05.05: A flexibility‐based element for second‐order inelastic analysis using plastic hinge method

Abstract

ABSTRACTIn the past decades, the stiffness‐based elements with plastic hinge method and the flexibility‐based elements with plastic zone method are widely used for second‐order inelastic analysis. The former emphasizes the computational efficiency with relatively less accurate structural responses while the later aims to precisely simulate the structural behaviour but normally needs more computer times. For the member under complex loads, several stiffness‐based elements are generally required to capture its plastic behaviour. In such case, one‐element‐per‐member for member initial imperfection required in second‐order direct analysis is violated. On the contrary, a flexibility‐based element with several integration points is sufficient for material yielding. However, the more integration points associated with fibre section the more computational efforts are needed. It is also noted that the conventional flexibility‐based type elements cannot meet the codified requirements of direct analysis due to lack of consideration of member initial imperfection. In this paper, a new flexibility‐based element equipped with plastic hinge method without huge computational time is proposed for second‐order inelastic analysis. This element is also able to take the member initial bowing into account. Thus, an innovative solution is proposed for routine design. Finally, several numerical examples are used to demonstrate the validity and accuracy of the proposed method.