Mapping porous microstructures to yield desired mechanical properties for application in 3D printed bone scaffolds and orthopaedic implants

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Ling Wang, Jianfeng Kang, Changning Sun, Dichen Li, Yi Cao, Zhongmin Jin
Porous design of orthopaedic implants affords the advantages of minimizing stress shielding and improving the osseointegration and long-term stability. However, the marked error in the manufactured porous structure relative to the designed model yields limited application of the porous design. This study aimed to develop a methodology to derive the relationship between the porosity, the structural characteristic parameters and the mechanical properties of a typical structural unit, to lay the foundation of a porous structural design for 3D-printed implants with gradient modulus. Mathematical expressions related to porosity were determined based on various parametrical characteristics of porous units; the effective modulus of such a porous structure was studied under variable axial loading by using finite element analysis to gain insight into the anisotropic properties of the porous structure, and to evaluate the effects of parametrical variation on the aforementioned properties. For validation purposes, samples were manufactured via selective laser melting (SLM) 3D printing technology and mechanically tested. Results indicated that porous design can reduce the effective modulus of implants by 75–80%. A general methodology was developed for evaluating BCC structural units to determine design parameter correlations, the porosity and the effective modulus of the structure.

Graphical abstract

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