A STUDY ON ELASTO-PLASTIC BEAM ELEMENT CONSIDERED PLASTIC HARDENING AND PLASTIC REGION SIZE : In case of monotonic loading

In analyzing structures composed of many members, the plastic hinge method or multi-spring model is applied to simulate the elastoplastic behavior of each member. The plastic hinge method is convenient to analyze the elastoplastic behavior. The method is sometimes applied to the elastoplastic problem with hardening, but it can not evaluate to expansion of the plastic region. This is because the consideration of plastic region is contradictory to the basic concept of the plastic hinge method. In comparison, the standard FEM enables us to solve those problems but it is very costly method. So in this paper, we suggest a convenient analytical method for the beams consists of two flanges with plastic hardening property. The numerical results prove the validity and the effectiveness of the present method, through the comparisons with results by the standard FEM