EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Lattice structures obtained by additive manufacturing and based on Triply Periodic Minimal Surfaces (TPMS) have been shown as a potential solution for implants to replace human bone owing to the control of the apparent mechanical properties they offer and the range they reach. The control of the mechanical properties allows the adapted solution to biomechanical problems that occur after the bone replacement with an architectured medical device.
In this study, two biomechanical problems are addressed; the minimization of the stress shielding and the long-term fatigue behaviour of a medical device. These are caused respectively by the high elasticity contrast between the medical device and the surrounding bone and the local stress concentrations on the unit cells. The main objective is the selection of one TPMS topology that can mimic the natural bone and reduce the effects of the former problems.
The numerical integrated design of TPMS-based lattices and the numerical investigation of their elastic properties using a periodic Homogenization method are described. Then, the local stresses on the unit cells are computed and compared statistically to highlight the impact of the topologies on the local stress field. The comparison of the results leads to the selection of the topology that can fit the design requirements.
The investigated topologies cover a large range of apparent elastic modulus based on the elastic modulus of the initial bulk material. Using the material properties of the biocompatible TA6V, we succeed to reach the targeted apparent elastic modulus of a bone that can reduce stress shielding. Regarding the local stress distribution, the topologies present different heterogeneous stress fields for same effective elastic properties investigated through a statistical approach to identify the suitable one.
The aforementioned results demonstrate the potential ability of the TPMS-based lattices to address various biomechanical problems concerning biomedical devices.