Finite Deformation Analysis using Natural Strain (Relation of Principal Axis of Stress and Principal Axis of Elastic Deformation after Pre-deformation)

摘要

The anisotropy induced by large pre-deformation is chosen as the subject of this study, and the analytical model of anisotropy is examined based on the Natural Strain theory proposed in this paper. Especially, two types of pre-deformations, i.e. uni-axial tension and large shear deformation, are treated as the first step of this study. Using the test piece of pure copper, which was given these pre-deformations, the proportional loading test by tension and torsion is carried out in elastic region. The direction of the principal axis of the elastic deformation is obtained from extensional strain components of the tri-axial strain gage in consideration of the Natural Strain theory, and the relation between the direction of the principal axis of stress and the direction of the principal axis of elastic deformation is confirmed experimentally. Simultaneously, the numerical model of anisotropy caused by pre-deformation is suggested in this paper, and we estimate the relation of both principal axes.