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1
Vakiener, Adam R. "Preliminary investigation of flange local buckling in pultruded wide flange structural shapes." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/19562.
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Sufran, Mansor. "COMPARISON OF STRENGTH, DUCTILITY AND STIFFNESS OF FREE FLANGE AND WELDED FLANGE PLATE CONNECTION." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2632.
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Steel structures have been in use in high-rise structures since its more economical as compared to the use of concrete. The steel frames constructed fall under ordinary moment-resisting structures or special moment-resisting structures. Since the occurrence of Northridge earthquake in 1994 and Kobe earthquake in 1995, a lot of research has been done on causes of structural failure as well as remedies to the faults previously present in the building before the occurrence of the earthquake.
3
Steau, Edward. "Web bearing behaviour and design of hollow flange beams." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/120162/1/Edward_Steau_Thesis.pdf.
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Thin-walled steel hollow flange channel beams are commonly used as joists and bearers in various flooring systems in buildings. They are mono-symmetric sections with two closed rectangular hollow flanges, which make them highly structurally efficient when compared with conventional cold-formed steel sections. The LiteSteel beam (LSB) section is a welded hollow flange channel beam with two rectangular hollow flanges. It is made from a single steel strip using a combined dual electric resistance welding and automated continuous rollforming process. Recent research studies made improvements to the LSB section, by eliminating the expensive welding and replacing them with a riveting process. This innovative hollow flange channel beams known as the rivet fastened rectangular hollow flange channel beam (RHFCB) section. The rivet fastened RHFCB is made by intermittently rivet fastening two torsionally rigid rectangular hollow flanges to a web plate element, which allows section optimisation by selecting appropriate combinations of web and flange widths and thicknesses. The LSB and rivet fastened RHFCB sections are thin-walled flexural members, hence becoming vulnerable to web bearing failures including web crippling, flange crushing and their combinations. However, no investigation has been conducted on the web crippling behaviour and capacity of LSB and the newly introduced rivet fastened RHFCB sections.
To address this issue, an experimental study was conducted consisting of over 170 web crippling tests to investigate the web crippling behaviour and capacities of LSBs and rivet fastened RHFCBs, based on the new AISI S909 standard test method. This study included LSBs and rivet fastened RHFCBs with their flanges unfastened and fastened to supports under all the four standard load cases used in web crippling studies - End-Two-Flange (ETF) Loading, Interior-Two-Flange (ITF) Loading, End-One-Flange (EOF) Loading and Interior- One-Flange (IOF) Loading. It provided significantly improved knowledge and understanding of the web bearing failures including web crippling, flange crushing and their combinations, and associated web bearing capacities.
Comparisons of experimental web crippling capacity results with predictions using the current AS/NZS 4600 and AISI S100 design standards showed that web crippling design equations are unconservative in some cases while being conservative in other cases for both LSB and rivet fastened RHFCB sections with flanges unfastened and fastened to supports under ETF, ITF, EOF and IOF load cases. Hence this research study has proposed new equations to determine the web crippling capacities of LSBs and rivet fastened RHFCBs based on experimental results. Flange crushing led to higher web crippling capacities and thus the same capacity equations are recommended as a conservative design approach. The web crippling tests with flanges fastened to support conditions showed that web crippling capacities increased by 10 to 90 % on average for both LSBs and rivet fastened RHFCBs under all four load cases. This has thus demonstrated the need to include the benefits of fastening to supports in the web crippling design.
Experimental results from this study showed that both hollow flange channel beams (LSB and rivet fastened RHFCB) perform structurally better due to their unique geometric characteristics (effective flanges), when compared to conventional open cold-formed channel sections. The two additional flange lips in the rivet fastened RHFCBs effectively stiffen the web plate and thus provide higher resistance against web crippling than the welded hollow flange channel beams (LSBs) without flange lips. Tests showed that intermittent rivet fastening can be used to produce similar outcomes as welded LSBs as there was no excessive separation between the web and flange plates during the tests. Based on the results from this study, a 100 mm rivet spacing is recommended for RHFCBs.
In summary, this thesis has presented the details of an extensive experimental study into the web crippling behaviour and capacities of an innovative group of welded and rivet fastened hollow flange beams known as LSBs and RHFCBs with their flanges unfastened and fastened to supports under ETF, ITF, EOF and IOF load cases, the results and the improved web crippling design equations developed within the guidelines of AS/NZS 4600 and AISI S100.
Such enhanced knowledge, understanding and design rules are expected to advance the use of those innovative sections as joists and bearers in floor systems.
4
Waara, Patric. "Wear reduction performance of rail flange lubrication." Licentiate thesis, Luleå, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26422.
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Rail and rail wheel flange wear on the rail track has been a problem of attention for the last 30 years. The problems arise in curves and depend on increased traffic volume, heavier axle load and also higher speed. Axle loads of 22,5-25 ton is common nowadays and the trend is towards heavier axle loads where the next step is 30-35 ton. Flange wear includes both wheel and rail flanges and is therefore a problem for the operating company as well as the infrastructure owner. The flange wear depend mainly on the number of passed axles, type of traffic, speed and curve radius but also the axle load contributes. Flange lubrication on high rail is a well known way to reduce wear since the middle of 70th and a number of techniques to lubricate the rail flange are developed as grease, aerosol of oil and dry stick with solid lubricants. The trackside lubricator can not apply the grease on the rail flange when the climate is during the winter. The infrastructure owner in Sweden was interested to evaluate the effectiveness of the track side lubricator. The investment in trackside lubricators over 20 years was about 75 Mkr (7,6 USD) and also an additional yearly costs to operate 3000 apparatuses. The work to evaluate effectiveness of the lubrication started 1997 there one of the important matter concern the possibility to use environmentally adapted lubricants without hazard the rail. This licentiate thesis concern effectiveness of trackside lubricators to reduce wear in sharp railroad curves. Also the environmentally aspects have been considered and therefore natural esters synthetic esters and additives suited for those kind of lubricants have been evaluated. The research proved that environmentally adapted lubricants could lubricate as good as earlier used greases. Some amount of metal removal is probably healthy for this kind of application. Lubricants as synthetic esters can be designed get those qualities. It was also found significant difference between the seasons concerning flange wear. This difference depends on the problem to apply grease on the rail flange during the winter.
5
Bishop, Cliff Douglas. "Flange bracing requirements for metal building systems." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47665.
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The analysis and design of bracing systems for complex frame geometries typically found in metal buildings can prove to be an arduous task given current methods. The American Institute of Steel Construction's Appendix 6 from the 2010 Specification for Structural Steel Buildings affords engineers a means for determining brace strength and stiffness requirements, but only for the most basic cases. Specifically, there are a number of aspects of metal building systems that place their designs outside the scope of AISC's Appendix 6 (Stability Bracing for Columns and Beams). Some of the aspects not considered by Appendix 6 include: the use of web-tapered members, the potential for unequally spaced or unequal stiffness bracing, combination of bracing types including panel and flange diagonal bracing, and the effects of continuity across brace points. In this research, an inelastic eigenvalue buckling procedure is developed for calculation of the ideal bracing stiffness demands in general framing systems. Additionally, the software provides a method of calculating the elastic lateral-torsional buckling load of members with generally stepped and tapered cross-sections, which satisfies an important need for rigorous design assessment. Extensive benchmarking to load-deflection simulations of geometrically imperfect systems is performed and recommendations are developed for determining the required design stiffness and strength of the bracing components based on the use of this type of computational tool.
6
Cao, J. J. "Tension circular flange joints in tubular structures." Thesis, University of Manchester, 1995. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527696.
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Berrington, R. E. "Rig design to provide flange methodology validation data." Thesis, Swansea University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636083.
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Over the years many researchers have investigated various aspects of bolted flanged joints. Much of this has been in the areas of flange sealing and fatigue characterisation of the joint components. Roll-Royce plc is researching new methods of analysing the flanged joints on its aero-engine casings, with the aim of reducing weight by up to thirty percent without compromising reliability or efficiency. In modern civil aero-engines, the need to withstand the excessive stresses induced by the loss of a fan blade is the design case for many of the structural casing flanges. These flanged joints tend to be thinner, and much more flexible, than their industrial counterparts due to the use of high strength alloys. Under high load conditions these joints experience a significant amount of plasticity, both in the bolts and in the flange areas between the bolt holes. This makes the basic strength of the joint difficult to predict accurately. To validate the prediction methods experimental data at high loads is required. This thesis presents the design and commissioning of a rig capable of testing to failure, in a controlled manner, an assembly of actual engine casings from the main structural load path of two large modern civil aero-engines. The casings are fully strain-gauged to provide as much validation data as possible. The rig will provide data under combinations of axial load, bending moment and pressure, extending from normal operating loads, through the ultimate design loads, and up to eventual failure. To ensure failure the rig can apply axial loads up to 400 tons and bending moments up to 12 million pound-inches.
8
Berninghaus, Garth B. "Stress distribution in welded flange-bolted web connections." Thesis, Monterey, California. Naval Postgraduate School, 1995. http://hdl.handle.net/10945/26269.
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Wappler, Gilberto Paulo. "Otimização paramétrica de um flange de motor elétrico." Universidade do Estado de Santa Catarina, 2014. http://tede.udesc.br/handle/handle/2065.
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Previous issue date: 2014-12-16<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>This work has the objective of implementing a structural optimization procedure in order to adjust the natural frequency of electric motors. This is accomplished by modifying some flange dimensions, which is the part connecting the motor to the system being driven. The implemented optimization algorithm is the PSO (Particle Swarm Optimization), which proved to be appropriate for the type of problem considered (non convex and with few design variables). The optimization formulation aims to get a motor/flange whose first natural frequency is equal to a specified value while observing the criterion of Rankine for brittle materials. Both the modal analysis and evaluation of the principal stresses are performed by a commercial finite element code. Due to the large computational cost associated to the combined use of PSO with an external finite element program, it is studied an approximation by least squares of the natural frequency and of the principal stresses. This procedure is effective and extremely efficient. Examples of flange designs
obtained using the proposed formulation are presented and discussed, showing the validity of the procedure adopted.<br>Este trabalho tem como objetivo implementar um procedimento de otimização estrutural aplicado ao ajuste da frequência natural de motores elétricos. Isto é realizado pela modificação de algumas dimensões do flange, elemento de ligação entre o motor e o sistema que está sendo acionado. O algoritmo de otimização implementado é o PSO (Otimização por enxame de partículas), que se mostrou adequado ao tipo de problema considerado (não convexo e com poucas variáveis de projeto). A formulação de otimização tem como objetivo obter um conjunto motor/flange cuja primeira frequência natural seja igual a um valor estipulado, respeitando o critério de Rankine para materiais frágeis. A análise modal e de tensões é realizada por um programa comercial de elementos finitos. Devido ao grande custo computacional associado ao uso conjunto do PSO com um programa externo de elementos finitos, é estudada uma aproximação por mínimos quadrados da frequência natural e das tensões principais. Este procedimento se mostrou eficaz e extremamente eficiente. Exemplos de projetos de flange obtidos com o uso da formulação proposta são apresentados e discutidos, mostrando a validade do procedimento adotado.
10
Assenso, Antwi Akwasi Manu. "Behavior of wide flange beams with web openings." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/978.
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Behavior of wide flanged beams is of much importance to civil engineers as this one of the main materials used in steel structures. Openings are made in the web of beams to pass services pipes from one side of the building to another, when these openings are made in the beams, the shear and moment capacity at this section will be reduced. This will increase stresses at this section of the beam and will subsequently affect the stress distribution in the beam with web opening. Longitudinal stiffeners are placed at the top and bottom edges of the web opening to increase both moment and shear capacity at the section with web opening. Four samples were used in this study; a solid wide flange beam, a wide flange beam with web opening and two beams with reinforced web openings. The von Mises stress and the first principal stresses were obtained from the nonlinear static analysis. The results from a nonlinear finite element analysis of the four simply supported beams are discussed. The AISC steel design guide series 2 provide equations for the design of reinforced web opening. The reinforced web opening beam using the AISC guidelines is evaluated by comparing it to the finite element analysis.
11
Sharma, Akhil. "Flange stability bracing behavior in metal building frame systems." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39485.
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The objective of this research is to evaluate the stiffness and strength demands on flange braces in metal building systems. This objective is accomplished by a targeted study of the effects of various attributes of metal building systems not fully addressed in existing bracing design procedures. Special emphasis is placed on attributes such as unequal brace spacing and stiffness, end brace point flexibility, nonprismatic member geometry, special requirements at knee joints and the specific configuration of combined girt/purlin, flange diagonal, diaphragm and X bracing systems used in metal building construction.
A sub-objective of the research is the demonstration of how virtual test simulation via full nonlinear finite element analysis may be applied to solve a structural engineering research problem that would be difficult to address by any other means. When conducted properly, virtual test simulation can serve as a valuable companion to experimental testing since attributes such as residual stresses and critical geometric imperfections can be controlled precisely and with relative ease in virtual test simulation.
Both highly simplified and more complex but relatively rigorous procedures are considered, with the ultimate goal being improved economy and safety of flange stability bracing in metal buildings.
12
Conforti, Evandro 1947. "Antena a guia cilindrico-circular comterminação em flange conica." [s.n.], 1987. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261303.
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Kalbhor, Mayank D. "Structural and Thermal Analysis of Flange for LNG Applications." Cleveland State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=csu1243355785.
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Tanawade, Atul Gunaji. "Probabilistic Structural and Thermal Analysis of a Gasketed Flange." Cleveland State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=csu1326916079.
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Anapayan, Tharmarajah. "Flexural behaviour and design of hollow flange steel beams." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/36210/1/Tharmarajah_Anapayan_Thesis.pdf.
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The LiteSteel Beam (LSB) is a new hollow flange channel section developed by OneSteel Australian Tube Mills using a patented Dual Electric Resistance Welding technique. The LSB has a unique geometry consisting of torsionally rigid rectangular hollow flanges and a relatively slender web. It is commonly used as rafters, floor joists and bearers and roof beams in residential, industrial and commercial buildings. It is on average 40% lighter than traditional hot-rolled steel beams of equivalent performance. The LSB flexural members are subjected to a relatively new Lateral Distortional Buckling mode, which reduces the member moment capacity. Unlike the commonly observed lateral torsional buckling of steel beams, lateral distortional buckling of LSBs is characterised by simultaneous lateral deflection, twist and web distortion. Current member moment capacity design rules for lateral distortional buckling in AS/NZS 4600 (SA, 2005) do not include the effect of section geometry of hollow flange beams although its effect is considered to be important. Therefore detailed experimental and finite element analyses (FEA) were carried out to investigate the lateral distortional buckling behaviour of LSBs including the effect of section geometry. The results showed that the current design rules in AS/NZS 4600 (SA, 2005) are over-conservative in the inelastic lateral buckling region. New improved design rules were therefore developed for LSBs based on both FEA and experimental results. A geometrical parameter (K) defined as the ratio of the flange torsional rigidity to the major axis flexural rigidity of the web (GJf/EIxweb) was identified as the critical parameter affecting the lateral distortional buckling of hollow flange beams. The effect of section geometry was then included in the new design rules using the new parameter (K). The new design rule developed by including this parameter was found to be accurate in calculating the member moment capacities of not only LSBs, but also other types of hollow flange steel beams such as Hollow Flange Beams (HFBs), Monosymmetric Hollow Flange Beams (MHFBs) and Rectangular Hollow Flange Beams (RHFBs). The inelastic reserve bending capacity of LSBs has not been investigated yet although the section moment capacity tests of LSBs in the past revealed that inelastic reserve bending capacity is present in LSBs. However, the Australian and American cold-formed steel design codes limit them to the first yield moment. Therefore both experimental and FEA were carried out to investigate the section moment capacity behaviour of LSBs. A comparison of the section moment capacity results from FEA, experiments and current cold-formed steel design codes showed that compact and non-compact LSB sections classified based on AS 4100 (SA, 1998) have some inelastic reserve capacity while slender LSBs do not have any inelastic reserve capacity beyond their first yield moment. It was found that Shifferaw and Schafer’s (2008) proposed equations and Eurocode 3 Part 1.3 (ECS, 2006) design equations can be used to include the inelastic bending capacities of compact and non-compact LSBs in design. As a simple design approach, the section moment capacity of compact LSB sections can be taken as 1.10 times their first yield moment while it is the first yield moment for non-compact sections. For slender LSB sections, current cold-formed steel codes can be used to predict their section moment capacities. It was believed that the use of transverse web stiffeners could improve the lateral distortional buckling moment capacities of LSBs. However, currently there are no design equations to predict the elastic lateral distortional buckling and member moment capacities of LSBs with web stiffeners under uniform moment conditions. Therefore, a detailed study was conducted using FEA to simulate both experimental and ideal conditions of LSB flexural members. It was shown that the use of 3 to 5 mm steel plate stiffeners welded or screwed to the inner faces of the top and bottom flanges of LSBs at third span points and supports provided an optimum web stiffener arrangement. Suitable design rules were developed to calculate the improved elastic buckling and ultimate moment capacities of LSBs with these optimum web stiffeners. A design rule using the geometrical parameter K was also developed to improve the accuracy of ultimate moment capacity predictions. This thesis presents the details and results of the experimental and numerical studies of the section and member moment capacities of LSBs conducted in this research. It includes the recommendations made regarding the accuracy of current design rules as well as the new design rules for lateral distortional buckling. The new design rules include the effects of section geometry of hollow flange steel beams. This thesis also developed a method of using web stiffeners to reduce the lateral distortional buckling effects, and associated design rules to calculate the improved moment capacities.
16
Tran, Dai Quang. "Toward improved flange bracing requirements for metal building frame systems." Thesis, Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/33908.
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This research investigates the application of the AISC Direct Analysis Method for stability bracing design of columns, beams, beam-columns and frames. Emphasis is placed on out-of-plane flange bracing design in metal building frame systems. Potential improvements and extensions to the 2005 AISC Appendix 6 stability bracing provisions are studied and evaluated. The structural attributes considered include various general conditions encountered in practical metal building design: unequal brace spacing, unequal brace stiffness, nonprismatic member geometry, variable axial load or bending moment along the member length, cross-section double or single symmetry, combined bending and axial load, combined torsional and lateral bracing from girts/purlins with or without diagonal braces from these components to the inside flanges, load height, cross-section distortion, and non-rigid end boundary conditions. The research addresses both the simplification to basic bracing design rules as well as direct computation for more complex cases. The primary goal is improved assessment of the demands on flange bracing systems in metal building frames.
17
Pezeshky, Payam. "Distortional Static and Buckling Analysis of Wide Flange Steel Beams." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36074.
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Existing design provisions in design standards and conventional analysis methods for structural steel members are based on the simplifying kinematic Vlasov assumption that neglects cross-sectional distortional effects. While the non-distortional assumption can lead to reasonable predictions of beam static response and buckling strength in common situations, past work has shown the inadequacy of such assumption in a number of situations where it may lead to over-predicting the strength of the members. The present study thus develops a series of generalized theories/solutions for the static analysis and buckling analysis of steel members with wide flange cross-sections that capture distortional effects of the web. Rather than adopting the classical Vlasov assumption that postulates the cross-section to move and rotate in its own plane as a rigid disk, the present theories assume the web to be flexible in the plane of the cross-section and thus able to bend laterally, while both flanges to move as rigid plates within the plane of the cross-section to be treated as Euler-Bernouilli beams. The theories capture shear deformation effects in the web, as well as local and global warping effects.
Based on the principle of minimum potential energy, a distortional theory is developed for the static analysis of wide flange steel beams with mono-symmetric cross-sections. The theory leads to two systems of differential equations of equilibrium. The first system consists of three coupled equilibrium differential equations that characterize the longitudinal-transverse response of the beam and the second system involves four coupled equilibrium differential equations of equilibrium and characterizes the lateral-torsional response of the beam. Closed form solutions are developed for both systems for general loading. Based on the kinematics of the new theory, two distortional finite elements are then developed. In the first element, linear and cubic Hermitian polynomials are employed to interpolate displacement fields while in the second element, the closed-form solutions developed are adopted to formulate special shape functions. For longitudinal-transverse response the elements consist of two nodes with four degree of freedom per node for longitudinal-transverse response and for lateral-torsional response, the elements consist of two nodes with eight degrees of freedom per node. The solution is able to predict the distortional deformation and stresses in a manner similar to shell solutions while keeping the modeling and computational effort to a minimum.
Applications of the new beam theory include (1) providing new insights on the response of steel beams under torsion whereby the top and bottom flanges may exhibit different angles of twist, (2) capturing the response of steel beams with a single restrained flange as may be the case when a concrete slab provides lateral and/or torsional restraint to the top flange of a steel beam, and (3) modelling the beneficial effect of transverse stiffeners in reducing distortional effects in the web.
The second part of the study develops a unified lateral torsional buckling finite element formulation for the analysis of beams with wide flange doubly symmetric cross-sections. The solution captures several non-conventional features. These include the softening effect due to web distortion, the stiffening effect induced by pre-buckling deformations, the pre-buckling nonlinear interaction between strong axis moments and axial forces, the contribution of pre-buckling shear deformation effects within the plane of the web, the destabilizing effects due to transverse loads being offset from the shear centre, and the presence of transverse stiffeners on web distortion. Within the framework of the present theory, it is possible to evoke or suppress any combination of the features and thus isolate the individual contribution of each effect or quantify the combined contributions of multiple effects on the member lateral torsional capacity. The new solution is then applied to investigate the influence of the ratios of beam span-to-depth, flange width-to-thickness, web height-to-thickness, and flange width-to-web height on the lateral torsional buckling strength of simply supported beams and cantilevers. Comparisons with conventional lateral torsional buckling solutions that omit distortional and pre-buckling effects quantify the influence of distortional and/or pre-buckling deformation effects. The theory is also used to investigate the influence of P-delta effects of beam-columns subjected to transverse and axial forces on their lateral torsional buckling resistance. The theory is used to investigate the load height effect relative to the shear centre. Comparisons are made with load height effects as predicted by non-distortional buckling theories. The solution is adopted to quantify the beneficial effect of transverse stiffeners in controlling/suppressing web distortion in beams and increasing their buckling resistance.
18
Bandy, Brent J. "Flexural behavior of a deep wide-flange FRP pultruded beam." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/21805.
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Arizou, Ramin. "Distortional Lateral Torsional Buckling of Doubly Symmetric Wide Flange Beams." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41574.
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Distortional lateral-torsional buckling theories assume that the flanges remain undistorted, while the web is free to distort as a thin plate. Most theories adopt a cubic polynomial distribution along the web height to relate the lateral displacement of the web to the displacements and angles of twist both flanges. The present study develops a family of finite element solutions for the distortional buckling of wide flange beams in which the flanges are assumed to remain undistorted. In contrast to past theories, the lateral displacement distribution along the web height is characterized by superposing (a) two linear modes intended to capture the classical non-distortional lateral-torsional behavior and (b) any number of user-specified Fourier terms intended to capture additional web distortion. In the longitudinal direction, all displacement fields characterizing the lateral displacements are taken to follow a cubic distribution.
The first contribution of the thesis develops a finite element formulation that is able to replicate the classical non-distortional lateral torsional buckling solutions when the distortional modes are suppressed while enabling more accurate predictions for distortional lateral torsional buckling compared to those solutions based on the conventional cubic interpolation of the lateral displacement. The formulation is used to conduct an extensive parametric study to quantify the reduction in critical moments due to web distortion relative to the classical non-distortional predictions in the case of simply-supported beams, cantilevers, and beams with an overhang. The solution is then used to generate interaction curves for beams with an overhang subjected to various proportions of uniformly distributed and point loads.
The second contribution of the thesis adds two additional features to the formulation (a) to capture the destabilizing effect due to the load height relative to the shear center and (b) a module that incorporates any number of user-defined multi-point kinematic constraints. The additional features are employed to investigate the effect of load height, bracing height, and combined effects thereof in practical design problems. A distortional indicator is then introduced to characterize the distribution of web distortion along the beam span as the beam undergoes distortional lateral buckling. A systematic design optimization technique is then devised to identify the location(s) along the span at which the addition of transverse stiffeners would maximize the critical moment capacity.
20
O'Neill, Leah. "Lateral-Torsional Buckling Capacity of Tapered-Flange Moment Frame Shapes." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5759.
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While moment frames are a popular lateral-force resisting system, their constant cross-section can lead to inefficiencies in energy absorption and stiffness. By tapering the flange width linearly toward the center of the beam length, the energy absorption efficiency can be increased, leading to a better elastic response from the beam and more elastic stiffness per pound of steel used. Lateral-torsional buckling is an important failure mode to be considered for tapered-flange moment frame shapes. No closed-form or finite element solutions have yet been developed for tapered-flange I-beams with a non-uniform, linear moment gradient and intermediate bracing conditions. In this study, finite element analysis is used to find the buckling stress of each W-shape in the AISC Steel Construction Manual with both a standard straight-flange and the proposed tapered-flange at several lengths and with three intermediate lateral bracing conditions (no bracing, mid-span bracing, and third-span bracing). Plots are generated for each shape at each bracing condition as the buckling stress versus length for both beams and columns. Overall, the results indicate that lateral-torsional buckling of tapered-flange I-beams is not a problem that would prohibit the wide-scale use of this configuration in moment frames. Also, the buckling capacity tapered-flange moment frame shapes can be reasonably estimated as 20% of the corresponding straight-flange moment frame shape.
21
Galatanu, Anca Daniela. "Behaviour and design of hollow flange beams under axial compression." Thesis, Queensland University of Technology, 1997. https://eprints.qut.edu.au/36012/1/36012_Galatanu_1997.pdf.
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The Hollow Flange Beam (HFB) is a relatively new cold-formed steel section
developed by Palmer Tube Mills (Australia) Pty. Ltd., released into Australian
markets in November 1993, and targeting applications in the light industrial and
domestic markets.
It was envisaged early in the product development that the section will be primarily
used as a flexural member. Therefore research and development effort was
concentrated in this area, and little is kno,vn about the HFB behaviour under axial
compression. Furthermore, because of its unique fabrication process and distorsional
buckling behaviour, the HFB is not completely compliant with either the ColdFormed
Steel Structures code AS 1538 (SA, 1988) or the Australian Steel Structures
code AS4100 (SA, 1990). As the HFB is a cold-formed steel section, current design
procedures are based on the general provisions of the Cold-Formed Steel Structures
code AS 1538. However, the manufacturers and designers of HFBs prefer the new
section to be designed according to the provisions of AS4100 as they allow for
greater benefits to be gained for HFBs.
The main objectives of this project were to investigate the behaviour of the HFB
members under axial compression and to determine whether the HFB could be
incorporated into the more popular Australian Steel Structures code AS4100.
Finite element analyses and experimental tests were conducted to investigate the
buckling and ultimate strength performance of the HFB members subject to axial
compression. Analytical and experimental results were compared with AS4 l 00
design specifications in order to establish an appropriate column curve for the design
of HFB sections. The results obtained from this investigation sho,ved that the HFB
sections can be designed using the provisions of the AS4 l 00 code. The column
curve with the member section constant a6 = 0.5 was recommended as a safe design
curve for HFB compression members. However, the column curve with ah = 0 may
prove to be a more appropriate design curve based on a reliability analysis.
22
Heldt, Tim J. "The use of hollow flange beams in portal frame buildings." Thesis, Queensland University of Technology, 1996.
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23
Dara, Martin Luther. "Direct Strength Method for Web Crippling of Cold-formed Steel C and Z Sections Subjected to Interior One Flange Loading and End One Flange Loading." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc822839/.
Full textAbstract:
The main objective of this research is to extend the “Direct strength method” for determining the web crippling strength of cold-formed steel C and Z sections subjected to End one flange loading and Interior one flange loading conditions. Direct strength method is applied for designing the columns and beams earlier. The existing specifications equation for calculating the web crippling strength of cold-formed steels designed by American Institute of Iron and Steel is very old method and it is based on the extensive experimental investigations conducted at different universities. Calculating the web crippling strength of cold-formed steels using direct strength method is a new technique. In the present research the web crippling strength of cold-formed steels were calculated using Direct Strength Method. The experimental data is collected from the tests that were conducted at different universities. The critical buckling strength of the members were calculated using Abaqus. Microsoft excel is used to generate the equations. The safety and resistance factors for the designed equations were calculated using “Load and resistance factor design” and “Allowable strength design” from North American Cold-Formed Steel Specification, 2012 edition book.
24
Noll, Florian Matthias. "New methods for manually falling trees using hydraulically powered flange spreaders." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/26368.
Full textAbstract:
Safety in forestry and especially in manual tree falling has become increasingly important
over the last decade. Manual tree falling is widely regarded as the most dangerous part of
forestry work. This thesis reports the results from a project that used a remotely operated
hydraulic flange spreader and a novel holding wood pattern, consisting of uncut strips (tension
strips) to remove the faller from the base of the tree when it starts to displace, since this is when
many accidents occur. The novel holding wood pattern uses uncut strips of wood on the backcut
side of the tree to hold the tree in static equilibrium while the flange spreader is inserted. Field
testing was conducted in three different trials and overall resulted in a 80% success rate. Success
of the system was analyzed using logistic regression and multi linear regression. Success of the
method used in the first trial was insensitive to tree species, diameter, and height; however, it
was strongly affected by tree imbalance. In the second trial the distance between the backcut and
the weakening cut was optimized to maximize success. In the third trial only one tension strip
was used, as opposed to two in the previous trial, and it was found that this design was simpler
for the faller to cut and performed similarly to the two strip design.
In this project the weight of the flange spreader used to initiate falling was considered an
important constraint; therefore, to limit the size of the flange spreader the separation force was
limited to 44.5kN. The strength of the tension strips had to be designed so the flange spreader
could initiate falling even when there was a small imbalance opposite to the direction of fall,
while also preventing the tree from displacing if a tree had an imbalance in the falling direction.
These competing constraints resulted in a design that sometimes failed because the tension strips
could not hold the tree against a lean or wind, and sometimes failed because the flange spreader
was not strong enough to initiate falling. The goal of future research is to design a tool with
iii
89kN of separation force, and weighing only 4.5kg. This new tool will permit the use of stronger
tension strips which will reduce the likelihood of trees falling before the faller is clear, while also
providing a reserve force to initiate falling of trees with an imbalance opposite to the falling
direction.
25
Iyer, Hariharan. "The Effects of Shear Deformation in Rectangular and Wide Flange Sections." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/31421.
Full textAbstract:
Shear deformations are, generally, not considered in structural analysis of beams and frames. But shear deformations in members with low clear span-to-member depth ratio will be higher than normally expected, thus adversely affecting the stiffness of these members. Inclusion of shear deformation in analysis requires the values of shear modulus (modulus of rigidity, G) and the shear area of the member. The shear area of the member is a cross-sectional property and is defined as the area of the section which is effective in resisting shear deformation. This value is always less than the gross area of the section and is also referred to as the form factor. The form factor is the ratio of the gross area of the section to its shear area. There are a number of expressions available in the literature for the form factors of rectangular and wide flange sections. However, preliminary analysis revealed a high variation in the values given by them. The variation was attributed to the different assumptions made, regarding the stress distribution and section behavior. This necessitated the use of three-dimensional finite element analysis of rectangular and wide flange sections to resolve the issue.
<p>
The purpose of finite element analysis was to determine which, if any, of the expressions in the literature provided correct answers. A new method of finite element analysis based on the principle of virtual work is used for analyzing rectangular and wide flange sections. The validity of the new method was established by analyzing rectangular sections for which closed form solutions for form factor were available. The form factors of various wide flange sections in the AISC database were calculated from finite element analysis and an empirical relationship was formulated for easy calculation of the form factor. It was also found that an empirical formula provided good results for form factors of wide flange sections.
<p>
Beam-column joint sub-assemblies were modeled and analyzed to understand the contribution of various components to the total drift. This was not very successful since the values obtained from the finite element analysis did not match the values calculated using virtual work. This discrepancy points to inaccuracies in modeling and, possibly, analysis of beam-column joints. This issue needs to be resolved before proceeding further with the analysis.<br>Master of Science
26
Lee, Wey-Jen. "Behavior of Connection with Beam Bearing on Bottom Flange of Girder." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/35529.
Full textAbstract:
An analytical investigation was conducted to study the behavior of a bottom flange bearing beam-to girder connection subjected to patch loading. This connection would be useful with deep deck (thickness greater than 3 in.) composite slabs as well as with commonly used deck where floor-to-floor height needs to be minimized. Five girder specimens were loaded until yielding during the initial phase of the research. The analysis section consists of the yield line theory and finite element study that were used to develop a model to predict the collapse loads of the girder sections. These results from the model were then compared to the experimental loads. A design procedure utilizing the proposed model and future work recommendations are then presented.<br>Master of Science
27
Hunn, Zachary D. "A Finite Element Study of Non-Orthogonal Bolted Flange Plate Connections." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1512045358760702.
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Carlson, Ryne. "Flexural Strength of Steel Beams with Holes in the Tension Flange." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563527519192391.
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29
Perera, Nilakshi. "Structural behaviour and design of innovative hollow flange steel plate grinders." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/123310/1/Liyanage%20Nilakshi%20Piyahasi_Perera_Thesis.pdf.
Full textAbstract:
This thesis proposes a new Hollow Flange Steel Plate Girder (HFSPG) by welding industrially available cold-formed Rectangular Hollow Sections (RHS) to a web plate for use in long span construction. Design procedures presented in the national and international design guidelines were reviewed and suitable improvements were made to accurately predict the structural behaviour and capacities of HFSPGs by undertaking detailed experimental and numerical studies into their unique structural behaviour. Local buckling/yielding, global buckling and local-global interaction failures were all considered in this thesis.
30
Hassan, Rusul. "Distortional Lateral Torsional Buckling Analysis for Beams of Wide Flange Cross-sections." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24008.
Full textAbstract:
Structural steel design standards recognize lateral torsional buckling as a failure mode governing the capacity of long span unsupported beams with wide flange cross-sections. Standard solutions start with the closed form solution of the Vlasov thin-walled beam theory for the case of a simply supported beam under uniform moments, and modify the solution to accommodate various moment distributions through moment gradient expressions. The Vlasov theory solution is based on the assumption that cross-sectional distortional effects have a negligible effect on the predicted elastic critical moment. The present study systematically examines the validity of the Vlasov assumption related to cross-section distortion through a parametric study.
A series of elastic shell finite element eigen-value buckling analyses is conducted on simply supported beams subject to uniform moments, linear moments and mid span point loads as well as cantilevers subject to top flange loading acting at the tip. Cross-sectional dimensions are selected to represent structural steel cross-section geometries used in practice. Particular attention is paid to model end connection details commonly used in practice involving moment connections with two pairs of stiffeners, simply supported ends with a pair of transverse stiffeners, simply supported ends with cleat angle details, and built in fixation at cantilever roots.
The critical moments obtained from the FEA are compared to those based on conventional critical moment equations in various Standards and published solutions. The effects of web slenderness, flange slenderness, web height to flange width ratio, and span to height ratios on the critical moment ratio are systematically quantified. For some combinations of section geometries and connection details, it is shown that present solutions derived from the Vlasov theory can overestimate the lateral torsional buckling resistance for beams.
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Lane, Andrew. "An experimental investigation of buckling mode interaction in PERP wide-flange columns." Thesis, University of Warwick, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269543.
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Kirkhope, Robert J. (Robert John) Carleton University Dissertation Engineering Civil and Environmental. "Behaviour of webs of welded wide flange shapes subjected to concentrated loads." Ottawa, 1995.
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33
Hernandez, Andrea Alejandra. "PLASTIC HINGE LOCATION EFFECTS ON THE DESIGN OF WELDED FLANGE PLATE CONNECTIONS." OpenSIUC, 2016. https://opensiuc.lib.siu.edu/theses/1863.
Full textAbstract:
Seismic design criteria have been heavily improved by the Federal Emergency Management Agency (FEMA) after the Northridge CA earthquake in 1994. Most of the damage observed was caused by brittle failure of moment frame connections. This failure was induced by the formation of the plastic hinge at undesirable locations in the beam and the column near the connection. Using welded flange plate (WFP) connections will force the formation of the plastic hinge away from the face of the column while preventing the brittle failure of the moment connection. FEMA-350 design criteria recommendations for WFP connections suggest that the plastic hinge will form away from the face of the column directly under the cover plate. The purpose of this research is to prove that the plastic hinge will form away from the face of the column, at a distance of approximately half the depth of the beam away from the cover plate. The further away the plastic hinge is from the face of the column the higher the connection demands. Therefore, underestimating the location of the plastic hinge could lead to under designed connections. The modeling and analysis of WFP connections was performed using finite element analysis software. A total of eight models with half beam half column configuration were considered in this study. Each selected section of beam and column was first designed, modeled and analyzed using WFP connections design recommendations from FEMA-350, with calculations modifications to account for the proposed plastic hinge location. Results were computed and comparisons were made in terms of plastic hinge location from the cover plates. Strength obtained for each model using finite element analysis software was also compared with hand calculations. This research also proves that increasing the thickness of the cover plates will generate an increase in the connection capacity and strength.
34
Meads, David. "P-DELTA EFFECTS ON STEEL MOMENT FRAMES WITH WELDED FLANGE PLATE CONNECTIONS." OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/555.
Full textAbstract:
The P-Delta effect occurs when a frame or structure is laterally displaced by either seismic or wind loadings. As the structure is being displaced laterally, gravity begins to act on the members causing a secondary effect of the forces and moments which in turn cause additional displacement. The purpose of this study is to investigate the P-Delta effect on multi-story steel framed structures with welded flange plate connections. The traditional method regarding the calculation of the P-Delta effect assumes the lateral displacement of the steel columns is due to lateral deflection only and does not take joint rotation into account. In this study, a finite element analysis using computer models will be used to investigate the additional lateral displacement from the P-Delta effect due to the addition of joint rotation.
35
Siahaan, Ropalin. "Structural behaviour and design of rivet fastened rectangular hollow flange channel beams." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/106913/1/Ropalin_Siahaan_Thesis.pdf.
Full textAbstract:
This thesis presents a study into the structural behaviour and design of the innovative rivet fastened Rectangular Hollow Flange Channel Beams (RHFCB). The RHFCB utilizes the inexpensive self-pierce rivet fastening in its fabrication, providing cost effective structural solutions in floor systems. The first part of the thesis focuses on the section moment capacities of the beams subject to local buckling effects while the second part investigates the member moment capacities of intermediate span beams subject to the unique lateral distortional buckling effects. Each part involves experimental investigations, advanced finite element analyses, parametric studies and design recommendations.
36
Petersen, Troy A. "The displacement ductility of steel moment resisting frames using welded flange plate connections /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1136091371&sid=2&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Do, Tan Dan. "The effect of bolt spacing on the tightness behavior of bolted flange joints." Mémoire, École de technologie supérieure, 2012. http://espace.etsmtl.ca/964/1/DO_Tan_Dan.pdf.
Full textAbstract:
Les assemblages à brides boulonnées munis de joints d’étanchéité sont les systèmes de
raccordement les plus répandus entre les différents éléments des réservoirs sous pression. Ils
sont largement utilisés dans l'industrie chimique, pétrochimique et nucléaire. Ce sont des
structures simples et des assemblages démontables. Ce qui les rend plus attractifs pour
connecter des équipements sous pression et la tuyauterie. En plus des risques de fuite, ils ont
besoin de maintenance en cours de fonctionnement au cas où les boulons doivent être
resserrés ou dévissés pour être remplacés. Bien que les arrêts de fonctionnement coûteux
soient à éviter, l’entretien en fonctionnement expose l'opérateur à un risque potentiel, car le
desserrement d’un boulon peut produire un déséquilibre de la contrainte de compression sur
le joint d’étanchéité entraînant un contact local du joint d’étanchéité en dessous d’une
certaine valeur critique, provoquant une fuite majeure et de ce fait pouvant mettre en péril la
vie de l'opérateur.
Cette proposition aborde la question de la variation de la déflexion du rebord de la bride afin
d'enquêter sur le déséquilibre de la contrainte de compression dans le joint lorsque les
boulons sont soumis à une modification de charge en fonctionnement. Cette étude peut être
utilisée pour aider à limiter l'augmentation de la charge de serrage ou le nombre maximum de
boulons qui doivent être remplacés en même temps et identifier les boulons qui ne peuvent
pas être remplacés en service.
L'objectif de cette étude est de développer une approche théorique pour identifier et analyser
les effets de la charge précontrainte et de la pression sur les assemblages à brides boulonnées
afin d’obtenir l'espacement optimal entre les boulons en fonction de la variation de la
contrainte de compression sur le joint d’étanchéité. Notre recherche comprend trois parties.
La première partie qui est une méthode analytique basée sur la théorie de la poutre circulaire
reposant sur une fondation élastique linéaire, sera développée pour prédire la distribution
circonférentielle de la contrainte de compression sur le joint d’étanchéité. Des modèles
éléments finis de brides boulonnées symétriques seront créés pour valider cette analyse. Une
comparaison des résultats d'études antérieures est nécessaire pour valider la solution
analytique linéaire. Ensuite, la deuxième étape de cette recherche consiste en une approche
qui a été construite à partir de la théorie de l'anneau sur le comportement d’une fondation non
linéaire élastique, permettant d’obtenir des résultats plus précis. La solution non-linéaire doit
être validée avec une analyse par la méthode des éléments finis. Dans la troisième partie, un
modèle de régression linéaire pour des brides boulonnées sera proposé pour une procédure de
calcul d’espacement de boulons. Ce travail aidera les services techniques sur la conception,
la maintenance et l'exploitation des réservoirs sous pression et systèmes de tuyauterie.
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Viljoen, P. de K. "Investigation into the top flange and web deformation in a crane girder panel." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49998.
Full textAbstract:
Thesis (MEng) -- Stellenbosch University, 2004.<br>ENGLISH ABSTRACT: The purpose of this project was to study the deformations of the top flange and web of
a girder panel resulting from loads, which have been imposed by an overhead
travelling crane. This was achieved by designing a crane girder that represents
dimensional ratios occurring in practice.
The first part of this project attempts to determine the properties of the crane girder.
The crane girder was built from drawings in the workshop of the University of
Stellenbosch’s Civil-Department. Positions were identified where the strains were to
be measured on the crane girder. The crane girder was subjected to loads according to
SABS 0160 - 1989 and measurements were taken. The same beam was also modelled
with finite elements. The numerical model was subjected to the same loads as the
experimental crane girder.
Comparisons were then made between the results of the experimental investigation
and those of the numerical model. Good comparisons were achieved between the
results and the numerical model was assumed to be correct.
Other students could now use this model for investigating local stresses and strain
effects that might cause fatigue and other in-service problems of electric overhead
travelling cranes support structures in practice.<br>AFRIKAANSE OPSOMMING: Die doel van hierdie projek was om die vervormings van die boonste flense en web
van ’n kraanbalkpaneel te ondersoek, as gevolg van laste wat onderworpe was aan ’n
oorhoofse kraanbalk. Dit was bereik deur ‘n balk te ontwerp wat dimensionele
verhoudings in die praktyk verteenwoordig.
In die eerste gedeelte van die projek word die eienskappe van die kraanbalk bepaal.
Die kraanbalk was vanaf tekeninge in die werkswinkel van die Universiteit van
Stellenbosch se Siviele Departement gebou. Posisies was geidentifiseer waar die
vervormings op die kraanbalk gemeet sou word. Die kraanbalk was onderwerp aan
laste volgens SABS 0160 - 1989 en meetings was geneem. Dieselfde balk was ook
gemodelleer met eindige elemente. Die numeriese model was aan dieselfde laste as
die eksperimentele balk onderwerp.
Vergelykings was toe verkry tussen the resultate van die eksperimentele ondersoek en
die numeriese model. Goeie vergelykings tussen die resultate was behaal en die
numeriese model word as korrek aanvaar.
Ander studente kan nou hierdie model gebruik vir die ondersoek na lokale spannings
en vervormingseffekte wat moontlik vermoeidheid en ander in-diens probleme van
elastiese oorhoofse kraan ondersteunende strukture in the praktyk kan veroorsaak.
39
Al, Karkour Khaleel. "Unreinforced masonry walls and flange effect: a parametric study through block-based modeling." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
Find full textAbstract:
This study reported in this thesis shows the flange effect in unreinforced masonry walls subjected to in-plane loading. Previous studies showed the importance of capturing the in-plane behaviour of flanged masonry walls for seismic studies. A generative tool was developed using Dynamo and Abaqus Scripting Interface (ASI) to make a parametric model covering most cases of constructing the flange wall. The analysis was held using Finite Element Method through ABAQUS software and masonry wall was modelled through block-based modelling strategy. Large parametric study was carried out to investigate the effects of several parameters on the collapse load and failure type. The effect of aspect ratio, length of flange part, location of the main part, vertical applied load and the applied boundary condition are represented in this thesis.
40
Hantouche, Elie. "Behavior Of Thick Flange Built-up T-stub Connections For Moment Resisting Frames." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1313687182.
Full text
41
Zhao, Wen-Bin. "Behaviour and design of cold-formed steel hollow flange sections under axial compression." Thesis, Queensland University of Technology, 2006. https://eprints.qut.edu.au/16909/1/Wen-Bin_Zhao_Thesis.pdf.
Full textAbstract:
The use of cold-formed steel structures is increasing rapidly around the world due to the many advances in construction and manufacturing technologies and relevant standards. However, the structural behaviour of these thin-walled steel structures is characterised by a range of buckling modes such as local buckling, distortional buckling or flexural torsional buckling. These buckling problems generally lead to severe reduction and complicated calculations of their member strengths. Therefore it is important to eliminate or delay these buckling problems and simplify the strength calculations of cold-formed steel members.
The Hollow Flange Beam with two triangular hollow flanges, developed by Palmer Tube Mills Pty Ltd in the mid-1990s, has an innovative section that can delay the above buckling problems efficiently. This structural member is considered to combine the advantages of hot-rolled I-sections and conventional cold-formed sections such as C- and Z-sections (Dempsey, 1990). However, this structural product was discontinued in 1997 due to the complicated manufacturing process and the expensive electric resistance welding method associated with severe residual stresses (Doan and Mahendran, 1996). In this thesis, new fastening methods using spot-weld, screw fastener and self-pierced rivet were considered for the triangular Hollow Flange Beams (HFBs) and the new rectangular hollow flange beams (RHFBs). The structural behaviour of these types of members in axial compression was focused in this research project. The objective of this research was to develop suitable design models for the members with triangular and rectangular hollow flanges using new fastening methods so that their behaviour and ultimate strength can be predicted accurately under axial compression.
In the first stage of this research a large number of finite element analyses (FEA) was conducted to study the behaviour of the electric resistance welded, triangular HFBs (ERW-HFBs) under axial compression. Experimental results from previous researchers were used to verify the finite element model and its results. Appropriate design rules based on the current design codes were recommended. Further, a series of finite element models was developed to simulate the corresponding HFBs fastened using lap-welds (called LW-HFBs) and screw fasteners or spot-welds or self-piercing rivets (called S-HFBs). Since the test specimens of LW-HFBs and S-HFBs were unavailable, the finite element results were verified by comparison with the experimental results of ERW-HFB with reasonable agreement.
In the second stage of this research, a total of 51 members with rectangular hollow flanges including the RHFBs made from a single plate and 3PRHFBs made from three plates fastened with spot-welds and screws was tested under axial compression. The finite element models based on the tests were then developed that included the new fasteners, contact simulations, geometric imperfections and residual stresses. The improved finite element models were able to simulate local buckling, yielding, global buckling and local/global buckling interaction failure associated with gap opening as agreed well with the corresponding full-scale experimental results. Extensive parametric studies for the RHFBs made from a single plate and the 3PRHFBs made from three plates were undertaken using finite element analyses. The analytical results were compared with the predictions using the current design rules based on AS 4100, AS/NZS 4600 and the new direct strength method. Appropriate design formulae based on the direct strength method for RHFBs and 3PRHFBs were developed. This thesis has thus enabled the accurate prediction of the behaviour and strength of the new compression members with hollow flanges and paved the way for economical and efficient use of these members in the industry.
42
Zhao, Wen-Bin. "Behaviour and design of cold-formed steel hollow flange sections under axial compression." Queensland University of Technology, 2006. http://eprints.qut.edu.au/16909/.
Full textAbstract:
The use of cold-formed steel structures is increasing rapidly around the world due to the many advances in construction and manufacturing technologies and relevant standards. However, the structural behaviour of these thin-walled steel structures is characterised by a range of buckling modes such as local buckling, distortional buckling or flexural torsional buckling. These buckling problems generally lead to severe reduction and complicated calculations of their member strengths. Therefore it is important to eliminate or delay these buckling problems and simplify the strength calculations of cold-formed steel members.
The Hollow Flange Beam with two triangular hollow flanges, developed by Palmer Tube Mills Pty Ltd in the mid-1990s, has an innovative section that can delay the above buckling problems efficiently. This structural member is considered to combine the advantages of hot-rolled I-sections and conventional cold-formed sections such as C- and Z-sections (Dempsey, 1990). However, this structural product was discontinued in 1997 due to the complicated manufacturing process and the expensive electric resistance welding method associated with severe residual stresses (Doan and Mahendran, 1996). In this thesis, new fastening methods using spot-weld, screw fastener and self-pierced rivet were considered for the triangular Hollow Flange Beams (HFBs) and the new rectangular hollow flange beams (RHFBs). The structural behaviour of these types of members in axial compression was focused in this research project. The objective of this research was to develop suitable design models for the members with triangular and rectangular hollow flanges using new fastening methods so that their behaviour and ultimate strength can be predicted accurately under axial compression.
In the first stage of this research a large number of finite element analyses (FEA) was conducted to study the behaviour of the electric resistance welded, triangular HFBs (ERW-HFBs) under axial compression. Experimental results from previous researchers were used to verify the finite element model and its results. Appropriate design rules based on the current design codes were recommended. Further, a series of finite element models was developed to simulate the corresponding HFBs fastened using lap-welds (called LW-HFBs) and screw fasteners or spot-welds or self-piercing rivets (called S-HFBs). Since the test specimens of LW-HFBs and S-HFBs were unavailable, the finite element results were verified by comparison with the experimental results of ERW-HFB with reasonable agreement.
In the second stage of this research, a total of 51 members with rectangular hollow flanges including the RHFBs made from a single plate and 3PRHFBs made from three plates fastened with spot-welds and screws was tested under axial compression. The finite element models based on the tests were then developed that included the new fasteners, contact simulations, geometric imperfections and residual stresses. The improved finite element models were able to simulate local buckling, yielding, global buckling and local/global buckling interaction failure associated with gap opening as agreed well with the corresponding full-scale experimental results. Extensive parametric studies for the RHFBs made from a single plate and the 3PRHFBs made from three plates were undertaken using finite element analyses. The analytical results were compared with the predictions using the current design rules based on AS 4100, AS/NZS 4600 and the new direct strength method. Appropriate design formulae based on the direct strength method for RHFBs and 3PRHFBs were developed. This thesis has thus enabled the accurate prediction of the behaviour and strength of the new compression members with hollow flanges and paved the way for economical and efficient use of these members in the industry.
43
Hognestad, Gunnar. "2-D composite structures : analysis of composite flange connections and determination of interlaminar strength." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334809.
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Lo, Sheng-Wei, and 羅盛威. "Seismic Performance of Steel Wide Flange Column-to-Beam Connections Using Internal Flange Stiffeners." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/36623254832863627569.
Full textAbstract:
碩士<br>國立交通大學<br>土木工程學系<br>100<br>The research presents test and finite element analysis results of steel wide flange column-to-beam connections using internal flange stiffeners (IFS). Four full-scale moment connections were tested. All specimens had bolted web connection and welded beam-to-column flange using complete joint penetration welds. One specimen without internal flange stiffeners was tested as a benchmark. Three rehabilitated moment connections had different shape stiffeners and beam material. All rehabilitated moment connections showed excellent performance under the AISC (2005) seismic loads in excess of 4% drift. All specimens were also modeled using the computer program ABAQUS (2003) for the correlation study.
45
Shih, Ching-Wei, and 施經緯. "Study on Flange Bush Forming." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/76040705696542948672.
Full textAbstract:
碩士<br>高苑科技大學<br>機械與自動化工程研究所<br>100<br>The study uses Deform 3D FEM analysis software to simulate the new product
development, and propose the analysis of various possible forming plans. This study
carries out the realistic cylinder compression to obtain the flow stress, and performes
really the ring compression to get the frictional factors between the dies and forged
materials in forming to simulate with. Deform 3D FEM analysis software. And the
tension test of rod has been carried out to obtain the critical damage value (CDV)
combining with Cockcroft & Latham and Normalized Cockcroft & Latham damage
ctcriteria. The optimization of parameters assembly has been obtained by Taguchi
method with orthgonal table L9(34) to adjust the shapes and dimensions of punch and
die, and do the confirmation simulation analysis to obtain the optimal parameters
assembly. The realistic multi-stage forging has been performed to realize the
effective stress, the effective strain, the velocity field and the multi-stage forging force
and.compare the product dimensions with the simulation results to verify the
acceptance of FEM analysis model. The similarity has been reached over 95%.
Furthermore, the tungsten steel materials made from the power metallurgy are difficult
to bear the circumferential tensile stress which easy to cause the mold kernel fracture.
Therefore, with a view to understanding the die stress distributions, especially explore
the radial stress, circumferential stress and the effective stress of mold kernel, mold
form and stress ring occurred by single mold form interference fit and stress ring
interference fit. The effect of the interference on the circumferential stress has been
understood, and aslo whether the effective stress occurred exceeds the allowable yield
strength of die material to avoid the die failure. The study proposes a series of
simulation investigations and experiment verifications as the forging industry
reference.
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Hu, You-Wei, and 胡祐瑋. "Effects of SM570M-CHW steel beam flange eccentricity and column flange thickness on electronic slag welding failure." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/f85bxe.
Full textAbstract:
碩士<br>國立臺灣大學<br>土木工程學研究所<br>106<br>Steel box columns are widely used in seismic steel building structures in Taiwan. In order to effectively transfer the beam-end moment to the column, diaphragm plates are welded inside the box column at the same elevations of the welded beam flanges. Electro-slag welding (ESW) procedure is common applied to attach the diaphragm plates to the column. Recently, SM570M-CHW grade high strength steel is also widely adopted in steel building structure in order to reduce the member sizes. In this study, two full-scaled welded SM570M-CHW steel beam-to-column moment connection specimens and three ESW component specimens were fabricated and tested. The key design parameters of these specimens include column flange thickness, beam flange eccentricity with respect to the diaphragm plate. This study investigates the applicability of stress modified critical stress (SMCS) and Degraded Significant Plastic Strain models (DSPS) in predicting the crack initiation fracture of the diaphragm-to-column ESW joint. The ESW component specimens were subjected to monotonic tensile loads, while the welded beam-to-column connection specimens were subjected to cyclically increasing displacement in order to investigate the effects of beam flange eccentricity and column flange thickness on the ESW fractures. Test results show that when the ESW was subjected to monotonic tension only, it remained intact even when the beam flange 27mm eccentricity was greater than the column flange thickness 25mm. This result is inconsistent with the findings from a former research, which suggested that the beam flange eccentricity should not be larger than the column flange thickness. This should be attributed to that a 36mm thicker diaphragm plate than the 25mm column flange has provided enough chamber for a large ESW fusion zone to develop. Thus, it has allowed the connection to sustain the 27mm beam flange eccentricity. Cyclic tests results of the welded beam-to-column moment connections showed that the connection with the 25mm column flange failed at the 3% IDR cycle, while the specimen with the 45mm column flange went through 5% IDR cycle without failure.
In order to compute the material parameter, α in the SMCS models, this study constructed finite element analysis (FEA) models to analyze the responses of ESW components and the circumferential notched test (CNT) specimens made from the ESW components. The FEA results confirm that all of key elements in the heat affected zone surrounding the ESW would not fail, which is consistent with the test results. This study also conducted the FEA on the welded beam–to-column moment connection models. The DSPS model parameter of SN490B steel computed in a previous research was adopted. The effects of column flange thickness on the EWS stress concentration and crack tip opening displacement (CTOD) under the cyclic loading are investigated. The FEA results show that when the column flange thickness increases from 25mm to 45mm, the stress concentrations are reduced and CTOD is decreased by 3 times. The comparison between the test and FEA results suggest that the DSPS model incorporated with the material toughness parameters obtained from SN490B steel can satisfactorily predict the fracture responses of the ESW diaphragm-to-column joint.
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Lu, Cheng-Fu, and 呂正富. "Preform Design of Double End Flange Stud." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/3w6299.
Full textAbstract:
碩士<br>國立高雄應用科技大學<br>模具系碩士在職專班<br>103<br>Double end flange studs have two threads with different dimensions. The billets for producing the studs required a multi-stepped rod with different diameters. In general, the billet for the double end flange stud can be produced by two processes, a two-stage forging process using a multi-stage horizontal forging press, and a machining process. To avoid the machining process and reduce the costs, it is widely interested to develop new methods for manufacturing the billet for threading studs.
This study proposed a three-stage preform design for producing the billet for a double end flange stud. The billet had two step rods for threading M8 and M10 screws. The first stage was to form the end with the smaller diameter. The stage used a backward extrusion process in a close die to avoid the problem with a large reduction rate of section and the difficulty in rotating a long billet during the transferring in a press. The stage was the key to the preform design for producing the billet. The second stage used a forward extrusion to fabricate the end with the larger diameter. The third stage employed an upsetting process to increase the diameter of the middle part of the workpiece and form the flange of the billet. The study considered the Cr-Mo steel (JIS SCM 435) for stud and used the simple upsetting to obtain the stress and strain curve for the simulations of the forming process using a finite element package, DEFORM. The proposed preforms were further used in the die design and die manufacturing. Finally, the experiments of extrusion and upsetting were conducted and the results were analyzed.
The results showed that the predicted loads were close to the experimental ones and the predicted the patterns of the metal flow were also in good agreement with those in the produced products. The proposed preform design can be used to successfully manufacturing the billet for threading the double end flange stud. The results not only could be the base of the preform design for producing screw billets in fastener industries but also could be the references for other metal forming industries.
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Liu, Chien-Kuo, and 劉建國. "CAE Analysis of PA66 Long-Cantilever-Span Flange." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/jz4pzj.
Full textAbstract:
碩士<br>國立臺北科技大學<br>製造科技研究所<br>102<br>The long-cantilever-span flange is the bracket mechanism used in piano grand wippen. This research attempts to use polyamide materials (PA) to make the bracket, so as to improve the damp problem of the original design which caused to not rotate smoothly. However, the mold of polyamide material injected generates warpage. This research intends to design the gate locations and gate sizes with reducing thickness of plastic wall method to improve and solve the problem of plastic molding warpage. This study adopts Moldex3D CAE (Computer Aided Engineering) injection simulation software to do research, through Taguchi Methods to process the optimal analysis and the most appropriate combination of process parameters.
Finally, in the analysis results, adjusting the position of gate properly could control the degree of warpage. After adjusting the gate position of the long-cantilever-span flange, the value of warpage change from 0.13 mm to 0.07 mm which the improvement rate up to 45%. Locations of gate have impact on the warpage of product mostly, the influence of size of gate secondly, and the method of reducing wall thickness of plastic thirdly.
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Vanevenhoven, Linda Marie. "LRFD factors for FRP pultruded wide-flange columns." 2007. http://catalog.hathitrust.org/api/volumes/oclc/191907377.html.
Full textAbstract:
Thesis (M.S.)--University of Wisconsin--Madison, 2007<br>Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 125-129).
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Tsai, Jau-Shin, and 蔡釗炘. "study on the flange forging of aluminium alloy." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/12302468844565806266.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>機械工程系<br>90<br>In this study , A6061 aluminum alloy are applied in the flange forging process to discuss the influences of process parameters to forging load and mechanical properties . The process parameters discussed in the study are types of lubricant , impact speed , forging temperature , and die radii . Use the Taguchi experimental method to reduced the numbers of experiment and use the ANOVA to analyze the effect of each factor . Except use the Taguchi experimental method to discuss the influences of process parameters to forging load and mechanical properties , Also have some experiments to discuss the influences of each factor under no the nature of interactions . Last , to dilute the lubricant and experimental to understand the effect of the light lubricant to forging load and mechanical properties .
The results of the experiments show that forging temperature was the main parameter affecting the forging load , then a type of lubricant ,
die radii and impact speed . Forging temperature was the main parameter affecting the mechanical properties , then die radii , impact speed and lubricant . Result obtained from verification experiments under optimal process parameters are in good agreement with the result of predication .