Tesis sobre el tema "Experimental modal analysi"
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ZANOTTI, FRAGONARA LUCA. "Dynamic models for ancient heritage structures". Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2502121.
Texto completoPotgieter, Brendon Ryan. "Experimental modal analysis and model validation of antenna structures". Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5423.
Texto completoENGLISH ABSTRACT: Numerical design optimisation is a powerful tool that can be used by engi- neers during any stage of the design process. Structural design optimisation is a specialised usage of numerical design optimisation that has been adapted to cater speci cally for structural design problems. A speci c application of structural design optimisation that will be discussed in the following report is experimental data matching. Data obtained from tests on a physical structure will be matched with data from a numerical model of that same structure. The data of interest will be the dynamic characteristics of an antenna structure, focusing on the mode shapes and modal frequencies. The structure used was a scaled, simpli ed model of the Karoo Array Telescope-7 (KAT-7) antenna structure. Experimental data matching is traditionally a di cult and time-consuming task. This report illustrates how optimisation can assist an engineer in the process of correlating a nite element model with vibration test data.
AFRIKAANSE OPSOMMING: Numeriese ontwerp-optimisering is 'n kragtige ingenieurshulpmiddel wat ty- dens enige stadium in die ontwerpsproses ingespan kan word. Strukturele ontwerp-optimisering is 'n gespesialiseerde gebruik van numeriese ontwerp- optimisering wat aangepas is om spesi ek van diens te wees by die oplos van strukturele ontwerpsprobleme. 'n Spesi eke toepassing van strukturele ontwerp-optimisering wat in hierdie verslag bespreek sal word, is eksperi- mentele datakorrelasie. Data afkomstig van toetse op 'n siese struktuur sal gekorreleer word met data afkomstig van 'n numeriese model van die selfde struktuur. Die data van belang is die dinamiese eienskappe van 'n anten- nastruktuur, spesi ek die modusvorme en modale frekwensies. Die betrokke struktuur wat gebruik is, is 'n vereenvoudigde skaalmodel van die Karoo Array Telescope-7 (KAT-7) antennastruktuur. Eksperimentele datakorrelasie is, tradisioneel gesproke, 'n moeilike en tydro- wende taak. Hierdie verslag sal illustreer op watter wyse optimisering 'n inge- nieur van hulp kan wees in die proses om 'n eindige elementmodel met vibrasietoetsdata te korreleer.
Aluri, Srinivas. "Updating low-profile FRP deck FE model using experimental modal analysis". Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4656.
Texto completoTitle from document title page. Document formatted into pages; contains vi, 76 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 60-61).
You, You y Daxin Chen. "Modal Analysis on a MIMO System : For an asphalt roller CC1200". Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-10998.
Texto completoMejri, Seifeddine. "Identification et modélisation du comportement dynamique des robots d'usinage". Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22688/document.
Texto completoMachining robots have major advantages over cartesian machine tools because of their flexibility, their ability to reach inaccessible areas on a complex part, and their important workspace. However, their lack of rigidity and precision is still a limit for precision tasks. The stresses generated by the cutting forces and inertia are important and cause static and dynamic deformations of the structure which result in problems of workpiece surface. The aim of the thesis work is to characterize the dynamic behavior of robots during machining operation. This work followed a three-step approach : Modeling a first model considered as a reference where the robot is at rest. Then the identification of the dynamic behavior in service. Finally, the prediction of the cutting stability using the robot dynamic model. The originality of this work is the development of new operational modal identification methods. They integrate the machining conditions and result into a more accurate model than the first model of reference without being biased by harmonics. Finally, guidlines of robot’s configurations and excitation forces’ direction are proposed to ensure the robotic machining stability
Venkataraman, Siddharth. "Analytic, Simulation and Experimental Analysis of Fluid-Pipe Systems". Thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-249996.
Texto completoEn analytisk lösning för egenfrekvenser och egenmoder för en icke-viskös fluid inuti ett tunt rörsystem är först framtagen med användning av en modbaserad modell för interaktion mellan fluid och struktur som randvillkor. Idealiserad randvillkor används för att jämföra och validera analytiska resultat med simulationer i COMSOL Multiphysics. Effekten av viskositet jämförs också med hjälp av en Newtonsk fluidmodell. Experiment genomförs med simpel rörgeometri samt fluid för att mäta acceleransen som är analyserad för till att få ut mo-der i omkretsled upp till fjärde ordningen; detta i sin tur används för att jämföra och validera de experimentella resultaten med simulering-ar. Det erhålls bra korrelation mellan de analytiska-, simulerade- samt experimentella resultaten. Undantaget för n=0 grundmoder då krävs modifikation av differentialekvationerna till att inkorporera kompressibilitetseffekter
Burkett, Jason Lee. "BENCHMARK STUDIES FOR STRUCTURAL HEALTH MONITORING USING ANALYTICAL AND EXPERIMENTAL MODELS". Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2660.
Texto completoM.S.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering
笹岡, 竜., Ryu SASAOKA, 秀幸 畔上, Hideyuki AZEGAMI, 紀明 川上 y Noriaki KAWAKAMI. "脊柱力学模型による特発性側彎症の成因解明". 日本機械学会, 2003. http://hdl.handle.net/2237/12189.
Texto completoAltunel, Fatih. "Model Updating Of A Helicopter Structure Using A Newly Developed Correlation Improvement Technique". Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12611300/index.pdf.
Texto completoNastran software. v Initial updating was processed first for the whole helicopter fuselage then, tail of the helicopter was tried to be updated. Furthermore, a new method was proposed for the optimum node removal location for getting better Modal Assurance Criterion (MAC) matrix. This routine was tried on the helicopter case study and it showed better performance than the Coordinate Modal Assurance Criterion (coMAC) that is often used in such analyses.
Marudachalam, Kannan. "An attempt to quantify errors in the experimental modal analysis process". Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-08142009-040508/.
Texto completoBraunwart, Paul R. "Experimental and Analytical Examination of Golf Club Dynamics". Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/31506.
Texto completoMaster of Science
Azoury, Chadi. "Analyse dynamique d’un vilebrequin nouvel élément fini filaire". Toulouse 3, 2007. http://www.theses.fr/2007TOU30023.
Texto completoThis work of research consists of analyzing the dynamical behavior of a crankshaft in order to get a simple linear finite element that can simulate its behaviors. A finite element model using tetrahedral volumetric elements is performed. This model produces the values of modes and frequencies of vibration of the crankshaft. Then the results of the finite element model are validated using the experimental modal analysis. The objective of this thesis is to replace the volumetric meshing with a simple linear meshing. Many new beam elements are proposed and studied on a test frame structure statically and dynamically. Finally the obtained numerical results show that the linear finite element can substitute volumetric finite elements
Matsuyama, Yukihiro, Ryu Sasaoka, Hideyuki Azegami, Shunji Murachi, Junzoh Kitoh, Yoshito Ishida, Noriaki Kawakami y Mitsunori Makino. "Investigation of Buckling Phenomenon Induced by Growth of Vertebral Bodies Using a Mechanical Spine Model". 日本機械学会, 2003. http://hdl.handle.net/2237/7283.
Texto completoRossetto, Gustavo Dalben. "Contribuição a teoria e pratica da analise modal acustica experimental". [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265319.
Texto completoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-07-31T18:15:00Z (GMT). No. of bitstreams: 1 Rossetto_GustavoDalben_M.pdf: 4484828 bytes, checksum: b149e9723524115d4c39c2ea81d0c5bc (MD5) Previous issue date: 2001
Resumo: Neste trabalho uma geometria simples (cavidade retangular) é usada para o estudo da metodologia aplicada na análise modal acústica. Modelos analítico e numérico são desenvolvidos para a comparação com os resultados experimentais. Três tipos de dispositivos de excitação do sistema acústico foram construídos. Um baseado num pistão conectado a um shaker, e outros dois usando um alto-falante do tipo driver. O primeiro atuador usando o driver é similar ao modelo desenvolvido por um projeto europeu, onde um tubo flexível com uma terminação instrumentada com um microfone é usado para a condução da excitação acústica. O segundo atuador baseado no uso do driver também usa um tubo flexível, mas este é instrumentado com dois microfones em sua terminação. O comportamento destes dois últimos atuadores em termos de aceleração de volume (essencial para a análise modal acústica experimental) e de potência ativa (necessária para Análise Estatística de Energia Experimental) sendo injetados no meio são investigados. A análise modal experimental da cavidade retangular é realizada e um método que utiliza a transformada de Fourier espacial multidimensional do campo de pressão medido é proposto para-a construção do campo de deslocamento de partícula para a visualização do modo acústico
Abstract: In the present work, a simple geometry (rectangular shallow cavity) is used to investigate the acoustic modal analysis methodology. Analytical and numerical models are developed for the comparison with the experimental results. Three types of excitation devices were constructed. One based on a shaker-driven piston and the other two using a driver loudspeaker. The first actuator based on a driver loudspeaker is similar to a model developed by an EEC project, where a flexible tube with a socket, instrumented with one microphone, at its termination is used to conduct the sound excitation. The second actuator based on a driver loudspeaker alse uses a flexible tube, but it is instrumented with two microphones in its socket instead of one. The behavior of these last two actuators in terms of volume acceleration (essential in the acoustic modal analysis) and active power (necessary for the Experimental Statistical Energy Analysis) being injected into the medium are investigated. The experimental modal analysis of the rectangular cavity is performed and a method using multi-dimensional spatial Fourier transforms of the array of pressure measurements is proposed for the construction of the partic1e displacement field for acoustic mode shape visualization
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica
Kaya, Huseyin. "Experimental Modal Analysis Of A Steel Grid Frame". Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/12604710/index.pdf.
Texto completoUwajambo, Pacifique y Nisha Thakur. "Numerical and Experimental Modal Analysis of CNC Machine". Thesis, Blekinge Tekniska Högskola, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-21652.
Texto completoTufano, Anna Rita. "Vibroacoustic coupling phenomena on heavy vehicles.Medium frequency experimental analysis and numerical applications for design specifications". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEC052.
Texto completoThe vibroacoustic performance is a matter of primary concern for modern vehicle manufacturers, that are constrained by health and safety legislation as well as by commercial needs: on the one hand, a number of norms exists regulating the level of vibration and noise that vehicle occupants can tolerate, but on the other hand a manufacturer is also interested in guaranteeing a high level of comfort in order to keep products competitive. The commercial vehicle industry presents some peculiarity with respect to other vehicle manufacturing businesses, and especially to the more known car industry: not only the architecture of a commercial vehicle is a class of its own, but what differentiates the most trucks from other ground vehicles are the configuration diversity and customization. A deep knowledge of the vibration and noise transmission mechanisms in trucks as well as source breakdown allows defining more rigorous and strict component specifications. Furthermore, the comprehension of the sensitivity of truck architecture parameters on vibroacoustic features provides even deeper means to assess the needed properties for a component to be installed on a vehicle. At present the verification is largely based on tests, both subjective (assessment by experimented test engineers) and objective (microphone and accelerometer acquisitions). This practice is extremely expensive, since, in order to take into account the large diversity of trucks, a large number of vehicles has to be tested. To overcome this limit, virtual testing - as opposed to physical testing - should be strengthened. Numerical methods are already largely used in the Volvo Group, but the available tools are considered partly unfit to the NVH demands and inappropriate with respect to their specific needs. The activities of the current thesis have been developed in the framework of the Interior Noise and Driveline Vibration group, which is responsible for the estimation of the acoustic comfort perceived by driver and passengers in all driving conditions and vehicle uses. This thesis will focus on the behaviour of the chassis as a primary component. The chassis is the main transfer path for engine-induced vibrations transmitted to the cabin. Besides, a peculiar attention will be given to the effect the chassis equipment components have on the chassis dynamics, even though limited interest will be put on the investigation of the dynamic signature of the equipment itself
Kleinknecht, Mathias y Álvarez Alfredo Fernández. "Wind turbine blade modeling - setting out from experimental data". Thesis, Linnéuniversitetet, Institutionen för maskinteknik (MT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-26054.
Texto completoOwolabi, Gbadebo Moses. "Crack identification procedures in beams using experimental modal analysis". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0034/MQ62411.pdf.
Texto completoMaamar, Asia. "Identification modale opérationnelle des robots d'usinage en service". Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC013/document.
Texto completoThe identification of the modal parameters of machining robots in service has a significant adverse influence on machining stability, which will, therefore, decrease the quality of the workpiece and reduce the tool life. However, in presence of strong harmonic excitation, the application of Operational Modal Analysis (OMA) is not straightforward. Firstly, the issue of choosing the most appropiate OMA method for an application in presence of harmonic components, is handled. For a comparison purpose, the modified Enhanced Frequency Domain Decomposition (EFDD) method, the Stochastic Subspace Identification (SSI) method, the PolyMAX method and the Transmissibility Function Based (TFB) method are investigated. The obtained results lead to the adoption of the Transmissibility Function Based (TFB) method for an OMA of machining robots. For an accurate modal identification procedure, the OMA of a machine tool is, initially, conducted. It is a preparation step in order to verify the performance of the chosen method under machining conditions as well as a machine tool is a rigid structure, thus, it has less variation in its dynamic behavior compared to a machining robot. Results demonstrate the efficiency of the TFB method to identify the machine tool modal parameters even in the presence of preponderant harmonic components. Finally, the OMA of the machining robot ABB IRB 6660, which has a flexible structure compared to a machine tool, is carried out for a machining trajectory. The obtained results allow the identification of a modal basis of the machining robot illustrating the evolution of its modal behavior, in service. The main novelty of this thesis lies in the development of a robust procedure for an operational modal identification of machining robots, in service, which makes it possible to continuously follow the variations in the modal parameters of machining robots
Baver, Brett C. "Property Identification of Viscoelastic Coatings Through Non-contact Experimental Modal Analysis". University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1459438426.
Texto completoAfolayan, Fatai Olayemi. "Modal Analysis of Simple Structures: Comparison Between Analytical, Numerical, and Experimental Methods". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/22486/.
Texto completoMartin, Guillaume. "Méthode de corrélation calcul/essai pour l'analyse du crissement". Thesis, Paris, ENSAM, 2017. http://www.theses.fr/2017ENAM0012/document.
Texto completoBrake squeal is a nuisance commonly encountered in the car industry which often results in financial penalties towards brake manufacturers, even if no robust solution exists for the conception. Numerical simulation and experimental characterizations are the classical two-track approaches to analyze squeal phenomena. Numerical simulation allows a fine analysis of vibration behaviors and the evaluation of conception modification impacts, but models are not perfect and their validity domain must be defined. Measurement guarantees that every parameter is taken into account, but it is often spatially poor and not really suited for modification prediction. In this context, the thesis objectives are to make an overview of test operating methods, to provide tools allowing an easier interaction between both test and simulation teams and to enforce the developments in a business application.After a review of the hypotheses and methods for modal identification, a critical analysis of the identification results leads to the characterization of biases and the introduction of detailed criteria to evaluate the quality of the result. Calculation/test correlation allows to qualify the models and tools are integrated to facilitate its implementation. Several criteria are defined to highlight the sources of bad correlation coming from the measure on the one hand and the model on the other hand. Sources of poor correlation are also identified with the MDRE expansion algorithm, whose limitations are compared with those of static and dynamic expansions.Model updating is then processed by a systematic procedure imbricating the steps of updating of geometry, material properties and contacts between components. A contact parametrization is proposed with a multi-model reduction allowing calculation times compatible with industrial time. It also allows sensitivity studies with the introduction of the notion of component modes in an assembly.Finally, a detailed analysis of a measurement campaign on a braking system under squeal conditions is carried out. A parallel between the changes of the limit cycle and the degree of coupling of the complex modes is proposed. In the time-frequency domain, variability, repeatability, reproducibility and the ability to aggregate sequential measurements are evaluated. The result is finally extended on the finite element model, which allows useful interpretations
Li, Xinzuo William. "A precision laser scanning system for experimental modal analysis : its test and calibration /". Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-08222009-040335/.
Texto completoSantos, Fabio Luis Marques dos. "Strain-based experimental modal analysis: advances in theory and practice". Instituto Tecnológico de Aeronáutica, 2015. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=3386.
Texto completoClement, Simon. "Mise en oeuvre expérimentale et analyse vibratoire non-linéaire d'un dispositif à quatre maquettes d'assemblages combustibles sous écoulement axial". Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4757/document.
Texto completoThe present study is in the scope of pressurized water reactors (PWR) core response to earthquakes. The goal of this thesis is to measure the coupling between fuel assemblies caused an axial water flow. The design, production and installation a new test facility named ICARE EXPERIMENTAL are presented. ICARE EXPERIMENTAL was built in order to measure simultaneously the vibrations of four fuel assemblies (2x2) under an axial flow. A new data analysis method combining time-frequency analysis and orthogonal mode decomposition (POD) is described. This method, named Sliding Window POD (SWPOD), allows analysing multicomponent data, of which spatial repartition of energy and frequency content are time dependent. In the case of mechanical systems (linear and nonlinear), the link between the proper orthogonal modes obtained through SWPOD and the normal modes (linear and nonlinear) is studied. The measures acquired with the ICARE EXPERIMENTAL installation are analysed using the SWPOD. The first results show characteristic behavior of the free fuel assemblies at their resonances. The coupling between fuel assemblies, induced by the fluid, is reproduced by simulations performed using the COEUR3D code. This code is based on a porous media model in order to simulate a fuel assemblies network under axial flow
Brien, Christopher J. "Factorial linear model analysis". Title page, table of contents and summary only, 1992. http://thesis.library.adelaide.edu.au/public/adt-SUA20010530.175833.
Texto completoBerg, Richard Hiram. "Application of sensors in an experimental investigation of mode dampings /". Online version of thesis, 1993. http://hdl.handle.net/1850/11046.
Texto completoBouchner, Michal. "Určení NVH parametrů rovinné desky". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378142.
Texto completoDiaby, M'Paly. "Caracterisation des materiaux viscoelastiques par analyse modale experimentale". Le Mans, 1998. http://www.theses.fr/1998LEMA1010.
Texto completoDeshpande, Shrirang. "Improving observability in experimental analysis of rotating systems". University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1414750479.
Texto completoSharma, Balaji R. "Feasibility of use of four-post road simulators for automotive modal applications". University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1277133229.
Texto completoNewton, Wesley E. "Data Analysis Using Experimental Design Model Factorial Analysis of Variance/Covariance (DMAOVC.BAS)". DigitalCommons@USU, 1985. https://digitalcommons.usu.edu/etd/6378.
Texto completoWagner, Benjamin. "Rotating Equipment Defect Detection Using the Algorithm of Mode Isolation". Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16230.
Texto completoBui, Tuan Anh. "Experimental and numerical uncertain vibration analysis of multilayered timber structures assembled using compressed wood dowels". Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0202.
Texto completoThis study presents an experimental and numerical investigation on the vibrational serviceability performance of novel adhesive free engineered wood products (AFEWPs), namely adhesive free laminated timber beams (AFLB) and adhesive free cross-laminated timber panels (AFCLT), assembled through thermo-mechanically compressed wood dowels (CWD). The experimental modal analyses were carried out under free-free conditions using a hammer impact. Natural frequencies, mode shapes, and damping ratio were assessed experimentally. In addition, similar glued timber beams (conventional glulam) were manufactured and tested for comparison purpose. A 3D FE model was developed and validated by comparison against experimental data and then used to predict the vibrational behavior of a realistic flooring system made with AFCLT panel measuring 4.5 m x 5.5 m. A parametric study was performed on the FE model to maximize the floor stiffness. The predicted FE results were discussed with regard to the Eurocode 5 vibrational serviceability design requirements showing acceptable vibrational performance. A simplified FE model was then developed to reduce computational cost. The variability level of the results for the AFEWPs was also studied and discussed. The numerical variability of frequencies of the AFEWPs was investigated based on the development of the Modal Stability Procedure (MSP). The MSP result was first compared with the FE result in the nominal case. Then, the statistic results (mean value, standard deviation, coefficient of variation and distribution) obtained from the MSP were compared with the results from the classical method (direct Monte Carlo simulation) and experimental results. A quick error estimation between the MSP and the direct Monte Carlo simulation was developed. Finally, the mean and standard deviation of the frequencies of the realistic AFCLT flooring system were predicted by the MSP
Poncet, Mélissa. "Effet de l'incorporation de systèmes hybrides sur les propriétés mécaniques de matériaux composites à matrice époxyvinylester et polyester insaturé". Thesis, Paris, ENMP, 2013. http://www.theses.fr/2013ENMP0025/document.
Texto completoThis thesis focuses on the development of a thermosetting matrix composite incorporating nanoscale reinforcements and/or an elatomeric phase to improve its stiffness, damping and resilience.To do so, we made formulations based on epoxy vinyl ester matrices, filled or not by an elastomeric phase, and reinforced with montmorillonite or sepiolite. Their viscoelastic properties were studied usingexperimental modal analysis and their impact properties were investigated using drop weight impacttesting. The microstructure of these composites was examined using X-ray diffraction and electronmicroscopy observations.Homogenization models based on H ALPIN -T SAI model and adapted to the studied composites were developed to provide a tool able to explicitly link the stiffness of the material to its morphology.A detailed parametric analysis allowed to determine the most influential morphological characteristics and to assess the efficiency of the process regarding the mechanical stiffening obtained.Experimentally, the incorporation of montmorillonite or sepiolite led to a significant increase in the elastic modulus and, with the presence of an elastomeric phase in the resin, the damping was doubled and the resilience was increased.Finally, the most efficient formulations were used to manufacture glass fibers reinforced composites.The improvement in mechanical properties was found, to a lesser extent, for the manufactured prototypes.The relevance of the use of these materials on an industrial scale was evaluated
Zhou, Lixing. "Dynamic generalized (multiple-set) structured canonical correlation analysis (dynamic GCANO): a structural equation model for simultaneous analysis of multiple-subject effective connectivity in functional neuroimaging studies". Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123190.
Texto completoSuivant les méthodes d'imagerie fonctionnelle cérébrale, une connectivité efficace est définie comme influence dépendant de causalité temporelle qu'une certaine région d'intérêt du cerveau (ROI) exerce sur une autre. La modélisation par équation structurelle (SEM) est régulièrement utilisée pour analyser la connectivité efficace. Ces dernières années, diverses méthodes de SEM ont été proposées pour la modélisation de la connectivité efficace. Cependant, il y a eu peu de tentative pour développer des méthodes de SEM pour analyser les modèles communs de connectivité efficace sur-sujets, malgré la prédominance de recherche sur des sujets multiples pour analyser la connectivité efficace. Cette thèse propose une méthode qui comble cette lacune. Cette méthode est appelée dynamique généralisée (multiples ensemble) structuré l'analyse de corrélation canonique (dynamique GCANO). Elle combine généralisée (multiples ensemble) structuré l'analyse de corrélation canonique (GCANO) avec multivariée des séries chronologiques autorégressif dans un cadre unifié. Cette thèse commence par un bref sommaire sur les techniques existantes de SEM et souligne leurs limites pour analyser les données de plusieurs sous réserve pour la connectivité efficace, ce qui a mené à développer la dynamique GCANO. Les techniques de base de la méthode proposée sont ensuite énumérées, y compris les spécifications du cadre de modélisation et un critère d'optimisation pour l'estimation de paramètres, qui est réduit par alternant algorithme des moindres carrés. L'efficacité du dynamique GCANO est démontrée par l'analyse des ensembles de données synthétiques et réels. Les données synthétiques montrent une récupération raisonnable de paramètre par la méthode proposée, alors que les données réelles montrent l'utilité de la méthode dans les recherches empiriques. Plusieurs fonctionnalités du dynamique sont mises en évidence par le biais de ces exemples. En conclusion, la thèse propose des extensions possibles de la méthode proposée.
Morone, Daniel Justin Reese. "Progressive Collapse: Simplified Analysis Using Experimental Data". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354602937.
Texto completoLibardi, Ana Lúcia. "Técnicas de cancelamento de massa em análise modal experimental". Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-11072018-120016/.
Texto completoThe goal of this dissertation is to develop a study on mass cancellation techniques and their applications in experimental modal analysis. These techniques are commonly employed in the reduction of experimental errors on the structure\'s measured frequency response data. Such errors are in turn caused by extra masses such as accelerometer and force transducers, that are utilized on the measurement of the system\'s Frequency Response Functions (FRF). The mass cancellation techniques studied here are developed through frequency domain input and output relationships as well as substructuring concepts. The analytical models employed in the mass cancellation problem are also applied in obtaining unknown FRF from a subset of measured FRF that are measured with extra masses attached to the structure. The methods studied are applied to numerically simulated data from discrete systems, as well as to experimental data coming from modal tests performed on simple structures. Reasonably good results are obtained in either the numerical and experimental analysis for the mass cancellation problem. In obtaining unknown FRF data, it was verified that the models generated reasonable results in some circumstances, and that experimental noise is a major source of error in using these mass cancellation techniques for the purpose of obtaining unmeasured data from a subset of measured FRF.
Han, Man-Cheol. "Improved approaches to the indirect force determination problems via experimental modal analysis". Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39412.
Texto completoPh. D.
Koricherla, Manindra Varma. "An experimental modal analysis of an Lithium-ion Battery using Dynamic Excitation". University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1502476407014686.
Texto completoOliveira, Junior Adelmo Fernandes de [UNESP]. "Estudo das características modais de um modelo de aeronave em alumínio". Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/148651.
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A análise modal experimental é uma das técnicas mais importantes na caracterização dinâmica de estruturas. No setor aeroespacial a analise modal experimental é conhecida como Ground Vibration Test (GVT). Na Força Aérea Brasileira, o órgão responsável para executar o GVT é o Laboratório de Ensaios de Vibração (LEVI) da Divisão de Integração e Ensaio (AIE) do Instituto de Aeronáutica e Espaço (IAE). Esta pesquisa foi realizada neste laboratório que possui as facilidades para a execução de GVT. O objetivo principal deste estudo foi aprimorar a metodologia de ensaio de análise modal aplicada a um modelo de aeronave em alumínio do tipo GARTEUR SM-AG-19. O estudo desenvolvido possibilita que em ensaios futuros os resultados sejam replicados, no intuito de avaliar a integridade do sistema de medição, levando em consideração aspectos da influência do torque na junta aparafusada entre a asa e a fuselagem. Para validar a metodologia os resultados obtidos neste estudo foram comparados com os resultados de dois estudos desenvolvidos no Brasil. A contribuição principal desta pesquisa é relacionada ao estudo do efeito da variação do torque na junta aparafusada entre a asa e a fuselagem sobre os parâmetros modais da estrutura.
The experimental modal analysis is one of the most important techniques in the dynamic characterization of structures. In the aerospace industry, the experimental modal analysis is known as Ground Vibration Test (GVT). In the Brazilian Air Force, the institution responsible for executing the GVT is the Laboratory of Vibration Testing (LEVI) of the Integration and Testing Division (AIE) of the Institute of Aeronautics and Space (IAE). This research was carried out on this laboratory that has the facilities to perform the GVT. The main objective of this study was to improve the modal analysis test methodology applied to an aluminium aircraft model named GARTEUR SM-AG-19. This study allows the results to be replicated in future tests in order to evaluate the integrity of the measurement system, taking into account aspects of the influence of the torque on the bolted joint between wing and fuselage. In order to validate the methodology the results obtained in this study were compared to the results of two studies developed in Brazil. The main contribution of this research is the study of the torque variation effect on the bolted joint between wing and fuselage on the modal parameters of the structure.
Jardim, Maurício Ferreira [UNESP]. "Análise teórica e experimental vibro-acústica utilizando a técnica de matrizes compactas". Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/94549.
Texto completoCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Em muitos problemas do nosso cotidiano ocorre acoplamento entre a resposta acústica no interior de uma cavidade e a excitação estrutural em um de seus contornos flexíveis, bem como a resposta estrutural nestes contornos também está relacionada à fonte acústica da cavidade. Interior de automóveis, cabine de caminhões e fuselagem de aviões são apenas alguns exemplos práticos destes tipos de sistemas. Acoplamento implica que o comportamento dos sistemas acústico e estrutural não são independentes um do outro, e ambos devem ser considerados como um único sistema global. O propósito deste trabalho é avaliar a técnica de matrizes compactas na solução de problema de acoplamento vibroacústico em cavidades de geometria regular e irregular. Preliminarmente, a análise do acoplamento vibro-acústico é baseado no método dos elementos finitos e o conjunto de equações não simétricas que modela o movimento é discutida. A aproximação vibro-acústica por matrizes compactas é feita utilizando conceitos de impedância e mobilidade. No modelo de matrizes compactas, o acoplamento é obtido através da avaliação dos modos acústicos e estruturais desacoplados da cavidade e da estrutura flexível, respectivamente. Simulações numéricas utilizando o método dos elementos finitos e a técnica de matrizes compactas são apresentadas para modelos vibro-acústicos de geometria regular e irregular. Testes experimentais são realizados em uma cavidade irregular feita de PVC e aço. A metodologia de análise dos resultados é baseada nas FRF(s) definidas pelas relações entre a resposta em pressão acústica da cavidade e a força estrutural e entre a resposta em velocidade e a força estrutural aplicada sobre a superfície flexível. A comparação dos modelos numéricos e experimentais mostra o potencial da técnica de matrizes compactas.
In many systems of day-life occurs the coupling between the acoustical response in a cavity and a structural excitation on a flexible boundary, whereas the structural response in this same boundary is also related to acoustical excitation source. Car interiors, cabs of trucks and aircraft fuselage are a just a few practical examples of this sort of systems. Coupling implies that the acoustical and structural system behavior is not independent from each other, and therefore they must be considered as a global system behavior. The aim of this work is to evaluate a compact matrix formulation to solve vibro-acoustic problems in regular and irregular shape cavity. Preliminary, the vibro-acoustic coupling analysis is based on finite element method and the set of non-symmetric equation that represents the movement is discussed. The compact matrix formulation approaches have been done using impedance and mobility concepts. In compact matrix model, the coupling is obtained by evaluating the uncoupled acoustic modes and structural modes of the cavity and flexible structure, respectively. Numerical simulation using the finite element method and the compact matrix formulation are shown for regular and irregular shape cavity model. Experimental tests are evaluated in an irregular rigid cavity made of PVC and steel. The results analysis methodology is based on FRF(s) defined by the relationship between the pressure acoustic response in the cavity and structural force and between the velocity response and structural force applied on the flexible boundary. The comparison of numerical and experimental models shows the potential of the compact matrix formulation.
Karim, Ali Abdul Jabbar, Johan Lessner y Mehrdad Moridnejad. "Model calibration of a wooden building block". Thesis, Linnéuniversitetet, Institutionen för bygg- och energiteknik (BE), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-26271.
Texto completoAtt bygga flervåningshus med lätta byggmaterial har blivit allt vanligare. Det finns många fördelar med att använda lätta material, såsom trä. En av fördelarna är att det är skonsamt för miljön. Emellertid är en av bristerna i lättviktsmaterial den akustiska prestandan. Överföring av ljud och vibrationer genom golv i flervåningshus i trä är en nackdel att överväga. Det finns flera studier som har behandlat denna fråga. Ofta görs finita element modeller samt tester i laboratorium. I dessa studier justerar man materialegenskaperna i FE-modellen för att korrelera mot laboratorieexperiment. Detta eftersom det finns en stor spridning i materialegenskaperna för trä i litteraturen. Med detta examensarbete, undersöks de faktiska materialegenskaperna hos träelementen genom försök. Dynamiska tester utförs för att bestämma spridningen i materialegenskaper. De testade materialen är spånskivor och två typer av träbalkar. De undersökta balkarna är både normala träreglar och laminerade faner balkar. När det dynamiska beteendet är känt för trädelarna, monteras de ihop till två små golvsystem. Golvsystemen består av fyra balkar och en träskiva. Den assemblerade modellen testas både dynamiskt i ett praktiskt försök och i ett FE program. I FEmodellen används de tidigare framtagna faktiska materialegenskaper för varje ingående enskild byggnadsdel. Resultaten från FE-modellen korrelerar väl med de praktiska experimenten. Med detta examensarbete visas att när materialegenskaperna är kända kan FE-modellen förutsäga det verkliga beteendet. De undersökta materialegenskaperna visar dock en stor spridning från balk till balk, etc. och mer kunskap om materialegenskaper hos trädelar behövs.
Nunes, Alexandre. "Analise modal teorica e experimental acustica de cavidades com absorção sonora". [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265183.
Texto completoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Mestrado
Estep, Robert Noah. "Examination of the application and limitations of structural mode extraction via force apportionment". Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-02132009-172353/.
Texto completoRose, John A. "The experimental characterization of the dynamics of a reciprocating freon compressor system". Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-12302008-063244/.
Texto completoBaldassarre, Alessandro. "FEM and experimental analysis of a wind turbine blade". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8533/.
Texto completoSaha, Reema. "Investigation of a continuum damage model using experimental and numerical techniques". Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/12542.
Texto completoNilsson, Oscar. "Experimental Procedures for Operational Modal Analysis of a Power Pack on a Drill Rig". Thesis, Linköpings universitet, Mekanik och hållfasthetslära, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-143046.
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