Non-linear structural benchmarking of 3D printed titanium TPMS lattices for patient-specific orthopaedic scaffold design

Can additively manufactured TPMS lattices be systematically benchmarked to guide patient-specific orthopaedic scaffold design? Triply periodic minimal surface architectures offer high surface area, fully interconnected porosity, and tuneable mechanical behaviour, but direct experimental comparisons across topologies within clinically relevant manufacturing limits remain underexplored. Here, fifty-four Ti-6Al-4V TPMS lattices (Gyroid, Diamond, Split-P) were fabricated using laser powder bed fusion (l-PBF) with wall thicknesses of 100-500 μm and unit cell sizes of 0.75-2.0 mm 3 . Quasi-static compression testing revealed strong geometry-dependent mechanical behaviour, with effective Young’s modulus ranging from 6.3-107 GPa, yield strength from 125-1030 MPa, and strain energy density from 2.23-12.66 MJ/m 3 . Increasing wall thickness increased stiffness and energy absorption, while increasing unit cell size consistently reduced stiffness across all architectures. Diamond and Split-P lattices exhibited higher average energy absorption ( 5.1 MJ/m 3 ) compared with Gyroid ( 4.05 MJ/m 3 ), whereas Gyroid structures showed more stable deformation behaviour. Comparison with Gibson-Ashby scaling revealed systematic deviation at relative densities above 0.45, highlighting topology-dependent load transfer and manufacturing effects. To translate these results into design guidance, a hybrid decision-making framework integrating Analytic Hierarchy Process, Target-Driven Decay, and TOPSIS (AHP-TDD-TOPSIS) was implemented to rank scaffold configurations against mechanical and biological criteria. The results provide experimentally validated guidance for patient-specific TPMS scaffold selection and orthopaedic implant optimisation.