Crashworthiness optimization of bio-inspired fish-cell lattice structures

Bio-inspired cellular structures have gained research interest in recent years due to their exceptional energy absorption capacity and lightweight potential in impact-critical applications. Although fish-cell topologies have recently been proposed as zero Poisson’s ratio metamaterials, their crashworthiness performance under compressive loading, particularly when combined with additive manufacturing and surrogate-based design optimization, remains largely unexplored. This study presents a novel fish-cell lattice structure fabricated from Acrylonitrile Butadiene Styrene (ABS) via fused deposition modeling (FDM) which is systematically investigated under quasi-static axial compression. To capture the precise deformation physics, a nonlinear finite element model was developed and validated against experimental force–displacement data using LS-DYNA. Following the validation, a Kriging surrogate-based optimization framework was implemented aiming to maximize Specific Energy Absorption (SEA) and Crush Force Efficiency (CFE) simultaneously. The optimized lattice geometry achieved remarkable performance, yielding an experimental SEA value of 2.582 kJ/kg and a near-unity CFE of 0.99 in the best-performing test, alongside a three-specimen mean of 2.489 kJ/kg and 0.964, respectively. These outcomes correspond to an improvement exceeding 200% in SEA over the baseline design. The experimental results confirmed the surrogate predictions with deviations below 5%, and demonstrated that the fish-cell zero Poisson’s ratio (ZPR) lattice configuration serves as a highly efficient, geometrically tunable, and robust solution for advanced lightweight energy-absorbing applications in the automotive, aerospace, and defense industries.