Computational modelling of geometric imperfections and buckling strength of cold-formed steel

Sadovský, Z.; Kriváček, J.; Ivančo, Vladimír; Ďuricová, A.

doi:10.1016/j.jcsr.2012.06.005

Cited by 35 publications

(19 citation statements)

References 13 publications

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“…Therefore, an imperfection measurement approach based on the initial local bending energy is adopted currently. It should be noted that similar approaches have also been adopted previously in investigations on the effects of local imperfection profiles in the response of simply-supported rectangular plates [36] and the imperfection sensitivity of lipped channel columns [55]. From classical plate bending theory [56], the generalized expression for local bending energy due to initial imperfections in each plate U 0 b,lp can be expressed thus:…”

Section: Unified Local Imperfection Measurement Criterionmentioning

confidence: 99%

Sensitivity to local imperfections in inelastic thin-walled rectangular hollow section struts

Shen

Wadee

2019

Structures

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Mass efficient inelastic thin-walled rectangular hollow section (RHS) struts practically always fail in a combination of local-global interactive buckling and material nonlinearity while also exhibiting high sensitivity to initial imperfections. Nonlinear finite element (FE) models for inelastic thin-walled RHS struts with pre-defined local and global geometric imperfections are developed within the commercial package Abaqus. Using a unified local imperfection measurement based on equal local bending energy, the effects of imperfect cross-section profiles, imperfection wavelength and the degree of localization in the longitudinal direction on the ultimate load and the nonlinear equilibrium path are investigated for four characteristic length struts at different material yielding stress levels. The corresponding most severe imperfection profiles are determined and are found to be qualitatively different to the linear eigenmodes in all cases. Moreover, it is found that the most severe purely periodic imperfections may be used to provide a safe approximation of the ultimate load when the corresponding amplitude is constrained to the manufacturing tolerance level. An extensive parametric study on the wavelength of the most severe periodic imperfection profile is conducted and a relationship for this is proposed in terms of the normalized local slenderness, which compares excellently with the FE results.

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Section: Unified Local Imperfection Measurement Criterionmentioning

confidence: 99%

Sensitivity to local imperfections in inelastic thin-walled rectangular hollow section struts

Shen

Wadee

2019

Structures

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“…The stress-strain curve used in the finite element analysis (FEA) for the CFS profiles was based on tensile coupon test results and at the same time on other studies of literature [14,15,17,23], with a nominal yield strength of 320 MPa, a tensile strength of 390 MPa and a modulus of elasticity of 210 GPa. Residual stresses and cold-work of forming (where the apparent yield stress in the corners is increased) were ignored in these analyses, in other words, the mechanical properties of steel were assumed to be uniform across the crosssection, like other researchers in this field did [9,24]. The thermal properties of the CFS sections at elevated temperatures considered in the model (mass density, thermal conductivity and specific heat) were those given in EN1993-1-2:2004 [25] and the reduction factors for the modulus of elasticity and the yield strength of steel at elevated temperatures were obtained from the annex E of EN1993-1-2:2004 [25], whereas the expansion was taken from [26].…”

Section: Materials Modellingmentioning

confidence: 99%

10.26: Parametric numerical analysis of cold‐formed steel Σ‐shaped beams under fire

Laím

Rodrigues

2017

ce papers

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A numerical investigation into the structural behaviour of cold formed steel beams commonly used in warehouses and industrial buildings subjected to fire is presented in this paper. The structural performance of cold-formed steel beams under fire conditions has been studied over the last years. However, the great majority of them have been performed on single and lipped channel beams and assumed that the internal forces and moments at supports of the members remain unchanged throughout the fire exposure. Hence, a detailed parametric numerical investigation into the response of axially and rotationally restrained compound cold-formed steel beams in fire has been addressed in this paper. Therefore, in the first phase of this research, a suitable finite element model was developed and calibrated with results of experimental fire tests previously carried out by the authors. And then, a parametric analysis was undertaken using the calibrated finite element model with the purpouse of investigating numerically the effect of some parameters such as section geometry, initial applied load on the beam, slenderness and the influence of those two ki nds of elastic restraint on the critical temperature of the beams. Finally, the results of this research showed mainly that the critical temperature of this type of beams with elastically restrained thermal elongation may drop significantly and, beyond a certain value of axial or rotational stiffness of the surrounding structure it may be no longer possible to change the fire response of them.

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“…(1) Regarding the geometric and material defects of CFST columns, Nia et al [6] investigated the influence of initial buckling on the mechanical performance of a square steel pipe under oblique loading. Sadovský et al [7] investigated the effect of initial geometric imperfections on the buckling strength of steel members. Zhang et al [8] studied the influence of initial buckling on the energy dissipation of steel pipes under axial compression.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on the Axially Loaded Performance of Notched Hexagonal Concrete‐Filled Steel Tube (CFST) Column

Liu

Ding

2019

Advances in Civil Engineering

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This study aimed to investigate the static performance of notched hexagonal concrete-filled steel tube (CFST) stub columns through axial loading. Notch length, notch location, and notch direction in 14 CFST stub columns were experimentally studied. Stress process, failure mechanism, and ultimate strength in the notched CFST columns were analyzed. Results show that notches in steel tubes can weaken the restraining effect of steel pipes on core concrete and induce a decrease in the ultimate strength of specimens. The failure mode of components is greatly affected by notch orientation. The notch is closed under axial compression in the horizontally notched specimen, and the slotting indicates outward buckling in the vertically notched specimen. Based on the test results, a method for calculating the ultimate strength of notched hexagonal CFST columns was established. This research encourages the extensive application of these structures in civil engineering.

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Computational modelling of geometric imperfections and buckling strength of cold-formed steel

Cited by 35 publications

References 13 publications

Sensitivity to local imperfections in inelastic thin-walled rectangular hollow section struts

Sensitivity to local imperfections in inelastic thin-walled rectangular hollow section struts

10.26: Parametric numerical analysis of cold‐formed steel Σ‐shaped beams under fire

Experimental Investigation on the Axially Loaded Performance of Notched Hexagonal Concrete‐Filled Steel Tube (CFST) Column

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