2023, Vol. 27 ›› Issue (9): 1340-1345

Finite element analysis and structural optimization design of 3D printed forearm braces

Peng Zhixin1, Yan Wengang1, Wang Kun1, Zhang Zhenjiang2   

Abstract: BACKGROUND: The use of 3D printing technology to make personalized braces for patients is widespread, but there is a lack of biomechanical verification of the protective effect of braces on fracture sites.
OBJECTIVE: To combine reverse modeling, finite element analysis and topology optimization, propose a feasible method of 3D printing forearm bracing, and to verify the effectiveness of the brace through finite element analysis.
METHODS: Reverse modeling was used to construct a male volunteer forearm model by medical image processing software Mimics. Parametric design software Grasshopper was used to process the forearm data collected by Rodin 4D and to establish the brace model. Based on the biomechanical properties of the forearm, finite element analysis was carried out on the whole model of the forearm wearing the brace. The topology optimization and drilling were carried out on the brace according to the finite element analysis results. Finally, the brace was printed with a 3D printer.
RESULTS AND CONCLUSION: (1) Under the pressure load of 100 N, the stress and displacement at fracture point were 1.53 MPa and 0.27 mm, respectively, while the stress and displacement at fracture point of the forearm under the protection of brace were 0.19 MPa and 0.005 mm, respectively. (2) Topology optimization was carried out on the premise of ensuring the mechanical properties of the brace. By comparing the stiffness results of the optimized brace, 40% volume reduction was selected as the optimization result. According to the optimization results, Grasshopper plug-in was used to drill holes and reduce materials for the support. (3) By comparing the strength analysis of the brace designed by the hollow out of different samples, the Tyson polygon was selected as the punching sample. (4) This article proposes the feasibility of using digital design and 3D printing technology for the forearm brace, and establishes a complete forearm brace design, verification and manufacturing system.
Key words: forearm fracture, biomechanics, reverse modeling, 3D printing, finite element analysis, topology optimization, digital design, Tyson polygon, hollow out design