Nonlinear buckling of built-up cold-formed sections

Abstract

An extensive numerical analysis was conducted to investigate the nonlinear buckling of built-up cold-formed sections. This paper presents the calibration of nonlinear finite element models to handle nonlinear buckling behaviour of cold-formed steel sections with geometrically unstable configurations. The two nonlinear finite element packages ANSYS and ABAQUS were used to validate 265 experimental tests. Two different numerical schemes (implicit static and explicit dynamic) under various iterative and non-iterative solution techniques, including Newton-Raphson, Arc-Length, Riks, and Central-Difference integration methods, were adopted to produce reliable solutions. Overall, the numerical analysis estimated the experimental results reasonably well with an adjustment factor of 0.88.

Experimental study of the cross-sectional capacity of cold-formed steel built-up columns

“…A simple design equation was proposed in [21] to predict the ultimate capacity of I-shaped and closed section built-up columns assembled from lipped channels stitch-welded together at various spacings and failing by distortional or global flexural buckling. The equation was based on the experimental and numerical data gathered in [12,22,23]. However, the authors suggested that more compression tests on other practical built-up geometries were needed to further validate the proposed equation.…”

Numerical investigation on behaviour and design of cold-formed steel built-up column composed of lipped sigma channels

“…In the past decades, some researchers have carried out experimental investigation to study the behaviour of CFS built-up columns all over the world, such as Salem et al (2004), Stone and LaBoube (2005), Sukumar et al (2006), Hosseini Hashemi and Jafari (2009), Whittle and Ramseyer (2009), Liu et al (2009), Piyawat et al (2011), Reyes and Guzman (2011), Craveiro et al (2016), Lu et al (2017), Liao et al (2017), Roy et al (2018) and Ting et al (2018). These investigations mainly focused on typical built-up columns that were formed by plain and lipped channel sections without web stiffeners.…”

Behaviour of cold-formed steel built-up I-section columns composed of four U-profiles

“…The complexities in built-up cross-section geometry and fasteners’ spacing challenge the researchers in developing simple design procedures. Early researches on the experimental buckling behaviour of CFS built-up columns subjected to axial compression are detailed in Salem et al (2004), Stone and Laboube (2005), Sukumar et al (2006), Becque (2008), Hashemi and Jafari (2009), Whittle and Ramseyer (2009), Piyawat et al (2011), Reyes and Guzman (2011) and Ting and Lau (2011), in which CFS built-up columns were formed by plain and lipped channel sections without web stiffeners. Some experiments as well as numerical researches on built-up open section column with an edge and web stiffeners are reported in Young and Chen (2008) and also studied the appropriateness of the direct strength method (DSM) for built-up columns.…”