, shaped-charge jets, high-velocity fragments, top-attack munitions, and buried mine/IED blast. This review therefore positions underbody energy absorbers within the wider layered protection architecture, while deliberately focusing its detailed assessment on mine/IED blast mitigation. Conventional metallic armour, ceramic-backed and fibre-reinforced systems, reactive protection, active protection, V-shaped hulls, metallic foams, aluminium honeycombs, and additively manufactured lattices are compared according to their primary protection function and appropriate performance metrics. Particular attention is given to laser powder bed fusion (LPBF) of A286 alloy because it combines precipitation-strengthened mechanical properties, corrosion and thermal stability, and practical LPBF processability with emerging high-strain-rate evidence. A286 is not treated as a ballistic replacement for RHA, MHA, HHA, or HNS; rather, A286 lattices are evaluated as sacrificial energy-absorbing elements intended to operate together with a structural hull and primary ballistic protection. The review separates quasi-static screening, Split Hopkinson Pressure Bar (SHPB) characterization, impact testing, and explosive-blast validation, and links LPBF porosity, lack-of-fusion defects, surface roughness, residual stress, and anisotropy to dynamic collapse and failure. The applicability of the Maxwell criterion is restricted to pin-jointed strut networks, whereas TPMS behaviour is discussed using surface/shell mechanics, curvature, relative density, and observed deformation modes. Ashby-type normalized maps and recent AI-enabled approaches are incorporated to compare architected systems and support defect detection, topology optimization, high-rate response prediction, and digital-twin design. The resulting framework identifies the evidence still required to translate LPBF lattices from coupon-scale energy absorbers to qualified, modular underbody blast-mitigation components in integrated AFV protection systems.