Modeling of axial strain in free-end torsion of textured copper

Abstract

Abstract The axial strains that develop during free-end torsion testing of copper wires have been modeled using the results of earlier measurements (L. S. Tóth, P. Szászvári, I. Kovács, J. J. Jonas: Mater. Sci. and Techn. 7 (1991) 458). In that work, the initial textures of the wires were changed by heat treatments. The as-received wires displayed shortening while the recrystallized ones lengthened during twisting at room temperature. In the simulations, the wire was divided into five cylindrical layers; in each layer, the texture development was simulated using the Taylor viscoplastic poly-crystal model up to large strains (γ ≈ 5). The distribution of the hydrostatic stress was derived from the equilibrium equation of torsion. Using a suitable numerical scheme, the condition of zero axial force (free-end testing) was satisfied in an iterative way. Good agreements between the measurements and simulations have been obtained.