AN EFFICIENT METHOD FOR YIELD AND FAILURE SURFACES OF THE STEEL I-SECTION

The paper presents a new method to generate efficiently yield and failure surfaces of the doubly symmetrical wide flange I-section under axial force combined with biaxial bending moments in nonlinear analysis of the steel frame. The I-section is divided into several rectangular areas, and the axial force is integrated from uniform stress on each area to form the equilibrium equations of the failure surface. Hyperbolic equations are proposed to approximate the biaxial bending moments of gradually yielding cross-section that represent the yield surfaces lie between limit elastic and failure surfaces. A computer code SPH developed with the implementation of the proposed method aims to perform analyses for numerous cross-sections. The proposed method may help to improve the effectiveness of the finite element analysis of the steel frame in comparison to the fiber method. Several computational examples are conducted to validate the accuracy and efficiency of the proposed method by comparing the results predicted by SPH with those retrieved from other methods. Copyright (C) 2020 by The Hong Kong Institute of Steel Construction. All rights reserved.