Abstract
Titanium porous cellular microstructures are commonly used in bone mimetic implants. The orientations of the internal strut architectures of these microstructures affect the mechanical performance under various loads; however, poor architectural designs may result in their failure. Three-dimensional (3D) finite element models of cubic, diamond, and body-centered cubic (BCC) geometries were constructed with 1-4 numbers of unit cells and 4-10-mm unit cell size. Mechanical testing of the finite models of the cubic, diamond, and BCC structures with porosities of 20-90% was performed under compression, bending, and torsional loads. The BCC structure showed moderate and relatively isotropic mechanical properties compared with those of the diamond and cubic structures. A design space for a BCC porous structure with a porosity of 40-65% was estimated to model a complete porous stem to mimic the bone properties. Furthermore, the stems with the determined porous mechanical properties of the BCC microstructures with 20-90% porosities were tested under physiological loading conditions. It was found that a porosity of 47.3% of the BCC structure exhibits the closest stiffness (469 N/mm) to an intact bone (422 N/mm). This was predicted by our suggested design space of the porosity. (c) 2018 Elsevier Ltd. All rights reserved.