Session Start Date

8-24-2012

Session End Date

8-25-2012

Abstract

This paper presents the optimisation of cold-formed steel open columns using the recently developed self-shape optimisation method that aims to discover new profile shapes. The strength of the cold-formed steel sections is calculated using the Direct Strength Method, and the rules developed in the present work to automatically determine the local and distortional elastic buckling stresses from the Finite Strip and constrained Finite Strip Methods are discussed. The rules are verified against conventional and optimum sections yielded in this research, and found to accurately predict the elastic buckling stresses. The principles behind the self-shape optimisation method are summarised herein and are applied to singly-symmetric (mono-symmetric) cold-formed steel columns. “Optimum” cross-sections for simply supported columns, 0.047 inch (1.2 mm) thick, free to warp and subjected to a compressive axial load of 11,167 lb (75 kN) are presented for column lengths ranging from 39.37 inches to 98.42 inches (1,000 mm to 2,500 mm). Results show that the optimum cross-sections are found in a relatively low number of generations, and typically shape to non-conventional “bean”, “oval” or rounded “Σ” sections. The algorithm optimises for distortional and global buckling, therefore likely subjecting the cross-sections to buckling interaction.

Department(s)

Civil, Architectural and Environmental Engineering

Research Center/Lab(s)

Wei-Wen Yu Center for Cold-Formed Steel Structures

Meeting Name

21st International Specialty Conference on Cold-Formed Steel Structures

Publisher

Missouri University of Science and Technology

Publication Date

8-24-2012

Document Version

Final Version

Rights

© 2012 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

Share

 
COinS
 
Aug 24th, 12:00 AM Aug 25th, 12:00 AM

Self-shape Optimisation of Cold-formed Steel Columns

This paper presents the optimisation of cold-formed steel open columns using the recently developed self-shape optimisation method that aims to discover new profile shapes. The strength of the cold-formed steel sections is calculated using the Direct Strength Method, and the rules developed in the present work to automatically determine the local and distortional elastic buckling stresses from the Finite Strip and constrained Finite Strip Methods are discussed. The rules are verified against conventional and optimum sections yielded in this research, and found to accurately predict the elastic buckling stresses. The principles behind the self-shape optimisation method are summarised herein and are applied to singly-symmetric (mono-symmetric) cold-formed steel columns. “Optimum” cross-sections for simply supported columns, 0.047 inch (1.2 mm) thick, free to warp and subjected to a compressive axial load of 11,167 lb (75 kN) are presented for column lengths ranging from 39.37 inches to 98.42 inches (1,000 mm to 2,500 mm). Results show that the optimum cross-sections are found in a relatively low number of generations, and typically shape to non-conventional “bean”, “oval” or rounded “Σ” sections. The algorithm optimises for distortional and global buckling, therefore likely subjecting the cross-sections to buckling interaction.