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1
Ahmed, Bashir. "Numerical modelling of connections in composite frames." Thesis, University of Nottingham, 1996. http://eprints.nottingham.ac.uk/12689/.
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The main objective of this thesis was to develop numerical modelling procedures for composite connections and to use results generated in conjunction with data from other sources as the basis for the preparation of design procedures. The finite element method has been used for the numerical simulation of composite endplate connections. The developed model was verified by comparing both local measures of response and overall behaviour with test results. The validated model was then used in conjunction with theoretical analysis to study the behaviour of composite endplate connections for variable shear to moment ratios. This permitted the identification of those cases for which changes in the shear to moment ratio affects the connection's moment capacity. The model was also used in conjunction with theoretical analysis to study the effect of varying levels of axial column loading on the connection moment capacity. Results of both studies indicated a need for modifications to the equations of EC3 (for bare steel connections but which are also applicable to composite connections) that consider the interaction with column loading. These are: the equations for column web compression resistance, column web shear resistance and the bolt force. Using the FEM results, available test results and EC3 and EC4 equations for the determination of basic component forces, design procedures for composite flush endplate, finplate and angle cleated connections are proposed. Predictions from the design method have been compared with a total of 53 test and finite element results for the flush endplate connections (32 laboratory tests from 7 different sources plus a further 21 numerical results) so as to provide validation over the full range of parameters. These comparisons gave an overall prediction to test ratio of 0.99 with a standard deviation of 0.14, thereby demonstrating that the proposed method can accurately predict the resistance of composite flush endplate connections under a variety of different connection arrangements and loading conditions. Similarly, the prediction from the design method was compared with 6 finplate test results which gave an average prediction to test ratio of 1.06 with a standard deviation of 0.18. Comparisons for the angle cleated connection using 16 test results from 4 different sources gave an average prediction to test ratio of 0.98 with a standard deviation of 0.13. Theoretical studies have been performed to develop equations to predict the initial stiffness for composite endplate connections and these have been verified against test results. Suggestions to predict the available rotation capacity of flush endplate connections have also been made. This two methods has been combined with the moment capacity model to develop a prediction method for the overall behaviour of the flush endplate connections. The finite element method has also been used to develop a numerical simulation of non-sway composite frames. Comparisons of results show good agreement with the observed test behaviour. It has been found that it is possible to model the non-sway frames in a way that can predict the frame moment distribution, connection moment - rotation response and the beam load displacement history with sufficient accuracy. This provides an economic tool to study different aspects of the behaviour of composite non-sway frames. A numerical model has been developed for un-braced steel frames by simplifying the composite frame model. This model was verified using numerical results selected from the work of other researchers. Using the model for steel frames, studies were conducted for sway behaviour which provide guidance on behaviour suitable as a basis for developing design procedures.
2
Mason, Brian H. "Analysis and design of composite curved frames." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06102009-063304/.
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Castro, Jose Miguel De Freitas. "Seismic behaviour of composite moment-resisting frames." Thesis, Imperial College London, 2006. http://hdl.handle.net/10044/1/7617.
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Na, Gwang-Seok. "Load-displacement behavior of frame structures composed of fiber reinforced polymeric composite materials." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26699.
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Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009.<br>Committee Chair: Dr. Leroy Z. Emkin; Committee Co-Chair: Dr. Abdul-Hamid Zureick; Committee Member: Dr. Dewey H. Hodges; Committee Member: Dr. Kenneth M. Will; Committee Member: Dr. Rami M. Haj-ali. Part of the SMARTech Electronic Thesis and Dissertation Collection.
5
Saim, A. Aziz. "Aspects of continuity in steel and composite frames." Thesis, University of Warwick, 1998. http://wrap.warwick.ac.uk/108331/.
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This thesis concerns the continuity in steel and composite frame and specifically the region of the connections. It reports on five main areas as follows: 1. Seven beam-to-beam connection tests were conducted to study the structural performance of composite end plate connections. Various parameters such as the types of connections, amount of reinforcement, beams sizes, and the degree of shear connection were investigated. The investigation confirmed a similar overall response of moment-rotation (M-φ) curves to beam-to-column tests and justified the restriction by current design codes of having partial shear connection in hogging moment region. A prediction method to estimate the initial stiffness of composite connection has also been proposed. 2. The effects of concrete encasement on structural response of end plate joints of slimfloor beams were investigated. Five specimens of beam-to-column connection of slimfloor were tested. Parameters such as end plate thickness and bolt sizes are included in the study. The results have shown that proper reinforcement and design are needed if the connections are to be considered as a composite joint. 3. Tests were carried out to improve the bond capacity of encased slimfloor. A total of six push-out tests each with different type of “shear enhancer” were performed. The load at initial slip is not greatly depend on the types of enhancer and there were indications that the resistance of the enhancer only became effective after slip, due to bond failure, had occurred. 4. As far as stability of composite beams in the negative moment region is concerned, local buckling has been identified as one of the problems. The action of reinforcement may reduce many hot-rolled section to be in Class 3. Studies were conducted on published data to explore the possibility of upgrading Class 3 to Class 1. The studies indicated that beams of Class 3 web showed the characteristics of beams with higher class if the connection was full strength. Many of the Class 3 beams used in composite beams can only be upgraded to Class 2 and not to Class 1. 5. A method applicable to the design of unbraced multi-storey frames to specified limits on horizontal sway deflection is proposed. Only simple calculation are required by the method and its application is illustrated by worked examples.
6
Woodson, Marshall Benjamin. "Optimal design of composite fuselage frames for crashworthiness." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/39142.
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This study looks at the feasibility of using structural optimization techniques to address the problem of designing composite fuselage frames for crashworthiness. A key feature of any optimization strategy for increasing structural crashworthiness is a progressive failure analysis. Currently, the most widely used analysis methods for progressive failure of composite structures are considered too expensive computationally for practical optimization in today's computing environment. Developing an efficient analysis method for progressive failure of composite frames is a first step in the optimization for crashworthiness. In the current work a progressive failure analysis for thin-walled open cross-section curved composite frames is developed using a Vlasov type beam theory. A curved thin-walled composite beam theory is developed and a finite element implementation of the beam theory is used for progressive failure analysis. The accuracy and limitations of this analysis method are discussed. A model for progressive failure of the composite fuselage frame is developed from an extension of the laminate progressive failure analysis of Tsai-Wu.
Comparisons based on a limited amount of available experimental data are encouraging. The first major failure event is captured by the theory, and the prediction of total energy absorbed follows the trend of the experimental data. It is believed that this accuracy is sufficient for preliminary design and optimization for crashworthiness. This progressive failure analysis is then incorporated into a frame optimization for crashworthiness based on the genetic algorithm method. The optimization methodology is demonstrated analytically to obtain frame designs with substantially increased crashworthlness. Laminate stacking sequence and cross-section shape are design variables for optimization<br>Ph. D.
7
Broderick, Brian Michael. "Seismic testing, analysis and design of composite frames." Thesis, Imperial College London, 1994. http://hdl.handle.net/10044/1/7366.
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8
Lizotte, Patrick L. "Stress analysis and fabrication of composite monocoque bicycle frames." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=24064.
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An analytical and experimental investigation was conducted to study the design and fabrication of carbon fiber track bicycle frames. A finite element software was used for the geometry development, laminate configuration, and for predicting failure using the maximum stress criteria. A load case and boundary conditions simulating actual riding conditions were developed. The stresses in each of the composite layers were found to be lower than the allowable stresses because of a properly designed geometry and laminate. Two composite frames were fabricated using the hand lay-up technique, using unidirectional and woven carbon fiber pre-preg material over an internal foam core. Using static testing techniques and comparisons with traditional tubular frames, the carbon fiber prototypes were shown to be better in all rigidity aspects. Combining the experimental and theoretical results, a good understanding of the critical problems related to composite monocoque bicycle frame design was obtained.
9
Rackham, James William. "The design of haunched composite beam frames for buildings." Thesis, City University London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358221.
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Madas, Panagiotis J. "Advanced modelling of composite frames subject to earthquake loading." Thesis, Imperial College London, 1993. http://hdl.handle.net/10044/1/7970.
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Li, Tieqiang. "The analysis and ductility requirements of semi-rigid composite frames." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239925.
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Pèrez, José G. "Energy Absorption and Progressive Failure Response of Composite Fuselage Frames." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/34447.
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Vertical drop testing of transport aircraft fuselage sections indicates that the frames play a major role in the process of absorbing the impact energy in the crushing of the substructure below the main passenger deck. Hence, static tests are performed on individula circumferential frames under a radially inward load to assess their progressive failure response and energy absorption characteristics. The test articles in the first series of tests are six-foot diameter, semicircular, I-section frames fabricated from graphite-epoxy unidirectional tape. The test articles in the second series of tests are J-section frames subtending a forty-eight degree circular arc, having an inside radius of 118 inches, a depth of 4.8 inches, and manufactured by resin transfer molding into a 2x2 2D triaxial braided composite preform made of AS4 graphite yarns. Frames of both materials exhibit fractures at the pint of load application and at selected locations around the circumference, but the delamination prevalent in the tape layup frames is not evident in the textile frames.
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A mathematical model developed to optimize open section curved composite frames for improved energy absorption is used to redesign the I-section frames by resizing the flanges. The test results of the redesigned frames show that the mathematical model predicted the correct sequence and locations of the failure events. However, the mathematical model does not predict the magnitude of the force and displacement at the first major failure event, which maybe due to the fact that delamination is not included in the progressive failure model
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Tests results from two of the J-section frames are compared with a beam finite element analysis using the computer code ABAQUS. Effective elastic moduli for the textile material are obtained from the computer code TEXCAD. The ABAQUS results correlate reasonably well with the experimental results prior to the first major failure enent.<br>Master of Science
13
Taylor, Joshua Michael. "Nonlinear analysis of steel frames with partially restrained composite connections and full or partially composite girders." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/19272.
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Vidalis, Carolos Antonios. "Improving the resistance to progressive collapse of steel and composite frames." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/18507.
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Several well publicised examples of progressive collapse have heightened concerns about the need to address robustness as a design requirement. Although research around the subject has been aimed at understanding the mechanics of progressive collapse, little work has been done on translating findings into better guidance on how to ensure adequate resistance without relying on the current prescriptive rules. Based on the Imperial College London method, which provides a soundly based analysis framework for calculating and comparing the performance of different designs, the work presented herein introduces a methodology for making realistic and effective design interventions, in order to allow designers to effectively enhance the robustness of their structure. This strategy is illustrated for both steel and composite frames and covers structures designed for both seismic and non seismic locations. Using the proposed step-by-step methodology, it is possible to redesign a simply designed composite frame in a way that it will be sufficiently robust to cope with any sudden column removal scenario. Comparison with simply increasing tying capacity reveals that the latter does not have a direct and proportional effect on the frame’s resistance and should be used within a more informed context. With the aim of performing a complementary study for moment resisting steel frames, three types of popular welded connections are modelled under progressive collapse loading conditions using the Component Method. Also, an analytical solution for the prediction of the response of irregular beam systems under sudden column loss is presented. Despite the excellent performance of most floor systems, moment frames are found vulnerable to certain column loss scenarios. Thus, these scenarios are further examined with the express purpose of identifying how the frame might best be configured so as to provide the necessary resistance. The findings show how design for seismic resistance and design to resist progressive collapse do not necessarily align and highlight which structural properties are the most important to consider in each frame type, therefore encouraging the use of the proposed redesigning methodology, which is capable of effectively remediating robustness by efficiently addressing localised weaknesses.
15
Bahr, Oliver [Verfasser]. "Numerical and Experimental Investigations on Unbraced Composite Frames in Fire / Oliver Bahr." Aachen : Shaker, 2011. http://d-nb.info/107259241X/34.
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Tsujii, Masato. "Response and design of steel-concrete composite frames subjected to earthquake motion." Thesis, Imperial College London, 2001. http://hdl.handle.net/10044/1/7454.
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Dissanayake, Udaya Indrajith. "The influence of the composite beam-to-steel column joint on the behaviour of composite beams in frames." Thesis, University of Sheffield, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389752.
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Hu, Jong Wan. "Seismic performance evaluations and analyses for composite moment frames with smart SMA PR-CFT connections." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22655.
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This thesis investigates the performance of composite frame structures with smart
partially-restrained (PR) concrete filled tube (CFT) column connections through
simplified 2D and advanced 3D computational simulations. It also provides a design
methodology for new types of innovative connections based on achieving a beam hinging
mechanism. These types of connections intend to utilize the recentering properties of
super-elastic SMA tension bars, the energy dissipation capacity of low-carbon steel bars,
and the robustness of CFT columns.
In the first part of this study, three different PR-CFT connection prototypes were
designed based on a hierarchy of strength models for each connection component.
Numerical simulations with refined three dimensional (3D) solid elements were
conducted on full scale PR-CFT connection models in order to verify the strength models
and evaluate the system performance under static loading. Based on system information
obtained from these analyses, simplified connection models were formulated by replacing
the individual connection components with spring elements and condensing their
contributions. Connection behavior under cyclic loads was extrapolated and then
compared with the monotonic behavior.
In the second part of this study, the application of these connections to low-rise
composite frames was illustrated by designing both 2D and 3D, 4 and 6 story buildings
for the Los Angeles region. A total of 36 frames were studied. Pushover curves plotted
as the normalized shear force versus inter story drift ratio (ISDR) showed significant
transition points: elastic range or proportional limit, full yielding of the cross-section,
strength hardening, ultimate strength, and strength degradation or stability limit. Based
on the transition points in the monotonic pushover curves, three performance levels were
defined: Design Point, Yield Point, and Ultimate Point. All frames were stable up to the
yield point level. For all fames, after reaching the ultimate point, plastic rotation
increased significantly and concentrated on the lower levels. These observations were
quantified through the use of elastic strength ratios and inelastic curvature ductility ratios.
The composite frames showed superior performance over traditional welded ones in
terms of ductility and stability, and validated the premises of this research.
19
Hobbs, Michael. "Effects of Slab-Column Interaction in Steel Moment Resisting Frames with Steel-Concrete Composite Floor Slabs." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2014. http://hdl.handle.net/10092/9946.
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Composite construction is widely used worldwide and is undergoing significant technological development. New Zealand is part of this development, with new beam options incorporating multiple unstiffened web openings and new deck profiles supported by extensive testing. However, one area where relatively little research has been undertaken is in the interaction of the composite slab with the seismic resisting system under lateral loading.
In order to provide important new information in this area, a series of full scale beam-column-joint-slab subassemblies were tested at the University of Canterbury. Specimens tested had moment end plate connections and different combinations of deck tray direction, and isolation of the slab from the column. An additional test uses a sliding-hinge type connection to assess the effect of the floor slab in this type of low damage connection.
In these tests the lateral capacity of the seismic resisting system was increased by up to 25% due to the presence of the slab in contact with the column. The increase in capacity is 10% greater for decking running in longitudinal direction than in the transverse direction as a result of a more substantial full depth slab bearing on the column. The floor slabs of the subassemblies with the slab cast against the column all showed a higher level of damage than for those with the isolated column and the post ultimate strength degradation of the subassemblies without special detailing was significant. The subassembly with a section of full depth slab surrounding the column also exhibited a higher capacity but with an improved post ultimate strength degradation. All moment end plate subassemblies sustained drifts of up to 5% without significant strength loss.
The sliding hinge joint showed little signs of damage under testing to 5% drift. Some inelastic deformation of the connection and beams was noted above 5% drift.
Results from both testing and numerical modelling have shown that the current methods used to design these systems are conservative but within 15% of the values observed. Further testing and modelling will be necessary before any meaningful changes can be made to the way in which these systems are designed. Recommendations have been made regarding the placements of shear studs in plastic hinge zones and the provision of slab isolation around beam-column connections.
20
Kuleib, M. M. A. "The analysis and behaviour of composite space frames with profiled steel sheet floors." Thesis, University of Salford, 1989. http://usir.salford.ac.uk/2055/.
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The objective of this research was to analyse and investigate the behaviour of a composite space frame. The space frame is assembled from individual inverted square-based pyramids. Each pyramid consists of a steelangle section top-tray and diagonals. When the top trays are connected together, they form the top-chord members of a double-angle section connected back to back. The investigation is primarily concerned with the composite section within the space frame system which comprises the top chord members, profiled steel sheeting and a concrete slab. This composite section is also assumed to work as a system of intersecting composite Tbeams. Each composite T-beam comprises of a top chord member, a certain width of profiled steel sheet and a concrete slab. The composite action is ensured by a series of self-tapping screws. The experimental work is based on two-unit space frame specimens. Each specimen represents two adjacent units with their top chord member which carries the highest compressive axial load in the real structure. Each unit is tested in a situation which simulates its position and loading within the real structure. In addition to the composite T-beams being tested, steel struts composed of the top chord member double-angles were tested. In the theoretical section, the real structure is analysed as composite beam elements and thin steel plate elements which all represent the top composite T-beams. The diagonals and the ties were considered as truss elements. A successful method of analysis was developed using matrix and finite element methods resulting in the force distribution and deformations for a full composite space frame. Additionally, the experimental work yielded useful information on the behaviour of composite struts of this type. Recommendations for future work are made. The investigation of the behaviour of the composite T-beams with different locations and numbers of shear connectors together with the analysis of the structure comprise the main part of this work.
21
Zhou, Feng. "Seismic behavior and design of composite moment frames with conventional and innovative connections." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144550.
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Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(工学)<br>甲第11879号<br>工博第2572号<br>新制||工||1360(附属図書館)<br>23659<br>UT51-2005-N713<br>京都大学大学院工学研究科建築学専攻<br>(主査)教授 中島 正愛, 教授 井上 一朗, 助教授 吹田 啓一郎<br>学位規則第4条第1項該当
22
Ho, Jimmy Cheng-Chung. "Modeling spanwise nonuniformity in the cross-sectional analysis of composite beams." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29638.
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Thesis (Ph.D)--Aerospace Engineering, Georgia Institute of Technology, 2009.<br>Committee Chair: Hodges, Dewey; Committee Member: Bauchau, Olivier; Committee Member: Volovoi, Vitali; Committee Member: White, Donald; Committee Member: Yu, Wenbin. Part of the SMARTech Electronic Thesis and Dissertation Collection.
23
Wong, Shao Young. "The structural response of industrial portal frame structures in fire." Thesis, University of Sheffield, 2001. http://etheses.whiterose.ac.uk/3005/.
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A number of recent fires in single-storey warehouses have drawn attention to a current lack of understanding about the structural response of industrial portal frame structures to elevated temperatures. This research project has investigated the subject by conducting fire tests on a scaled model and by computer modelling using the non-linear finite element program VULCAN. This program has been developed in-house by the University of Sheffield and is capable of modelling the behaviour of three-dimensional steel and composite frames at elevated temperatures. It has been validated throughout its development. An initial investigation was conducted to validate the program for analysing inclined members, which form part of a pitched- roof portal frame, but for which it was not initially developed. Additional features were implemented into the program where necessary. A series of indicative fire tests was conducted at the Health and Safety Laboratories, Buxton. A scaled portal frame model was designed and built, and three major fire tests were conducted in this structure. In the third of these tests the heated rafters experienced a snap-through failure mechanism, in which fire hinges could clearly be identified. The experimental results were then used for validating the numerical results produced by VULCAN analyses. The correlations were relatively close, both for predictions of displacements and failure temperatures. This gave increased confidence in using VULCAN to conduct a series of parametric studies. The parametric studies included two- and three-dimensional analyses, and a number of parameters were investigated, including the effects of vertical and horizontal load, frame geometry, heating profiles and base rotational stiffness. The influence of secondary members was investigated in the three-dimensional studies using different fire scenarios. A simplified calculation method has been developed for estimating the critical temperatures of portal frames in fire. The results compare well with predictions from VULCAN. The current guidance document for portal frames in boundary conditions has been reviewed, and the concept of performance-based design for portal frame structures has been discussed.
24
O'Dell, Jason. "Wood plastic composite sill plate for continuous anchorage of shear walls in light-frame wood structures." Online access for everyone, 2008. http://www.dissertations.wsu.edu/Thesis/Summer2008/j_odell_060108.pdf.
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Reyes-Salazar, Alfredo 1962. "Inelastic seismic response and ductility evaluation of steel frames with fully, partially restrained and composite connections." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282375.
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The damage suffered by steel structures during recent strong earthquakes forced the profession to reevaluate issues related to the seismic design of steel structures. The evaluation of the maximum inelastic deformation of a structure subjected to a strong motion earthquake is a critical part of this process. A ductility parameter can also be used to calculate the maximum inelastic deformation of a structure. It is pointed that there is no unanimity on the definition of ductility, although it is constantly used in the profession. In this research several definitions of story ductility for MDOF systems are studied and the most appropriate one is identified. Definitions for local and global ductility are proposed. The presence of PR and composite connections on the structural response is also addressed in this study. Conventional analysis and design of steel frames structures is based on the assumptions that beam-to-column connection are either fully restrained (FR) or perfectly pinned (PP) connections. However, almost all steel connections used in practice are essentially partially restrained (PR) connections with different rigidities. The effect of PR and composite connections on the nonlinear seismic response of steel frames is evaluated. For this purpose, first the structural responses in terms of maximum interstory displacements and maximum top lateral displacements of three steel frames are calculated considering all of the frame connections to be of FR-type. Then the structural responses are evaluated for the frames with PR connections and finally for the frames with composite connections. Responses are compared for the three different cases. The recommendations to consider the effect of the vertical component on the structural response of two major seismic design guidelines for buildings are also studied. The first one is the National Earthquake Hazard Reduction Program (NEHRP) Recommended Provisions for Seismic Regulations for New Building (1994) and the second one is the Mexico City Seismic Code. Specifically, the effect of the vertical component on the structural responses of steel frames is evaluated first analytically and then according to the NEHRP Provisions and the Mexican Code. Finally, the analytical results are compared with the codes' recommendations.
26
Zhang, Wei. "Study of the Influence of Gravity Connections on the Lateral Response of Steel-Concrete Composite Moment Frames." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1336683755.
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Giuseppe, Antonio Marzano. "Multiple-Damage State Retrofit of Steel Moment-Resisting Frames with Composite Beam Sections Using Minimal-Disturbance Arm Damper." Kyoto University, 2020. http://hdl.handle.net/2433/254524.
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Poudel, Sanchit. "EFFECTS OF CONCRETE SLAB ON THE DUCTILITY, STRENGTH AND STIFFNESS OF STEEL MOMENT FRAMES WITH REDUCED BEAM SECTION CONNECTIONS." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1798.
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It was not thought that there would be some major flaws in the design of widely used steel moment frames until the Northridge Earthquake hit the California on January 17, 1994. Until then, steel moment frames were practiced as the most ductile system and were used in buildings from few stories to skyscrapers. The heavy devastation from Northridge Earthquake was an alarm for all the people related to the design and construction of such structures and pushed everybody to act fast to find some possible solutions to such never-expected-problems. Following the earthquake, FEMA entered into a cooperative agreement with the SAC joint venture in order to get a transparent picture of the problems in the seismic performance of steel moment frames and to come up with suitable recommendations. The research was specifically done to address the following things: to inspect the earthquake-affected buildings in order to determine the damage incurred in the buildings, to find out ways to repair the damaged buildings and upgrade the performance of existing buildings, and to modify the design of new buildings in order to make them more reliable for seismic performance. Among the various new design suggestions, the Reduced Beam Section (RBS) connection has been one of the most efficient and reliable option for high ductility demands. The purpose of this research was to study the behavior of concrete slabs in the performance of steel moment frames with reduced beam sections based on ductility, strength and stiffness. The slab is an integral part of a building. It is always wiser to consider the slab in order to assess accurately the seismic behavior of a building under the earthquake loading. In this research, two sets of finite element models were analyzed. Each set had one bare steel moment frame and one concrete slab frame which acted as a composite section. The connections were designed using the AISC Seismic Design manual (AISC 2012). The finite element modeling was done using NISA DISPLAY-IV (NISA 2010). All the models, with and without the slab were analyzed under the same boundary conditions and loads. Both non-linear and linear analyses were performed. The results from non-linear analysis were used to compare the ductility and strength whereas linear analysis results were used to compare the stiffness between bare steel and composite frame models.
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Subramaniam, C. "Chemorhelogical Modeling Of Amine-Cured Multifunctional Epoxy Resin Systems Used As Matrices In Aerospace Composites." Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/127.
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High performance multifunctional epoxy resin systems are becoming increasingly important as matrix materials for the advanced composites used in aerospace, electronics, automotive and other industries. In a composite based on epoxy resin systems, a three-dimensional network of the matrix is formed around the reinforcing fibre as a result of the chemical reaction between the resin and the curing agent. This chemical process, known as curing, is an important event to he considered in the production of composite components made up of these resin systems. Two process parameters namely viscosity and chemical conversion are of paramount significance in the production of composite materials Curing studies of the resin systems based on these two parameters, would therefore assume great importance in deciding the performance reliability of the end product.
The objectives of the present investigation are
1. to study the cure kinetics of three thermoset resin systems, viz.,
i) epoxy novolac (EPIT)/ diamino diphenyl methane{DDM), ii) trigylcidyl para- ammo phenol (TGPAP)/toluene diamine (TDA) and iii) tetraglycidyl diamino diphenyl methane (TGDDM)/pyridine diamine(PDA) using the cure kinetic models based on chemical conversion (α), Theological conversion (β) and viscosity.
2.to develop a correlation between a and viscosity (η) and modify an existing autocatalytic model based on α, to the viscosity domain and
3.to investigate the cure behaviour of these systems in terms of the TTT cure diagram and its associated models.
EPN/DDM, TGPAP/PDA and TGDDM/PDA resin systems were chosen for the studies to represent a range of functionalities, The cure was monitored using differential scanning calorimetry (DSC), fourier transform infrared (FTIR) and dynamic mechanical analysis (DMA) techniques by following the changes in enthalpy, functional groups and rheology, respectively.
The kinetic parameters namely, order of reaction and activation energy were estimated from dynamic DSC data using the methods of Freeman-Carroll and Ellerstein using nth rate expression. Barton, Kissinger and Osawa methods were employed to find out the activation energy from the peak/equal conversion at different heating rates. Isothermal DSC data were also analyzed using nth order model and it was observed that the data could be fitted satisfactorily only for higher temperatures The results obtained from the analysis of both dynamic and isothermal DSC data using nth order model clearly indicate that this model is inadequate for describing the cure behavior. The isothermal DSC data was analyzed by the autocatalytic models of Hone and Kamal Good correlation was observed with Hum and Kamal models up to 60-70%, 25% and 45% conversions for EPN/DDM, TGPAP/TDA and TCDDM/PDA systems respectively. However, the parameters m and n in Kamal model were found to be temperature dependent for EPN/DDM and TCPAP/TDA systems. The limited applicability of the autocatalytic models IK attributed to the counter-effect offered by the intra-molecular bonding taking place.
The primary amine and epoxy groups conversions obtained from FTIR were analyzed using autocatalytic model and the kinetic parameters were calculated. The reactivity ratio of the primary amine and the secondary amine with epoxy was found to be dependent on temperature in agreement with the recent findings reported m the literature.
The existing models that relate the cure kinetics and the rheological changes, are dual Arrhenius nth order model and autocatalytic model The nth order kinetic model was used to evaluate the kinetic parameters using the viscosity data at different cure temperatures under isothermal conditions As the storage modulus, G' is proportional to the chemical cross links and becomes significant only after the g<4 point, it was used to follow the changes in conversion known as rheoconversion after the gel point The rheoconversion was found by normalizing the G' data with G1^, the storage modulus of the fully cured resin It was used to study the cuie kinetics using an autocatalytic model The kinetic parameters such as rate constant, acceptation and retardation parameters were evaluated and that temperature dependence was established.
While the existing models relate viscosity and conversion only up to gel point the new proposed model, termed VISCON model takes into account the changes up to vitrification. The relation so developed is used to modify the autocatalytic cure model based on chemical conversion. The parameters appearing in this model were evaluated using Levenberg-Marquardt error minimization algorithm. The kinetic parameters obtained are comparable with the values estimated using the DSC data.
All the models cited above represent the microkinetic aspects. The models based on the information of TTT cure diagrams, however, represent the macrokinetic aspects of the cure, as they are based on the cure stages such as gelation and vitrification TTT diagram relates the cure characteristics like cure temperature, cure time, Ta and, indirectly, chemical conversion Hence the ultimate properties of the composite could he predicted and established with the help of the models based on TTT cure diagrams The changes in the storage modulus, G1 and loss modulus, G", were followed to identify the gel and vitrification points of the resin systems at different cure temperatures Gel point and vitrification point were used to generate gelation and vitrification hues in the construction of TTT cure diagrams for EPN/DDM, TGPAP/TDA and TGDDM/PDA resin systems Theoretical TTT diagrams were generated and IBO-T, contours were established using the TTT diagram-based models The cure schedule for the resin systems investigated could be determined from the TTT diagram and the respective rheological data.
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Jeannin, Baptiste. "Transformation of a metallic frame into a composite frame." Thesis, KTH, Lättkonstruktioner, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-243868.
Full textAbstract:
This document is a report of my thesis which deals with the transformation of a metallic frame into a composite frame. A composite frame would require less assembly time since it is composed of less components. The maintenance plan, required for metallic structures, would not be required anymore. Finally, the weight of the structure could be reduced.The resolution of this problematic is done in the following way. Once the pre-design of the frame settled, the finite element model is modified accordingly. The finite element outputs give the load per finite element and enable a sizing of the whole structure per section and per element. The design of the frame is then modified according to the results, the finite element model modified again and the sizing conducted another time until the design is in accordance with the design and sizing requirements.The results of this whole procedure give a structure that can withstand the critical loads but an increase in the weight by 1,65kg. When analyzing the results, the design of the frame, taken from a metallic frame and thus higher than a usual composite frame, appears to be unappropriated. Furthermore, the sizing of the skin for buckling failure is already at its limit. A modification in the shape of the frame, and especially the height, would be the most efficient way to adapt the design.Though possible, this modification would require a laborious and important change of the finite element model, which is not the aim of the thesis but could constitute another interesting topic to work on.
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Beshir, Moustafa. "Robustness of composite framed structures in fire." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-composite-framed-structures-in-fire(9c72a722-5b6a-477b-ac84-cd243ab73f34).html.
Full textAbstract:
This thesis presents the results of a research study to investigate the behaviour of axially restrained composite beams at ambient and elevated temperatures, and how composite beams and their connections contribute to the robustness of composite framed structures in fire. The commercial finite element analysis package (ABAQUS, 2010) was used to develop the numerical simulation models. This research includes the following four main parts: (1) validation of the simulation model; (2) behaviour of axially restrained composite beams with partial shear interaction at ambient and elevated temperatures; (3) behaviour of composite beams with realistic connections at elevated temperatures and methods of increasing composite beam survival temperatures; and (4) response and robustness of composite frame structures with different extents of damage at elevated temperatures. Based on the results of composite beams, it was found that the survival of axially restrained beams is dominated by the development of catenary action. By utilising catenary action, it is possible for composite beams to develop load carrying capacity significantly above that based on bending resistance. During the development of catenary action, the compression force in the concrete flange of the composite beam decreases, thus reducing the forces in the shear connectors. As a result, the behaviour of shear connector failures ceases to be an issue during the catenary action stage. The results further show that, the load carrying capacities/survival temperatures of composite beams increase by increasing the level of axial restraint up to a certain limit and then decrease at higher levels. Typical realistic composite structures can provide composite beams with sufficient axial restraint to develop catenary action. For detailed composite beams with composite connections, three different beam sizes were investigated using flushed and extended end plate connections with different amounts of slab reinforcement, different load ratios and different bolt sizes. It has been found that the most important method to increase the survival time of composite beams is to use extended end plate connections with sufficient top and bottom reinforcement meshes in the concrete slab, i.e. increasing the amount of slab reinforcement is more beneficial than increasing the bolt size or the number of bolts. Based on the results of modelling a four bay (9 m each, two storey, 4 m high) composite frame with different extents of fire damage to different members, it was found that whenever any of the columns failed, progressive collapse of the frame would occur. Therefore, damages to columns should be prevented or the columns should be designed and constructed to allow for possible damage. If the beams are damaged, it is still possible for the damaged frame to achieve the reference fire resistance time of the undamaged structure (which is used as the criterion to accept that the damaged frame has sufficient robustness) by developing catenary action in the damaged beam. For this to happen, the columns should be designed to resist the catenary tensile force (tying force) in the beams, in addition to the compressive force.
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Steele, John Phillip. "Composite RCS frame systems: construction and peformance." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/181.
Full textAbstract:
The objective of this research program is to further evaluate the performance and constructability of reinforced concrete (RC) column-steel beam-slab systems (RCS) for use in low- to mid-rise space frame buildings located in regions of high wind loads and/or moderate seismicity. To better understand these systems, two full scale RCS cruciform specimens were tested under bidirectional quasi-static reversed cyclic loading. The experimental portion of this research program included the construction and testing of two full-scale cruciform specimens with identical overall dimensions but with different joint detailing. The two joint details evaluated were joint cover plates and face bearing plates with localized transverse ties. The construction process was recorded in detail and related to actual field construction practices. The specimens were tested experimentally in quasi-static reversed cyclic loading in both orthogonal loading directions while a constant axial force was applied to the column, to simulate the wind loads in a subassembly of a prototype building. To compliment the experimental work, nonlinear analyses were performed to evaluate the specimen strength and hysteretic degradation parameters for RCS systems. In addition, current recommendations in the literature on the design of RCS joints were used to estimate specimen joint strength and were compared with the experimental findings.
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Gillie, Martin. "The behaviour of steel-framed composite structures in fire conditions." Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/1466.
Full textAbstract:
Over the last decade it has become increasingly clear that the traditional methods of fire safety design can be unnecessarily conservative and therefore expensive. In 1995 a series of fire tests were carried out at Cardington, UK on a full-scale eight storey steel-concrete composite building. These tests produced an extensive body of data about the response of such structures to fire conditions and it is intended that this data be used to develop a clearer understanding of the structural behaviour involved. This thesis presents a method of analysing the behaviour of structures such as the Cardington frame using the commercial finite element package ABAQUS, with the addition of user defined subroutines; applies the method to two of the Cardington tests and analyses the results. FEAST, a suite of computer programmes that defines the behaviour of shell finite elements using a stress-resultant approach, was programmed for use with ABAQUS. The FEAST suite consists of two main programmes. The first, SRAS, is designed to model the behaviour of orthotropic plate sections at elevated temperatures. The second, FEAI, interfaces with the finite element package ABAQUS and allows realistic models of the behaviour of whole structures in fire conditions to be obtained. Phenomena modelled by FEAST include non-linear thermal gradients, non-linear material behaviour and coupling between membrane and bending forces. FEAST was used to analyse the behaviour of the Cardington Restrained Beam Test and the Cardington Corner Test. In both cases it was possible to produce a comprehensive set of results showing the variation of forces, moments and deflections in the structure under fire conditions. In addition, a number of parametric studies were performed to determine the effect of factors such as slab temperature and coefficient of thermal expansion on the behaviour of the structure. Special attention was given to the role of tensile mebrane action. The results showed that the behaviour of the heated structure was very different to that of an unheated structure. The response of the structure was shown to be very strongly governed by restrained thermal expansion and by thermal gradients. Degradation of material properties were found to have only a secondary effect on the structural behaviour.
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Muniasamy, D. "Behaviour of semi-rigid composite connections for steel framed buildings." Thesis, Engineering systems department, 2009. http://hdl.handle.net/1826/3974.
Full textAbstract:
During propped construction the steel-concrete composite action resists dead as well as
imposed loads. Conversely, the steel section alone resists the floor self-weight in unpropped
beams. The major difference between propped and unpropped composite beams lies in the
ductility requirements rather than in the strength requirements. Relatively few studies have
been carried out to assess the rotation requirements for unpropped semi-continuous
composite beams. The outstanding critical factor in the case of unpropped construction is the
dead load stress that must be carried by the steel beam alone prior to hardening of the
concrete.
This research overcomes the difficulties involved in modelling the composite and noncomposite
stages by using a numerical integration technique developed from the basic
principles of structural mechanics. The method incorporates the fully non-linear material
properties and requires very little assumption. The technique was initially validated using the
experimental results from plain steel beam bending tests. The subsequent comparison
between the model predictions and the results from the large-scale frame test carried out for
this research purpose, showed that the method is capable of predicting non-elastic load vs.
end rotation behaviour within a high degree of accuracy. Thus the model can be used with
confidence in order to predict the connection rotation requirements for a wider range of
loading configurations than is practically possible from experimental testing alone.
A parametric study is carried out using the numerical integration technique developed for the
semi-continuous composite beam on a total of 2160 different beam configurations, utilising
different steel grades and loading conditions. In this study the influence of dead load stress on
the connection rotation requirement has been thoroughly evaluated along with several other
factors including span to depth ratio, location within the building frame, ratio between the support (connection) moment capacity and span (beam) moment capacity, loading type, steel
grade and percentage of the beam strength utilised during design. The connection rotation
capacity requirements resulting from this study are assessed to establish the scope for
extending the use of composite connections to unpropped beams.
The large-scale experiment that has been carried out provided an opportunity to investigate
the behaviour of a modified form of composite connection detail for use at perimeter
columns (single-sided composite connections) with improved rebar anchorage.
Additionally, another extensive parametric study is carried out using the numerical
integration technique developed for the steel beam to establish the influence of strainhardening
on elastic-plastic frame instability design.
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Xie, Yanmei. "Numerical Simulation and Structural Optimization of Composite Rigid Frame Bridge." Thesis, North Dakota State University, 2017. https://hdl.handle.net/10365/28357.
Full textAbstract:
A composite rigid frame bridge replaces a certain portion of the concrete middle span of a bridge with a section of the steel girder. While the steel span improves the bending moment distribution of the rigid frame structure, it increases the stress level of certain cross-sections of the girder. There is little research reporting the effects of the addition of the steel span on the layout and structural design. This research studies the influence of the steel span on the structural behavior of the rigid frame bridge and conducts the structural optimization regarding the steel span ratio, curve order of the girder?s bottom line, and height-to-span ratio using the bending strain energy as the objective function. Finally, this study develops the computer program for structural analysis of composite rigid frame bridge structure using MATLAB, which can be used for advanced structural optimization.<br>Department of Construction Management and Engineering (NDSU); College of Engineering at North Dakota State University
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Pilkington, Lawrence O. "Impact Response and Failure of a Textile Composite Fuselage Frame." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/10059.
Full textAbstract:
Impact tests are performed on two circular circumferential frame segments using a drop tower apparatus. These frames have a nominal radius of 120 inches, a forty-eight - degree included angle, a thin-walled cross section in the shape of the letter J, and are typical of the transverse fuselage frames found in a large transport aircraft. The material is a 2D triaxial braided composite of carbon fiber yarns. Impact speeds of the 91.6 lb drop mass are 23.7 ft/s or less. This speed range is the order of the vertical speed considered in a survivable crash on a runway. Transient response characteristics and failure sequence are compared to nominally identical frames tested quasi-statically in a previous study. The peak load at the first major failure event and the corresponding displacement are larger in impact tests than in the quasi-static tests. However, the fracture sequence in the vicinity of the impact location is similar to what was observed in the static tests. Preliminary transient simulations of the frame impact tests using the LSDyna software were also performed. Using the available composite material failure criteria in the software, reasonable correlation was achieved between the simulation and the tests on the load-displacement plot. The computed strains distributions did not compare as well to the measured strains at the first major failure event.<br>Master of Science
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Troup, Simon. "Numerical analysis and investigation of composite semi-rigid connections." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286960.
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Duchateau, Kristin Anne. "Structural design and performance of composite wall-foundation connector elements." Online access for everyone, 2005. http://www.dissertations.wsu.edu/Thesis/Summer2005/k%5Fduchateau%5F071405.pdf.
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Hart, Daniel Constantine. "Development of a Progressive Failure Finite Element Analysis For a Braided Composite Fuselage Frame." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/34026.
Full textAbstract:
Short, J-section columns fabricated from a textile composite are tested in axial compression to study the modes of failure with and without local buckling occuring.The textile preform architecture is a 2x2, 2-D triaxial braid with a yarn layup of [0 deg 18k/+-64 deg 6k] 39.7% axial. The preform was resin transfer molded with 3M PR500 epoxy resin. Finite element analyses (FEA) of the test specimens are conducted to assess intra- and inter- laminar progressive failure models. These progressive failure models are then implemented in a FEA of a circular fuselage frame of the same cross section and material for which test data was available. This circular frame test article had a nominal radius of 120 inches, a forty-eight degree included angle, and was subjected to a quasi-static, radially inward load, which represented a crash type loading of the frame. The short column test specimens were cut from some of the fuselage frames. The branched shell finite element model of the frame included geometric nonlinearity and contact of the load platen of the testing machine with the frame. Intralaminar progressive failure is based on a maximum in-plane stress failure criterion followed by a moduli degradation scheme. Interlaminar progressive failure was implemented using an interface finite element to model delamination initiation and the progression of delamination cracks. Inclusion of both the intra- and inter- laminar progressive failure models in the FEA of the frame correlated reasonably well with the load-displacement response from the test through several major failure events.<br>Master of Science
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Brown, Nigel David. "Aspects of sway frame design and ductility of composite end plate connections." Thesis, University of Warwick, 1995. http://wrap.warwick.ac.uk/3708/.
Full textAbstract:
This thesis reports work on two aspects of framed structures: part I is concerned with sway frames and part II with the ductility of composite flush end plate connections. Part I has investigated the effect of adopting standardised end plate connections as the method of providing the load path between the structural members of a steelwork sway frame. Practical low to medium rise multi-storey frame geometries have been designed in accordance with limit state principles in conjunction with the Wind-Moment Method. Each frame was analysed by undertaking a second-order elastic-plastic computer analysis to ascertain their structural performance, with particular emphasis directed towards problems associated with stability and sway deflections. The computer simulation necessitated the formulation of a prediction equation that modeled the initial stiffness characteristics of the standard connections. This model has been verified by comparison with full scale experimental test results, mainly taken from the literature. The investigation confirms that standardised end plate connections provide levels of stiffness and resistance which enable unbraced steel frames to be safely designed by the Wind-Moment method. There are however certain frame geometries where serviceability considerations dictate that stiffening to the frame would be necessary, if the standardised end plate connections were used. Part II has investigated the ductility of five major axis composite flush end plate connections that incorporate nominally identical amounts of reinforcement in conjunction with either 457 or 533 serial size Universal Beams. Other variable parameters include end plate thickness and horizontal spacing of the rebars. The work was undertaken experimentally and the results analysed in the context of connection performance. The results have shown that it will not prove difficult to ensure virtually rigid behaviour of the overall composite connection, despite the use of relatively thin end plates. Moreover, the experiments also show that the rotation capacity of composite connections in which 1% reinforcement is provided, would be sufficient to allow plastic methods of design to be used for composite beams with 457 serial size designations; however, ductility remains a problem when the depth of beam is further increased. To this end, an empirical model for assessment of ductility has been proposed, based on the observed deformation characteristics of the joint as a whole. This enables the total rotation capacity of one type of a composite connection to be determined when the failure occurs by fracture of the reinforcing bars.
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TUNC, GOKHAN. "RC/COMPOSITE WALL-STEEL FRAME HYBRID BUILDINGS WITH CONNECTIONS AND SYSTEM BEHAVIOR." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1020441384.
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Ball, Jeffrey Craig. "Design and analysis of multifunctional composite structures for nano-satellites." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2572.
Full textAbstract:
Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2017.<br>The aim of this thesis is to investigate the applications of multifunctional compos-
ite (MFC) technology to nano-satellite structures and to produce a working concept
design, which can be implemented on future Cube-Satellites (CubeSats). MFC tech-
nologies can be used to optimise the performance of the satellite structure in terms
of mass, volume and the protection it provides. The optimisation of the structure
will allow further room for other sub-systems to be expanded and greater payload
allowance. An extensive literature view of existing applications of MFC materials has
been conducted, along with the analysis of a MFC CubeSat structural design account-
ing for the environmental conditions in space and well-known design practices used in
the space industry. Numerical analysis data has been supported by empirical analysis
that was done where possible on the concept material and structure. The ndings
indicate that the MFC technology shows an improvement over the conventional alu-
minium structures that are currently being used. Improvements in rigidity, mass and
internal volume were observed. Additional functions that the MFC structure o ers
include electrical circuitry and connections through the material itself, as well as an
increase electromagnetic shielding capability through the use of carbon- bre composite
materials. Empirical data collected on the MFC samples also show good support for
the numerical analysis results. The main conclusion to be drawn from this work is that
multifunctional composite materials can indeed be used for nano-satellite structures
and in the same light, can be tailor-made to the speci c mission requirements of the
satellite. The technology is in its infancy still and has vast room for improvement
and technological development beyond this work and well into the future. Further
improvements and additional functions can be added through the inclusion of various
other materials.
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Lamont, Susan. "The behaviour of multi-storey composite steel framed structures in response to compartment fires." Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/1485.
Full textAbstract:
For many years, the ability of highly redundant composite framed structure to resist the effect of a fire have been undervalued and misunderstood. A great deal of work on the behavior of composite steel-concrete structures in fire has been developed since the Cardington frame fire tests (UK) conducted in the 1990s.
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Showalter, Sheldon Lee. "Investigation of Ultimate Strength of Composite Open-Web Joist-Girders." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/40930.
Full textAbstract:
The goal of this research was to study several methods of generating composite action using open-web joist-girders, designed and manufactured by Nucor Corporation. In addition to comparing the relative performance of these systems, it was intended to determine whether the current accepted design procedure for composite joists could be extended to joist-girders.<br>Master of Science
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Kohlman, Lee W. "Evaluation of Test Methods for Triaxial Braid Composites and the Development of a Large Multiaxial Test Frame for Validation Using Braided Tube Specimens." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1333047848.
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Klusen, Philip [Verfasser]. "Rechtliche Fragen bei der Transplantation von Vascularized Composite Allografts (VCA) / Philip Klusen." Frankfurt a.M. : Peter Lang GmbH, Internationaler Verlag der Wissenschaften, 2018. http://d-nb.info/1180215974/34.
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Kaymak, Yalcin. "A Composite Frame/joint Super Element For Structures Strengthened By Externally Bonded Steel/frp Plates." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1052547/index.pdf.
Full textAbstract:
A materially non-linear layered beam super element is developed for the analysis of RC beams and columns strengthened by externally bonded steel/FRP plates. The elasto-plastic behavior of RC member is incorporated by its internally generated or externally supplied moment-curvature diagram. The steel plate is assumed to be
elasto-plastic and the FRP laminate is assumed to behave linearly elastic up to
rupture. The thin epoxy layer between the RC member and the externally bonded lamina is simulated by a special interface element which allows for the changing failure modes from steel plate yielding/FRP plate rupture to separation of the bonded plates as a result of bond failure in the epoxy layer. An empirical failure criterion based on test results is used for the epoxy material of the interface.
The most critical aspect of such applications in real life frame structures is the anchorage conditions at the member ends and junctions. This has direct influence on the success and the effectiveness of the application. Therefore, a special corner piece anchorage element is also considered in the formulation of the joint super
element, which establishes the fixity and continuity conditions at the member ends
and the joints.
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Lang, Elemer M. "Modeling the behavior of wood-based composite sheathing under hygrothermal load." Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/40035.
Full textAbstract:
In light-frame residential construction wood-based composite panels used externally or internally are exposed to relative humidity and/or temperature changes. The subsequent moisture content change of the panels will result in two types of deformations as follows: 1. elastic deformation of the panel due to the constraint, 2. warpage of the panel due to the unbalanced expansion of the layers. Such deformations can cause unacceptable serviceability problems in light-frame wood construction.
A model was developed to predict quantitatively the global deflection of wood-based composite panels exposed to relative humidity changes. The model was based on the constitutive relationship of the Classical Lamination Theory and the thermal stress analogy in composites. As an alternative solution, the applicability of the eccentrically loaded column formula was evaluated.
The developed models were experimentally validated for OSB and plywood sheathing. Test variables included the panel type, exposure (symmetric and non-symmetric MC gradient) and specimen configuration (single span, multiple span). The comparison of measured and predicted deflections are presented. The important elastic and hygroscopic material properties were acquired through testing. Statistical analyses of test results are discussed.
The uncertainty analysis was used to make statistical inference comparing the means of measured deflection to the uncertainty interval of predictions. Good agreement between predicted and measured deflections was found for single span test structures. Also, for double span structures the models predicted the experimental response fairly veil. Uncertainties in Me measurements made the prediction less reliable when symmetric moisture content gradient developed during the exposure. Due to its lower variability in material properties, the response of OSB sheathing to moisture content changes is more predictable.<br>Ph. D.
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Corby, Thomas James Patrick. "The disappearing frame : a practice-based investigation into composing virtual environment artworks." Thesis, University of the Arts London, 2000. http://ualresearchonline.arts.ac.uk/6126/.
Full textAbstract:
Through creative art making practice, research seeks to contribute a body of knowledge to an under researched area by examining how key concepts germane to computer based, interactive, three-dimensional, virtual environment artworks might be explicated, potential compositional issues characterised, and possible production strategies identified and/or proposed. Initial research summarises a range of classifications pertaining to the function of interactivity within virtual space, leading to an identification and analysis of a predominant model for composing virtual environment media, characterised as the "world as model": a methodological approach to devising interactive and spatial contexts employing visual and behavioural modes based on the physical world. Following this alternative forms of environmental organisation are examined through the development of a series of artworks beginning with Bodies and Bethlem, and culminating with Reconnoitre: a networked environment, spatially manifest through performative user input. Theoretical corollaries to the project are identified placing it within a wider critical context concerned with distinguishing between the virtual as a condition of simulation: a representation of something pre-existing, and the virtual as potential structure: a phenomena in itself requiring creative actualisation and orientated toward change. This distinction is further developed through an analysis of some existing typologies of interactive computer based art, and used to generalise two base conditions between which various possibilities for practice might be situated: the "fluid" and "formatted" virtual.
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Ache, Michel. "Influence de la nature des fraises utilisees en prothese conjointe sur les criteres d'etat de surface des composites." Paris 5, 1990. http://www.theses.fr/1990PA05M032.
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