Gradient structure design and mechanical performance analysis of porous bone scaffold based on FDM technology

Bone scaffolds represent a crucial treatment strategy for bone defects. However, conventional scaffolds often lead to stress shielding and bone resorption due to mechanical mismatch with native bone tissue. To address this, the present study introduces two tailored design strategies for porous bone scaffolds: Gyroid-based pore shape variations and radially graded porosity distributions. Scaffold samples were fabricated via fused deposition modeling (FDM), and the influence of pore geometry and porosity gradient on stress–strain response, mechanical properties, and deformation mechanisms was systematically investigated. Finite element method simulations and experimental tests demonstrated that scaffolds with radial porosity gradients exhibit a Young’s modulus of 338 MPa and a yield strength of 11.2 MPa. By modifying the pore shape, these properties were enhanced to 607 and 23.6 MPa, respectively. Furthermore, a novel hybrid scaffold (Type D60-α70°) combining both porosity gradient and pore shape modulation was developed, achieving a Young’s modulus of 677 MPa and a yield strength of 25.1 MPa, closely matching the mechanical properties of human cancellous bone, thereby effectively mitigating stress shielding effects. The proposed methodology allows parametric control over scaffold performance, offering valuable theoretical insights for the design and optimisation of porous bone scaffolds.