Compression tests of cold-formed plain and dimpled steel columns

Nguyen, Van Bac; Wang, Changjiang; Mynors, Diane J.; English, Martin; Castellucci, Michael

doi:10.1016/j.jcsr.2011.07.004

Cited by 26 publications

(12 citation statements)

References 10 publications

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“…-Allocation of The effect of the dimpling process on the mechanical and structural properties of the steel material has been the subject of some recent experimental investigations through micro-hardness, tensile, bending and compression tests of plain and dimpled steel specimens [3][4][5][6][7]. The tests revealed that the strength of dimpled specimens was significantly greater than plain specimens originating from the same coil material, and this enhancement is a result of the cold work applied to the material during the dimpling process.…”

Section: Introductionmentioning

confidence: 99%

Dimpling process in cold roll metal forming by finite element modelling and experimental validation

Nguyen

Wang

Mynors

et al. 2014

Journal of Manufacturing Processes

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(2014) Dimpling process in cold roll metal forming by finite element modelling and experimental validation. Journal of Manufacturing Processes, 16 (3). pp. 363-372. ISSN 1526-6125 This version is available from Sussex Research Online: http://sro.sussex.ac.uk/48964/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the URL above for details on accessing the published version. Copyright and reuse:Sussex Research Online is a digital repository of the research output of the University.Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available.Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. AbstractThe dimpling process is a novel cold-roll forming process that involves dimpling of a rolled flat strip prior to the roll forming operation. This is a process undertaken to enhance the material properties and subsequent products' structural performance while maintaining a minimum strip thickness. In order to understand the complex and interrelated nonlinear changes in contact, geometry and material properties that occur in the process, it is necessary to accurately simulate the process and validate through physical tests. In this paper, 3D non-linear finite element analysis was employed to simulate the dimpling process and mechanical testing of the subsequent dimpled sheets, in which the dimple geometry and material properties data were directly transferred from the dimpling process. Physical measurements, tensile and bending tests on dimpled sheet steel were conducted to evaluate the simulation results. Simulation of the dimpling process identified the amount of non-uniform plastic strain introduced and the manner in which this was distributed through the sheet. The plastic strain resulted in strain hardening which could correlate to the increase in the strength of the dimpled steel when compared to plain steel originating from the same coil material. A parametric study revealed that the amount of plastic strain depends upon on the process parameters such as friction and overlapping gap between the two forming rolls. The results derived from simulations of the tensile and bending tests were in good agreement with the experimental ones. The validation indicates that the finite element analysis was able to successfully simulate the dimpling process and me...

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Section: Introductionmentioning

confidence: 99%

Dimpling process in cold roll metal forming by finite element modelling and experimental validation

Nguyen

Wang

Mynors

et al. 2014

Journal of Manufacturing Processes

Self Cite

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“…The dimpled sheet can then be progressively formed into a desired profile by passing through a series of rolls, arranged in tandem, or by press braking. It has been reported through experimental tests and numerical simulations that the strength of dimpled samples was significantly greater than plain samples originating from the same coil material [24][25][26][27][28][29]. The greater strength of dimpled samples is caused mainly by the work hardening of the material during the dimpling process.…”

Section: Introductionmentioning

confidence: 99%

“…The greater strength of dimpled samples is caused mainly by the work hardening of the material during the dimpling process. In previous articles, the response of open-section dimpled steel columns under quasi-static compression loads has been studied experimentally as well as numerically [27][28][29]. However, the study only focused on the response of the open section till the buckling point, and the strain rate effect is not taken into account.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical study on crashworthiness of cold-formed dimpled steel columns

Wang¹,

Nguyen²,

English³

et al. 2017

Thin-Walled Structures

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The UltraSTEEL ® forming process forms plain steel sheets into dimpled steel sheets and this process increases the sheet material's strengths by generating plastic deformation on the material during the process. This paper presented experimental testing and developed a finite element (FE) model to predict the energy absorption characteristics of dimpled thin-walled structures under axial impact loads, and compared the energy absorption efficiencies (specific energy absorption) of plain and dimpled columns. Dynamic experimental tests were conducted using the drop tower at two different impact velocities. Explicit FE analysis were then carried out to simulate the experiments. The FE method was validated by comparing the numerical and experimental failure modes, crushing force response and specific energy absorptions. The validated FE method was then applied in an optimization study on the parameter of forming depth. The effects of forming depth on both geometry and material properties have been taken into account in the optimization study. It has been found that the specific energy absorption of dimpled columns is up to 16.3% higher than the comparable plain columns.

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“…Traditional thin-walled sections with a variety of open-and closed-section configurations have been studied extensively [1][2][3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Experimental study and analysis of inner-stiffened cold-formed SHS steel stub columns

Zhu

Zhang

et al. 2016

Thin-Walled Structures

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A series of axial compression tests was conducted to investigate the compressive behaviour of cold-formed steel stub columns with relatively thick walls (6mm and 10mm, respectively). Four different inner-stiffener arrangements were considered.Tensile coupons were cut from different parts of the square hollow section (SHS) sections to obtain a full picture of the enhanced material properties due to the cold-forming process. A finite element model was also developed and employed to provide a numerical perspective of the behaviour of the SHS columns. The applicability of two code-specified methods for the calculation of the strength of thin-walled cold-formed SHS columns for the present thick-walled cases is examined. The comparison shows that the AISI (and similarly AS/NZS) method tends to overestimate the sectional strength for the unstiffened and partially stiffened 6-mm thick columns, but predicts generally well (with slight underestimate) in the cases of well-stiffened 6-mm columns and all the 10-mm thick columns. The GB method, on the other hand, appears to predict well for all cases where the stiffening effect was less significant, but underestimates the sectional strength in the well-stiffened cases.

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Compression tests of cold-formed plain and dimpled steel columns

Cited by 26 publications

References 10 publications

Dimpling process in cold roll metal forming by finite element modelling and experimental validation

Dimpling process in cold roll metal forming by finite element modelling and experimental validation

Experimental and numerical study on crashworthiness of cold-formed dimpled steel columns

Experimental study and analysis of inner-stiffened cold-formed SHS steel stub columns

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