The use of generalized beam theory, finite elements and experimental testing to investigate the stability of light gauge steel sections subject to axial load

Chinan, JAM

Abstract

The aim of the project is to study and investigate the buckling behaviour of unbranched open cold-formed steel sections. First the advantages and disadvantages of cold-formed steel when compared to hot-rolled steel are demonstrated. Thin-wall steel members have lower stiffness which may lead to increased instability and buckling issues for this kind of member. Buckling issues such as Euler buckling, buckling load factors, linear and non-linear analysis, buckling modes (global, distortional and local buckling) and buckling analysis methods (finite element method, finite strip method and generalized beam theory) are addressed. The literature review is concerned with computer software applications, theoretical analyses and experimental tests which can predict buckling loads and related mode shapes for light gauge steel sections. The study focuses on the Generalized Beam Theory (GBT) using the Finite Difference method for solution with a view to developing models using MATLAB to predict buckling loads, buckling mode shapes and non-linear yielding loads of members subjected to axial load for different boundary conditions. Some applications (beam subjected to concentrated load), linear analysis of buckling problems (Eigen value problems) and non-linear analysis (Imperfect Problems) have been addressed. Also, the finite element method (ANSYS) was used to predict the linear eigen-buckling loads and related mode shapes, and the non-linear material and geometric analyses with the post-buckling and initial imperfection effects were addressed. Finally, for validation purposes, a set of 36 cold-formed steel samples (lipped C-section and Zed-section) members with different boundary conditions (pinned and fixed end conditions) were tested in the laboratory to obtain the actual failure loads and failure shape and compare them with the two analytical methods. Good agreement between the analytical methods and the experimental data was evident, and recommendations for development of the GBT analysis are made.

Citation

Chinan, J. (in press). The use of generalized beam theory, finite elements and experimental testing to investigate the stability of light gauge steel sections subject to axial load. (Thesis). University of Salford

• Thesis Type: Thesis
• Acceptance Date: Mar 1, 2017
• Deposit Date: Feb 22, 2018
• Publicly Available Date: Feb 22, 2018