Design of hollow section joints using the component method

In the field of cold bending, it is necessary to use ball mandrels, especially to bend thin-walled tubes with a small radius. However, the bending process with a ball mandrel is complex and expensive, and it is easy to jam the core ball inside the tube. To solve these issues, we designed two kinds of hollow non-ball mandrel schemes with low stiffness that were suitable for the small radius bending of thin-walled tubes. We evaluated the forming quality of cold bending numerically and the influence of the hollow section length and thickness on the forming indices. Our results showed that the thickness of the hollow section has a greater influence on forming quality than the length. As the hollow section’s thickness increased, the wrinkling rate first declined by approximately 40% and then increased by above 50%. When the thickness was 11 mm in scheme 1 and 13 mm in scheme 2, the wrinkling rate reached minimum values of 1.32% and 1.50%, respectively. As the hollow section’s thickness increased, the flattening rate decreased by more than 60% and the thinning rate increased by about 40%. A multi-objective optimization of forming indices was carried out by ideal point method and grey wolf optimizer. By comparing the forming results before and after optimization, the feasibility of using the proposed hollow mandrel was proved, and the hollow mandrel scheme of standard cylinder is therefore recommended.

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Advanced multivariate cumulative sum control charts based on principal component method with application

Quality and Reliability Engineering International ◽

10.1002/qre.2889 ◽

2021 ◽

Author(s):

Muhammad Riaz ◽

Babar Zaman ◽

Rashid Mehmood ◽

Nasir Abbas ◽

Mu'azu Abujiya

Keyword(s):

Control Charts ◽

Principal Component ◽

Cumulative Sum ◽

Principal Component Method ◽

Component Method ◽

Cumulative Sum Control

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Design and analysis of concrete-filled tubular flange girders under combined loading

Advances in Structural Engineering ◽

10.1177/13694332211001520 ◽

2021 ◽

pp. 136943322110015

Author(s):

Rana Al-Dujele ◽

Katherine Ann Cashell

Keyword(s):

Finite Element ◽

Axial Force ◽

Failure Modes ◽

Numerical Study ◽

Combined Loading ◽

Torsional Stiffness ◽

Fe Model ◽

Combined Effects ◽

Element Analysis ◽

Hollow Section

This paper is concerned with the behaviour of concrete-filled tubular flange girders (CFTFGs) under the combination of bending and tensile axial force. CFTFG is a relatively new structural solution comprising a steel beam in which the compression flange plate is replaced with a concrete-filled hollow section to create an efficient and effective load-carrying solution. These members have very high torsional stiffness and lateral torsional buckling strength in comparison with conventional steel I-girders of similar depth, width and steel weight and are there-fore capable of carrying very heavy loads over long spans. Current design codes do not explicitly include guidance for the design of these members, which are asymmetric in nature under the combined effects of tension and bending. The current paper presents a numerical study into the behaviour of CFTFGs under the combined effects of positive bending and axial tension. The study includes different loading combinations and the associated failure modes are identified and discussed. To facilitate this study, a finite element (FE) model is developed using the ABAQUS software which is capable of capturing both the geometric and material nonlinearities of the behaviour. Based on the results of finite element analysis, the moment–axial force interaction relationship is presented and a simplified equation is proposed for the design of CFTFGs under combined bending and tensile axial force.

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