Elastic-platic stress and deformation analysis of annular plates under prescribed radial loading

A modified form of constitutive equation for an isotropic elastic-plastic deformation of circular plates subjected to radial tensile loading on the inner surface is introduced. The form takes into consideration the effect of rotation of various principal axes and material hardening during the process of continued deformation. Plastic instability analysis of plates is carried out to determine stresses at the onset of cavity formation. Both symmetric and antisymmetric modes of deformation are determined. It was found out that the modified form which is derived in this study leads to deformation stresses which are lower than those obtained when classical plasticity relations are used, and therefore, are comparable with the results obtained experimentally. It is found also that deformation is asymmetric with respect to the plate axis and depends not only on the stress in the current state but also on the prescribed incremental traction ratio and material properties.