The application of nonlinear gauge method to the analysis of local finite deformation in the necking of cylindrical bar

Localized deformation and instability is the focal point of research in mec hanics. The most typical problem is the plastic analysis of cylindrical bar necking and shear band under uniaxial tension. Traditional elasto-plastic mechanics of infinitesimal deformation can not solve this problem successfu lly. In this paper, on the basis of S(strain)-R(rotation) decomposition the orem, the authors obtain the local strain distribution and progressive stat e of axial symmetric finite deformation of cylindrical bar under uniaxial t ension adopting nonlinear gauge approximate method and computer modelling t echnique.