Strength curves for web crippling design of cold-formed stainless steel hat sections

Abstract

a b s t r a c tThe web crippling design guides are based on empirical adjustments of available test data. These equations differ from the basic concept underpinning most of the other instabilities, the so-called strength curves. This investigation presents a new design approach for web crippling design of stainless steel hat sections based on strength curves controlled by slenderness-based functions χ(λ). The effects of web crippling on such cross-sections were studied numerically and the obtained results were used to derive the design expressions. Comparisons with tests and FE data, and with design guides show that the proposed design approach provides more accurate web crippling resistance.

Testing and numerical analysis of stainless steel I-sections under concentrated end-one-flange loading

“…Since then, tests have been performed on cold-formed carbon steel members with different cross-section shapes, including I-sections, C-sections, Z-sections, hat-sections, deck sections, and hollow sections [9][10][11][12][13][14], on members with and without flange restraints [15][16][17], on those with web openings [18] and on cold-formed stainless steel members [19][20][21][22][23][24][25][26]. Numerical studies on cold-formed stainless steel [23,[27][28][29], aluminium [30] and carbon steel members [31] have also been performed. Tests on cold-formed members under concentrated transverse loading are often referred to web crippling tests due to the failure mode exhibited during the experiments.…”

07.06: Numerical determination of plastic collapse loads for sections under concentrated transverse forces

“…The general-purpose shell element S4R, which is a four-noded doubly-curved shell element with reduced integration, was used to model the investigated steel plates and cold-formed steel beams. The accuracy of this element type has been illustrated in previous investigations of plates under compressive edge loading and cold-formed beams under transverse loads [2,4]. An elastic-perfectly plastic material model was utilised in the finite element models, where the Young's modulus was taken as 200 GPa and the Poisson's ratio was assumed to be equal to 0.3.…”

“…For structural elements under uniform loading and with regular geometry and boundary conditions, the former is suitable, while for those with complex non-uniform stress distributions, which may arise due to concentrated transverse loading, numerical analyses are often necessary. For the prediction of the plastic collapse loads of elements under concentrated loading, Materially Nonlinear Analyses (MNA) with an elastic perfectly-plastic material model have typically been adopted in the literature [1,2]. However, in many cases, the determination of the actual plastic collapse load from a MNA is not straightforward since (i) a MNA can abort prematurely because of its failure to satisfy the necessary convergence criteria or (ii) the obtained load-deformation path can flatten out only after unrealistically large deformations have been reached, with the result that the corresponding load does not reflect the nature of collapse mechanism that would arise in practice.…”

Design of stainless steel sections with circular openings in shear

“…Tests on web crippling of C and square hollow sections beams subject to local loads are presented [3], which proposed a modification to the web crippling formulae in EN1993-1-3 (also used in EN1993- [1][2][3][4] for loading close to the support and internally within the span.…”