Topology-regulated load transfer mechanisms and mechanical performance of sheet-based TPMS titanium scaffolds

Triply periodic minimal surface (TPMS) structures provide a route to control stiffness while retaining pore space, but quantitative links among topology, load transfer, and mechanical response remain limited. This study establishes a topology-load transfer-mechanical response framework by integrating quasi-static compression experiments, Digital Image Correlation, and validated finite element analysis on representative Triply Periodic Minimal Surface titanium scaffolds. The Gyroid-Sheet scaffold exhibits a topology-regulated progressive instability-restabilization deformation mode, distinctly different from the conventional lattice structures exhibiting plateau-dominated yielding behavior. GS20 exhibited experimental Young's modulus and yield strength of 2.26 GPa and 49.6 MPa, whereas FEA predicted 2.68 GPa and 65.43 MPa; therefore, simulations were used only for comparative interpretation. Numerically, its normalized modulus and strength were 13.40 GPa and 327.15 MPa, approximately 36% and 20% higher than PS20, respectively, indicating superior predicted material utilization under identical idealized conditions rather than experimentally validated cross-topology mechanical properties for fabricated TPMS scaffolds. Gibson-Ashby analysis suggests that the Gyroid-Sheet topology retains mechanical efficiency as relative density decreases. A multiscale framework combining elastic anisotropy, principal-stress streamlines, and strain-energy density was then used to interpret how topology governs load transfer and localized mechanical response patterns. The Gyroid-Sheet structure exhibits a near-isotropic elastic response (Zener index = 1.13), along with a higher proportion of stress streamline segments with deflection angle θ < 15° (5.19%) and local turning angle φ < 15° (39.96%), indicating enhanced directional coherence and spatial continuity of load transfer paths. G GS20 testing and comparative simulations suggest that continuous sheet topology promotes load-transfer continuity, material utilization, and resistance to localized energy concentration. These characteristics may support stiffness regulation and load sharing while preserving interconnected pore space for potential fluid and tissue access. The proposed mechanics-based framework therefore provides a basis for screening orthopedic scaffold architectures, although broader experimental validation remains necessary.