Master's Thesis

Distortional-Global Interaction in Cold-Formed Steel Lipped Channel Columns: Buckling Analysis, Structural Behavior and Strength

Interação Distorcional-Global em Colunas de Perfis Formados a Frio com Seção U Enrijecido: Análise da Flambagem, Comportamento Estrutural e Resistência

Joao Alfredo de Lazzari — 2020

Key information

Authors:

Joao Alfredo de Lazzari (João Alfredo de Lazzari)

Supervisors:

Eduardo de Miranda Batista

Published in

03/19/2020

Abstract

The goal of the present research is the distortional-global (D-G) buckling interaction of cold-formed steel (CFS) lipped channel (LC) columns, in its buckling, structural behavior and strength nature. Some studies on this topic have been conducted in the literature, however, the D-G interaction is not well known and needs more attention. For an elastic buckling analysis, a software entitled FStr Computer Application Program is developed. The application is based on the Finite Strip Method, mainly focused in a simple and accessible interface. The FStr program generates the modal shapes and insert as initial geometric imperfections in the finite element software ANSYS, in order to perform a geometric and material nonlinear analysis. Both, the FStr program and the finite element model are validated with available numerical examples and laboratory tests from the literature. Moreover, for the structural behavior and column strength, it is carried out stability paths from previous nonlinear analysis, for different combination of initial geometric imperfection of global and distortional modes. The buckling mode combination as initial geometric imperfection helps to understand the D-G buckling interaction, which is difficult to predict with a simple elastic buckling analysis. The results of the initial imperfection combination have shown that, for high yielding steel, the global initial geometric imperfection provides the most detrimental ultimate load. Additionally, a parametric study varying the column’s length have shown that the nominal axial strength for global buckling equation, already in the standards, is enough to cover the DG coupled phenomenon.

Publication details

Authors in the community:

Degree Name

Master of Science, in Civil Engineering

Fields of Science and Technology (FOS)

civil-engineering - Civil engineering

Keywords

  • Distortional-global buckling interaction
  • Coldformed steel columns
  • FSM elastic buckling analysis
  • FEM numerical non-linear analysis

Publication language (ISO code)

eng - English

Rights type:

Open access

Financing entity

CNPq

Title of the project, award or grant: Bolsa de Mestrado do CNPq

Funding Stream: Conselho Nacional de Desenvolvimento Científico e Tecnológico

Number for the project, award or grant: 131199/2018-8

Financing entity

FAPERJ

Title of the project, award or grant: PROGRAMA BOLSA NOTA 10 – CATEGORIA MESTRADO NOTA 10

Funding Stream: Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro

Number for the project, award or grant: E-26/200.825/2019 (242580)