Effective Elastic Response of Triply Periodic Minimal Surface Lattice Structures Fabricated from 316L Stainless Steel by Laser Powder Bed Fusion

Triply periodic minimal surface (TPMS) lattices are an emerging class of cellular architectures whose smooth, mathematically defined surfaces enable highly tailorable mechanical performance. This study quantifies the compressive elastic response of three sheet-based TPMS topologies, i.e., Diamond, Gyroid, and Lidinoid, through finite element (FE) analysis and experimental validation. For each topology, the effective Young’s modulus was computed by single-cell finite element analysis under uniaxial compression boundary conditions on a 2 mm unit cell across five wall thicknesses (0.35, 0.45, 0.65, 0.95, and 1.30 mm), corresponding to relative densities from approximately 25% to 95%. Experimentally, cylindrical specimens of 316L stainless steel at 70% relative density were fabricated by laser powder bed fusion (LPBF) and tested in uniaxial compression with a strain rate of 10−3 s−1 per ISO 13314:2011 (i.e., 0.02 mm/s). The Diamond topology exhibited the highest effective modulus across the full density range, followed by Lidinoid and Gyroid. FE predictions agreed with experimental moduli within 4.7% for Diamond (100.2 GPa vs. 95.5 ± 3.9 GPa), 0.04% for Gyroid (79.8 GPa vs. 79.8 ± 0.88 GPa), and 1.5% for Lidinoid (85.6 GPa vs. 86.9 ± 3.5 GPa). Moreover, the Gibson–Ashby exponents determined span the range from stretching- to bending-dominated deformation with n = 1.69 for Diamond, 1.74 for Lidinoid, and 2.08 for Gyroid. Single-cell FE analysis accurately captured the effective elastic response of LPBF 316L stainless steel TPMS lattices examined.