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Bolduc, Maxime. "Acquiring statistical energy analysis damping loss factor for complex structures with low to high damping characteristics." Thèse, [S.l. : s.n.], 2007. http://savoirs.usherbrooke.ca/handle/11143/1801.
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Beshara, Maha. "Energy flows in structures with compliant nonconservative couplings." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360211.
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Keane, A. J. "Statistical energy analysis of engineering structures." Thesis, Brunel University, 1988. http://bura.brunel.ac.uk/handle/2438/5204.
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This thesis examines the fundamental equations of the branch of linear oscillatory dynamics known as Statistical Energy Analysis (SEA). The investigation described is limited to the study of two, point coupled multi-modal sub-systems which form the basis for most of the accepted theory in this field. Particular attention is paid to the development of exact classical solutions against which simplified approaches can be compared. These comparisons reveal deficiencies in the usual formulations of SEA in three areas, viz., for heavy damping, strong coupling between sub-systems and for systems with non-uniform natural frequency distributions. These areas are studied using axially vibrating rod models which clarify much of the analysis without significant loss of generality. The principal example studied is based on part of the structure of a modem warship. It illustrates the simplifications inherent in the models adopted here but also reveals the improvements that can be made over traditional SEA techniques. The problem of heavy damping is partially overcome by adopting revised equations for the various loss factors used in SEA. These are shown to be valid provided that the damping remains proportional so that inter-modal coupling is not induced by the damping mechanism. Strong coupling is catered for by the use of a correction factor based on the limiting case of infinite coupling strength, for which classical solutions may be obtained. This correction factor is used in conjunction with a new, theoretically based measure of the transition between weakly and strongly coupled behaviour. Finally, to explore the effects of non-uniform natural frequency distributions, systems with geometrically periodic and near-periodic parameters are studied. This important class of structures are common in engineering design and do not posses the uniform modal statistics commonly assumed in SEA. The theory of periodic structures is used in this area to derive more sophisticated statistical models that overcome some of these limitations.
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Libardi, Ana Lúcia. "Vibração em estruturas acopladas sujeitas a excitações em altas freqüencias." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-12022016-141655/.
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Este trabalho baseia-se no estudo e aplicação da Análise Estatística de Energia (SEA). Tal técnica é amplamente empregada nos estudos de vibrações em altas freqüências, dominadas por altas densidades modais e oferecendo toda a solução para o modelo em termos de parâmetros estatísticos. Aplica-se SEA tanto a modelos teóricos e numéricos quanto a modelos experimentais. Qualquer uma das duas abordagens descrita anteriormente tem como objetivo a obtenção dos parâmetros SEA, conhecidos por fator de perda por dissipação interna, fator de perda por acoplamento e densidade modal. Para o estudo e aplicação experimental da técnica SEA utiliza-se o Método de Injeção de Potência, sendo este aplicado a estruturas acopladas do tipo viga, numa configuração em T e estruturas acopladas do tipo placa que formam uma caixa. O estudo numérico e analítico também faz parte deste trabalho, tendo como base o desenvolvimento de uma formulação para vigas relativamente espessas, mostrando a influência geométrica na transmissão da vibração entre subsistemas. Comparações também são feitas entre os resultados obtidos experimentalmente na caixa e na viga T com os obtidos analiticamente e computacionalmente e em ambos os casos estes apresentaram uma boa correlação. Por fim, uma estrutura composta por uma cavidade acústica é estudada e um aparato o para injeção de potência é construído com base no estudo em altas freqüências.<br>This work is based in the study and application of the Statistical Energy Analysis (SEA), which is applied to high frequencies vibrations characterized by high modal densities and the solution, is given in statistical terms. This analysis is used in numerical, analytical and experimental models and the principal objective is the estimative of the SEA parameters, known by damping loss factors, coupling loss factors and modal densities. The experimental model is based on the Power Injection Method (PIM), and this was applied in coupled structures, like beam type, that was coupled in a T-beam configuration and the other type of coupling was studied in a box type structure. An analytical model was developed in this thesis, it was based on the Timoshenko beam formulation and the possible geometrical effects were studied. The results obtained as experimentally as numerically or analytically were compared and showed a good agreement. Finally, an acoustic cavity was studied and a new display was constructed to inject power in the cavity and a high frequency study was performed.
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Chohan, Ghulam Yasin. "Statistical energy analysis of nonconservative dynamical systems." Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239507.
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Shorter, Philip. "Combining finite elements and statistical energy analysis /." Online version, 1998. http://bibpurl.oclc.org/web/23511.
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Erskine, Jon S. "Effects of welding on energy dissipation in a watertight bulkhead." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FErskine.pdf.
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Ezanno, Philippe. "Vibration localization and statistical energy analysis in coupled systems." Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-06112009-063056/.
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Connelly, Terence. "Structural vibration transmission in ships using statistical energy analysis." Thesis, Heriot-Watt University, 1999. http://hdl.handle.net/10399/1234.
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This thesis presents the results of an investigation into the application of statistical energy analysis (SEA) to predict structure-borne noise transmission in ship structures. The first three chapters introduce the problems of noise and vibration in ships; the previous research on the application of SEA to ships; the basic theory of SEA and the experimental measurement techniques and procedures used to gather data The main body of this thesis presents a wave transmission model for the hull frame joint which is commonly encountered on the hull, bulkheads and deck plates of ship structures. The wave model allows the transmission coefficients to be calculated for hull frame joints which can be used in the coupling loss factor equations of SEA models. The joint model has been verified against measured data taken on a simple two subsystem single joint laboratory structures and a large complex 38 plate test structure with multiple joints intended to represent a 1/10' scale model of a hull section. In addition to the laboratory structures, the SEA modelling of sections of a ship is presented for a large ribbed deck plate, a section of the ship superstructure and a section of the ships hull. The results from the SEA models are compared with measured attenuation data taken on the respective ship sections. A large amount of damping data has been gathered on the test and ship structures and an equation for the internal steel based on data gathered by other researchers has been verified. It has been shown in this thesis that SEA can be applied to ships. Better agreement is found with real structures in contrast to the poor results presented for SEA when applied to simple one dimensional structures. The level of detail of the model is important as a coarse model yields better predictions of vibration level. As with all models the results are sensitive to the damping level and it is necessary to include bending, longitudinal and transverse wave types in any SEA model to obtain the best prediction. It was also found that the flange plates can be neglected from the frame joint model without compromising the accuracy.
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Bashir, Hussam. "Calculation of Wave Propagation for Statistical Energy Analysis Models." Thesis, Uppsala universitet, Tillämpad mekanik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-267928.
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This thesis investigates the problems of applying Statistical Energy Analysis (SEA) tomodels that include solid volumes. Three wave types (Rayleigh waves, Pressure wavesand Shear waves) are important to SEA and the mathematics behind them is explainedhere. The transmission coefficients between the wave types are needed for energytransfer in SEA analysis and different approaches to solving the properties of wavepropagation on a solid volume are discussed. For one of the propagation problems, asolution, found in Momoi [6] is discussed, while the other problem remains unsolveddue to the analytical difficulties involved.
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Skittides, Christina. "Statistical modelling of wind energy using Principal Component Analysis." Thesis, Heriot-Watt University, 2015. http://hdl.handle.net/10399/2930.
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The statistical method of Principal Component Analysis (PCA) is developed here from a time-series analysis method used in nonlinear dynamical systems to a forecasting tool and a Measure-Correlate-Predict (MCP) and then applied to wind speed data from a set of Met. Office stations from Scotland. PCA for time-series analysis is a method to separate coherent information from noise of measurements arising from some underlying dynamics and can then be used to describe the underlying dynamics. In the first step, this thesis shows that wind speed measurements from one or more weather stations can be interpreted as measurements originating from some coherent underlying dynamics, amenable to PCA time series analysis. In a second step, the PCA method was used to capture the underlying time-invariant short-term dynamics from an anemometer. These were then used to predict or forecast the wind speeds from some hours ahead to a day ahead. Benchmarking the PCA prediction against persistence, it could be shown that PCA outperforms persistence consistently for forecasting horizons longer than around 8 hours ahead. In the third stage, the PCA method was extended to the MCP problem (PCA-MCP) by which a short set of concurrent data from two sites is used to build a transfer function for the wind speed and direction from one (reference) site to the other (target) site, and then apply that transfer function for a longer period of data from the reference site to predict the expected wind speed and direction at the target site. Different to currently used MCP methods which treat the target site wind speed as the independent variable and the reference site wind speed as the dependent variable, the PCA-MCP does not impose that link but treats the two sites as joint observables from the same underlying coherent dynamics plus some independent variability for each site. PCA then extracts the joint coherent dynamics. A key development step was then to extend the identification of the joint dynamics description into a transfer function in which the expected values at the target site could be inferred from the available measurements at the reference site using the joint dynamics. This extended PCA-MCP was applied to a set of Met. Office data from Scotland and benchmarked a standard linear regression MCP method. For the majority of cases, the error of the resource prediction in terms of wind speed and wind direction distributions at the target site was found to be between 10% and 50% of that made using the standard linear regression. The target mean absolute error was also found to be only the 29% of the linear regression one.
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Mangisa, Siphumlile. "Statistical analysis of electricity demand profiles." Thesis, Nelson Mandela Metropolitan University, 2013. http://hdl.handle.net/10948/d1011548.
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An electricity demand profile is a graph showing the amount of electricity used by customers over a unit of time. It shows the variation in electricity demand versus time. In the demand profiles, the shape of the graph is of utmost importance. The variations in demand profiles are caused by many factors, such as economic and en- vironmental factors. These variations may also be due to changes in the electricity use behaviours of electricity users. This study seeks to model daily profiles of energy demand in South Africa with a model which is a composition of two de Moivre type models. The model has seven parameters, each with a natural interpretation (one parameter representing minimum demand in a day, two parameters representing the time of morning and afternoon peaks, two parameters representing the shape of each peak, and two parameters representing the total energy per peak). With the help of this model, we trace change in the demand profile over a number of years. The proposed model will be helpful for short to long term electricity demand forecasting.
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Straka, Martin. "Výpočtové modelování vysokofrekvenčního hluku v kabině letounu EV-55M." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230560.
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This thesis describes methods of high frequency noise and vibrations computation of cabin part of EV–55M (aircraft developed by Evektor Kunovice). There is a brief summary of methods used for determining high frequency noise and vibrations in the first part of the thesis. Detailed explanation is given for Statistical Energy Analysis (SEA) which is nowadays the most dominant method in this area. The energy balance equation is derived in this chapter and SEA parameters such as modal density, damping loss factor, coupling loss factor and power input are introduced here. Next part deals with main noise sources of propeller driven and jet aircraft and passive and active noise controls are discussed. Practical part of this thesis deals with modeling aircraft EV–55M fuselage using VA One SEA module. Two models were created. First of them is only an outside fuselage with aircraft flooring and the second one is extended by interior trim panels and is applicable for simulation of noise control treatments. Computational modeling is accompanied by experimental measurement of passive noise control material characteristics. Postprocessing of information obtained from impedance tube measurement was performed in FOAM – X. Determined characteristics of porous material were used as inputs to VA One and reduction of sound pressure level in fuselage cavities by using noise control treatment was found. In conclusion there is a summary of noise transmission paths from sources to interior cavity and some treatments of them are simulated
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Steel, J. A. "Structural vibration transmission in framed buildings using statistical energy analysis." Thesis, Heriot-Watt University, 1990. http://hdl.handle.net/10399/889.
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Platten, Michael Francis. "Sound and vibration transmission in aircraft using statistical energy analysis." Thesis, Heriot-Watt University, 1998. http://hdl.handle.net/10399/625.
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Fraser, Grant. "Structure borne sound in motor-vehicles using statistical energy analysis." Thesis, Heriot-Watt University, 1998. http://hdl.handle.net/10399/1285.
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This Thesis is about the application of Statistical Energy Analysis (SEA) to the study of noise and vibration in motor vehicles. Methods for predicting the transmission of structural waves between body panels in motor cars are given. A complex joint technique based on the wave dynamic stiffness approach is discussed in detail. This technique can account for the complexities of the joint structures found in motor vehicles. Transmission of vibration energy between panels connected by a curved section of panel has been investigated using the complex joint modelling technique. Wave Intensity Analysis(WIA) and SEA were used to calculate the coupled panel vibration levels based on transmission coefficients calculated using the complex joint techniques. Energy Level Differences (ELDs) were measured for comparison with predicted results using laboratory models. SEA failed to accurately predict the ELDs except at low frequencies. However WIA was able to predicted the ELDs with reasonable accuracy using an existing expression for transmission at a panel corner joint. Two SEA models of a small passenger car have also been constructed. One assumes simpler joint configurations when calculating transmission coefficients and the other uses the complex joint technique. Panel ELDs were measured using a small passenger car. The SEA model using the complex joint method gives better agreement with measured ELDs than did the model using the simpler joints. saloon Sound Pressure Level (SPL) as a result of engine noise was measured. Both SEA models of the vehicle gave good agreement between measured and predicted Saloon SPL. A noise problem associated with exhaust misalignment is also investigated.
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Mohammed, Adnan Dawood. "A study of uncertainty in applications of statistical energy analysis." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292436.
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Yap, Fook Fah. "Statistical Energy Analysis of structural vibration : analytical and computational investigations." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308199.
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Whitehead, Andile. "Statistical-thermodynamical analysis, using Tsallis statistics, in high energy physics." Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/13391.
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Includes bibliographical references.<br>Obtained via the maximisation of a modified entropy, the Tsallis distribution has been used to fit the transverse momentum distributions of identified particles from several high energy experiments. We propose a form of the distribution described in Cleymans and Worku, 2012, and show it to be thermodynamically consistent. Transverse momenta distributions and fits from ALICE, ATLAS, and CMS using both Tsallis and Boltzmann distributions are presented.
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Suzuki, Yohichi. "Free energy landscape of dipolar system : statistical and dynamical analysis." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/136910.
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Lafont, Thibault. "Statistical vibroacoustics : study of SEA assumptions." Thesis, Ecully, Ecole centrale de Lyon, 2015. http://www.theses.fr/2015ECDL0003/document.
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La méthode SEA (Statistical Energy Analysis) est une approche statistique de la vibroacoustique permettant de décrire les systèmes complexes en termes d'échanges d'énergies vibratoires et acoustiques. En moyennes et hautes fréquences, cette méthode se présente comme une alternative aux méthodes déterministes (coût des calculs dû au grand nombre de modes, de degrés de liberté, unicité de la solution) Néanmoins, son utilisation requiert la connaissance et le respect d'hypothèses fortes qui limitent son domaine d'application. Dans ce mémoire, les fondements de la SEA ont été examinés afin de discuter chaque hypothèse. Le champ diffus, l'équipartition de l’énergie modale, le couplage faible, l'influence des modes non résonants et l'excitation rain-on-the-roof sont les cinq hypothèses qui ont été abordées. Sur la base d'exemples simples (oscillateurs couplés, plaques couplées), les équivalences et leurs influences sur la qualité des résultats ont été étudiées pour contribuer à la clarification des hypothèses nécessaires à l'application de la SEA ct pour borner son domaine de validité SEA<br>Statistical energy analysis is a statistical approach of vibroacoustics which allows to describe complex systems in terms of vibrational or acoustical energies. ln the high frequency range, this method constitutes an alternative to bypass the problems which can occur when applying deterministic methods (computation cost due to the large number of modes, the large number of degrees of freedom and the unicity of the solution). But SEA has numerous assumptions which are sometimes forgotten or misunderstood ln this thesis, foundations of SEA have been examined in order to discuss each assumption. Diffuse field, modal energy equipartition, weak coupling, the influence of non-resonant modes and the rain on the roof excitation are the five look up hypotheses. Based on simple examples (coupled oscillators, coupled plates), the possible equivalences and their influence on the quality of the results have been discussed to contribute to the clarification of the useful SEA assumptions and to mark out it's the validity domain
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Nanopoulos, Andrew. "Valuation of wind energy projects and statistical analysis of wind power." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/74932.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 221-225).<br>As energy becomes an increasingly important issue for generations to come, it is crucial to develop tools for valuing and understanding energy projects from an economic perspective since ultimately only economically viable solutions will be pushed forward. A model is developed for valuing a generic offshore floating wind farm from a corporate finance perspective. The model is used to value the project based on multiple valuation metrics and to generate sensitivity analyses on multiple important technical, cost and financial parameters. It is found that offshore wind projects can be economically viable under current conditions contingent on high annual mean wind speed and government support. In addition, it is also found that financial parameters prove to be equally or even more important than technical parameters in affecting the overall project value. Furthermore, the wind speed and power output are modeled using a mean reverting Ornstein - Uhlenbeck process whereby it is found that while wind speed is positively autocorrelated, the averaging period plays an important role in determining the nature and extent of the autocorrelation. Finally, the valuation is extended and generalized to a Black-Scholes option based valuation of any project whose underlying asset follows a mean reverting process, whereby a model is developed to find the debt and equity values under the assumption of time independence. The tools developed for this purpose can prove to be useful in other applications besides energy, such as shipping and commodities, as the underlying characteristics of energy projects are often similar across other markets.<br>by Andrew Nanopoulos.<br>S.M.
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Robinson, Matthew. "Prediction of sound and vibration response using transient statistical energy analysis." Thesis, University of Liverpool, 2012. http://livrepository.liverpool.ac.uk/5493/.
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Transient sounds generated from structure-borne and airborne excitation are very common in buildings and cause the majority of disturbances in dwellings. The maximum sound pressure level corresponds well with annoyance and disturbance and current guidelines use this descriptor to describe the threshold for sleep disturbance. Hence this thesis addresses a need for methods to quantify transient sound sources and prediction models that can determine maximum sound pressure levels due to these sound sources. Statistical Energy Analysis (SEA) provides a framework that describes sound radiation and structure-borne sound transmission in buildings. SEA is used in this thesis as a basis on which to develop Transient Statistical Energy Analysis (TSEA) for building acoustics. The TSEA power balance describes energy exchange between subsystems in the time domain and is controlled by the time interval. Limits for the time interval are proposed based upon energy decay and path statistics of the source subsystem. New methods are proposed for measuring and quantifying the transient power input from airborne and structure-borne excitation. Detailed analysis is also used to quantify the signal processing errors, due the time-weighted level detector and filters, associated with the measurement of maximum levels. The use of steady-state SEA coupling loss factors in TSEA for sound radiation and structure-borne sound transmission is validated through good agreement in comparisons of measurements and predictions of maximum sound and vibration levels. This validation is extended to complex transient sources that have been incorporated into TSEA, such as the ISO rubber ball, transients overlaying stationary noise and airborne transients. Case studies of heavyweight buildings show that accurate predictions of maximum sound pressure and vibration levels are given if Ns ≥ 1 and Mav ≥ 0.5. TSEA has also been validated for the prediction of structural decay curves, numerical experiments have been carried out to quantify the error in the estimation of the total loss factor and to develop an improvement to the evaluation of decay curves.
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Buchanan, William. "Statistical Analysis of Wind Data and Modeling Regulating Reserves." ScholarWorks @ UVM, 2012. http://scholarworks.uvm.edu/graddis/33.
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The desire to reduce dependence on fossil fuels is resulting in numerous policy incentives for increased renewable energy sources within the power grid. Because wind generation is arguably the most affordable per MWh of the renewable energy sources it is growing nearly as quickly as conventional generation techniques. Due to this significant increase in wind penetration levels, numerous largescale wind integration studies have been produced to determine the reliability impacts of large-scale wind power. Using data from two large US wind interconnection studies, this thesis provides evidence that mesoscale meteorological models under-predict the variability in wind data particularly on short time scales, indicating that data from mesoscale meteorological models need to be used with caution for some types of analyses. These types of analyses include most notably regulating reserves, which are used to rebalance supply and demand on a second-by-second bias. This thesis will also describe and evaluate a new method for jointly quantifying the amount of spinning and regulating reserves required to meet reliability requirements within a balancing area with significant amounts of wind power using high resolution wind data. The method is based on jointly minimizing dispatch costs and reserve allocations, across two time scales (seconds to minutes, and minutes to hours) to satisfy North American Electric Reliability Corporation (NERC) Area Control Error (ACE) requirements.
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Vijayaraghavan, Rajesh. "Statistical estimation of strain energy release rate of delaminated composites." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4965.
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Thesis (M.S.)--West Virginia University, 2006.<br>Title from document title page. Document formatted into pages; contains xv, 133 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 126-133).
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Yayladere, Cavcar Bahar. "Prediction Of Noise Transmission In A Submerged Structure By Statistical Energy Analysis." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615067/index.pdf.
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The aim of this study is to develop a sound transmission model that can be used to predict the vibration and noise levels of a submerged vessel. The noise transmitted from the mechanical vibrations of the hull of a submarine and the turbulent boundary layer excitation on the submarine are investigated. A simplified physical model of the submarine hull including the effects of bulkheads, end enclosures, ring stiffeners and fluid loading due to the interaction of the surrounding medium is presented in the study. An energy approach, i.e., Statistical Energy Analysis (SEA) is used for the analysis because the characterization of the hull of the structure can be done by a very large number of modes over the frequency range of interest and the deterministic analysis methods such as finite element and boundary element methods are limited to low frequency problems. The application consists of the determination of SEA subsystems and the parameters and the utilization of power balance equations to estimate the energy ratio levels of each subsystem to the directly excited subsystem. Through the implementation of SEA method, the sound pressure levels of the hull of the structure are obtained. In terms of military purposes, the sound levels of the submarine compartments are vital in the aspects of the preserving of submarine stealth.
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Smith, Jeremy Richard Denham. "Statistical energy analysis of marine structures with periodic and near-periodic components." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287051.
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Lopez, Rémy. "Adaptation des méthodes “statistical energy analysis” (sea) aux problèmes d'électromagnétisme en cavités." Toulouse 3, 2006. http://www.theses.fr/2006TOU30045.
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Modéliser des phénomènes électromagnétiques par des méthodes déterministes requiert une division du volume étudié en éléments discrets dont la taille est de l'ordre du dixième de la longueur d'onde. La demande en ressource informatique augmente donc avec la fréquence. De plus, compte tenu de la complexité des problèmes et des incertitudes sur les données d'entrées, il devient illusoire de réaliser un calcul déterministe pour chaque variable analysée. De nouvelles méthodes, dites énergétiques, sont développées pour étudier les systèmes grands devant la longueur d'onde. Elles permettent d'estimer statistiquement la valeur du champ à l'intérieur d'un système. Une de ces techniques, la Statistical Energy Analysis (SEA), développée en acoustique, est transposée ici en électromagnétisme. La SEA permet de décrire les échanges d'énergies entre les différents systèmes composant une structure. L'énergie de chaque système dépend des notions de mode de résonance, de perte et de couplage. Les paramètres liés à ces notions sont évalués analytiquement et numériquement. Une méthode de sous structuration automatique est également présentée Les résultats obtenus semblent confirmer l'intérêt de cette méthode<br>Modeling electromagnetic phenomena by deterministic methods requires a subdivision of the volume under study into a number of discrete elements with sizes of the order of tenth of the wavelength. So, the demand for computer resources significantly grows with increasing frequencies. Moreover, taking into account the complexity of the problems and the uncertainties on the input data, it becomes illusory to make a deterministic calculation for each studied variable. New methods, called energetic methods, were developed to study systems large in front of the wavelength. They allow to estimate statistically the value of the field inside a system One of these methods, the Statistical Energy Analysis (SEA), developed in acoustic, is transposed here in electromagnetism. The SEA allows to describe the exchanges of energy between the different systems of a structure. The energy of each system depends on the concepts of mode of resonance, loss and coupling. The parameters linked with these concepts are assessed by analytical formulae and numerical simulations. An automatic sub structuring method is also presented. The results obtained seem to confirm the interest of this method
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Hung, Aaron. "ENERGY EFFICIENCY AND STATISTICAL ANALYSIS OF BUILDINGS AT CASE WESTERN RESERVE UNIVERSITY." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1446477944.
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Yilmazel, Canan. "Analysis Of High Frequency Behavior Of Plate And Beam Structures By Statistical Energy Analysis Method." Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605133/index.pdf.
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Statistical Energy Analysis (SEA) is one of the methods in literature to estimate high frequency vibrations. The inputs required for the SEA power balance equations are damping and coupling loss factors, input powers to the subsystems. In this study, the coupling loss factors are derived for two and three plates joined with a stiffener system. Simple formulas given in the literature for coupling loss factors of basic junctions are not used and the factors are calculated from the expressions derived in this study. The stiffener is modelled as line mass, Euler beam, and open section channel having double and triple coupling. Plate is modelled as Kirchoff plate. In the classical SEA approach the joint beam is modelled as another subsystem. In this study, the beam is not a separate subsystem but is used as the characteristics of the joint and to calculate the coupling loss factor between coupled plates. Sensitivity of coupling loss factors to system parameters is studied for different beam approaches.
The derived coupling loss factors and input powers are used to calculate the subsystem energies by SEA. The last plate is joined to the first one to simulate the fuselage structure. A plate representing floor structure and acoustic volume are also added. The different modelling types are assessed by applying pressure wave excitation. It is shown that deriving the parameters as given in this study increases the efficiency of the SEA method.
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Park, Woo Sun. "The sources of variability in the statistical energy analysis of two rectangular plates." Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271652.
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Li, Wei. "Numerical Modelling and Statistical Analysis of Ocean Wave Energy Converters and Wave Climates." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-305870.
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Ocean wave energy is considered to be one of the important potential renewable energy resources for sustainable development. Various wave energy converter technologies have been proposed to harvest the energy from ocean waves. This thesis is based on the linear generator wave energy converter developed at Uppsala University. The research in this thesis focuses on the foundation optimization and the power absorption optimization of the wave energy converters and on the wave climate modelling at the Lysekil wave converter test site. The foundation optimization study of the gravity-based foundation of the linear wave energy converter is based on statistical analysis of wave climate data measured at the Lysekil test site. The 25 years return extreme significant wave height and its associated mean zero-crossing period are chosen as the maximum wave for the maximum heave and surge forces evaluation. The power absorption optimization study on the linear generator wave energy converter is based on the wave climate at the Lysekil test site. A frequency-domain simplified numerical model is used with the power take-off damping coefficient chosen as the control parameter for optimizing the power absorption. The results show a large improvement with an optimized power take-off damping coefficient adjusted to the characteristics of the wave climate at the test site. The wave climate modelling studies are based on the wave climate data measured at the Lysekil test site. A new mixed distribution method is proposed for modelling the significant wave height. This method gives impressive goodness of fit with the measured wave data. A copula method is applied to the bivariate joint distribution of the significant wave height and the wave period. The results show an excellent goodness of fit for the Gumbel model. The general applicability of the proposed mixed-distribution method and the copula method are illustrated with wave climate data from four other sites. The results confirm the good performance of the mixed-distribution and the Gumbel copula model for the modelling of significant wave height and bivariate wave climate.
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Ghinet, Sebastian. "Statistical energy analysis of the transmission loss of sandwich and laminate composite structures." Thèse, Université de Sherbrooke, 2005. http://savoirs.usherbrooke.ca/handle/11143/1770.
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The present study emerges from a present industry need for accurate and fast numerical modeling approaches to estimate the vibro-acoustic behaviours of multilayered composite and viscoelastic treatments configurations.The structure is modeled using a wave approach applied to various multilayer configurations such as: symmetrical laminate composite, symmetrical sandwich composite and general symmetrical or unsymmetrical laminate or sandwich composite as well as viscoelastic treatments. Three behavioural modeling approaches are investigated: smeared laminate, discrete layer sandwich and general discrete layer laminate. Smeared laminate approach is devoted to symmetrical laminate composite panels and uses equivalent elastic properties computed by smearing out the layers' properties through the panel's thickness. Discrete layer sandwich approach is devoted to symmetrical sandwich composite panels and uses individual displacement fields for each layer. Classical assumptions of thick skins sandwich panels are adopted. General discrete laminate approach accommodates both laminate and sandwich composite panels of symmetrical or unsymmetrical layout. Individual displacement fields are used for each layer. These three behavioural modeling approaches are applied in the present work to flat and curved panel configurations as well as laminated beams. Dispersion relations are developed for each configuration and solved in a generalized polynomial eigenvalue problem context. These solutions are used in a SEA framework to compute the group velocity, the modal density, the radiation efficiency as well as the resonant and non-resonant contributions to the transmission coefficient. Moreover, the dispersion relations are used to develop general expressions to compute the ring frequency and the critical frequencies. In the context of viscoelastic treatments modeling the mechanical impedance, the input mobility, the deformation energy as well as the equivalent loss factor are computed for several boundary conditions.The presented approaches are successfully validated with experimental results and previously published theories. In addition to their proven accuracy, the proposed approaches are quick and general.
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Kiremitci, Utku. "Interior And Exterior Noise Analysis Of A Single Engine Propeller Aircraft Using Statistical Energy Analysis Method." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610558/index.pdf.
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Two different Statistical Energy Analysis (SEA) models of a single turbo-prop engine propeller aircraft have been developed to predict the interior and exterior noise levels. The commercial software VA One is used for the analysis. First model is a pure SEA model developed with ribbed plates on the aircraft exterior. Second model is a hybrid model which employs finite element (FE) modeling of aircraft components with low modal density. These models have been analyzed for three different flight conditions, namely, take-off, cruise and climb for three different damping loss factors in each condition. Wind tunnel measurements are used to estimate the turbulent boundary layer (TBL) information on the surface of the aircraft. Propeller noise together with TBL loading are then used as the excitation for the models. Flow paths of energy are identified and cabin interior noise levels are predicted for the developed models. Results of analyses are comparatively evaluated.
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Peng, Bo. "Applying the Newmark Method to the Discontinuous Deformation Analysis." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/51092.
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Discontinuous deformation analysis (DDA) is a newly developed simulation method for discontinuous systems. It was designed to simulate systems with arbitrary shaped blocks with high efficiency while providing accurate solutions for energy dissipation. But DDA usually exhibits damping effects that are inconsistent with theoretical solutions. The deep reason for these artificial damping effects has been an open question, and it is hypothesized that these damping effects could result from the time integration scheme. In this thesis two time integration methods are investigated: the forward Euler method and the Newmark method.
The work begins by combining the Newmark method and the DDA. An integrated Newmark method is also developed, where velocity and acceleration do not need to be updated. In simulations, two of the most widely used models are adopted to test the forward Euler method and the Newmark method. The first one is a sliding model, in which both the forward Euler method and the Newmark method give accurate solutions compared with analytical results. The second model is an impacting model, in which the Newmark method has much better accuracy than the forward Euler method, and there are minimal damping effects.<br>Master of Science
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Spyrou, Maria S. "Multi-scale analysis of the energy performance of supermarkets." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/19598.
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The retail sector accounts for more than 3% of the total electricity consumption in the UK and approximately 1% of total UK CO2 emissions. The overarching aim of this project was to understand the energy consumption of the Tesco estate (the market leader), identify best practice, and find ways to identify opportunities for energy reduction. The literature review of this work covered the topic of energy consumption in the retail sector, and reviewed benchmarks for this type of buildings from the UK, Europe and the US. Related data analysis techniques used in the industry or presented in the literature were also reviewed. This revealed that there are many different analysis and forecasting techniques available, and that they fall into two different categories: techniques that require past energy consumption data in order to calculate the future consumption, such as statistical regression, and techniques that are able to estimate the energy consumption of buildings, based on the specific building's characteristics, such as thermal simulation models. These are usually used for new buildings, but they could also be used in benchmarking exercises, in order to achieve best practice guides. Gaps in the industry knowledge were identified, and it was suggested that better analytical tools would enable the industry to create more accurate energy budgets for the year ahead leading to better operating margins. Benchmarks for the organisation's buildings were calculated. Retail buildings in the Tesco estate were found to have electrical intensity values between 230 kWh/m2 and 2000 kWh/m2 per year. Still the average electrical intensity of these buildings in 2010-11 was found to be less than the calculated UK average of the 2006-07 period. The effect of weather on gas and electricity consumption was investigated, and was found to be significant (p < 0.001). There was an effect related to the day-of-the-week, but this was found to be more related to the sales volume on those days. Sales volume was a proxy that was used to represent the number of customers walking through the stores. The built date of the building was also considered to be an interesting factor, as the building regulations changed significantly throughout the years and the sponsor did not usually carry out any fabric work when refurbishing the stores. User behaviour was also identified as an important factor that needed to be investigated further, relating to both how the staff perceives and manages the energy consumption in their work environment, as well as how the customers use the refrigeration equipment. Following a statistical analysis, significant factors were determined and used to create multiple linear regression models for electricity and gas demands in hypermarkets. Significant factors included the sales floor area of the store, the stock composition, and a factor representing the thermo-physical characteristics of the envelope. Two of the key findings are the statistical significance of operational usage factors, represented by volume of sales, on annual electricity demand and the absence of any statistically significant operational or weather related factors on annual gas demand. The results suggest that by knowing as little as four characteristics of a food retail store (size of sales area, sales volume, product mix, year of construction) one can confidently calculate its annual electricity demands (R2=0.75, p < 0.001). Similarly by knowing the size of the sales area, product mix, ceiling height and number of floors, one can calculate the annual gas demands (R2=0.5, p < 0.001). Using the models created, along with the actual energy consumption of stores, stores that are not as energy efficient as expected can be isolated and investigated further in order to understand the reason for poor energy performance. Refrigeration data from 10 stores were investigated, including data such as the electricity consumption of the pack, outside air temperature, discharge and suction pressure, as well as percentage of refrigerant gas in the receiver. Data mining methods (regression and Fourier transforms) were employed to remove known operational patterns (e.g. defrost cycles) and seasonal variations. Events that have had an effect on the electricity consumption of the system were highlighted and faults that had been identified by the existing methodology were filtered out. The resulting dataset was then analysed further to understand the events that increase the electricity demand of the systems in order to create an automatic identification method. The cases analysed demonstrated that the method presented could form part of a more advanced automatic fault detection solution; potential faults were difficult to identify in the original electricity dataset. However, treating the data with the method designed as part of this work has made it simpler to identify potential faults, and isolate probable causes. It was also shown that by monitoring the suction pressure of the packs, alongside the compressor run-times, one could identify further opportunities for electricity consumption reduction.
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May, James E. "Non-Linear Control of Long, Flexible Structures Employing Inter-Modal Energy Transfer [Modal Damping]." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1247711518.
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Sandberg, Erik. "Energy and scrap optimisation of electric arc furnaces by statistical analysis of process data." Licentiate thesis, Luleå, 2005. http://epubl.luth.se/1402-1757/2005/21.
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Lednik, Dusan. "The application of Transient Statistical Energy Analysis and wave propagation approach to coupled structures." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239300.
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James, Philippe Pierre. "A technique for the assessment of strength of coupling between statistical energy analysis subsystems." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245304.
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Nyman, Timmy. "Experimental Investigation of Added Mass and Damping on a Model Kaplan Turbine for Rotor Dynamic Analysis." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-67573.
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The concept of added hydrodynamic properties such as added mass is of importance in modern hydropower development, mainly for rotor dynamic calculations. Added mass could result in reduced natural frequencies and altered mode compared to existing simulation models. It is of importance to quantify added mass but also added damping to make the simulation models more accurate. Experiments are conducted on a model Kaplan turbine, D = 0,5 m, and a steel cube, S = 0,2 m, for linear vibrations in still water confined in a cylindrical tank. The experiments are conducted in air and water for evaluation of added forces. The vibrations are generated with an electrodynamic vibration exciter with a frequency range of approximately 1-10 Hz with amplitudes 0,5-3 mm. The experiments were repeated to check test rig reliability. Each individual working point [frequency, amplitude] were in total tested 40 times in 15 s intervals. The added mass was found to be function of acceleration for the model Kaplan with an increase in added mass from 10 % at 4 m/s2 to 35 % at 0,5 m/s2. The damping forces was at best measured at ±30 %, making added damping calculations unreliable. The cube experiments resulted in small differences between water and air. Cube results must be interpreted with caution due to test rig uncertainties.
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Kurtoglu, Ilker. "Acoustically Induced Stress Analysis Of Center Fuselage Skin Panels Of A Basic Training Aircraft Using Statistical Energy Analysis." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610698/index.pdf.
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Two sample statistical energy analysis (SEA) models are generated for a section of the fuselage panel of an aircraft, namely the uniform panel model which includes the frames and stringers, and the ribbed panel model in which the frames and stringers are smeared into the skin. Turbulent boundary layer (TBL) excitation is used as the primary acoustic excitation source. Stress levels are estimated from the average velocity data of the panels. The stress results are found comply with those obtained by the AGARD method. Effect of radiation from panels to exterior and interior of the sample skin panel as well as the pressurization of the skin panels are investigated separately to analyze their effects on the stress levels. The method is then used in the analysis of center fuselage skin panels on a basic training aircraft. Two models are generated for the aircraft analysis, namely the complete aircraft model and the simplified model which excludes the wings and the empennage. In addition to TBL, propeller noise is used as the primary acoustic excitation source. The effects of the wings and the empennage on the stress levels in the center fuselage skin panels are also investigated along with the radiation from panels to the exterior and interior of the aircraft and pressurization of the pilot cabin.
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Barbagallo, Mathias. "Statistical energy analysis and variational principles for the prediction of sound transmission in multilayered structures." Doctoral thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-118427.
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Multilayered structures have many application in industry and society: they have peculiar properties and serve a variety of purposes, like structural support, thermal insulation, vibrational and acoustic isolation. This thesis concerns the prediction of sound transmission in multilayered structures. Two problems are herein investigated: the transmission of energy through structures and the transmission of energy along structures. The focus of the analysis is on the mid to high frequency range. To predict sound transmission in these structures, statistical energy analysis (SEA) is used.SEA models are devised for the prediction of the sound reduction index for two kinds of multilayered structures, double-walls used in buildings and trim-panels in vehicles; the double-walls comprise an air cavity in between flat plasterboard or glass plates, whereas the trim-panels a porous layer in between curved aluminium and rubber layers. The SEA models are based upon the wave-types carrying energy. The novelty in these SEAs is an element describing the waves in the air cavity, or in the porous layer, fully coupled to the mass-impeded external layers. Compared to measurements, the proposed SEA performs well: for double-walls, it performs better than previous models; for trim-panels, it is an original result. The parameters of the new SEA element, such as modal density, are derived from the coupling equations describing the fully coupled waves. For double-walls, these equations are derived via Newton's laws. For trim-panels, a variational approach based upon a modified Hamilton's principle valid for non-conservative systems is preferred, because it is a powerful machinery for deriving equations of motion and coupling conditions of a medium as complex as the porous layer. The modified Hamilton's principle for non-conservative systems is based upon a self-adjoint functional analogous to the Lagrangian, inspired by Morse and Feshbach's construction. A self-adjoint variational principle for Biot's equations in the displacement formulation is devised. An equivalent mixed formulation is obtained changing the coordinates of the displacement formulation via Lagrange multipliers. From this mixed formulation, the Lagrangian for a porous material with a limp frame is derived, which yields the continuity of the total displacement of the porous layer. Lagrange multipliers help to obtain the correct coupling functionals between a porous material and a solid. The Lagrange multipliers introducing the continuity of the frame and the solid displacements equal the traction of the in-vacuo frame, thus disappearing if the latter is limp. Measurements to gather material parameters for a Biot model of the porous layer have been conducted.The effects of spatial energy decay in the transmission along structures predicted by SEA is studied: a major effect is the increased relevance of indirect coupling loss factors between SEA elements. This may jeopardize the usefulness of SEA at higher frequencies.<br><p>QC 20130218</p>
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Sanjab, Anibal Jean. "Statistical Analysis of Electric Energy Markets with Large-Scale Renewable Generation Using Point Estimate Methods." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/74356.
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The restructuring of the electric energy market and the proliferation of intermittent renewable-energy based power generation have introduced serious challenges to power system operation emanating from the uncertainties introduced to the system variables (electricity prices, congestion levels etc.). In order to economically operate the system and efficiently run the energy market, a statistical analysis of the system variables under uncertainty is needed. Such statistical analysis can be performed through an estimation of the statistical moments of these variables. In this thesis, the Point Estimate Methods (PEMs) are applied to the optimal power flow (OPF) problem to estimate the statistical moments of the locational marginal prices (LMPs) and total generation cost under system uncertainty. An extensive mathematical examination and risk analysis of existing PEMs are performed and a new PEM scheme is introduced. The applied PEMs consist of two schemes introduced by H.P. Hong, namely, the 2n and 2n+1 schemes, and a proposed combination between Hong's and M. E Harr's schemes. The accuracy of the applied PEMs in estimating the statistical moments of system LMPs is illustrated and the performance of the suggested combination of Harr's and Hong's PEMs is shown. Moreover, the risks of the application of Hong's 2n scheme to the OPF problem are discussed by showing that it can potentially yield inaccurate LMP estimates or run into unfeasibility of the OPF problem. In addition, a new PEM configuration is also introduced. This configuration is derived from a PEM introduced by E. Rosenblueth. It can accommodate asymmetry and correlation of input random variables in a more computationally efficient manner than its Rosenblueth's counterpart.<br>Master of Science
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Hall, Braydon Day. "The Dynamic Analysis of a Composite Overwrapped Gun Barrel with Constrained Viscoelastic Damping Layers Using the Modal Strain Energy Method." DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/1972.
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The effects of a composite overwrapped gun barrel with viscoelastic damping layers are investigated. Interlaminar stresses and constrained layer damping effects are described. The Modal Strain Energy method is developed for measuring the extent to which the barrel is damped. The equations of motion used in the finite element analysis are derived. The transient solution process is outlined. Decisions for selected parameters are discussed. The results of the finite element analyses are presented using the program written in FORTRAN. The static solution is solved with a constant internal pressure resulting in a calculated loss factor from the Modal Strain Energy Method. The transient solution is solved using the Newmark-Beta method and a variable internal pressure. The analyses conclude that strategically placed viscoelastic layers dissipate strain energy more effectively than a thick single viscoelastic layer. The optimal angle for maximizing the coefficient of mutual influence in a composite cylinder is not necessarily the optimal angle when viscoelastic layers are introduced between layers.
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Smith, R. Sean. "Sound transmission through lightweight parallel plates." Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/1290.
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This thesis examines the transmission of sound through lightweight parallel plates, (plasterboard double wall partitions and timber floors). Statistical energy analysis was used to assess the importance of individual transmission paths and to determine the overall performance. Several different theoretical models were developed, the choice depending on the frequency range of interest and method of attachment of the plates, whether point or line, to the structural frame. It was found that for a line connected double wall there was very good agreement between the measured and predicted results, where the dominant transmission path was through the frame and the cavity path was weak. The transition frequency where the coupling changes from a line to a point connection is when the first half wavelength is able to fit between the spacings of the nails. For point connected double walls, where the transmission through the frame was weaker than for line connection, the cavity path was dominant unless there was absorption present. When the cavity was sufficiently deep, such that it behaved more like a room, the agreement between the measured and predicted results was good. As the cavity depth decreases the plates of the double wall are closer together and the agreement between the measured and predicted results were not as good. Detailed experiments were carried out to determine the transmission into the double wall cavities and isolated cavities. It was found that the transmission into an isolated cavity could be predicted well. However, for transmission into double wall cavities the existing theories could not predict transmission accurately when the cavity depth was small. Extensive parametric surveys were undertaken to analyse changes to the sound transmission through these structures when the material or design parameters are altered. The SEA models are able to identify the dominant mechanisms of transmission and will be a useful design tool in the design of lightweight partitions and timber floors.
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Treloar, Graham John, and edu au jillj@deakin edu au mikewood@deakin edu au wildol@deakin edu au kimg@deakin. "A Comprehensive Embodied Energy Analysis Framework." Deakin University. School of Architecture and Building, 1998. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20041209.161722.
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The assessment of the direct and indirect requirements for energy is known as embodied energy analysis. For buildings, the direct energy includes that used primarily on site, while the indirect energy includes primarily the energy required for the manufacture of building materials. This thesis is concerned with the completeness and reliability of embodied energy analysis methods. Previous methods tend to address either one of these issues, but not both at the same time. Industry-based methods are incomplete. National statistical methods, while comprehensive, are a black box and are subject to errors. A new hybrid embodied energy analysis method is derived to optimise the benefits of previous methods while minimising their flaws.
In industry-based studies, known as process analyses, the energy embodied in a product is traced laboriously upstream by examining the inputs to each preceding process towards raw materials. Process analyses can be significantly incomplete, due to increasing complexity. The other major embodied energy analysis method, input-output analysis, comprises the use of national statistics. While the input-output framework is comprehensive, many inherent assumptions make the results unreliable.
Hybrid analysis methods involve the combination of the two major embodied energy analysis methods discussed above, either based on process analysis or input-output analysis. The intention in both hybrid analysis methods is to reduce errors associated with the two major methods on which they are based. However, the problems inherent to each of the original methods tend to remain, to some degree, in the associated hybrid versions.
Process-based hybrid analyses tend to be incomplete, due to the exclusions associated with the process analysis framework. However, input-output-based hybrid analyses tend to be unreliable because the substitution of process analysis data into the input-output framework causes unwanted indirect effects.
A key deficiency in previous input-output-based hybrid analysis methods is that the input-output model is a black box, since important flows of goods and services with respect to the embodied energy of a sector cannot be readily identified. A new input-output-based hybrid analysis method was therefore developed, requiring the decomposition of the input-output model into mutually exclusive components (ie, direct energy paths).
A direct energy path represents a discrete energy requirement, possibly occurring one or more transactions upstream from the process under consideration. For example, the energy required directly to manufacture the steel used in the construction of a building would represent a direct energy path of one non-energy transaction in length. A direct energy path comprises a product quantity (for example, the total tonnes of cement used) and a direct energy intensity (for example, the energy required directly for cement manufacture, per tonne).
The input-output model was decomposed into direct energy paths for the residential building construction sector. It was shown that 592 direct energy paths were required to describe 90% of the overall total energy intensity for residential building construction. By extracting direct energy paths using yet smaller threshold values, they were shown to be mutually exclusive. Consequently, the modification of direct energy paths using process analysis data does not cause unwanted indirect effects.
A non-standard individual residential building was then selected to demonstrate the benefits of the new input-output-based hybrid analysis method in cases where the products of a sector may not be similar. Particular direct energy paths were modified with case specific process analysis data. Product quantities and direct energy intensities were derived and used to modify some of the direct energy paths. The intention of this demonstration was to determine whether 90% of the total embodied energy calculated for the building could comprise the process analysis data normally collected for the building. However, it was found that only 51% of the total comprised normally collected process analysis. The integration of process analysis data with 90% of the direct energy paths by value was unsuccessful because:
typically only one of the direct energy path components was modified using process analysis data (ie, either the product quantity or the direct energy intensity);
of the complexity of the paths derived for residential building construction; and
of the lack of reliable and consistent process analysis data from industry, for both product quantities and direct energy intensities.
While the input-output model used was the best available for Australia, many errors were likely to be carried through to the direct energy paths for residential building construction. Consequently, both the value and relative importance of the direct energy paths for residential building construction were generally found to be a poor model for the demonstration building. This was expected. Nevertheless, in the absence of better data from industry, the input-output data is likely to remain the most appropriate for completing the framework of embodied energy analyses of many types of productseven in non-standard cases.
Residential building construction was one of the 22 most complex Australian economic sectors (ie, comprising those requiring between 592 and 3215 direct energy paths to describe 90% of their total energy intensities). Consequently, for the other 87 non-energy sectors of the Australian economy, the input-output-based hybrid analysis method is likely to produce more reliable results than those calculated for the demonstration building using the direct energy paths for residential building construction.
For more complex sectors than residential building construction, the new input-output-based hybrid analysis method derived here allows available process analysis data to be integrated with the input-output data in a comprehensive framework. The proportion of the result comprising the more reliable process analysis data can be calculated and used as a measure of the reliability of the result for that product or part of the product being analysed (for example, a building material or component).
To ensure that future applications of the new input-output-based hybrid analysis method produce reliable results, new sources of process analysis data are required, including for such processes as services (for example, banking) and processes involving the transformation of basic materials into complex products (for example, steel and copper into an electric motor).
However, even considering the limitations of the demonstration described above, the new input-output-based hybrid analysis method developed achieved the aim of the thesis: to develop a new embodied energy analysis method that allows reliable process analysis data to be integrated into the comprehensive, yet unreliable, input-output framework.
Plain language summary
Embodied energy analysis comprises the assessment of the direct and indirect energy requirements associated with a process. For example, the construction of a building requires the manufacture of steel structural members, and thus indirectly requires the energy used directly and indirectly in their manufacture. Embodied energy is an important measure of ecological sustainability because energy is used in virtually every human activity and many of these activities are interrelated.
This thesis is concerned with the relationship between the completeness of embodied energy analysis methods and their reliability. However, previous industry-based methods, while reliable, are incomplete. Previous national statistical methods, while comprehensive, are a black box subject to errors.
A new method is derived, involving the decomposition of the comprehensive national statistical model into components that can be modified discretely using the more reliable industry data, and is demonstrated for an individual building. The demonstration failed to integrate enough industry data into the national statistical model, due to the unexpected complexity of the national statistical data and the lack of available industry data regarding energy and non-energy product requirements.
These unique findings highlight the flaws in previous methods. Reliable process analysis and input-output data are required, particularly for those processes that were unable to be examined in the demonstration of the new embodied energy analysis method. This includes the energy requirements of services sectors, such as banking, and processes involving the transformation of basic materials into complex products, such as refrigerators. The application of the new method to less complex products, such as individual building materials or components, is likely to be more successful than to the residential building demonstration.
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Olukayode, Falayi Elijah. "Statistical Analysis of Geomagnetic Storms Global Effects and Space Weather Influence on Energy and Fuel Industry." Thesis, University of Sussex, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506921.
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Kent-Dobias, Jaron P. "Energy-Driven Pattern Formation in Planar Dipole-Dipole Systems." Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/hmc_theses/66.
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A variety of two-dimensional fluid systems, known as dipole-mediated systems, exhibit a dipole-dipole interaction between their fluid constituents. The com- petition of this repulsive dipolar force with the cohesive fluid forces cause these systems to form intricate and patterned structures in their boundaries. In this thesis, we show that the microscopic details of any such system are irrelevant in the macroscopic limit and contribute only to a constant offset in the system’s energy. A numeric model is developed, and some important stable domain morphologies are characterized. Previously unresolved bifurcating branches are explored. Finally, by applying a random energy background to the numer- ics, we recover the smörgåsbord of diverse domain morphologies that are seen in experiment. We develop an empirical description of these domains and use it to demonstrate that the system's nondimensional parameter, which is the ratio of the line tension to the dipole–dipole density, can be extracted for any domain using only its shape.
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Marshall, Justin D. "Development, Analysis and Testing of a Hybrid Passive Control Device for Seismic Protection of Framed Structures." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/30152.
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A new seismic protection strategy called the hybrid passive control device (HPCD) has been developed which combines typical passive energy dissipation devices. It consists of a high damping rubber (HDR) sandwich damper in series with a buckling restrained brace (BRB). The HPCD provides energy dissipation at small deformations without significantly decreasing the structural period. The significant energy dissipation capacity of a BRB is provided for significant seismic events in the second phase. The transition between these two phases consists of an increasing stiffness as the device transitions from rubber damper to BRB. The HPCD reduces deformations, forces and accelerations from seismic events. The hyperelastic or stiffening effect also prevents resonant build-up and aids in collapse prevention due to p-delta effects.
The first phase of this work included characterization of high damping rubber compounds and analytical modeling of the HPCD concept. Experimental testing was completed to measure both the static and dynamic material properties of six different rubber compounds. The two most promising rubber compounds were selected for possible inclusion in the device. Analytical models of these selected materials were developed for nonlinear solid finite element analysis. The most promising configuration of the device was selected from several options. The selected configuration was analyzed using the commercial finite element program ABAQUS. These models were used to confirm the validity of the theoretical behavior of the device. Additionally these tests were used to determine which of the rubber compounds performed best.
Experimental testing of a half-scale HPCD specimen was carried out in the Structures and Materials Research Laboratory at Virginia Tech. The prototype was tested under cyclic and static loads. The experimental tests confirmed the potential of the hybrid device while highlighting minor issues with the design of the prototype. The final component in the research was an analytical study using hybrid devices in a 9-story steel moment frame structure. The devices were found to provide improved response over a special steel moment frame and a moment frame combined with a buckling restrained brace frame.<br>Ph. D.