The Influence of Cross-Section Shape Changing on Work of Cold Formed Beam

2014 ◽  
Vol 1025-1026 ◽  
pp. 361-365 ◽  
Author(s):  
Alexander Tusnin ◽  
Ilya Selyantsev

The Necessity of taking into account the ability of cold-formed steel thin-walled profiles to gradually change its cross section shape proportionally to the load acting on it is considered. Free torsion constants Jt value for cold-formed profiles is justified. Underestimation of beam torsion due to ignoring of the cross-section contour deformation is assessed. The thin-walled Z and C-shaped cold formed steel sections recently are becoming more and more popular in the constructions of low-rise buildings. A characteristic feature of cold-formed thin-walled profiles in these structures is the need to consider not only the longitudinal and bending deformations, but also the deformations of torsion. Presently there are two approaches to analysis of structures of thin-walled cold-formed steel sections. One of them is based on the thin-walled beam theory designed by V.Z. Vlasov, another one is based on the super-critical load-carrying capacity theory. In the first approach the contour of the cross-section is non-deformable, in the second caseanalysis is carried out on the basis of a reduced cross-section, caused by local buckling of the compressed cross-section elements. Both approaches do not take into account the ability of cold-formed steel thin-walled profiles to change itscross section shape proportionally to the load acting on it. In this connection it is necessary to conduct theoretical and experimental studies of the cross-section deformation effect on behavior of cold-formed steel profiles.First of all,it is important to find out the range of section-length characteristics for cold-formed profiles in which the fact of not taking into account of contour deformation of the cross-section leads tothe significant, from an engineering point of view, error in the calculations. Also it is needed to estimatehowload types and connections applied on cross section influence on cross-section form changing.

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2119
Author(s):  
Luís Mesquita David ◽  
Rita Fernandes de Carvalho

Designing for exceedance events consists in designing a continuous route for overland flow to deal with flows exceeding the sewer system’s capacity and to mitigate flooding risk. A review is carried out here on flood safety/hazard criteria, which generally establish thresholds for the water depth and flood velocity, or a relationship between them. The effects of the cross-section shape, roughness and slope of streets in meeting the criteria are evaluated based on equations, graphical results and one case study. An expedited method for the verification of safety criteria based solely on flow is presented, saving efforts in detailing models and increasing confidence in the results from simplified models. The method is valid for 0.1 m2/s 0.5 m2/s. The results showed that a street with a 1.8% slope, 75 m1/3s−1 and a rectangular cross-section complies with the threshold 0.3 m2/s for twice the flow of a street with the same width but with a conventional cross-section shape. The flow will be four times greater for a 15% street slope. The results also highlighted that the flood flows can vary significantly along the streets depending on the sewers’ roughness and the flow transfers between the major and minor systems, such that the effort detailing a street’s cross-section must be balanced with all of the other sources of uncertainty.


2021 ◽  
Author(s):  
Teng Man ◽  
Herbert Huppert ◽  
Ling Li ◽  
Sergio Galindo-Torres

<p>The collapse of granular columns, which sheds light on the kinematics, dynamics, and deposition morphology of mass-driven flows, is crucial for understanding complex flows in both natural and engineering systems, such as debris flows and landslides. However, our research shows that a strong size effect and cross-section shape influence exist in this test. Thus, it is essential to better understand these effects. In this study, we explore the influence of both relative column sizes and cross-section shapes on the run-out behavior of collapsed granular columns and analyze their influence on the deposition morphology with the discrete element method (DEM) with Voronoi-based spheropolyhedron particles. We link the size effect that occurs in granular column collapse problems to the finite-size scaling functions and investigate the characteristic correlation length associated with the granular column collapses. The collapsing behavior of granular columns with different cross-section shapes is also studied, and we find that particles tend to accumulate in the direction normal to the edge of the cross-section instead of the vertex of it. The differences in the run-out behavior in different directions when the cross-section is no longer a circle can also be explained by the finite-size analysis we have performed in this study. We believe that such a study is crucial for us to better understand how granular material flows, how it deposits, and how to consider the size effect in the rheology of granular flows.</p>


2019 ◽  
Vol 136 ◽  
pp. 315-322 ◽  
Author(s):  
David Bilston ◽  
Dong Ruan ◽  
Artur Candido ◽  
Yvonne Durandet

2015 ◽  
Vol 49 (3) ◽  
pp. 869-887 ◽  
Author(s):  
Georgia E. Thermou ◽  
Konstantinos Katakalos ◽  
George Manos

1993 ◽  
Vol 8 (12) ◽  
pp. 3229-3232 ◽  
Author(s):  
Huajian Gao ◽  
Tsai-Wei Wu

A perturbation method is used to confirm that the elastic contact stiffness associated with a flat-ended punch indenting a layered medium is insensitive to the cross-section shape of the punch as long as the shape does not differ too much from a circle. This result supports the practice of modeling nonaxisymmetric indenters such as Vickers or Berkovich indenters as an axisymmetric flat-ended cylindrical punch.


2014 ◽  
Vol 679 ◽  
pp. 1-5 ◽  
Author(s):  
Sumayah Abdulsalam Mustafa ◽  
Mohd Zulham Affandi bin Mohd Zahid ◽  
Md.Hadli bin Abu Hassan

Cross sectional areas optimization is to be implemented to study the influence of the cross section shape on the optimum truss weight. By the aid of analysis and design engines with advanced finite element analysis that is the steel design software STAAD. Four rolled steel sections (angle, tube, channel, and pipe) which are used in industrial roof trusses are applied for comparison. Many previous studies, use the areas of cross sections as design variables without highlight to the shape of cross section at the start of the process, consequently the result area will be adequate if the designer choose the effective shape than others. Results of this research show that the chosen cross section shape has a significant impact on the optimum truss weight for same geometry of truss type under the same circumstances of loading and supports.


Author(s):  
Jiang LiuYi ◽  
Zhang Hong ◽  
Duan QingQuan

There are many closed side branches in the gas conveying pipeline system. When the gas passes through the closed side branch, the shear layer will arouse the acoustic resonance in the closed side branch, which is harmful to the safe operation of the pipeline. The research work is insufficient about the influence of the cross-section shape of the closed side branch on acoustic resonance. Using the Detached-Eddy Simulation (DES) model, the acoustic resonance characteristics caused by the side branch pipe with different square cross-sections are simulated at the inlet boundary conditions of 25 m/s, 30 m/s and 35 m/s. The results show that in the center axis of the side branch, a 1/4 wavelength standing wave was formed, and the acoustic resonance occurs at a higher Strouhal number in circular branch. The cross-section shape of the side branch does not affect the acoustic resonance frequency, but it has a certain influence on the amplitude of pressure fluctuation and has a significant influence on the high-order frequency components.


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