FORMULATIONS FOR PLANE BEAM-COLUMN ELEMENT WITH GENERALIZED PLASTIC HINGES AT BOTH ENDS : Application of kinematic hardening rules to singular yield surfaces, revisited

Abstract

We present a consistent framework for applying kinematic hardening rules to the singular yield surfaces of the generalized plastic hinges located at both ends of plane beam-column elements. It is known that, when a plastic hinge yields at a singular point of its yield surface, serious numerical difficulties may arise due to indeterminacy of plastic strains. To overcome many of the difficulties, we modify Prager's rule so that the direction of yield surface translation becomes consistent with the plastic stiffness matrix that reflects plastification of the whole element. The validity of the present approach is demonstrated through a numerical example.