Analysis of principal and equivalent strains in equal channel angular deformation

Abstract

Only shear and "equivalent" strains are commonly used to describe the intensity of equal channel angular deformation (ECAD). However, the equations used in their calculation are often only valid when the strain concerned is very small, and it is important to know about the principal strains. In this analysis, the magnitude and direction of the principal strains in ECAD were calculated using a matrix algebra method which is suitable for describing large plastic deformation. It showed that the principal strain axes rotated during ECAD although the principal stress axes remained fixed. It was further demonstrated that the so-called "equivalent strain" widely used in the literature was not an in..