Numerical Simulation of High Strength Cold-Formed Supacee Sections in Combined Bending and Shear (No. R913)

Abstract

The report describes numerical non-linear simulation, based on the finite element method (FEM) using the software package ABAQUS/Standard, of high strength cold-formed SupaCee sections in shear, combined bending and shear, and bending only. These high strength (450 MPa) C-profile steel sections called SupaCee contain additional return lips and web stiffeners which enhance the bending and shear capacity of the sections (Lysaght, 2003). They are used widely in Australia as purlins in roof and wall systems. The results of nonlinear analyses by using the finite element method (FEM) depend heavily on the imperfection assumption for the analysis of the thin-walled members. Geometric imperfections are often taken as a scaled multiple of the eigenvalue modes. Different buckling modes (Mode 1 Anti-Symmetric and Mode 2 Symmetric) are assumed with different magnitude levels of imperfection as proposed by Camotim in Portugal and Schafer in the USA. Studies of the effects of boundary condition, element types as well as mesh size are also included. This report summarises the results of the finite element nonlinear simulations of the tests on SupaCee sections performed at the University of Sydney on a variety of section sizes and thicknesses. The test series include predominantly shear (V), combined bending and shear (MV), and bending only (M) test series. The FEM results are compared with the tests to calibrate the imperfection magnitudes and modes against the tests. Conclusions regarding the size and type of imperfection are made in the report. It is demonstrated that the finite element analysis can therefore be used to design and optimize thin-walled sections of high strength steel.