Mechanoregulation modelling of stretching versus bending dominated periodic cellular solids

Abstract

With additive manufacturing advancements, the possibility of creating lattice-based 3D-printed implants can enhance the osseointegration of orthopedic devices. To this date, there is no study that characterizes Ti6Al4V lattice structure microscopic geometrical parameters based on mechano-regulatory theories. This research compared twenty-four different lattice topologies using bone ingrowth stimulations, at ten different relative densities (between 5 % and 50 %) subjected to four different pressures (0.5 MPa, 1 MPa, 1.5 MPa and 2 MPa). A total of 964 results from the numerical mechano-regulation analysis are presented. Sub-groups of Stretching-dominated lattice (SDL) and Bending-dominated lattice (BDL) topologies were compared. The analyzed topologies include AFCC, Auxetic, BCC, Diamond, FBCC, FCC, G7/ Octahedron, Kelvin cell, Vintile, Rhombic Dodecahedron, Cubic, Octet, Cuboctahedron, Rhombicuboctahedron, Iso-truss, Truncated Cube, Truncated Cuboctahedron, and BCCZ, FCCZ, FBCCXYZ and Cubic Center. Higher deformation and fluid flow were observed in BDL topologies leading to better mature bone growth stimulation compared to the SDL topologies. Topologies with lower Young’s Moduli were also leading to better growth stimulation. It is found that the most favourable BDL topologies include, BCC, Diamond, FBCC, G7, Octahedron. On the other hand, the most favourable SDL are Tetrahedron and Tesseract. Material selection design charts are created which will help in the design of novel Ti6Al4V lattice-based implants.