PLASTIC DEFORMATION CAPACITY OF STRUCTURAL STEEL UNDER VARIOUS AXIAL STRAIN HISTORIES

Abstract

In the field of energy based seismic design, the structural performance of steel structures is determined by the energy dissipation capacity, which depends greatly on the plastic deformation capacity of the structural components that form the whole system. The plastic strain capacity of the structural steel is one of the primary factors that determine the components' plastic deformation capacity. Most of the cyclic loadings employed in the structural steel tests are the recommended standard (typically incremental or constant amplitude) loading protocols, which is insufficient to study the deformation capacity under random loadings such as earthquake effects. This paper focuses on the evaluation of the plastic strain capacity of structural steel under various axial strain histories till ductile fracture. A series of element specimens made of SS400 and SN400 steel were tested under diverse cyclic axial strain loadings. The deformation capacity of the structural steel under cyclic axial loading till fracture was evaluated by studying the experimental strain capacity/energy dissipation capacity of the skeleton curve and the Bauschinger part. The error range of this method was proved smaller than that of the Miner's rules.