Member distortional buckling behaviour of hybrid double-I-box beams

2018 ◽  
Vol 45 (8) ◽  
pp. 605-622 ◽  
Author(s):  
M.S. Deepak ◽  
V.M. Shanthi
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Parametric Study ◽  
Flexural Rigidity ◽  
Numerical Study ◽  
Plate Thickness ◽  
Distortional Buckling ◽  
Study Results ◽  
Box Beams ◽  
The Moment

This paper compiles the experimental and finite-element parametric study on member distortional buckling behaviour of new built-up metal hybrid double-I-box beams (HDIBBs). The cross-section of this built-up beam is unique and looks similar to the shape of a double-I-box fabricated using four channel sections. The flange plates were provided with an intermediate stiffener. In these built-up beams there is more material in the flange portions far away from the horizontal centroidal axis of their cross-section. Hence, there is an increase in the flexural rigidity that enhances the moment capacity of the beam, under major axis bending. The geometry consists of torsionally rigid closed-box web portion that provides high resistance to minor axis lateral-buckling. The varying parameters considered were the ratio of yield stresses of the flange to the web steel plates, the ratio of breadth to the depth of the section, and the flange plate thickness. In the experimental programme, all the HDIBB members failed due to kinds of distortional buckling which was identified by web buckling and flange twist along edges. The results revealed that when flange plate slenderness increases there is a drop in the moment resistance capacity of the beams. The numerical study was performed using ABAQUS software. In comparison, there was good agreement between experimental and numerical results. The validated finite element models were further extended to perform parametric studies on ideal HDIBB models. Both the experimental and parametric study results were compared with the predicted strengths using effective width method equations specified in the Euro code standards EN 3-1-3. It was found that the current Euro code design rules slightly over-estimate the distortional buckling resistance capacity of closed form built-up cold-formed steel members. A new design equation was formulated and recommended for estimating the reduction in distortional buckling moment resistance capacity for HDIBBs.

scholarly journals Compactness Effect on Bending Behavior of Cold Formed Steel Beams

2020 ◽  
Author(s):  
Zeynep Yaman ◽  
Elif Ağcakoca
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Parametric Study ◽  
Experimental Tests ◽  
Steel Beams ◽  
Collapse Mechanism ◽  
Finite Element Models ◽  
Cross Sectional ◽  
Steel Members ◽  
The Moment

With respect to the determination of the strength of the structural steel members, first the behavior of cross section and then that of the overall member should be considered. In this study, it is aimed to determine the compactness behavior of U-shaped steel sections that exposed to minor-axis bending. Thus, the study questions whether the U-shaped cross section exhibits sufficient dimensions for the collapse mechanism to occur by aiding the moment redistribution in the structural system by supplying sufficient hinge rotation capacity. In order to investigate compactness behavior, three different channel section steel profiles are selected. Four point experimental tests are carried out to validate finite element models of the selected profiles. Upon validated finite element models, parametric studies are performed with finite element analyses. In the parametric study two steel classes, different beam lengths and cross-sectional geometries are taken as parameters. At the end of the study the plate slenderness condition required for plastic design calculated based on Eurocode3 is evaluated with the results of parametric study.

scholarly journals Modeling inflatable fabric with undevelopable surfaces by motion folding method

2019 ◽  
Vol 14 ◽  
pp. 155892501988640
Author(s):  
Xiao-Shun Zhao ◽  
He Jia ◽  
Zhihong Sun ◽  
Li Yu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Numerical Study ◽  
Technical Problem ◽  
Three Dimensional ◽  
Element Model ◽  
Model Errors ◽  
Folding Model ◽  
Study Results ◽  
The Stability

At present, most space inflatable structures are composed of flexible inflatable fabrics with complex undevelopable surfaces. It is difficult to establish a multi-dimensional folding model for this type of structure. To solve this key technical problem, the motion folding method is proposed in this study. First, a finite element model with an original three-dimensional surface was flattened with a fluid structure interaction algorithm. Second, the flattened surface was folded based on the prescribed motion of the node groups, and the final folding model was obtained. The fold modeling process of this methodology was consistent with the actual folding processes. Because the mapping relationship between the original finite element model and the final folding model was unchanged, the initial stress was used to modify the model errors during folding process of motion folding method. The folding model of an inflatable aerodynamic decelerator, which could not be established using existing folding methods, was established by using motion folding method. The folding model of the inflatable aerodynamic decelerator showed that the motion folding method could achieve multi-dimensional folding and a high spatial compression rate. The stability and regularity of the inflatable aerodynamic decelerator numerical inflation process and the consistency of the inflated and design shapes indicated the reliability, applicability, and feasibility of the motion folding method. The study results could provide a reference for modeling complex inflatable fabrics and promote the numerical study of inflatable fabrics.

Parametric Study of Beam to Column Extended Endplate Connection in Fire

2012 ◽  
Vol 594-597 ◽  
pp. 779-784
Author(s):  
Meng Wang
Keyword(s):  
Cross Section ◽  
Failure Modes ◽  
Numerical Study ◽  
Numerical Models ◽  
Great Influence ◽  
Load Ratio ◽  
Simulation Methodology ◽  
Study Results ◽  
Endplate Connection ◽  
In Fire

In this paper, numerical study results using ABAQUS are presents to demonstrate the failure modes and the behaviour of endplate connection with different parameters at elevated temperature. Numerical models and simulation methodology are first validated by the comparison to experimental data. Then the behaviour of beam and the failure modes endplate connection with different parameters- including beam span, beam load ratio, column cross section, endplate type- are studied. It can be concluded that all these parameters has a effects on the behaviour of the connection, while some parameters has a great influence on the survivability of the joint.

scholarly journals Experimental Study and Direct Strength Method for Cold-Formed Steel Built-Up I-Sectional Columns under Axial Compression

2021 ◽  
Vol 2021 ◽  
pp. 1-22
Author(s):  
Xingyou Yao
Keyword(s):  
Finite Element ◽  
Axial Compression ◽  
Numerical Study ◽  
Experimental Results ◽  
Distortional Buckling ◽  
Cross Sectional ◽  
Direct Strength Method ◽  
Comparison Results ◽  
Cold Formed Steel ◽  
Interactive Buckling

The objective of this paper is to investigate the buckling behavior and design method of the ultimate strength for the cold-formed steel (CFS) built-up I-sectional columns under axial compression which failed in distortional buckling and interactive buckling. A total of 56 CFS built-up I-sectional columns subjected to axial compression were tested, and the different buckling modes and ultimate strengths were analyzed in detail by varying the thickness, the length, the spacing of screws, the end fastener group, and the cross-sectional dimensions of CFS built-up I-sectional columns. It was shown in the test that noticeable interaction of local and distortional buckling or interaction of local, distortional, and global buckling was observed for the built-up I-sectional columns with different lengths and cross-sectional dimensions. A finite element model (FEM) was developed and validated with experimental results. A further parametric study has been conducted including different cross sections and slenderness ratios for the built-up I-sectional columns. The load-carrying capacities obtained from the experimental and numerical study were used to investigate the feasibility of the current direct strength method (DSM) when DSM was applied to CFS built-up I-sectional columns. The comparison results showed that the current DSM is not safe for CFS built-up columns failed in distortional buckling and interactive buckling. Therefore, the improved design formulas were proposed, and their accuracy was verified by using finite element analysis (FEA) and experimental results of CFS built-up I-sectional columns subjected to axial compression.

scholarly journals Spider Diagram for Tubular Expansion with Restraints

2013 ◽  
Vol 10 (1) ◽  
pp. 1
Author(s):  
F Marketz ◽  
SA Al-Hiddabi
Keyword(s):  
Finite Element ◽  
Statistical Analysis ◽  
Cross Section ◽  
Strong Correlation ◽  
Parametric Study ◽  
Element Model ◽  
Two Dimensional ◽  
Operational Parameters ◽  
Expansion Process ◽  
Borehole Data

 The aim of this study is to explain the mechanics of tubular expansion in irregularly shaped boreholes such as those frequently observed in the upper Natih reservoirs. Statistical analysis of borehole data does not indicate a strong correlation between the non-circularity and expanded tubular’s in such boreholes. A two-dimensional (2-D) finite element model was developed using commercial software to determine the non-circularity of an expanded tubular and those data were compared with the measured values. A parametric study was also conducted and spider plots were generated to determine the amount of irregularity in the expanded tubulars so that optimum operational parameters could be identified to limit cross-section irregularities during the expansion process. 

A Numerical Study of Natural Convective Heat Transfer From Two-Sided Inclined Square Plates Having a Finite Thickness

2019 ◽  
Author(s):  
Rafiq Manna ◽  
Patrick H. Oosthuizen
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Numerical Study ◽  
Finite Thickness ◽  
Plate Thickness ◽  
Side Surface ◽  
Bottom Surface ◽  
Study Results ◽  
Inclination Angles

Abstract Simultaneous natural convective heat transfer from the top, bottom and side surfaces of two-sided inclined square plates having various thicknesses has been numerically investigated. The aim of this work is to determine whether the plate thickness has a significant influence on the heat transfer rates from the plate surfaces when the plate is inclined to the horizontal and to determine how the heat transfer rate varies with this angle of inclination. The upper, lower and side surfaces of the plate have been assumed to be isothermal and at the same temperature which is higher than that of the surrounding fluid. The range of conditions considered is such that laminar, transitional, and turbulent flow occur over the plate. The numerical solution has been obtained using the commercial CFD solver ANSYS FLUENT©. In this study, results have only been obtained for the case where the plate is exposed to air. Inclination angles of between 0 and 40 degrees from the horizontal and plate dimensionless thicknesses (thickness-to-side length ratios) of between 0 and 0.3 have been considered. Variations of the mean Nusselt number with Rayleigh number for the top surface, bottom surface, side surface and that averaged over all heated surfaces of the plate for various inclination angles and for various plate dimensionless thicknesses have been obtained.

scholarly journals FINITE ELEMENT ANALYSIS OF UNFASTENED COLD-FORMED STEEL CHANNEL SECTIONS WITH WEB HOLES UNDER END-TWO-FLANGE LOADING AT ELEVATED TEMPERATURES

2021 ◽  
Keyword(s):  
Finite Element ◽  
Parametric Study ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Reduction Factor ◽  
Strength Reduction Factor ◽  
Element Analysis ◽  
Study Results ◽  
Cold Formed Steel ◽  
Factor Equation

This paper presents the results of a finite element investigation on cold-formed steel (CFS) channel sections with circular web holes under end-two-flange (ETF) loading condition and subjected to elevated temperatures. The stress strain curve for G250 CFS with 1.95 mm thickness at elevated temperatures was taken from Kankanamge and Mahendran and the temperatures were considered up to 700 oC. To analyse the effect of web hole size and bearing length on the strength of such sections at elevated temperatures, a parametric study involving a total of 288 FE models was performed. The parametric study results were then used to assess the applicability of the strength reduction factor equation presented by Uzzaman et al. for CFS channel-sections with web holes under ETF loading from ambient temperature to elevated temperatures. It is shown that the reduction factor equation is safe and reliable at elevated temperatures.

Applicability of Net-Section Collapse Load Approach to Multiple-Cracked Pipe Assessment: Numerical Study

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Myeong-Woo Lee ◽  
So-Dam Lee ◽  
Yun-Jae Kim
Keyword(s):  
Finite Element ◽  
Test Data ◽  
Parametric Study ◽  
Fracture Strain ◽  
Numerical Study ◽  
Damage Analysis ◽  
Collapse Load ◽  
Fracture Test ◽  
Strain Model

In this paper, applicability of net-section collapse load approach to circumferential multiple-cracked pipe assessment is investigated using finite element (FE) damage analysis. The FE damage analysis based on the stress-modified fracture strain model is validated against limited fracture test data of two circumferential surface-cracked pipes. Then, the systematic parametric study is performed using the FE damage analysis for symmetrical and asymmetrical surface-cracked pipes. It is found that predictions using the net-section collapse load approach tend to be more accurate with increasing the distance between two symmetrical cracks. For asymmetrical cracks, it is found that the deeper crack plays a more important role and that the existing net-section collapse load expression can be potentially nonconservative. Idealization to symmetrical cracks based on the deeper crack is proposed.

scholarly journals Конструкция плиты для сборных дорожных покрытий

2018 ◽  
Vol 17 (6) ◽  
pp. 465-470
Author(s):  
S. I. Zinevich
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Plate Thickness ◽  
High Strength ◽  
Longitudinal Axis ◽  
Element Model ◽  
Longitudinal Ribs ◽  
Loose Soil ◽  
Load Action ◽  
Residual Deformations

Experience in the operation of prefabricated concrete pavements with intensive traffic of heavy vehicles has shown that despite a high strength of the concrete slabs themselves it is necessary to arrange strong foundations. While laying concrete on the ground residual deformations are accumulating in it due to pressures which are initiated by elastically bending plates when vehicles are passing that leads to formation of voids under the plate and cracks in the plate itself. In order to increase rigidity of the plate (reduction of its settlement during the passage of vehicles) the author has proposed to arrange plates with two longitudinal ribs, and the plates themselves are to be laid on loose soil mixed with cement. The ribs are proposed to be placed on roll bars, i. e. symmetrically with respect to a longitudinal axis of the plate at a distance from each other which is equal to the distance between wheels of the calculated vehicle on one axis. In order to determine dependence of plate rigidity on a shape and a size of a cross section in longitudinal ribs calculations have been made while using a PC “Lira” and a finite element method. A finite element model of the plate has included 19152 nodes and 18943 finite elements. An elastic foundation has been modeled by vertical elastic links which are in every bottom node. The plate has been loaded with a load which is equivalent to the load from a calculated vehicle wheel at four points: a wheel in the middle of the plate; a wheel on the corner of the plate; two wheels at the same time on the line which is perpendicular to the longitudinal axis of the plate and located at the beginning (or end) of the plate; two wheels at the same time on the line which is perpendicular to the longitudinal axis of the plate and passing through its center. The following forms of a longitudinal rib having the same crosssectional area have been studied at the beginning: triangular, oval (semicircle) and rectangular. In the context of plate rigidity increase the most optimal form has been a triangular shape. Height differences in such a plate are the least in case of load action. So, for example, in comparison with a typical plate (plate without longitudinal ribs), presence of longitudinal ribs of triangular cross – section increases plate rigidity by an average of 50 % depending on the location of the calculated wheel on the plate (39–64 %). After determining an optimal shape of cross section for longitudinal ribs the dependence has been found for plate rigidity and it depends on a height of longitudinal triangular ribs. While having a constant volume of the plate and a constant a size of the rib base (32 cm) (approximate width of a calculated vehicle wheel) a rib height and a plate thickness have been changed. The calculations have made it possible to determine dependence of the plate rigidity on a height of a longitudinal rib. It has been determined that as for the given volume and dimensions of the plate the optimal rib height is 25 cm.

Incremental Launching Construction Analysis of Continuous Skewed Bridge with Uniform Cross Section

2011 ◽  
Vol 368-373 ◽  
pp. 293-298
Author(s):  
Chuan Xi Li ◽  
Zhi Xian Luo ◽  
Jia Jun Li ◽  
Jian Ren Ou
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Structural Parameters ◽  
Finite Element Formulation ◽  
Element Formulation ◽  
Stiffness Ratio ◽  
Uniform Cross Section ◽  
The Moment ◽  
Equivalent Load ◽  
Skewed Bridge

The finite element formulation was used to analyze the influences of structural parameters such as the skewed angle and the stiffness ratio of flexure to torsion on the distributions of moment and torsion. The moment and torsion factors figure were presented according to the different structural parameters such as the skewed angle and the stiffness ratio of flexure to torsion. Some equivalent load vectors of non-nodal load acting on the skewed supported beam were derived.

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