Multi-objective field-based collaborative design of multi-layer IWP lattice enhancement mechanisms and mechanical properties

Triply periodic minimal surface (TPMS) structures face challenges in balancing lightweighting with mechanical performance. This study proposes a multi-objective field-driven design strategy. Using laser powder bed fusion (LPBF) technology, we fabricated multi-layer lattice structures from 316 L stainless steel, including isotropic (IWP-IWP) and anisotropic (IWP-D) configurations. Through quasi-static compression experiments, finite element simulations, and theoretical predictions, their compressive behavior, energy absorption characteristics, and deformation mechanisms were systematically investigated. Results demonstrate that multi-layer structures exhibit significant performance enhancements over primary structures at equivalent densities. Specifically, the heterogeneous IWP-D-21% structure achieved maximum increases of 57.46% and 64.72% in yield strength and elastic modulus, respectively. While the IWP-IWP-27% structure achieved maximum increases of 76.11% and 59.87% in plateau stress and energy absorption per unit volume, respectively. The deformation mechanisms differ markedly: IWP-IWP exhibits “drum-shaped” deformation, while IWP-D demonstrates uniform overall deformation. The established finite element model based on Johnson-Cook constitutive mechanics accurately predicts mechanical properties with an error below 9.82%. This strategy opens new avenues for designing high-performance multifunctional lattice structures in fields such as aerospace critical load-bearing components.