Study on mechanical properties and permeability of elliptical porous scaffold based on the SLM manufactured medical Ti6Al4V

Abstract

In this paper, we take the elliptical pore structure which is similar to the microstructure of cancellous bone as the research object, four groups of bone scaffolds were designed from the perspective of pore size, porosity and pore distribution. The size of the all scaffolds were uniformly designed as 10 × 10 × 12 mm. Four groups of model samples were prepared by selective laser melting (SLM) and Ti6Al4V materials. The statics performance of the scaffolds was comprehensively evaluated by mechanical compression simulation and mechanical compression test, the manufacturing error of the scaffold samples were evaluated by scanning electron microscope (SEM), and the permeability of the scaffolds were predicted and evaluated by simulation analysis of computational fluid dynamics (CFD). The results show that the different distribution of porosity, pore size and pores of the elliptical scaffold have a certain influence on the mechanical properties and permeability of the scaffold, and the reasonable size and angle distribution of the elliptical pore can match the mechanical properties and permeability of the elliptical pore scaffold with human cancellous bone, which has great potential for research and application in the field of artificial bone scaffold.

Fig 1. CAD diagram of four groups of scaffolds.

Fig 2. Finite element analysis model of porous scaffold.

Fig 3. Four groups of Ti6Al4V samples manufactured by SLM.

Fig 4

Mechanical compression test: (a) test operation diagram; (b) schematic diagram of test.

Fig 5. Boundary conditions of CFD analysis.

Fig 6

SEM morphology of SAP scaffolds: (a) and (b) side view of pores at different locations, (c) view of top surface, (d) micro-morphology of trabeculae, (e) single pore view, (f) view of the pore wall under a high-power microscope.

Fig 7

Finite element analysis cloud map: a) equivalent stress cloud map, b) displacement cloud map.

Fig 8

Stress-strain curve of scaffolds: a) Stress-strain curve by finite element simulation; b) Stress-strain curve obtained by compression test.

Fig 9

Four groups of scaffolds pressure drop cloud: (a) SU pressure drop cloud, (b) SA pressure drop cloud, (c) SP pressure drop cloud of direction +Z, (d) SP pressure drop cloud of direction -Z, (e) SAP pressure drop cloud of direction +Z, (f) SAP pressure drop cloud of direction–Z.

Fig 10

Four groups of scaffolds velocity cloud: (a) SU velocity cloud map, (b) SA velocity cloud map, (c) SP velocity cloud map of direction +Z, (d) SP velocity cloud map of direction -Z, (e) SAP velocity cloud map of direction +Z, (f) SAP velocity cloud map of direction–Z.

Fig 11. Pressure drop and permeability of four groups of scaffolds.