Mechanical and fluid dynamic characteristics of S-type triply periodic minimal surface radial functionally graded bone scaffolds

• GP composite scaffolds, featuring a radial gradient from P-type to G-type topology and porosity from 35% to 65%, achieve a balance between mechanical strength and mass transport, outperforming homogeneous scaffolds. • The GP composite scaffold exhibited the lowest maximum Mises stress and displacement, indicating superior stress distribution and structural stability under load. • Permeability of the GP composite scaffold (3.4×10⁻⁹ m²) was significantly higher than single-structure scaffolds and fell within the optimal range for cancellous bone, enhancing nutrient transport. • Wall shear stress values for all scaffolds were within the optimal range for bone regeneration (0.4-3 Pa), with the GP scaffold providing a favorable fluidic microenvironment for cellular activity.