Design and mechanical testing of porous lattice structure with independent adjustment of pore size and porosity for bone implant

Abstract

Porosity is considered to be one of the key factors affecting the structural properties of porous lattices, but in fact, pore size also plays an important role, and it has great potential to adjust pore size and porosity independently to improve structural properties. In this work, by adjusting the sheet thickness of the triply periodic minimal surface (TPMS) lattice structures and adjusting the height of the single row structure according to linear and constant laws, the TPMS lattice structures with given porosity and adjustable pore size are designed, and the mechanical response is investigated. Based on preparing samples by Ti6Al4V laser powder bed fusion, the results of the tests show that the elastic modulus ranges of linear change TPMS (LC-TPMS) and constant TPMS (C-TPMS) lattice structures are 3625.6 MPa–4575.1 MPa and 3820.0 MPa–4509.1 MPa, respectively. In the plateau stage, the LC-TPMS lattice structures have a longer and more stable plateau stage, higher yield stress and better energy absorption capacity than the C-TPMS lattice structures. The maximum energy absorption difference is 62.7 MJ/mm3 and the maximum energy absorption efficiency difference is 0.12. The LC-TPMS lattice structures can also obtain a larger damping ratio under larger compressive strain.