On incorporating local-global buckling interaction in the economical global analysis of thin-walled structural assemblies

Abstract

The main purpose of the research presented in this thesis is the development of a new economical and practical analytical method for modeling thin-walled structural members. In this method, the coupling of local buckling and global buckling can be incorporated. Currently available analysis tools and design methods are first reviewed. The currently available tools are too expensive to give a global analysis for practical structural assembles, and there is a common deficiency in all of the current design procedures. To bridge this gap with the analysis and design of thin-walled members, a technique named the “Pregnant element method” is proposed. With theoretical deduction and empirical simplification, a straightforward configuration of the stiffness matrix is obtained by extending the stiffness matrix of a standard beam-column element. This method is tested on a hollow box section column with bifurcation buckling analysis, which shows its efficiency. The technique is then extended to include lateral-torsional buckling, where the warping effect is taken into account. The Pregnant element method shows its ability in simulating the lateral-torsional buckling of an I-section beam example. For wider applications, a linear and nonlinear package is developed with this technique. The ABAQUS Finite Element model is used as a benchmark after it is verified by experimental and numerical results in the literature. The Pregnant element method is applied to different loading cases (including axial loading, pure bending loading, combined loading of bending and axial loading) and for different sections (including a box section, a stiffened panel/T-section, a channel section and a Z-section). The method produces good simulation results for those loading cases and member section shapes. Finally, the method shows its ability in global analysis with typical analysis examples of a toggle frame and a portal frame. With all of this work, the technique is systematically established. Remarks and directions for future work are given in conclusion.

Date of Award	15 Feb 2007
Original language	English
Awarding Institution	City University of Hong Kong
Supervisor	Sritawat KITIPORNCHAI (Supervisor)