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1
Lazarin, Juan Reuben. "Optimum Design of Composite Wing Spar Subjected to Fatigue Loadings." DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1816.
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Composites are now being incorporated into aircraft designs because of their high strength to weight ratio compared to traditional metal materials. Due to the complexity of the material, composite parts are presently being over designed to satisfy static and fatigue requirements. A greater understanding of composite fatigue behavior will allow for even greater weight savings leading to increased fuel economy. A critical part of an aircraft that is subjected to fatigue bending loads are its wings. The forces acting on the wings include its lift distribution, powerplant, and fuel which can be carried in the wing body. When in flight these forces repeatedly cause cyclic displacements which could ultimately lead to failure. It is important to design the wing spars which carry the bending loads, to be fatigue resistant so that damage or expensive inspections could be avoided.
Wing models were be made from composite materials with a NACA 0016 airfoil shape, chord length of 9.25”, and a span of 15.25”. The C – channel spars were located at 22% and 72% of the chord. Strain gages on the wing model were used to measure strain at different locations. Static test were conducted on the specimens in order to validate a finite element analysis(FEA) model to be used for simulations. Overall, the strain measurements on the leading edge from two of the wings matched the model within 9% of the simulation results. Additional spar designs were then analyzed to determine the optimal one for static and fatigue bending loads. The wings were fatigue tested under displacement control at a test frequency. A model 8801 servo-hydraulic Instron machine and Wave Matrix software was used to fatigue the wings. After 100,000 cycles the test would be deemed a success and concluded.
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Kite, Adam Howard. "Nondestructive evaluation of a carbon fiber wing spar using air-coupled ultrasound." [Ames, Iowa : Iowa State University], 2007.
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Hála, Aleš. "Návrh změny kostrukčního řešení hlavních závěsů křídla letounu Z 242." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417468.
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This diploma thesis deals with modernization of the Z 242 L aircraft wing. The main emphasis is given to the connection of the wing and fuselage. The new concept of both main and rear wing spar is designed together with integral fuel tank. The strength of the structure is evaluated analytically and numerically by use of Finite element analysis. Wide range of milling operations is implemented into manufacturing process as well. This thesis shows how to innovate current aircraft with respect to feasibility of the design in case of future project realization.
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Thompson, Eric J. "Design of a multi-piece removable mandrel mold tool to fabricate and control inner mold surface contour of a composite wing spar." Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/11141.
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Thesis (M.S.)--West Virginia University, 2010.Title from document title page. Document formatted into pages; contains viii, 69 p. : col. ill. Includes abstract. Includes bibliographical references (p. 69).
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Cejpek, Jakub. "Analysis of Aeronautical Composite Structures under Static Loading." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-385288.
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Poměrně velké množství soukromých firem v České republice vyrábí lehká sportovní letadla. Značná část těchto letadel využívá kompozitní pružiny ve svých přistávacích zařízení. Tyto pružiny jsou buďto menší díly, absorbující energii (na příďové noze či ostruze), anebo jde celé pružnice hlavního podvozku. Všechny tyto pružiny sdílí základní charakteristiky: jsou vyrobeny převážně z jednosměrného kompozitu s významnou tloušťkou, hlavním druhem zatížení je ohybový moment a jsou očekávány velké deformace. Podobnou charakteristiku můžeme použít i při popisu hlavního nosníku křídla. Jak vypadá návrh a analýza takovýchto dílů? V zásadě jsou dvě možnosti. První z nich je poměrně jednoduchá analytická analýza, případně naprogramovaná v tabulkovém výpočetním prostředí. Nevýhody tohoto řešení jsou limitované možnosti výpočtu a jeho nízká flexibilita. Druhou možností je využít komerční konečno-prvkový systém pro analýzu, případně i pro optimalizaci. Pochopitelnou nevýhodou této možnosti je cena programu a obsluhy. Cílem této disertační práce je vytvořit program, jež nabídne třetí možnost, která umožní provádět zevrubnou analýzu řešených produktů bez nutnosti pořizovat nákladný software. Tento program zjednoduší a urychlí návrh a pevnostní kontrolu. Umožní uživateli rychle analyzovat více návrhových variant. Program dále bude zohledňovat specifika analyzovaných produktů (například velké deformace a lokální koncentrace napětí kolmo na vlákno). Z pohledu uživatele by program měl být jednoduchý na ovládání. Minimum množství vstupních dat a přehledné grafické rozhraní zajistí komfortní používání. Samostatně spustitelný program (bez instalace a bez podpůrného softwaru) zlepšuje rozšiřitelnost programu.
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Mestrinho, João Rafael da Conceição. "Design of a variable-span morphing wing." Master's thesis, Universidade da Beira Interior, 2009. http://hdl.handle.net/10400.6/2048.
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The present work focuses on the study, design and validation of a variable-span morphing wing to be tted to the UAV \Olharapo". Using an optimization code, which
uses a viscous two-dimensional panel method formulation coupled with a non-linear
liftingline algorithm and a sequential quadratic programming optimization routine, na aerodynamic analysis is performed to estimate the optimal values of wing span which ensure minimum drag across the ight speed envelope. The UAV ies in a relatively
short speed range - from about 12 m/s to 30 m/s. Near its maximum speed it is possible
to obtain a 20% drag reduction with the variable-span wing in comparison with
the original xed wing. A stability analysis is also performed to estimate the roll rate
available with asymmetric span control. The variable-span wing matches the aileron in
terms of roll power and maximum roll rate. It is concluded that roll control is possible
with asymmetric span control. A new electro-mechanical actuation mechanism is developed
using a simple and cheap rack and pinion system. The wing model is designed
with graphical CAD/CAM tools and then a full scale model is built for bench testing
the wing/actuator system. The concepts used on the morphing wing for both xed and
movable part are considered simple and e ective. The actuation concept is also feasible
but needs improvements in the attenuator. A powerful servo is also needed to more
easily deploy the wing. Some future modi cations at structural level and ideas for an
in-flight automatic span controller are also presented.
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Proskovics, Roberts. "Dynamic response of spar-type offshore floating wind turbines." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=26017.
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In recent years there has been a significant increase in the interest in floating offshore wind turbines from the wind energy industry, governments and academia. Partially driven by the recent nuclear disaster in Japan, but also by the lack or complete absence of shallow waters in various countries around the globe (making fixed offshore wind turbines infeasible), multiple different topology floating offshore wind turbines have been proposed and, in some cases, prototypes built and installed offshore. The most well-known of these is Hywind by Statoil, which has been operational off the coast of Norway since the end of 2009. While small scale prototypes had been installed even before Hywind, for example Blue-H in 2007, no guidelines have yet emerged that would give recommendations and guiding principles in designing new floating offshore wind turbines. The aim of this thesis is to provide some knowledge base for future design of floating offshore wind turbines by looking at what simplifications could be made and what effect these would have on the preliminary designs of new floating offshore wind turbines. This thesis starts by comparing different topology floating offshore wind turbines and choosing one, deemed the most promising, as the base case scenario for use in the subsequent analysis and calculations. This thesis also looks at the importance of unsteady representations of the aerodynamics compared with quasi-steady when designing a new floating offshore wind turbine, by comparing quasi-steady aerodynamic loads first with fully-attached unsteady loads and later with fully-unsteady (fully-attached, separated and dynamic stall). A chapter is allocated to identifying which degree-of-freedom of loading is the most damaging to the system, as floating offshore wind turbines operate in very harsh and unstable environments. Once identified, this knowledge can be used to further improve floating offshore wind turbines, hence making them even more feasible. Finally, the wind turbine previously chosen as a base case has its floating support shortened and four different draft designs proposed that would allow it to be deployed in medium-to-deep waters, in which fixed supports for wind turbines are not economical.
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Solberg, Thomas. "Dynamic Response Analysis of a Spar Type Floating Wind Turbine." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16215.
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Wind power is a large natural source for renewable energy, and many countries have shown interest in establishing floating offshore wind parks. There are many advantages with floating offshore wind turbines, but also many challenges connected to them. This report focuses on establishing a model for wave-wind induced loading on a Spar type floating wind turbine named OC3-Hywind. The OC3-Hywind is a modified version of an original design developed by Statoil. Two fellow MSc students have developed models for a tension leg platform (TLP) and a semi-submersible, and a comparison between the three concepts have been done. The model has been constructed by the use of the well known software tools HydroD and DeepC. In addition, a DLL extension, TDHMILL3d, was used to obtain thrust force. HydroD was used in calculations of the hydrodynamic coefficients of the floater. DeepC was used to run coupled floater and mooring analysis in time domain. Important parameters like hydrodynamic coefficients and natural frequencies compare well to data from the literature. Simulations showed that the Spar is mostly influenced by wind loads in the operational conditions. At rated wind speed of 11.4 m/s the pitch motions of the Spar was showed to be large. To reduce these motions a simple filter was used to extend the turbine control system. In situations where wind and waves have different directions, the Spar experiences large yaw motions. Several factors that may contribute to these motions have studied. To achieve good accuracy in statistical parameters, 10 or more simulations with different seeds were needed.The original depth of 320 m was changed to 160 m. Only minor changes to the mooring system were needed to obtain similar performance as the base case. In the comparison part typical trends of the different floaters was studied. Based on these trends, positive and negative response characteristics were discovered. The semi-submersible had the largest pitch and surge motions, while the TLP had the largest accelerations below rated. This may result in difficulties in maintenance operations. Only the Spar showed sign of excessive yaw motions. The semi-submersible had the lowest nacelle accelerations and STD for all load cases. In addition, the semi-submersible is the most versatile when it comes to water depth.
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Lee, Sungho Ph D. Massachusetts Institute of Technology. "Dynamic response analysis of spar buoy floating wind turbine systems." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46545.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaves 83-84).
The importance of alternative energy development has been dramatically increased by the dwindling supplies of oil and gas, and our growing efforts to protect our environment. A variety of meaningful steps have been taken in order to come up with cleaner, healthier and more affordable energy alternatives. Wind energy is one of the most reliable energy alternatives for countries that have sufficiently large wind sources. Due to the presence of steady and strong winds, and the distance from coastline residential, the offshore wind farm has become highly attractive as an ideal energy crisis solution. Floating wind turbine systems are being considered as a key solution to make the offshore wind farm feasible from an economic viewpoint, and viable as an energy resource. This paper presents the design of a synthetic mooring system for spar buoy floating wind turbines functioning in shallow water depths. Nacelle acceleration, static and dynamic tensions on catenaries, the maximum tension acting on the anchors are considered as design performances, and a stochastic analysis method has been used to evaluate those quantities based on sea state spectral density functions. The performance at a 100-year hurricane condition is being defined as a limiting case, and a linear wave theory has been the most fundamental theory applied for the present analysis.
by Sungho Lee.
S.M.
10
Sanches, Tiago Nunes. "Longitudinal flight control with a variable span morphing wing." Master's thesis, Universidade da Beira Interior, 2012. http://hdl.handle.net/10400.6/2006.
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The present study focuses on the design of a longitudinal flight controller for an unmanned aircraft equipped with dissymmetric variable-span system (VSMW or Variable-Span Morphing Wing). Its primary role consists in the longitudinal flight stabilization of the aeroplane while in levelled cruise flight, although, it was designed to offer longitudinal flight stabilization for other flight phases as well, such as e.g. take-off and landing. The stabilization algorithm relies on the most up-to-date developments in the state-of-the-art LQR and Batz-Kleinman controller techniques to stabilize the aircraft on its intended longitudinal attitude upon any small atmospheric disturbances inflicted. It was designed for the experimental UAV prototype Olharapo equipped with the VSMW, so it can automatically adjust the VSMW overall wingspan in accordance with the flight speed and stabilize the aircraft in the desired attitude, although, its modular concept allows it to be used for different configurations of the aircraft or even for a different aircraft. The development, simulation and testing of the algorithm were done using the MATLAB® software and the aircraft’s stability and control derivatives previously obtained using the XFLR5® software. Minor adaptations of the flight dynamics equations were performed to allow the compatibilization with the VSMW. The required implementation of imposed flight qualities was also performed to ensure proper scaling the controller weight matrix for optimal values. Finally, the algorithm was tested using three different methods: Classic Disturbances Simulation, Sinusoidal Pitch Variation Test Response and Random Pitch Variation Test Response.O presente trabalho consiste na projeção, programação e teste de um controlador de voo longitudinal destinado a uma aeronave não-tripulada equipada com um sistema de variação dissimétrica da envergadura das asas (conhecido como VSMW, asa dissimétrica ou asa telescópica). Este trabalho tem como principal objetivo desenvolver um controlador capaz de assegurar a estabilidade longitudinal da aeronave em voo nivelado a velocidade de cruzeiro, contudo, este foi também projetado para providenciar essa mesma estabilidade noutras fases de voo tais como a aterragem ou a descolagem. O algoritmo de estabilização baseia-se nas mais sofisticadas técnicas de controlo de voo atualmente disponíveis, mais concretamente LQR e Batz-Kleinman, para estabilizar a aeronave na atitude pretendida aquando da ocorrência de quaisquer pequenas perturbações atmosféricas que afetem a aeronave durante o voo. A aeronave a que se destina trata-se de um protótipo designado de Olharapo equipado com uma asa telescópica que permite ajustar a envergadura total das asas de acordo com a velocidade de voo. No entanto, o conceito modular da estrutura do programa permite que o controlador possa ser utilizado para diferentes configurações da mesma aeronave, ou até mesmo com uma aeronave totalmente diferente. Tanto o desenvolvimento como as simulações e testes do algoritmo foram efetuados com recurso ao software MATLAB® , tendo as necessárias derivadas de estabilidade e controlo iniciais sido providenciadas pelo software XFLR5® . As equações de voo foram devidamente adaptadas para permitirem uma compatibilização com o sistema da asa telescópica e a sua integração nos métodos de controlo LQR e Batz-Kleinman. As qualidades de voo da aeronave foram devidamente definidas e impostas ao controlador para garantir a afinação da matriz de ponderação para valores ótimos. Por fim, o algoritmo foi sujeito a três tipos de testes e simulações: Simulação Clássica por meio de Imposição de Perturbações Atmosféricas, Teste de Resposta a uma Variação Sinusoidal do Ângulo de Arfagem, e Teste de Reposta a uma Variação Aleatória do Ângulo de Arfagem.
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Berhe, Awot M. "Aerodynamic analysis of finite-span wings." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79998.
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This thesis presents a new method of solution for the aerodynamics of finite-span wings, which overcomes the difficulties of the previous methods. The present method uses velocity singularities in the Trefftz plane (situated downstream at infinity) to derive the contributions in the solution of the circulation distribution caused by the changes in the spanwise variation of the wing chord and incidence. The new specific functions derived for these contributions contain both natural and forced symmetry and antisymmetry terms, and thus represent a correct mathematical modeling of the physical problem. The correct mathematical representation of these contributions leads to a highly accurate theoretical solution which is not the case in the previous methods.The method has been validated in comparison with the results obtained by theoretical methods such as Rasmussen & Smith, and Carafoli for rectangular and tapered wings of uniform incidence, and with panel method (Katz & Plotkin) results. Accurate theoretical solutions have been derived for various wing geometries of aeronautical interest, such as wings with curved leading and trailing edges, and wings with asymmetric incidence variations caused by symmetric and antisymmetric deflection of flaps and ailerons (which are more difficult to model using the panel methods).
Furthermore, the present method of solution has been extended to solve the problem of swept wings. A procedure has been developed to specifically treat this problem.
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Zhang, Xi M. Eng Massachusetts Institute of Technology. "Wind effect on long span bridge." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/74418.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 41-42).
This thesis has studied different types of reactions of long span bridge under wind load, such as vortex shedding, flutter and buffeting. Since all of these conditions have the chance to damage bridge structure, we calculate the particular wind speed and magnitude that will maximize the reaction. To check if the theory works well, a bridge model is set up and analyzed in SAP2000 and the results are compared with one from mechanics theory. A cable-stayed bridge from Hong Kong is selected for analysis. After we compare the bridge reaction by different methods, we find that theory of aerodynamics can provide reasonable result. However, we're still looking for a better performance from the bridge and improved motion control. Thus, to optimize the structure, design of a tuned mass damper is included as well. Summarily, wind effect on long span bridge is predictable and could be well controlled by various means based on the analysis in this thesis.
by Xi Zhang.
M.Eng.
13
Rashid, Adnan. "Investigation of through-thickness assembly stresses in composite wing spars." Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.722699.
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Wiggins, Leonard D. III. "Structural Design and Analysis of a Kinematic Mechanism for a Morphing Hyper-Elliptic Cambered Span (HECS) Wing." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/9668.
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The HECS wing was developed by NASA Langley Research Center and has a nonplanar, hyper-elliptically swept leading and trailing edge as well as spanwise camber. For this wing, the leading and trailing edges are swept back according to a hyper-elliptical equation. The span of the wing is also defined with hyper-elliptical anhedral giving it nonplanar spanwise camber. A single-degree-of-freedom mechanism is developed to provide a means for the wing to continuously change shape from its nonplanar to planar configuration. The mechanism uses a repeating quaternary-binary link configuration to translate motion from one segment to the next. A synthesis of the mechanism is performed, such that with one input to the first segment of the chain, the other wing segments move into their desired positions. Linear aerodynamic theory is applied to the HECS wing configuration at certain morphed positions in order to predict the aerodynamic loads.
This work performs a linear static analysis of the mechanism at different morphed positions. A finite element representation of the mechanism as a structure is developed. Using the predicted aerodynamic loads, a structural analysis is performed. The analysis investigates different materials and cross sections of the members to determine a need for redesign due to failure from buckling and bending stress. From the analysis of the mechanism, a design is finalized which lightens the structure as well as increases the strength. These results are beneficial for the next phase of model development of the mechanism.Master of Science
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Moy, Inge. "Parameter Sensitivity of Short-term Fatigue Damage of Spar-type Wind Turbine Tower." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18511.
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The World’s energy demand is rapidly increasing and a good viable renewable energy source is wind power. The land-based knowledge and experience the onshore wind turbine industry possess is used to develop offshore wind turbines. With this knowledge together with the experience and knowledge of the marine industry we can design and produce a floating wind turbine. The main advantages of an offshore wind turbine are that the wind is stronger and less turbulent at sea, visual and noise annoyances can be avoided and there are large available areas at sea. In this thesis coupled time domain analyses of a floating spar-type wind turbine are performed with the intension to study parameters affecting fatigue damage at base of the tower. The software applied is SIMO/Riflex with the extension TDHmill, which gives the wind thrust force and gyro moment on the wind turbine as point loads in the tower top. Short term environment conditions are chosen from a joint distribution of simultaneous wind and waves which is based on measurements from a site in the North Sea in the period 1973 – 1999. In total 141 different environmental conditions are chosen for the sensitivity study. Mean value, standard deviation, skewness and kurtosis are calculated for axial stresses at the base of the tower. Fatigue damage is calculated from the Palmgren-Miner sum with a nominal stress SN-curve from the DNV fatigue standard. The axial stress-cycle distribution used in the Palmgren-Miner sum is found by rainflow counting. Time domain simulations are carried out for the different sea states and fatigue damage is calculated for each case. The statistical properties and fatigue damage are averaged over seven samples with different random seed number to ensure acceptable statistical uncertainty. Accumulated standard deviation shows that 5 samples of each load case are sufficient to ensure acceptable statistical uncertainty. Sensitivity study of different simulation length shows that 30 minute simulations give close to equal fatigue damage and standard deviation as 2.5 hour simulations. Sensitivity of fatigue to wave height and peak period is carried out to study the effect of varying parameters. This study suggests that the highest waves dominate the fatigue damage for the smallest peak periods. For some small wave heights the damage will be constant for a given peak period range. From this sensitivity study it is shown that if the deviation of fatigue damage between the different load cases is small, then the dominating load case of the accumulated long term fatigue damage will be dominated by the marginal probability of each load case.
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Mehler, Felix Eckhart. "The structural testing and modification of a full-scale ornithopter's wing spars." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29368.pdf.
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Henry, Janisa Jernard. "Roll control for UAVs by use of a variable span morphing wing." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3288.
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Thesis (M.S.) -- University of Maryland, College Park, 2005.Thesis research directed by: Dept. of Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Saracevic, Nermina. "Comparison of electricity production between semi-submersible and spar-buoy floating offshore wind turbines." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-381386.
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The paper compares electricity production between the semi-submersible and the spar-buoy floating wind turbine systems under normal, stochastic and extreme wind conditions at Utsira Nord site located on the Norwegian continental shelf in the North Sea. The analysis of complex behavior of the floating wind turbine system and the fluid-structure interaction is performed in aero-servo-hydro-elastic code ASHES. The results indicate a slightly better energy performance of the semi-submersible than the spar in all load cases but one. The pitch and heave degrees of freedom are evaluated as the most relevant for the power output. It is shown that pitch and heave platform motions have smaller displacement in the semi-submersible floater than in the spar under average environmental conditions and at the rated wind speed operating range. The simulation also confirmed that the energy yield is very sensitive to the magnitude of the loads: the spar performed best under mild environmental conditions, while the semi-submersible was better under medium environmental conditions. Small difference in energy yield is attributed to the same baseline blade and external controller properties used for both floaters where generator torque was kept constant to limit the power excursions above the rated power. The method proposed under this paper has demonstrated that a good approximation of the energy performance of the floating wind turbine system can be performed in a fast and effective manner.
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Blondeau, Julie E. "Development and testing of a variable aspect ratio wing using pneumatic telescopic spars." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1761.
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Thesis (M.S.) -- University of Maryland, College Park, 2004.Thesis research directed by: Dept. of Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Dziubinschi, Alexandru. "Analysis of finite span wings based on velocity singularities." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30242.
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The thesis presents the analysis, based on velocity singularities, of the upswept finite span wings of various planforms and distributions of incidence.The method of velocity singularities has been first introduced by Mateescu for the analysis of the flow past airfoils, based on the singular behaviour of the fluid velocity near the leading edge and ridges.
In this work, the method of velocity singularities is extended to determine the solution of the flow in the Trefftz plane normal to the uniform stream.
Velocity singularities are used to obtain directly the complex expression of the perturbation velocity in the cross-flow coordinates. The spanwise variation of the circulation is obtained by integrating the real part of the complex conjugate velocity in the Trefftz plane, and then is related to the local intensity of the circulation on the wing.
Two methods of solutions were developed, one applicable only for wings with symmetrical distribution of incidence, and a more general one applicable for both symmetrical and non-symmetrical distribution of incidence.
Both methods have been validated by comparison with Carafoli's solutions for symmetrical wings. Then the more general method has been used to obtain solutions for various wings with non-symmetrical distribution of incidence, such as the case of wings with anti-symmetrically deflected ailerons.
The method was proven to be more efficient and accurate than the comparable methods that are currently employed.
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Dziubinschi, Alexandru. "Analysis of finite-span wings based on velocity singularities." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0030/MQ64218.pdf.
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Karimirad, Madjid. "Stochastic Dynamic Response Analysis of Spar-Type Wind Turbines with Catenary or Taut Mooring Systems." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12458.
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Floating wind turbines can be the most practical and economical way to extract the vast offshore wind energy resources at deep and intermediate water depths. The Norwegian Ministry of Petroleum and Energy is strongly committed to developing offshore wind technology that utilises available renewable energy sources. As the wind is steadier and stronger over the sea than over land, the wind industry recently moved to offshore areas. Analysis of the structural dynamic response of offshore wind turbines subjected to stochastic wave and wind loads is an important aspect of the assessment of their potential for power production and of their structural integrity. Of the concepts that have been proposed for floating wind turbines, spar-types such as the catenary moored spar (CMS) and tension leg spar (TLS) wind turbines seem to be well-suited to the harsh environmental conditions that exist in the North Sea. Hywind and Sway are two examples of such Norwegian concepts; they are based on the CMS and TLS, respectively. Floating wind turbines are sophisticated structures that are subjected to simultaneous wind and wave actions. The coupled nonlinear structural dynamics and motion response equations of these turbines introduce geometrical nonlinearities through the relative motions and velocities. Moreover, the hydrodynamic and aerodynamic loading of this type of structure is nonlinear. A floating wind turbine is a multibody aero-hydro-servo-elastic structural system; for such structures, the coupled nonlinear equations of motion considering nonlinear excitation and damping forces, including all wave- and wind-induced features, should be solved in the time domain. In this thesis, the motion and structural responses for operational and extreme environmental conditions were considered to investigate the performance and the structural integrity of spar-type floating wind turbines. The power production and the effects of aerodynamic and hydrodynamic damping, including wind-induced hydrodynamic and wave-induced aerodynamic damping, were investigated. Negative damping adversely affects the power performance and structural integrity. In this thesis, the controller gains were tuned to remove servo-induced instabilities. The rotor configuration effect on the responses and power production was investigated by comparing the upwind and downwind turbines. To develop robust design tools for offshore wind power, the competencies of the offshore technology and wind technology must be combined. Both the offshore and wind energy industries have begun to extend their existing numerical codes to account for the combined aerodynamic and hydrodynamic effects on the structure. As a result verifications of extended codes by doing experiments and code-to-code comparisons are needed. One of the aspects of the present research was to fill this gap by performing hydrodynamic and hydro-elastic comparison between commercial codes. For both CMS and TLS concepts, the comparisons were carried out prior to using the tools to study the behaviour of the CMS and TLS under wave- and wind-induced loads. Offshore structures encounter a variety of operational and harsh environmental conditions. Limit states such as ultimate, fatigue, accidental collapse and serviceability limit states (ULS, FLS, ALS and SLS) are defined as the design criteria for offshore structures. In performing realistic ultimate limit state analysis, the extreme responses of a floating wind turbine over its life should be estimated. This estimation requires detailed analysis of the extreme response. In the present thesis, extreme value analysis for spar-type wind turbines subjected to simultaneous wave and wind actions was preformed. The structural responses and the effect of modelled forces such as turbulence on these responses were investigated. The joint distribution of the environmental characteristics of the wave and wind was applied through the contour surface method. Stochastic wave and wind analysis showed that, while rigid body modelling was sufficient for obtaining accurate motions, consideration of the elastic behaviour of the tower/support structure was necessary to predict structural responses. The blades structural responses were found to be significantly affected by the turbulent wind. However, the mean and standard deviation of global motion and structural responses were not affected by the turbulence. Thus, to reduce the simulation time in fatigue analysis, a constant wind speed model can be applied. The CMS and TLS wind turbines are inertia-dominated structures, and the hydrodynamic viscous drag did not affect their wave-induced responses, while an increase in viscous drag could effectively reduce the resonant responses of such turbines. Under operational conditions, aerodynamic damping was found to be active in reducing both wave frequency and resonant responses. The results showed that, for a floating wind turbine, extreme response could occur in survival conditions, while for a fixed wind turbine, the extreme response occurs in operational cases related to the rated wind speed. To estimate the extreme value responses, extrapolation methods were used to reduce the sample size in Monte Carlo simulations. The accuracy of methods to estimate the extreme responses as a function of sample size and methods applied was investigated. The normalized responses for both CMS and TLS offshore wind turbines were presented to draw more generalized conclusions.
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Sohaib, Muhammad. "Parameterized Automated Generic Model for Aircraft Wing Structural Design and Mesh Generation for Finite Element Analysis." Thesis, Linköpings universitet, Maskinkonstruktion, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-71264.
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This master thesis work presents the development of a parameterized automated generic model for the structural design of an aircraft wing. Furthermore, in order to perform finite element analysis on the aircraft wing geometry, the process of finite element mesh generation is automated. Aircraft conceptual design is inherently a multi-disciplinary design process which involves a large number of disciplines and expertise. In this thesis work, it is investigated how high-end CAD software‟s can be used in the early stages of an aircraft design process, especially for the design of an aircraft wing and its structural entities wing spars and wing ribs. The generic model that is developed in this regard is able to automate the process of creation and modification of the aircraft wing geometry based on a series of parameters which define the geometrical characteristics of wing panels, wing spars and wing ribs.Two different approaches are used for the creation of the generic model of an aircraft wing which are “Knowledge Pattern” and “PowerCopy with Visual Basic Scripting” using the CATIA V5 software. A performance comparison of the generic wing model based on these two approaches is also performed. In the early stages of the aircraft design process, an estimate of the structural characteristic of the aircraft wing is desirable for which a surface structural analysis (using 2D mesh elements) is more suitable. In this regard, the process of finite element mesh generation for the generic wing model is automated. The finite element mesh is generated for the wing panels, wing spars and wing ribs. Furthermore, the finite element mesh is updated based on any changes in geometry and the shape of the wing panels, wing spars or wing ribs, and ensure that all the mesh elements are always properly connected at the nodes. The automated FE mesh generated can be used for performing the structural analysis on an aircraft wing.
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Bubert, Edward A. "Highly extensible skin for a variable wing-span morphing aircraft utilizing pneumatic artificial muscle actuation." College Park, Md. : University of Maryland, 2009. http://hdl.handle.net/1903/9332.
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Thesis (M.S.) -- University of Maryland, College Park, 2009.Thesis research directed by: Dept. of Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Seytre, Jean-François. "Theoretical solutions for finite span wings of arbitrary shapes using velocity singularities." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=29547.
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This thesis presents a new theoretical approach based on the concept of velocity singularities developed by Mateescu for airfoils in subsonic flows and for wing-body systems in supersonic regime. The present approach uses the velocity singularities in the Trefftz plane to derive the contributions of the wing incidence and chord changes in the solution of the circulation variation along the wing span. The new specific functions derived for these contributions contain both natural and forced symmetry and anti-symmetry terms, and represent the first correct mathematical modeling of the physical problem. The new forced symmetry and anti-symmetry terms and the new contributions of the incidence and chord distribution changes, which were missing from the previous methods, determine a high level of accuracy of the solution, which is free of spurious oscillations. (Abstract shortened by UMI.)
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Olivato, Giuseppe [Verfasser], and Dieter [Akademischer Betreuer] Dinkler. "Managing Wind Risk on Long Span Roofs / Giuseppe Olivato ; Betreuer: Dieter Dinkler." Braunschweig : Technische Universität Braunschweig, 2010. http://d-nb.info/1175826936/34.
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Matus, Manuel A. Mr. "Experimental Investigation of Wind-induced Response of Span-wire Traffic Signal Systems." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3655.
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The purpose of this investigation was to identify key design parameters that might significantly affect the response of span wire traffic light systems during extreme wind events. The performance of these systems was assessed through physical testing in an effort to quantify the effect of sag ratio, wire tension and wire clearance. The Wall of Wind experimental facility at Florida International University was utilized for testing the systems at different wind speeds and wind directions.
The findings showed that, at all tested wind directions, lift, drag and tension forces increased with increasing wind speeds. On the contrary, increasing the wind speed resulted in higher inclination on the traffic lights, lower drag coefficients and higher lift coefficients. Overall, when the wind was approaching from the rear face of the traffic signals, increased drag coefficients were recorded. When the sag was set at 7% lower drag coefficients were observed.
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Gluck, Jeffrey Weston, and Jeffrey Weston Gluck. "Water Tunnel Experiments on Span-wise Variation of Laminar Separation Bubbles for Swept and Unswept Wings using Particle Image Velocimetry." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/621851.
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An inverted airfoil mounted above a flat plate was used to create laminar separation bubbles on a flat plate in water tunnel experiments at low Reynolds numbers. Boundary layer suction ensured that the flow remained attached to the wing. Two-dimensional PIV measurements were used to qualitatively and quantitatively characterize the spanwise bubble variation on an unswept wing and on the same wing featuring a 22 degree sweep. The separation bubbles were recorded at varied span-wise locations in a 31.5 cm wide region of the flow. The limitations of this measurement region were dictated by the focal length of the laser optic used for PIV measurements. The straight wing exhibited approximately uniform time averaged separation positions across the span of the wing. The reattachment locations varied only slightly which was expected due to the transition to turbulent flow before reattachment. A form of bubble "breathing" was observed in the laminar separation bubbles on the straight wing and is believed to have affected the mean reattachment locations for two data points recorded. The shedding frequencies on the straight wing were slightly higher than those obtained from CFD simulations. The swept wing planform showed significantly more variation in the mean separation and reattachment locations with respect to the leading edge of the wing. There is a general trend of the separation locations moving upstream in the direction of the aft leading edge. The reattachment points are shown to move downstream as the separation points move upstream relative to the leading edge and visa versa, displaying an inverse relationship between the two. The bubble lengths were found to be slightly longer on the swept wing compared to the straight wing usually by about 10%. The shedding frequencies on the swept wing were found to be lower than the straight wing. The quality of flow in the water tunnel may have degraded over time, showing signs of increased free stream turbulence. After data collection, it was also discovered that the boundary layer suction on the wing was not constant at all span-wise locations. It is believed that the introduction of wing sweep intensified the effect of insufficient suction on the structure of the bubbles observed. The present results were in agreement with previous research for bubble structure but the dynamic instabilities were found to differ slightly.
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Ashtiani, Abdi Iman. "Experimental And Numerical Investigation Of The Wind Effects On Long Span Bridge Decks." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613615/index.pdf.
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Long span bridges are susceptible to wind. Hence it is important to study their wind-induced vibrations to avoid any probable structural failures. In this thesis, the results of an experimental and computational investigation of the aerodynamic characteristics of trapezoid bridge deck cross-sections with three different aspect ratios (10, 12 and 15) and four different side angles (75º, 60 º
, 45 º
and 30 º
) are analyzed and presented. The flow around rigid fixed bridge deck models is investigated to obtain the relevant aerodynamic coefficients and the vortex shedding frequency and Strouhal number. Two dimensional unsteady Reynolds Averaged Navier-Stokes equations are solved using commercial CFD software at different Reynolds numbers. The numerical results are compared with the experimental data obtained by testing the model bridge decks geometries in a low speed wind tunnel. The results of this study demonstrate that the models aerodynamic parameters except their lift coefficient are almost dependent on the aspect ratio. In addition, the influence of side angle on all aerodynamic parameters has to be taken in account.
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De, Shuvodeep. "Structural Modeling and Optimization of Aircraft Wings having Curvilinear Spars and Ribs (SpaRibs)." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/88467.
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The aviation industry is growing at a steady rate but presently, the industry is highly dependent on fossil fuel. As the world is running out of fossil fuels and the wide-spread acceptance of climate change due to carbon emissions, both the governments and industry are spending a significant amount of resources on research to reduce the weight and hence the fuel consumption of commercial aircraft. A commercial fixed-wing aircraft wing consists of spars which are beams running in span-wise direction, carrying the flight loads and ribs which are panels with holes attached to the spars to preserve the outer airfoil shape of the wing. Kapania et al. at Virginia Tech proposed the concept of reducing the weight of aircraft wing using unconventional design of the internal structure consisting of curvilinear spars and ribs (known as SpaRibs) for enhanced performance. A research code, EBF3GLWingOpt, was developed by the Kapania Group. at Virginia Tech to find the best configuration of SpaRibs in terms of weight saving for given flight conditions. However, this software had a number of limitations and it can only create and analyze limited number of SpaRibs configurations. In this work, the limitations of the EBF3GLWingOpt code has been identified and new algorithms have been developed to make is robust and analyze larger number of SpaRibs configurations. The code also has the capability to create cut-outs in the SpaRibs for passage of fuel pipes and wirings. This new version of the code can be used to find best SpaRibs configuration for multiple objectives such as reduction of weight and increase flutter velocity. The code is developed in Python language and it has parallel computational capabilities. The wing is modeled using commercial FEA software, MSC.PATRAN and analyzed using MSC.NASTRAN which are from within EBF3GLWingOpt. Using this code a significant weight reduction for a transport aircraft wing has been achieved.PHD
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Lindqvist, Mattias, and Jonas Lundin. "Spare Part Logistics and Optimization for Wind Turbines : Methods for Cost-Effective Supply and Storage." Thesis, Uppsala University, Division of Systems and Control, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-122891.
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The wind power industry is maturing and the amount of electricity produced by wind turbines in the world is rapidly increasing every year. Service and maintenance of wind turbines has proven to be difficult and expensive, especially offshore. A well coordinated support organisation and optimized maintenance strategies are required to effectively reduce the costs associated with WT support, where cost-efficient supply and storage of spare parts are important. The aim of this thesis is to model spare part logistics for wind turbines to analyse different strategies and compare the profitability. Optimal stock levels and reorder sizes have been calculated with the software tool OPUS10. Wind turbine and spare part data have been provided by Vattenfall Vindkraft AB and field studies were made to the wind farms Lillgrund and Horns Rev to gather information.
Our analyses show that different spare part strategies only affect a minor part of the total support costs generated for a wind farm. Still there are many improvements possible and money to be saved if using an optimal spare part strategy instead of one based on personal experiences and intuition. For a large wind power system, including a number of wind farms with the same wind turbine types, we also show convincing results that pooling of spare parts are a much more cost-efficient spare part strategy compared to local storage and handling only. Using a central depot for spare part reordering and storage of critical spare parts, such as gearboxes, generators and blades, are more profitable
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Kaya, Halil. "Aerodynamic Analysis Of Long-span Bridge Cross-sections Using Random Vortex Method." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615072/index.pdf.
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In this thesis, two dimensional, incompressible, viscous flow past bluff bodies and a bridge section, in which strong vortex shedding and unsteady attribute of flow are generally found, is simulated by means of random vortex method.
The algorithm and method are described in detail. The validation and applicability of the developed numerical implementation to general wind engineering problems is illustrated by solving a number of classical problems, such as flow past circular and square cylinders. An application of the numerical implementation in the area of computational wind engineering is performed by analyzing a bridge deck section. Moreover, all results are compared with experimental and numerical studies in literature.
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Johansson, Jim. "Utilizing Energy Storage Applied on Floating Wind Turbine Economics Using a Spot-Price Based Algorithm." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-328934.
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In this paper, a new algorithm for utilizing energy storage is proposed and applied on floating wind turbine economics. The proposed algorithm’s decision making on storing energy or selling electricity onto the grid is based on the electricity price, which makes it unique and different from similar algorithms. From the literature review, it was concluded Ocean Renewable Energy Storage to be most suitable with the Spar-Type and Semi-Submersible floating wind turbine to which the paper is based upon. The objective of this paper is to find the suitable ratio of energy storage versus wind farm, find the product of increase in wholesale, and evaluate whether the proposed method makes the hybrid economically sound. The algorithm was applied on spot-price data from Denmark due to its large share of wind energy with wind data from off the coast of Morro Bay in California, USA. Additionally, a sensitivity analysis is applied to evaluate to energy storage cost impact as well as evaluate the algorithm by lowering the required energy storage size. Using the algorithm, the wind farm must account for nine days’ worth of energy production with a product of energy storage versus wind farm ratio of 1.42. The wholesale price increased with 11.9-21.5% for the four years studied, however, all financial results favored not utilizing energy storage. By the results derived from the sensitivity analysis, it was concluded that with future cost reductions, the algorithm will still favor no energy storage. However, by fine tuning the algorithm to reduce the need for storage, positive financial result might be achievable. The key to achieve a profitable result seems to rely on minimizing the need for energy storage, to which the proposed algorithm fail to achieve. Conclusively, spot-price decision-based energy storing is not economically sound.
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Mohammadi, M. Sajad, and Rishiraj Mukherjee. "Wind Loads on Bridges : Analysis of a three span bridge based on theoretical methods and Eurocode 1." Thesis, KTH, Bro- och stålbyggnad, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-125349.
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The limitations lying behind the applications of EN-1991-1-4, Eurocode1, actions on structures-general actions-wind load-part 1-4, lead the structural designers to a great confusion. This may be due to the fact that EC1 only provides the guidance for bridges whose fundamental modes of vibration have a constant sign (e.g. simply supported structures) or a simple linear sign (e.g. cantilever structures) and these modes are the governing modes of vibration of the structure. EC1 analyzes only the along-wind response of the structure and does not deal with the cross wind response. The simplified methods that are recommended in this code can be used to analyze structures with simple geometrical configurations. In this report, the analytical methods which are used to describe the fluctuating wind behavior and predict the relative static and dynamic response of the structure are studied and presented. The criteria used to judge the acceptability of the wind load and the corresponding structural responses along with the serviceability considerations are also presented. Then based on the given methods the wind forces acting on a continuous bridge whose main span is larger than the 50 meters (i.e. > 50 meter requires dynamic assessment) is studied and compared with the results which could be obtained from the simplified methods recommended in the EC1.
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Baro, Laura [Verfasser], and Udo [Akademischer Betreuer] Peil. "Long span bridges under wind actions / a non-linear fluid force model / Laura Baro ; Betreuer: Udo Peil." Braunschweig : Technische Universität Braunschweig, 2011. http://d-nb.info/1175824178/34.
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Ji, Wenhao. "A study into the sustainable system between the wind and the villages in Rincón de Ademuz. Spain." Doctoral thesis, Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/39001.
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El objetivo del estudio es analizar el sistema sostenible de Rincón de Ademuz, donde perdura en el tiempo un poblado que permanece asentado desde hace dos mil años.Ji, W. (2014). A study into the sustainable system between the wind and the villages in Rincón de Ademuz. Spain [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/39001
TESIS
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Cerqueira, Sandro Melo. "Aspetos morfológicos dos insetos e sua importância na polinização." Master's thesis, Universidade de Évora, 2015. http://hdl.handle.net/10174/17441.
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A maioria das plantas com flor é visitada por grande diversidade de insetos com diferentes formas e tamanhos, que acumulam grãos de pólen nos seus corpos.
Neste trabalho analisou-se a relação entre os parâmetros morfométricos dos insetos visitantes florais (comprimento do corpo, envergadura das asas e comprimento da probóscide no caso dos lepidópteros) e número de grãos de pólen transportados.
Verificou-se um efeito linear positivo relativamente ao comprimento do corpo dos insetos, ou seja, quanto maior o comprimento do corpo, maior o número de grãos de pólen transportados; também se verificou um efeito de alisamento negativo relativamente à envergadura, isto é, número de grãos de pólen transportados parece diminuir com o aumento da envergadura das asas.
No caso dos lepidópteros, há uma correlação muito forte entre o comprimento da probóscide e comprimento do corpo, sugerindo que o efeito significativo do comprimento seja um proxy para a probóscide e não um efeito do comprimento; Abstract:
Morphological aspects of insects and their importance in pollination
Most flowering plants are visited by a great number of insects with different shapes and sizes, which accumulate pollen grains on their bodies.
In this study we analyzed the relationship between the morphometric parameters of the flower visiting insects (body length, wing span, and the length of the proboscis in the case of Lepidoptera) and number of pollen grains carried.
There was a positive linear effect regarding the body length of the insects, that is, the greater the body length, the higher number of pollen grains carried; it was also observed a negative smoothing effect regarding the wingspan, i.e. the number of pollen grains carried appears to decrease with increased wingspan.
In the case of lepidoptera, there is a strong correlation between body length and proboscis, suggesting that this significant effect is a proxy for the proboscis rather than an actual effect of body length.
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Rensa, Pavel. "Návrh koncepce systému vztlakové klapky pro novou generaci sportovního letounu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-228926.
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ploma thesis deals with design of a four-seat sport aircraft for basic training, tourist flying and glider towing, which can be used in aeroclubs and by private owners. The objective of this thesis was to design the outer shapes of the aircraft, compute the basic aerodynamic characteristics and performance, design of structural and aerodynamic layout of the wing and design of flap system with governing.
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Jančář, Milan. "Prodloužení životnosti letounů ZLIN Z 126 a 226." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230182.
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This master's thesis discusses the possibilities of safe-life extension program for ZLIN Z 126 and 226 airplanes, which despite their age and long-end production are still widespread and popular not only in the Czech Republic. The age of these aircraft is also related to the fact, that some aircraft are already approaching its border life, so there is an interest for the longest possible technical and legislative airworthiness. As mentioned in my bachelor's thesis, during the existence of this model series, there was no major damage occurred, except for sporadic exfoliation corrosion of wing flanges. Experience with maintenance of this aircraft points to certain underestimation of the current 5500hrs lifetime and it is obvious to suggest possible steps to increase the current limit. The thesis is therefore considered in this context the possibility of producing new wing flanges made of another material, performed the calculation for wing fatigue exchanged with flanges and designed technological process of this exchange, so that ZLIN Z 126 and 226 airplanes can be safely operated in the future.
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Vojtěšek, Jiří. "MORAVSKÉ VINAŘSKÉ CENTRUM BRNO." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-354946.
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The city of Brno has always been a center of Moravian wine. The new draft of wine center responds to this reality and represents the grandeur of wineries in its full glory. Respect for nature, love for traditions and love for order/system are the main aspects of the design. The proposal is essentially open to the public, however, the necessary modesty is preserved. Conversely taciturnity of production part of buliding holds the secrets of the deep traditions of Viticulture and Enology. Designed buildings are used for production, wine storage, administration associated with the production, tasting and selling wine, conferences, accommodation and, finally, wellness and other activities. The size of the building is the result of an optimal design that does not interfere with nearby historical buildings. The emphasis is on minimizing costs both during construction and during operation. Flor plan shape resembling the letter L is oriented towards the west courtyard. This raises a unique viticultural area court with a wide staircase. The amphitheater can be used for seasonal exhibitions, pilgrimages or feast of local entertainment. The yard is connected with the street Hlinky, which paraphrases the historic entrance portals into winecellars. The northern part of the building bites into the ground and connects the original winecellars with new facilities. Small narrow windows reflects the desired taciturnity, just as it was with winecellars in South Moravia for centuries.
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Kasalová, Nicol. "MORAVSKÉ VINAŘSKÉ CENTRUM BRNO." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-354971.
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The study design includes the new building of the Moravian wine and cultural center on the Hlinky street in Brno. There are spaces designed for wineries (producing, maturing and storing wine), administration, congress center (with business lounges), spa, restaurant and gastro-studio, shops, exhibition, hotel and parking. The building is trapezoidal shape and replace the existing object in a vacant lot, only some historical cellars will be retained. The supporting structure consists of reinforced concrete skeleton system and reinforced concrete reinforcing inner core around the staircase leading to all floors, the building is covered by a flat green roof. On the facade dominates the element that its shape resembles the vine shoots, which holds the glass facade. The construction is divided into two expansion units - the main part of the building and garage, which is set into the ground sloping towards the south. The building has six floors and one underground floor. The first four floors are connected by open gallery at the southern facade.
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Pereira, da Silva Carlos Manuel Baptista. "Design and testing of an active aircraft wing spar with bending-torsion coupling." Thesis, 2007. http://hdl.handle.net/1828/2228.
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An experimental investigation on active aeroelastic aircraft structures with bending-torsion coupling properties is presented. Two techniques for vibration and flutter alleviation are studied and tested. The passive approach is based on the use of carbon composite spars with misaligned fibres. The second technique involves an active spar with a multi-cross section embedded with PZT actuators. A wing was designed and manufactured for testing in a wind tunnel and subsequently implemented on a demonstrator platform for flight testing.
Results show that a carefully designed misalignment of the fibres can lead to significant performance increase. The active system based on PZT actuators with a linear controller exhibits significant improvements in aeroelastic performance compared to the passive system. The research findings lead to the conclusion that significant vibration reduction and flutter envelope extension can be achieved using the proposed strategies.
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Cunha, Rui Filipe Martins Fernandes. "Structural analysis of a variable-span wing-box." Master's thesis, 2014. http://hdl.handle.net/10400.6/5223.
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This dissertation describes the work done to analyse the wing-box of a variable-span wing. Based on previous work in the CHANGE project the main objective of this study is the experi-mental analysis of the wing-box structure’s prototype build at Universidade da Beira Interior, one of the CHANGE project partners. Surrounding the preliminary design of this project, a nu-merical model written, concerning a parallel work, was modified and used to analyse the mass and displacement variations according to the moving fraction and semi-span of the morphing wing-box. It was first dimensioned the jig to statically validate this structural model that con-cerns the following work. Through the use of Computer Aided Design tools and numerical cal-culation, it was designed and built an experimental setup. Based on computational structural analysis tools, the numerical model allowed the parametric study of the preliminary wing-box design comprising the mass and displacement changes in accordance of the two following pa-rameters: moving fraction and semi-span. In order to complement this study, various configu-rations of the preliminary wing-box were analysed such as the reduction of the composite sand-wich skin’s thickness. With the help of programming tools two polynomial functions were cal-culated from the respective variations previous described. Finally, experimental tests were performed on the prototype of the preliminary wing design. The numerical model was validated and the values are in good agreementEsta dissertação de mestrado descreve o trabalho realizado para analisar a estrutura da caixa de torção de uma asa de envergadura variável. Com base no trabalho realizado anterior-mente no projeto CHANGE o principal objetivo desta dissertação é a validação do modelo nu-mérico, feito por Pedro Santos, da caixa de torção envolvente no desenho preliminar para este projeto. Primeiramente foi dimensionado o estaleiro para validar estaticamente este modelo estrutural em que se constituiu o seguinte trabalho. Através do uso de ferramentas computaci-onais de desenho (CAD) e cálculo numérico, foi projetada e construída a montagem experimen-tal. Com base em ferramentas de análise estrutural computacional, o modelo numérico permi-tiu o estudo paramétrico, um dos objetivos deste trabalho. De modo a complementar este estudo, foram analisadas várias configurações da asa preliminar para compreender a variação do peso da estrutura e da flexão de acordo com a fração da envergadura móvel. Com a ajuda de ferramentas de programação obtiveram-se dois polinómios calculados a partir das respetivas variações anteriormente descritas. Finalmente foram feitos testes experimentais no protótipo do desenho da asa preliminar..
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Felício, João Miguel Inácio. "Development and testing of a variable-spam morphing wing." Master's thesis, 2010. http://hdl.handle.net/10400.6/3663.
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The present work focuses on the development and validation of a variable-span morphing wing (VSW) to be fitted to a mini UAV. An electro-mechanical actuation mechanism is developed using a simple rack and pinion system. The wing model is designed with the help of graphical CAD/CAE tools and then a full scale model is built for bench testing the strength, power consumption, deployment time and efficiency. The concepts used on the morphing wing for both fixed and moving wing parts are considered simple and effective. Construction methods and materials were evaluated in order to obtain a system as reliable as possible. Still, in future work the VSW structure can be improved by changing some interface components to achieve a smoother deployment. Also, some work is planned on the design optimization code: implementation of a coupled aero-structural analysis model for simultaneous aerodynamic and structural design optimization problems. Main results: deployment times; efficiency.
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Sultania, Abhinav. "Reliability analysis of a spar buoy-supported floating offshore wind turbine." Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-08-1864.
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While wind energy has witnessed faster growth than any other renewable energy source in recent years, two issues—the decreasing availability of large land expanses for new wind farms and transmission difficulties arising from siting wind farms in remote regions far from load centers—have slowed down this growth considerably. Siting wind turbines offshore places the generating capacity closer to population and load centers; thus, reducing grid congestion. Also, at offshore sites, one can expect higher wind speeds, decreased turbulence, and reduced noise and visual impact constraints. Offshore wind turbines that have been built thus far have had foundations (such as monopiles or jacket structures) that have extended to the seabed. Such offshore wind turbines have thus been confined to shallow waters closer to the shore. Sites farther offshore provide better wind resources (i.e., less turbulence and smoother, stronger winds) while also reducing visual impact, noise, etc. However, deeper waters encountered at such sites make bottom-supported turbines less economical. Wind turbines mounted atop floating platforms are, thus, being considered for deeper water offshore sites. Various floating platform concepts are under consideration; the chief differences among them arise from the way they provide stability to counter the large mass of the rotor-nacelle assembly located high above the mean water level. Of these alternative concepts, the spar buoy platform is a deep draft structure with a low center of gravity, below the center of buoyancy.
Reliability analysis of a spar buoy-supported floating offshore 5MW wind turbine based on stochastic simulation is the subject of this study. Environmental data from a selected deepwater reference site are employed in the numerical studies. Using time-domain simulations, the dynamic behavior of the coupled platform-turbine system is studied; statistics of tower and rotor loads as well as platform motions are estimated and critical combinations of wind speed and wave height identified.text
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Hou, Tzu-Hsuan, and 侯詞軒. "Scale Effect of Wing Span and Flight Kinematic Strategies in Free-Flying Butterflies." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/7k94xr.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
105
The scale of butterflies largely variate among species, and might affect their flight performance intrinsically. In this work, we carry out experimental observations and numerical analysis to investigate how flight performances and flight motions of butterflies correlate with their sizes, and a flight strategy to enhance wing loading of small size butterflies is proposed accordingly. Four different species of Taiwan butterflies with significant differences on wingspan (variating from 44-136 mm) were selected to study experimentally. The motions of butterflies were recorded with high-speed cameras when they were freely flying in an experimental chamber. The images of flight that close to forward flight were selected and analyze with the image processing software (Image J). The experimental results indicate that the wing loading of butterflies positively correlate to their wingspan, and the irregularity of the flight trajectory is not as evident as the previous research (Dudley, 1990). In addition, the flapping frequency and body angle amplitude of the small butterflies are found to be higher than that of large butterflies in our experiments. Numerical models of butterflies in different scales are further created to analyze the size effect quantitatively since various parameters in experiments are combined and are unable to control separately. The butterfly in the simulation translate freely along the vertical and horizontal directions; the flight speeds determined by calculating the aerodynamic force and gravity force. The shape and flight motions of butterflies are considered as the same in each cases, and the mass is manually controlled to find the maximum wing loading of butterflies in specific size. The simulations results show that the wing loading decreases with the wingspan sharply while the shapes and the flight motions are considered as the same. The decreasing rate is more rapid than the trend recorded from experiments, which implies that small butterflies may adjust their flight motions, flapping frequency and body angle amplitude in our observation, to enhance their wing loading in nature. To clarify the effects of these two motions, we further adjust the flapping frequency and rotation amplitude in the simulation model. The results show that both ways effectively improve the wing loading of the butterflies as excepted; moreover, the butterflies are able to achieve higher forward speed with the former motion and are more energy-efficient with the latter motion. Butterflies may alter the flapping frequency or rotation amplitude. Our results provide relations between the size of butterflies and the flight parameters. In an engineering perspective, these relations are especially important for the designing of flight vehicles; for example, determining the total weight of vehicles and power required of the motor. In addition, by comparing the difference between the experimental and simulation results, we proposed a motion control strategy to adjust the flight speed and power consumption of micro aircraft vehicles.
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Mcclelland, Charles. "Asymmetric Blade Spar for Passive Aerodynamic Load Control." 2013. https://scholarworks.umass.edu/theses/1136.
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Asymmetric bending is explored as a means of inducing bend-twist coupling in an isotropic, fixed-wing airfoil. An analytical model describing the bend-twist coupling behavior of a constant-section airfoil undergoing steady wind loading is derived from Euler-Bernoulli beam theory, and evaluated over a range of structural and material stiffness. Finite element analysis is carried out in the ANSYS Parametric Design Language environment for an asymmetric, two-dimensional beam. Three-dimensional finite element analysis is carried out for two candidate blade models created in Pro/Engineer based on the NACA 64618 airfoil. Deformation results for the two- and three-dimensional finite element models are compared with analytical solutions. Results of this investigation highlight the dependency between the cross-sectional properties of a spar support and its tendency to exhibit twist-coupling under transverse loading.
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Salvatori, Luca. "Assessment and mitigation of wind risk of suspended-span bridges /." 2007. http://www.gbv.de/dms/bs/toc/566320371.pdf.
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Hung, Shih-Pei, and 洪詩姵. "Dynamic characteristics of long span roof structure under wind loading." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/88948104209612537350.
Full textAbstract:
碩士淡江大學
土木工程學系碩士班
97
Due to the increase of span length and the reduction of total structural mass, the structural behavior of long span roof structure become more complicated. The sensitivity to wind for this type of structure is also increased. Because Taiwan is a typhoon prone area, the importance of wind resistant design of the type of structures can not be ignored. The main purpose of this thesis is to develop a method combined POD and Ritz vectors for improving the efficiency of calculations in the dynamic analysis of the long span roof structures under wind excitations. The numerical results obtained from this approach are compared with those obtained from direct integration and traditional modal analysis. Two examples are used to demonstrate the validity and the efficiency of this method. It can be inspected from the results that using a few POD modes and Ritz vectors can obtain satisfactory results efficiently. It is shown that this approach can save a lot of calculation time and still maintain the validity in both two examples. A parametric analysis including number of POD modes and number of Ritz vectors adopted in the analysis is also performed.
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Wu, Tzung-Shu, and 吳宗書. "Time Series Simulation of Wind Loads on Long-Span Bridges." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/25613865153651672350.
Full textAbstract:
碩士淡江大學
土木工程學系
88
The developments of bridge construction techniques and the improvements of high strength materials have made modern bridges designed and built towards longer spans with more slender sections. Because these types of bridges are more flexible than the other types of bridges, they are very sensitive to wind loading. This paper is made use of time domain analysis. Therefore, it is required to simulate a continuous time series of gusty wind with a specified power spectral density, and the next step is to compute the dynamic response and internal force of the structures with the numerical explicit integral method. In this paper, a parametric model method can be built as the technique for generating the simulated time series. First, setting the target spectrum, using the multi-dimensional AR and ARMA model, and the simulation accuracy of a generated time series must be tested by a comparison with a target spectrum. Flutter and buffeting of long-span bridges subjected to wind loading are considered in this paper. Flutter force is mainly induced to self-excited force, and critical velocity and flutter frequency of bridges are calculated. In low wind speed, buffeting force is mainly induced to the excited force of turbulence, and the dynamic displacement response of bridges is calculated. Buffeting force and self-excited force are looked upon as the external forces in the dynamic analysis. The method of time series model has been used as a simulated technique for buffeting force. In this paper, two examples of cable-stayed bridge model are analyzed with Finite Element Method. First, establishing time series model of spectra of velocity fluctuations, and investigating discrepancies between time and frequency domain calculations in the same conditions. The critical velocity calculated from both frequency and time domains also match well, the difference is only 2%. The dynamic displacement response calculated from those domains agree well and the difference is lower than 8%.