Towards the development of reliable finite element models of Ti6Al4V trabecular structures fabricated via laser powder bed fusion for biomedical applications

Abstract

Additive manufacturing technologies are commonly adopted for the fabrication of trabecular-based orthopedic prostheses made of titanium alloys due to their ability in producing complex and intricate designs. In this scenario, the use of finite element models represents a powerful tool for designing such devices and assessing their biomechanical behavior. Nevertheless, the usefulness of a numerical approach depends on the reliability of the adopted models, a crucial aspect when dealing with trabecular structures present within orthopedic implants. Indeed, the description of their effective geometry and the characterization of the material mechanical properties represent a tough challenge that hinders the development of high-fidelity numerical models. Specifically, the small dimensions of the trabeculae approach the accuracy limit of additive manufacturing leading to relevant uncertainties in their production. The existing studies dealing with the finite element modeling of 3D-printed trabecular structures often neglect the geometrical and material peculiarities of thin struts, making questionable the reliability of the developed numerical models. Namely, they either make simplifications in describing the mechanical properties of the material or do not account for realistic geometries. To address this gap, the present work aims to propose a systematic approach that achieves the development of accurate finite element models of trabecular structures, by integrating experimental activities with numerical simulations. This approach is exemplified by using two distinct trabecular structures used in the design of a custom talus prosthesis.