A Simplified Formula for Calculating the Elastic Distortional Bucking Stress of Steel Channel Bending Members with Complex Edge Stiffeners and Intermediate Stiffeners in Elements

2013 ◽  
Vol 405-408 ◽  
pp. 648-651
Author(s):  
Chun Gang Wang ◽  
Da Qian Zhao ◽  
Xin Yong Yu

In order to research the simplified formulas of bending steel channels with complex edge stiffeners for their elastic distortional buckling stress, each 70 members for lipped channels with complex edge stiffeners, Σ style channels with complex edge stiffeners and channels with complex edge stiffeners and intermediate V type stiffeners in the web were numerical analyzed by the finite strip software CUFSM. Based on the existed expression for local bucking and introducing distortional buckling coefficient, each of the suggested simplified formulas for distortional buckling stress of the above members were summarized. Besides, formulas for lipped channels with complex edge stiffeners and channels with complex edge stiffeners and intermediate V type stiffeners in the web were united as one. All the formulas were confirmed for their availability.

2013 ◽  
Vol 405-408 ◽  
pp. 644-647
Author(s):  
Chun Gang Wang ◽  
Nai Wen Zhang ◽  
Ping Ma

In order to investigate the simple calculative method of channels with complex edge stiffeners for the elastic distortional buckling stress under axial compressive load, a total of 90 cold-formed thin-walled steel channels with Σstyle web stiffeners and complex edge stiffeners , channels with complex edge stiffeners and intermediate V type stiffeners in the web were analyzed by finite strip software CUFSM. The influence of the parameters for the elastic distortional buckling stress was analyzed. Simplified formulas for calculating the elastic distortional buckling stress of Σstyle channels with complex edge stiffeners, channels with complex edge stiffeners and intermediate V type stiffeners in the web under axial compressive load were provided. The availability of the formulas was verified.


2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Jiaxing Ma ◽  
Tao Wang ◽  
Yinhui Wang ◽  
Kikuo Ikarashi

Numerical analyses and theoretic analyses are presented to study the elastic buckling of H-section beam web under combined bending and shear force. Results show that the buckling stress of a single web with clamped edges gives a good agreement with the buckling stress of an H-section beam web when the local buckling of the beam is dominated by the web buckling. Based on theoretic analyses, a parametric study is conducted to simplify the calculation of buckling coefficients. The parameters involved are clarified first, and the improved equations for the buckling coefficient and buckling stress are suggested. By applying the proposed method, the web buckling slenderness ratio is defined. It is verified that the web buckling slenderness ratio has a strong correlation with the normalized ultimate strength of H-section beams when the buckling of the beams is dominated by web buckling. Finally, a design equation is proposed for the ultimate strength of H-section beams.


Author(s):  
Imene Mahi ◽  
Mohamed Djelil ◽  
Naoual Djafour ◽  
Mustapha Djafour

This paper presents a method that allows calculating the elastic critical stress for the distortional buckling mode, based on the buckling mode classification of typical lipped channel columns. In our case, Cold-Formed Steel Lipped Channel Columns are subjected to compression. Moreover, in order to consolidate the important findings of this work, a comparative study was carried out to assess the reliability of various distortional buckling models that are provided by different design Standards. It was found that the American and Australian approaches, given in the codes of practice, are closer to the Finite Strip Method than to the European method. An analytical solution was proposed for the determination of the distortional buckling stress on the basis of a statistical method; it corresponds to lipped channel sections with a flange width to web width ratio b/h ranging from 0.1 to 1, and a lip width to web width ratio c/h between 0 and 0.5. After comparison with the results given by the finite strip method for pure distortional buckling, it turned out that the proposed approach provides a reasonable prediction for the elastic distortional buckling stress for lipped channel sections subjected to compression. In fact, this method gives better results than the American approach.


Author(s):  
Tatsuro Nakai ◽  
Hisao Matsushita ◽  
Norio Yamamoto

The objective of this study is to obtain basic data for discussing the structural integrity of aged ships, especially hold frames of aged bulk carriers. Firstly, shapes of corrosion pits observed on hold frames of bulk carriers have been investigated. It was shown that the shape of the corrosion pits is a circular cone and the ratio of the diameter to the depth is in the range between 8 to 1 and 10 to 1. Secondly, a series of tensile tests has been conducted to investigate the effect of pitting corrosion on tensile strength. It was pointed out that the tensile strength decreases gradually and the total elongation decreases drastically with the increase of thickness loss due to pitting corrosion. Thirdly, a series of 4-point bend tests with structural models which consist of shell, web and face plates simulating hold frames of bulk carriers has been carried out to investigate the effect of pitting corrosion on collapse behavior and lateral-distortional buckling behavior. Following the experiment, a series of non-linear FE-analyses has been also made. In the case where tensile load acted on the face plate, cracks were initiated at the bottom of the pits when pitting concentrated on the web near the face plate. On the other hand in the case where compression load acted on the face plate, lateral-distortional buckling has been observed and the ultimate load of the structural models where pitting developed regularly on the web was found to be almost the same as that of the structural models where the web has uniform corrosion corresponding to the average thickness loss.


2017 ◽  
Vol 11 (1) ◽  
pp. 244-257 ◽  
Author(s):  
Xingyou Yao

Background: Cold-formed steel structural sections used in the walls of residential buildings and agricultural facilities are commonly C-shaped sections with web holes. These holes located in the web of sections can alter the elastic stiffness and the ultimate strength of a structural member. The objective of this paper is to study the buckling mode and load-carrying capacity of cold-formed thin-walled steel column with slotted web holes. Methods: Compression tests were conducted on 26 intermediate length columns with and without holes. The tested compressive members included four different kinds of holes. For each specimen, a shell finite element Eigen-buckling analysis and nonlinear analysis were also conducted. The influence of the slotted web hole on local and distortional buckling response had also been studied. The comparison on ultimate strength between test results and calculated results using Chinese cold-formed steel specification GB50018-2002, North American cold-formed steel specification AISI S100-2016, and nonlinear Finite Element method was made. Result: Test results showed that the distortional buckling occurred for intermediate columns with slotted holes and the ultimate strength of columns with holes was less than that of columns without holes. The ultimate strength of columns decreased with the increase in transverse width of hole in the cross-section of member. The Finite element analysis results showed that the web holes could influence on the elastic buckling stress of columns. The shell finite element could be used to model the buckling modes and analysis the ultimate strength of members with slotted web holes. The calculated ultimate strength shows that results predicted with AISI S100-2016 and analyzed using finite element method are close to test results. The calculated results using Chinese code are higher than the test results because Chinese code has no provision to calculate the ultimate strength of members with slotted web holes. Conclusion: The calculated method for cold-formed thin-walled steel columns with slotted web holes are proposed based on effective width method in Chinese code. The results calculated using the proposed method show good agreement with test results and can be used in engineering design for some specific cold-formed steel columns with slotted web holes studied in this paper.


1956 ◽  
Vol 7 (4) ◽  
pp. 275-296 ◽  
Author(s):  
K. C. Rockey

SummaryThe correct design of intermediate vertical stiffeners on web plates subjected to shear becomes very important when the web plates are designed to operate at loads close to their buckling loads. This paper presents details of an extensive series of tests conducted on stiffened web plates subjected to shear. From the analysis of the results obtained from these tests, new empirical relationships between the flexural rigidity and spacing of the intermediate stiffeners and the buckling stress of the stiffened web plate have been obtained.One interesting and important feature of these new relationships is that they define more clearly than hitherto the difference in the behaviour of single-and double-sided stiffeners.


2013 ◽  
Vol 405-408 ◽  
pp. 664-667
Author(s):  
Chun Gang Wang ◽  
Yu Fei Cao ◽  
Lian Guang Jia ◽  
Hong Liu

This paper presents finite element analysis on cold-formed steel-section columns with complex edge stiffeners and web holes under axial compression. A total of 18 channel models with different parameters such as length, thickness and flange width are simulated. Failure modes, the ultimate load and the stress distribution around web holes are researched. The analysis results show that, the main failure mode of-section columns with complex edge stiffeners and web holes is distortional buckling. The carrying efficiency is higher as the thickness-width ratio increasing. Because of perforations on the web, the position of the max stress changes from the web near the mid-height of the specimens to the location adjacent to holes.


2011 ◽  
Vol 378-379 ◽  
pp. 230-236
Author(s):  
Li Zhong Jiang ◽  
Wang Bao Zhou ◽  
Yao Luo

Aluminium alloy members under axial force have broad application in structural field. Owing to low elastic modulus, aluminium alloy members are easier buckling than steel members. Based on the reasonable and equivalent calculation model and the related calculation formulas of rotational restraint stiffness kφ, lateral restraint stiffness kx, and distortional buckling critical half-wave length λ that provided by lipped channel web plate to flange under longitudinal distribution stress, the distortional buckling load calculation formula of the lipped channel is derived combining the thin-walled bar buckling theory in elastic medium. The distortional buckling loads and distortional buckling critical half-wave lengths at the different wall thickness have been calculated using the calculation formulas of this paper, and the results have been comparatived with the finite strip method. The comparison results show that: the average ratio of caculation results from formulas of this paper and results from CUFSM is 0.997and0.971 respectively,the corresponding variance is 2.9*10-5and 7.5*10-5. So the calculation results of this paper is in good agreement with the finite strip software, the calculation formula of this paper has enough calculation precision and good stability. At the same time, the calculation results of this paper is more concise than calculation formula for the same type, easy to be applied, may be used in practical applications and taken account into design codes and guidelines.


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