Verification of a material model and estimation of the friction coefficient on the contouring of Ti rods

Abstract

This study explores the efficacy of 2D Digital Image Correlation (DIC) for material characterization of titanium spinal rods, particularly under large strain conditions. The research aims to address the lack of comprehensive material data by performing tensile tests of cylindrical specimens and applying 2D digital image correlation to derive the true stress-strain curve during plastic deformation, assuming negligible out-of-plane displacements and adopting Gromada’s coefficient of correction for triaxial stress state. The verification process includes a direct comparison with available manufacturer and literature specifications, as well as an experimental four-point bending test in conjunction with a numerical model for comparative analysis. Results demonstrate that 2D DIC, with adjustments for triaxial stress states, can reliably determine material properties, showing less than 5% deviation from established literature values. The findings advocate for the cost-effective use of 2D DIC as a promising tool for enhancing the accuracy of finite element models, especially in applications involving large deformation.