Influence of Cell Size and Porosity on Permeability in Bone Scaffold TPMS Structures

In bone tissue engineering, bone scaffold structures based on triply periodic minimal surfaces (TPMS) are of significant interest, with permeability being a key indicator of scaffold performance. This paper constructs three types of bone scaffold TPMS structures—Diamond (D), Gyroid (G), and IWP—in both sheet (S) and network (N) forms, and it specifically investigates the impact of two structural parameters—cell size and porosity—on the permeability of these porous structures through numerical simulation. The results demonstrate that permeability increases with both cell size and porosity. Among the structures, the IWP type exhibits significantly higher permeability compared to the other two types. Under identical conditions, N-form structures show superior permeability over S-form structures within the same type. Additionally, empirical formulae for calculating the permeability of the three N-form structures, based on the two parameters of cell size and porosity, are derived. These formulae have been experimentally validated, demonstrating that the errors within a reasonable and acceptable range. These findings provide theoretical guidance for the optimized design and practical application of bone scaffold TPMS structures.