Validation of lumbar fusion device TILIF (Ti-6Al-4 V) manufactured by EBM additive manufacturing through fem modeling high cycle fatigue tests

Abstract

This study aims to validate the computational fatigue analysis of a Transforaminal Lumbar Intervertebral Fusion (TLIF) prosthesis using high cycle fatigue (HCF) test data through the Finite Element Analysis Method (FEM). The Additive Manufacturing by Electron Beam Fusion process enables the construction of complex geometries for lumbar fusion prostheses, making it the preference of manufacturers for high-scale production. However, ensuring the structural validation of such products through static and dynamic tests can be time-consuming and expensive. Computational simulations using FEM can provide preventive and predictive analyses to anticipate structural problems arising from loads specified in projects, allowing for the development of geometric models that meet the mechanical tests requested by the ASTM F2077-18 standard. The HCF specimens were tested for fatigue life assessment between 107 cycles, improving test duration compared to traditional methods. The mechanical properties of the material, such as modulus of elasticity, yield strength, ultimate tensile strength, and density, were taken into account during testing. The results obtained through FEM were effective, demonstrating the predictive capability of this method in the development of new products manufactured by additive manufacturing technology using Titanium Grade 5. This research also compares the use of virgin powder and recycled powder in the manufacturing process, showing the differences in fatigue between the two materials. The study indicates that the mechanical properties of recycled powder are inferior to those of virgin powder, and as a result, the fatigue life of parts manufactured using recycled powder is lower than those manufactured with virgin powder. In conclusion, this study demonstrates the effectiveness of using computational fatigue analysis through FEM to predict the mechanical behavior of lumbar prostheses. The research provides valuable insights for manufacturers, indicating that the use of virgin powder in the manufacturing process can lead to longer fatigue life of the parts compared to the use of recycled powder.