Elasto-plastic behavior of the structure on multi-axial loading

In the limit analysis of a structure, the Interaction Curve (abbreviated to I.C) defined by the generalized internal forces is usually treated as similar to a yield curve defined by the conventional stress. On the analysis, the plastic deformation is believed to proceed in the normal direction on an I.C.; that is defined as the normal flow rule. Although the normal flow rule, suggested by R.Hill or D C.Drucker for the conventional plastic flow, is applied to the generalized plastic deformation, our previous studies assert that the radial flow rule is reasonable rather than the normal flow rule for the plastic deformation. On the radial flow rule, the plastic deformation proceeds in the radial direction on an I.C. In this research, the plastic behavior of the right-angle bent bar structure (introduced by Heyman) is studied. The collapse load according to the radial flow rule is compared with that according to the normal flow rule by investigating the deformational behavior. Moreover, the collapse load derived by the upper and lower bound theorems is discussed here.