Session Start Date

10-17-1996

Abstract

Uniformly compressed cold-formed metal columns are susceptible to instability in a variety of modes. In the stability analysis of such a column, using any of the available numerical methods with the exception of the eigenvalue method, the perfect geometry of the column must be ' seeded' with an imperfection in order to cause it to collapse. If the member buckles in a global mode, it is easy to introduce an appropriate imperfection in form of a suitable displaced shape. However, it is more difficult to define the imperfections for the distortional and local buckling modes due to the unknown nature of the critical buckling patterns. The eigenvalue method can be used to predict the bifurcation buckling of a perfect member and linear solutions of eigenvalue problems have been well developed and documented. However, because many members buckle in the nonlinear region, it is necessary to develop non-linear solutions for eigenvalues. In the authors' studies, the eigenvectors from linear eigen-solutions have been introduced as the imperfections in non-linear finite element analysis using ABAQUS version 5.4. However, this may not always be sufficiently accurate because the patterns of linear buckling and non-linear buckling could be different. Unfortunately, if a problem with a large number of degrees of freedom is analyzed using the finite element method, the existing methods are expensive in terms of either time or memory consumption. In this paper, a non-linear solution of eigenvalue problems set up using the finite element method is developed. The method has been used to analyze some stability problems in the uniformly compressed uprights of steel pallet racks. The results from analyses and tests agree well [1].

Department(s)

Civil, Architectural and Environmental Engineering

Research Center/Lab(s)

Wei-Wen Yu Center for Cold-Formed Steel Structures

Meeting Name

13th International Specialty Conference on Cold-Formed Steel Structures

Publisher

University of Missouri--Rolla

Publication Date

10-17-1996

Document Version

Final Version

Rights

© 1996 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

Share

 
COinS
 
Oct 17th, 12:00 AM

Non-linear Buckling Analysis of Thin-walled Metal Columns

Uniformly compressed cold-formed metal columns are susceptible to instability in a variety of modes. In the stability analysis of such a column, using any of the available numerical methods with the exception of the eigenvalue method, the perfect geometry of the column must be ' seeded' with an imperfection in order to cause it to collapse. If the member buckles in a global mode, it is easy to introduce an appropriate imperfection in form of a suitable displaced shape. However, it is more difficult to define the imperfections for the distortional and local buckling modes due to the unknown nature of the critical buckling patterns. The eigenvalue method can be used to predict the bifurcation buckling of a perfect member and linear solutions of eigenvalue problems have been well developed and documented. However, because many members buckle in the nonlinear region, it is necessary to develop non-linear solutions for eigenvalues. In the authors' studies, the eigenvectors from linear eigen-solutions have been introduced as the imperfections in non-linear finite element analysis using ABAQUS version 5.4. However, this may not always be sufficiently accurate because the patterns of linear buckling and non-linear buckling could be different. Unfortunately, if a problem with a large number of degrees of freedom is analyzed using the finite element method, the existing methods are expensive in terms of either time or memory consumption. In this paper, a non-linear solution of eigenvalue problems set up using the finite element method is developed. The method has been used to analyze some stability problems in the uniformly compressed uprights of steel pallet racks. The results from analyses and tests agree well [1].