Abstract
The Natural Strain is obtained by integrating an infinitesimal strain increment on an identical line element. Therefore, this theory has merits that the rigid body rotation can be removed from the rotating angle of a line element and the additive law of strain on an identical line element can be satisfied. Using specimens, which have already received large pre-deformations of simple shear, the relations between direction of principal axis of stress and principal axis of strain are investigated by performing proportional loading tests for tension and torsion in an elastic region. Especially the different deformation histories, i.e. the large simple shear in a certain direction and in the opposite direction, are chosen as the pre-deformation. The co-relation between the anisotropy of elastic modulus G and the magnitude of strain hardening induced by these pre-deformation are discussed in this report.
