Nonlinear finite element analysis of steel pipe with stiffener plate

Abstract

This thesis presents the numerical studies of steel hollow section columns connected to corbels under industry crane loads, and the stiffening design using steel plates to enhance the maximum loading capacity against premature local buckling failures. The influences of inelastic material properties and geometry nonlinearity on the overall load carrying capacity of the columns were considered. Square hollow section columns were modelled in 3D using standard eight-node solid finite elements using an ANSYS software. The plate stiffener design algorithm involving variation of plate thicknesses was coded in MATLAB with a direct application programming interface to ANSYS. The full history of elastoplastic structural responses of the column was mapped out, and described its intrinsic local buckling behaviors at the contact forces. In essence, this study showed the two major tension and compression failures associated with the slendernesses of column section. Two strengthening techniques, namely external ring stiffener and internal plate fabrication, were proposed to extend the overall load carrying capacity and hence the service life of the column. The applications of the proposed analysis and design schemes were illustrated through standard warehouse structures.