FE‐Based Biomechanical Analysis of AZ31B Sub‐Orbital Osteosynthesis Implant Manufactured by Superplastic Forming

ABSTRACT Fully customized biomedical implants must respect both aesthetic and functional requirements, which makes both the design and the manufacturing steps not trivial. Therefore, a solid methodology cannot only be focused on the manufacturing process: the final geometry, despite being fully respectful of the patient's morphology, is characterized by heterogeneities that could negatively affect the implant's capability of withstanding a specific loading condition. Therefore, a concurrent approach is necessary by merging manufacturing and structural needs in a proper biomechanical scenario: by extensively relying on the numerical simulation, the manufacturing process can be simulated and the results (in terms of post‐process properties of the part) imported as boundary conditions for the evaluation of the load‐bearing capacity of the implant interacting with biological structures like the bone tissue and muscle actuators. In the present work, the concurrent approach has been applied for the design of an Mg‐based sub‐orbital osteosynthesis implant produced using a metal forming process (the superplastic forming). The manufacturing step was simulated to obtain the geometry of the implant: the post‐forming properties were then imported into a second numerical model for simulating realistic loading conditions that the implant is subjected to during its service. The resulting state of stress and the occurrence of localized plastic deformation, while accounting for the degradation of the material's yield point due to the grain growth, were used as indicators to tailor the manufacturing step and optimize the post‐forming properties (mainly the thickness of the undeformed blank): it was found out that only by increasing the initial thickness of the blank and reducing the forming time (to limit the degradation of the material properties) the plastic deformation could be limited in the implant and a plate design compatible with a realistic biomechanical scenario could be thus obtained.