Hencky strain as a measure to evaluate large deformations caused by giant straining processes

Abstract

The Hencky strain is a logarithmic strain extended to a three-dimensional analysis. By considering logarithm of matrix, components of the Hencky strain are calculated for tensile and shear deformations. ECAP (Equal-Channel Angular Pressing) and HPT (High Pressure Torsion) are giant straining processes based on simple shear deformation. To describe large deformations caused by such giant straining processes, components of the Hencky strain and its equivalent strain are derived for the simple shear deformation. It is shown that the Hencky strain is an appropriate measure to deal with deformations caused by the giant straining processes. © 2010 The Japan Institute of Metals.