Finite Element Analysis of Prosthetic Finger Connectors: Comparison of Ti-6Al-4V and PEEK-Based Polymers Using COMSOL

Introduction/Objectives: The mechanical reliability of prosthetic finger connectors is critical for daily prosthesis use, as these small load-bearing elements transmit forces between finger segments and are prone to localized stress concentration at hinge transitions. The objective of this study was to quantitatively evaluate the mechanical performance of prosthetic finger connectors and determine how material selection influences stress distribution and deformation behavior when connector geometry is maintained constant. Methods: A controlled comparative finite element analysis was performed using COMSOL Multiphysics 6.2 on a single prosthetic finger connector geometry manufactured from four candidate materials: titanium alloy Ti-6Al-4V (E = 110 GPa), polyetheretherketone (PEEK, E = 4.0 GPa), AvaSpire AV-621 NT (E = 3.0 GPa), and KetaSpire KT-820 FP (E = 4.1 GPa). Three representative loading scenarios were simulated using an axial grip force of 50 N and a bending moment of 0.5 N·m: (1) axial loading, (2) combined axial and forward bending, and (3) combined axial and reverse bending. Results: Across all loading conditions, peak von Mises stresses consistently localized at the hinge-transition region of the connector. Ti-6Al-4V demonstrated the lowest peak stress (approximately 2.2 MPa under combined forward bending) and the smallest maximum displacement (approximately 0.0005 mm). In contrast, the PEEK-family polymers showed greater deformation (0.0125–0.0167 mm) due to their lower elastic modulus, while maintaining comparable peak stresses of approximately 2.5–2.6 MPa. The stress profiles along the connector arc length were nearly identical among all materials, indicating that connector geometry primarily governs stress localization, whereas material stiffness mainly determines deformation magnitude. Conclusions: This study demonstrates that material selection strongly affects prosthetic finger connector compliance, while stress concentration behavior is mainly controlled by geometry. The obtained quantitative comparison provides design-oriented guidance for selecting between Ti-6Al-4V and PEEK-based polymers for the development of lightweight and mechanically reliable prosthetic finger connectors.