COMPUTER ASSISTED DESIGN AND STRUCTURAL TOPOLOGY OPTIMIZATION OF CUSTOMIZED CRANIOFACIAL IMPLANTS

摘要

Modern design and manufacturing engineering technologies have greatly improved the way in which modern craniofacial implants are designed and fabricated. However, few efforts have been made in order to optimize their design. While the weight of polymer-based implants (e.g. PMMA implants) may not affect the patient's comfort, the higher weight of metal-based implants (e.g. titanium implants), could greatly affect the patient's comfort, causing in some cases nuisances and imbalance problems. Thus, the optimization of the implant becomes relevant in order to guarantee its structural stiffness but with a reduced weight. In this paper, the design and structural optimization of customized craniofacial implants based on the use of modern engineering technologies is presented. The aim is to introduce an engineering methodology for the design and optimization of customized craniofacial implants. The methodology starts from the patient's medical images, obtained from a computerized tomography (CT), which are processed to reconstruct the digital 3D model. Next, the geometrical design of the implant is carried out in a computer aided design (CAD) system using the patient's 3D model. Then, the structural analysis of the implant is performed using the Finite Element Method (FEM) and considering a quasi-static load. The topology optimization of the implant is made using the Solid Isotropic Material Penalization (SIMP) method. Finally, the optimized customized implant is fabricated in an additive manufacturing (AM) system. A case study of a craniofacial implant is presented and the results reveal that the proposed methodology is an effective approach to design and optimize craniofacial implants.