Reference Type: Journal Article Record Number: 1 Author: Iu, C. K. and Bradford, M. A. Year: 2011 Title: Higher-order non-linear analysis of steel structures part ii : refined plastic hinge formulation Journal: Advanced Steel Construction Volume: 8 Issue: 2 Pages: 16 Start Page: 183 Short Title: Higher-order non-linear analysis of steel structures part ii : refined plastic hinge formulation DOI: 10.18057/IJASC.2012.8.2.6 Keywords: Beam-column, Frames, Interaction surface, Material non-linearity, Refined plastic hinge method, Strain hardening Abstract: In the companion paper, a fourth-order element formulation in an updated Lagrangian formulation was presented to handle geometric non-linearities. The formulation of the present paper extends this to include material non-linearity by proposing a refined plastic hinge approach to analyse large steel framed structures with many members, for which contemporary algorithms based on the plastic zone approach can be problematic computationally. This concept is an advancement of conventional plastic hinge approaches, as the refined plastic hinge technique allows for gradual yielding, being recognized as distributed plasticity across the element section, a condition of full plasticity, as well as including strain hardening. It is founded on interaction yield surfaces specified analytically in terms of force resultants, and achieves accurate and rapid convergence for large frames for which geometric and material non-linearity are significant. The solutions are shown to be efficacious in terms of a balance of accuracy and computational expediency. In addition to the numerical efficiency, the present versatile approach is able to capture different kinds of material and geometric non-linearities on general applications of steel structures, and thereby it offers an efficacious and accurate means of assessing non-linear behaviour of the structures for engineering practice. Author Address: Centre for Infrastructure Engineering and Safety, School of Civil and Environmental Engineering, The University of New South Wales, UNSW Sydney, NSW 2052, Australia