On the Deformation Modes of Continuous Bending under Tension Test

In this paper the continuous bending under tension (CBT) test is analyzed by numerical simulation. In CBT test, the material is deformed to high level of strain that is beyond the achieved strain by the standard tensile test. The main stability criterion describes the importance of compressive stress produced by bending in stabilizing the deformation. At the symmetry line of the strip, the material can be assumed simply to deform by bending and stretching in plane strain condition. The focus of this paper is to study the deformation modes through thickness at the symmetry line. It is found that the material experiences three deformations modes. The cyclic parts through thickness experiences two deformation modes: the first is limited between uniaxial tension and plane strain and the second deformation mode is limited between pure shear and uniaxial compression. The third deformation mode is observed at the middle part through thickness and it is based on tension and the contribution of through thickness stress.