Study on the impact resistance of foam concrete-filled straight-walled Tetra-ligament aluminium alloy anti-chiral honeycomb structures

Objective To enhance the energy-absorption efficiency of auxetic (negative Poisson’s ratio, NPR) honeycombs for naval blast protection, a novel in-plane NPR honeycomb is proposed that combines a straight-wall, tetra-ligament, anti-chiral aluminium alloy skeleton with a foam-concrete infill.

Methods Finite-element models were built in ABAQUS using S4R shell elements for the 6061-T6 alloy framework and C3D8R solid elements for the foam-concrete filler. In-plane crushing was simulated at 1 m s⁻¹, 15 m s⁻¹ and 100 m s⁻¹, and the collapse modes (crushing mode), stress-strain responses and volumetric specific energy absorption (SEA) of unfilled, polyurethane-filled and foam-concrete-filled specimens were compared.

Results The foam-concrete infill altered the collapse mode, distributed stresses more uniformly and introduced brittle-material characteristics into the stress–strain curves. At high (100 m s⁻¹), medium (15 m s⁻¹) and low (1 m s⁻¹) impact velocities the SEA of the filled honeycomb exceeded that of the unfilled baseline by more than 200 %.

Conclusion The tetra-ligament, anti-chiral architecture successfully couples the ductility of the metallic framework with the brittle crushing behaviour of foam concrete, offering a promising solution for lightweight, high-efficiency blast protection in ship structures.