Local Buckling Analysis of Aluminum I Section Beams

2010 ◽  
Vol 168-170 ◽  
pp. 1921-1933
Author(s):  
Yuan Qing Wang ◽  
Huan Xin Yuan ◽  
Yong Jiu Shi ◽  
Ming Cheng
Keyword(s):  
Local Stability ◽  
Numerical Study ◽  
Design Method ◽  
Local Buckling ◽  
Initial Imperfection ◽  
Steel Structures ◽  
Thickness Ratio ◽  
Parameter Analysis ◽  
Element Analysis ◽  
Material Constitutive Relation

Low elastic modulus of aluminum alloy gives prominence to lateral and local buckling of members, especially when thin walled sections are adopted to save material usage. Under certain conditions of loads and constraint, local buckling would occur in aluminum beams. A numerical study to assess the local stability of aluminum I section beams is presented in this paper. The study focused on two aspects: the local buckling of aluminum flange plate under compression, the local buckling of aluminum web plate under bending and shear. An extensive parameter analysis including width-to-thickness ratio, initial imperfection, material constitutive relation and restriction effect from adjacent plates was carried out with the purpose of extracting several governing parameters and investigating their effects on the local buckling of aluminum plate. Based upon the results of finite element analysis (FEA), a new design method in connection with the local stability of aluminum I section beams has been developed. By virtue of the proposed design method, three key indicators that include the critical value of width-to-thickness ratio to prevent local buckling of aluminum flange plate under compression, the local stability of aluminum web plate under bending/shear and the bearing capacity of aluminum I section beams under the condition that the post buckling strength of web is taken into account, could be obtained to provide more rational and efficient designs. The proposed design method is different from the current Eurocode but acts in accordance with Chinese code for design of steel structures (Chinese steel code) in order to satisfy applicability.

Study on the Local Buckling Behavior of Steel Equal Angle Members under Axial Compression with the Steel Strength Variation

2011 ◽  
Vol 374-377 ◽  
pp. 2430-2436
Author(s):  
Gang Shi ◽  
Zhao Liu ◽  
Yong Zhang ◽  
Yong Jiu Shi ◽  
Yuan Qing Wang
Keyword(s):  
Finite Element ◽  
Axial Compression ◽  
High Strength Steel ◽  
Local Buckling ◽  
Steel Structures ◽  
High Strength ◽  
Element Analysis ◽  
Equal Angle ◽  
Buckling Behavior ◽  
Steel Strength

High strength steel sections have been increasingly used in buildings and bridges, and steel angles have also been widely used in many steel structures, especially in transmission towers and long span trusses. However, high strength steel exhibits mechanical properties that are quite different from ordinary strength steel, and hence, the local buckling behavior of steel equal angle members under axial compression varies with the steel strength. However, there is a lack of research on the relationship of the local buckling behavior of steel equal angle members under axial compression with the steel strength. A finite element model is developed in this paper to analyze the local buckling behavior of steel equal angle members under axial compression, and study its relationship with the steel strength and the width-to-thickness ratio of the angle leg. The finite element analysis (FEA) results are compared with the corresponding design method in the American code AISC 360-05, which provides a reference for the related design.

Effects of Diameter to Thickness Ratio and External Pressure on the Velocity of Dynamic Buckle Propagation in Offshore Pipelines

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Z. Omrani ◽  
K. Abedi ◽  
A. R. Mostafa Gharabaghi
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Element Model ◽  
External Pressure ◽  
Thickness Ratio ◽  
Small Scale ◽  
Element Analysis ◽  
Models Comparison ◽  
Buckle Propagation ◽  
Exerted Pressure

In this paper, a numerical study of the dynamic buckle propagation, initiated in long pipes under external pressure, is presented. For a long pipe, due to the high exerted pressure, local instability is likely to occur; therefore, the prevention of its occurrence and propagation are very important subjects in the design of pipelines. The 3D finite element modeling of the buckle propagation is presented by considering the inertia of the pipeline and the nonlinearity introduced by the contact between its collapsing walls. The buckling and collapse are assumed to take place in the vacuum. The numerical results of the nonlinear finite element analysis are compared with the experimental results obtained by Kyriakides and Netto (2000, “On the Dynamics of Propagating Buckle in Pipelines,” Int. J. Solids Struct., 37, pp. 6843–6878) from a study on the small-scale models. Comparison shows that the finite element results have very close agreement with those of the experimental study. Therefore, it is concluded that the finite element model is reliable enough to be used for nonlinear collapse analysis of the dynamic buckle propagation in the pipelines. In this study, the effects of external pressure on the velocity of dynamic buckle propagation for different diameter to thickness ratios are investigated. In addition, the mathematical relations, based on the initiation pressure, are derived for the velocity of buckle propagation considering the diameter to thickness ratio of the pipeline. Finally, a relation for the buckle velocity as a function of the pressure and diameter to thickness ratio is presented.

scholarly journals Code Calculations for Local Stability of Shaft Guides

2017 ◽  
Vol 39 (3) ◽  
pp. 11-16 ◽  
Author(s):  
Przemysław Fiołek ◽  
Jacek Jakubowski ◽  
Kamil Tomczak
Keyword(s):  
Cross Sections ◽  
Local Stability ◽  
Local Buckling ◽  
Steel Structures ◽  
Inertia Moment ◽  
Corrosion Loss ◽  
Class 1 ◽  
Guiding System ◽  
Hot Rolled ◽  
Considerable Loss

Abstract Steel structures for a conveyance guiding system are subjected to prolonged, intense corrosion during their operation leading to a considerable loss of material and structure capacity reduction. Shaft guides are made of closed profiles welded from hot-rolled channel sections. These profiles are categorized as class 1 cross-sections according to Eurocode 3, which means that they are resistant to local instability upon bending [1]. With an increase in the corrosion loss of the guides, the inertia moment of the cross-section is reduced. The resistance of profiles to local buckling is also reduced. However, calculations for local stability in guides upon bending are not required by the local Polish regulations on the operation of conveyance in shafts [2]. The question is whether this constitutes a shortcoming and risk for safe operation. Calculations according to steel construction standards [1] supported by numerical simulation were used to evaluate shaft steelwork guides resistance to buckling and their sensitivity to corrosion loss. It was shown that the guides of corrosion loss of 52–63%, depending on profile size, are prone to local buckling.

scholarly journals Proposal of C-core Type Transverse Flux Motor for Ship Propulsion – Increasing Torque Density by Dense Stator Configuration –

2014 ◽  
Vol 2 (3) ◽  
pp. 28 ◽  
Author(s):  
Y. Yamamoto ◽  
T. Koseki ◽  
Y. Aoyama
Keyword(s):  
Numerical Study ◽  
Design Method ◽  
Element Analysis ◽  
Low Speed ◽  
Torque Density ◽  
Ship Propulsion ◽  
High Torque ◽  
Transverse Flux ◽  
Effective Use ◽  
Simple Modeling

Electric ship propulsion system has been drawing attention as a solution for savings in energy and maintenance costs. The system is mainly composed of motor, converter and gearbox and required for high torque at low speed. In this situation, transverse flux motors (TFMs) have been proposed to fulfill the low-speed high-torque characteristic due to suitable for short pole pitch and large number of poles to increase torque output. In this trend, we have proposed C-core type motors taking advantage of TFMs’ structure. In this manuscript, a simple design method based on the magnetic-circuit theory and simple modeling of the motor is proposed to search a design parameter for maximizing torque as a pre-process of numerical study. The method takes into consideration the effects of magnetic leakage flux, magnetic saturation and pole-core combination in accordance with the systematic theory. The simple modeling is conducted based on a dense armature structure in previous axial flux motors (AFMs) applied to the new motor design. The validity of the method is verified by 3-D finite element analysis (FEA) and relative error is at most 20%. The minimalist design is shown to be advantageous for effective use in 3-D FEA. As a detailed design by the FEA, high torque density and low cogging to output ratio can be achieved simultaneously in the proposed machine.

scholarly journals Design and Model Test of a Modularized Prefabricated Steel Frame Structure with Inclined Braces

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xuechun Liu ◽  
Ailin Zhang ◽  
Jing Ma ◽  
Yongqiang Tan ◽  
Yu Bai
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Design Method ◽  
Steel Structures ◽  
Steel Frame ◽  
Frame Structure ◽  
Element Analysis ◽  
High Rise ◽  
High Degree ◽  
Steel Frame Structure

Modularized prefabricated steel structures have become the preferred design in the industrialization of steel structures due to their advantages of fast construction speed, high degree of industrialization, low labour intensity, and more. Prefabricated steel structures have some engineering applications, but all are low-rise structures with few applications in the field of high-rise buildings. Using finite element analysis with line and solid elements, full-scale experiments were conducted to study the single-span frame, which is the core load-bearing part of a modularized prefabricated high-rise steel frame structure with inclined braces. The mechanical mechanisms, computation methods, and design formulas of truss girders were obtained by comparing the finite element and model experiments and building a theoretical and experimental basis for the compilation of design codes. The mechanical characteristics under design load, the deformation and stress state, the elastic-plastic law of development, and the yield failure mode and mechanism under horizontal ultimate load were also obtained. Based on theoretical analysis, finite element analysis, and experiments, the design method of this frame was summarized and incorporated into the design code.

Cyclic Performance Evaluation of Hollow Structural Section (HSS) and Concrete-Filled Tube (CFT) Braces

2019 ◽  
Vol 19 (11) ◽  
pp. 1950140 ◽  
Author(s):  
Samira Ebrahimi ◽  
Seyed Mehdi Zahrai ◽  
Seyed Rasoul Mirghaderi
Keyword(s):  
Compressive Strength ◽  
Energy Dissipation ◽  
Cross Sections ◽  
Numerical Study ◽  
Local Buckling ◽  
Diameter Ratio ◽  
Thickness Ratio ◽  
Cyclic Response ◽  
Concrete Filled Tubes ◽  
Energy Dissipation Capacity

Hollow structural sections (HSS) are widely used as braces because they have inherent axial, flexural, and torsional capacities. Delaying or preventing local buckling is accomplished by concrete infill in HSS braces to improve their cyclic response heavily relying upon three key parameters: (1) presence of concrete infill, (2) width (diameter)-to-thickness ratio, and (3) length-to-width (diameter) ratio impress the cyclic response of HSS braces. Nevertheless, it is not clear that based on which parameter, concrete infill can significantly enhance the peak compressive strength and energy dissipation capacity of HSS braces. This paper aims to investigate this concern while presenting a numerical study on the cyclic response of 120 HSS and Concrete-Filled Tubes (CFT) braces with various geometric characteristics. Square and circular cross-sections, 10, 12, 13.33, 20, 30, 33.33, and 50 width (diameter)-to-thickness ratios and 10, 15, 20, 25, 30, 37.5, 45, 50, 75, and 112.5 length-to-width (diameter) ratios are selected for the numerical investigation. Obtained results indicated that concrete infill can increase peak compressive and post-buckling strengths and energy dissipation capacity of HSS braces around 81%, 43%, and 73%, respectively. It was found that concrete infill and parameters of width (diameter)-to-thickness ratio and length-to-width (diameter) ratio influence the cyclic response of HSS braces differently. On the other hand, concrete infill noticeably enhances the peak compressive strength of HSS braces with larger values of width (diameter)-to-thickness ratio and energy dissipation capacity of such braces with lower values of length-to-width (diameter) ratio.

scholarly journals Experimental study and finite element analysis of energy dissipating outriggers

2016 ◽  
Vol 20 (8) ◽  
pp. 1196-1209 ◽  
Author(s):  
Qingshun Yang ◽  
Xinzheng Lu ◽  
Cheng Yu ◽  
Donglian Gu
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Local Buckling ◽  
Tall Buildings ◽  
Initial Imperfection ◽  
High Strength ◽  
Test Results ◽  
Element Analysis ◽  
Global Buckling ◽  
Energy Dissipation Capacity

The outriggers are widely adopted in tall and super-tall buildings. Their energy dissipation capacity can significantly influence the nonlinear seismic responses of the entire building structure. Based on an actual tall building project, the structural responses and energy dissipation capacities of three different outriggers were studied through experiments and finite element analyses. The test results of conventional outrigger specimen showed a steep deterioration after peak strength and an unfavorable energy dissipation capacity due to the global buckling of the braces and the local buckling of the chords after flexural yielding. Using buckling-restrained braces and reduced beam sections in a new design of the outriggers, the energy dissipation capacity and the ductility of the outriggers were significantly improved. The yield and peak strengths were further improved with the use of high-strength steel in chords on a third specimen. The finite element simulation of the three specimens indicated that the initial imperfection of the specimens shall be considered, and the developed finite element models yielded good agreements with the test results. The outcome of this work can provide additional references for the application of the outriggers in tall buildings.

Numerical study on bonding strength of ribbed reinforcing bars in UHPC with material ductility

2019 ◽  
Author(s):  
Xuefei Shi ◽  
Yi Gao ◽  
Shenghui Cao
Keyword(s):  
Bonding Strength ◽  
High Performance ◽  
Failure Modes ◽  
High Performance Concrete ◽  
Numerical Study ◽  
Design Method ◽  
Reinforcing Bars ◽  
Element Analysis ◽  
Pull Out ◽  
Material Ductility

<p>This paper mainly studies the bonding mechanism of ribbed steel reinforcing bars in ultra-high performance concrete (UHPC) considering the influence of material ductility. In recent years, the bond slip behavior of reinforcing bars in UHPC has received extensive attention. In the previous pull-out tests, it was found that the classical splitting theory still plays role in bond failure modes. In this paper, the pull-out test is simulated by finite element analysis, and it is found that unlike ordinary concrete, UHPC can still hold the load for a period of time after the tensile stress on splitting surfaces reaches the critical value, due to the ductility of the material. It is found from the numerical results that the bonding stresses are not evenly distributed along the steel bar when the pull-out failure occurred. Through theoretical analysis and experimental verification, the maximum bonding force of ribbed reinforcing bars in UHPC is closely related to the material ductility. Based on this, a new theoretical model for calculating the bonding strength of ribbed steel reinforcing bars in UHPC is proposed, and can be used for the design method of urban bridge built with UHPC.</p>

scholarly journals Numerical Study on the Local Buckling Behaviour of Bolted Steel Plates in Steel Jacketing

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Xiao-liang Xu ◽  
Zhou-dao Lu ◽  
Ling-zhi Li ◽  
Chang-jiu Jiang
Keyword(s):  
Numerical Simulation ◽  
Experimental Study ◽  
Numerical Model ◽  
Parametric Study ◽  
Numerical Study ◽  
Local Buckling ◽  
Initial Imperfection ◽  
Field Capacity ◽  
Steel Plates ◽  
Previous Experimental Study

A numerical simulation was conducted to investigate the local buckling behaviour of the bolted steel plates in steel jacketing technique. The numerical model was firstly validated by the results of a previous experimental study. Then a parametric study was conducted to investigate the influence of different restraint measures on the local buckling behaviour and the sensitivity of the buckling behaviour to the initial imperfection. Fitted formulae were developed to calculate the structural field capacity of the bolted steel plates, and recommended values of stiffener size were also provided to facilitate the strengthening design of steel jacketing.

Behaviour of partly stiffened cold-formed steel built-up beams: Experimental investigation and numerical validation

2018 ◽  
Vol 22 (1) ◽  
pp. 172-186 ◽  
Author(s):  
M Adil Dar ◽  
N Subramanian ◽  
A R Dar ◽  
M Anbarasu ◽  
James BP Lim ◽  
...  
Keyword(s):  
Failure Modes ◽  
Numerical Study ◽  
Local Buckling ◽  
Steel Structures ◽  
Vital Role ◽  
Steel Beams ◽  
Design Strength ◽  
Finite Element Software ◽  
Cold Formed Steel ◽  
Reserve Strength

To address the various instability problems in cold-formed steel members, many researchers have mainly focused on developing innovative sectional profiles wherein geometry of the section plays a vital role in enhancing the inherent resistance of such sections against premature buckling. However, the process of forming such innovative shapes is not only complex and time-consuming but sometimes such sections fail to mobilize their complete reserve strength. Hence, a stiffening arrangement of weaker zones for mobilizing the untapped reserve strength is suggested. The contribution of this simple, effective and partly stiffening arrangements, aimed at eliminating/delaying the premature local buckling, is studied both experimentally and numerically and also compared with existing codes. Experimental study was carried out on different simply supported cold-formed steel beams with judiciously proposed stiffening arrangements under four-point loading. An equivalent hot-rolled steel beam was also tested to compare the efficiency of the cold-formed steel beams. The cold-formed steel beams investigated had different width-to-thickness ratio, different geometries and different stiffening arrangements. The test strengths, failure modes, deformed shapes, load versus mid-span displacements and geometric imperfections were measured and reported. The test strengths of the beam models are also compared with the design strength predicted by North American Standards and Eurocode for cold-formed steel structures. To validate the test results further, a numerical study was carried out on such stiffened cold-formed steel beams using finite element software ABAQUS. All these results show that the proposed strengthening system is efficient and economical and allow cold-formed steel beams to reach greater load carrying capacity.

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