Cyclic plasticity of steel

Abstract

During an earthquake, structural members in buildings can experience a relatively small number of completely plastic load cycles. Unexpected failures of structural members as a result of the Northridge and Kobe earthquakes during the 1990s illustrated a lack of understanding of how steel behaves under this type of load condition. Experiments have been carried out to investigate how the work hardening of a 350 MPa yield structural steel varies under cyclic loading and monotonic loading. Comparisons between these two conditions have been drawn on the basis of material toughness. This was done in an attempt to predict the fracture performance of cyclically deformed steel using the properties determined by monotonic loading of the same steel. Previous work at the University of Auckland has considered how monotonic work hardening affects the fracture properties of steel. The aim of this research, then, was to extend the results previously obtained and to improve the ability to predict failure.