Relevant bibliographies by topics / Modèle vibrationnel

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Academic literature on the topic 'Modèle vibrationnel'

Author: Grafiati
Published: 4 June 2021
Last updated: 3 February 2022

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Journal articles on the topic "Modèle vibrationnel"

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Cao, Yongqi, Weihe Shen, Fangzhi Li, Huan Qi, Jiaxiang Wang, Jianren Mao, Yang Yang, and Kai Tao. "All-in-One High-Power-Density Vibrational Energy Harvester with Impact-Induced Frequency Broadening Mechanisms." Micromachines 12, no. 9 (September 8, 2021): 1083. http://dx.doi.org/10.3390/mi12091083.

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This paper proposes an electrostatic-piezoelectric-electromagnetic hybrid vibrational power generator with different frequency broadening schemes. Both the nonlinear frequency broadening mechanisms and the synergized effect of the electrostatic-piezoelectric-electromagnetic hybrid structures are investigated. The structure and performance of the composite generator are optimized to improve the response bandwidth and performance. We propose that the electrostatic power generation module and the electromagnetic power generation module be introduced into the cantilever beam to make the multifunctional cantilever beam, realizing small integrated output loss, high output voltage, and high current characteristics. When the external load of the electrostatic power generation module is 10 kΩ, its peak power can reach 3.6 mW; when the external load of the piezoelectric power generation module is 2 kΩ, its peak power is 2.2 mW; and when the external load of the electromagnetic power generation module is 170 Ω, its peak power is 0.735 mW. This means that under the same space utilization, the performance is improved by 90%. Moreover, an energy management circuit (ECM) at the rear end of the device is added, through the energy conditioning circuit, the device can directly export a 3.3 V DC voltage to supply power to most of the sensing equipment. In this paper, the hybrid generator’s structure and performance are optimized, and the response bandwidth and performance are improved. In general, the primary advantages of the device in this paper are its larger bandwidth and enhanced performance.
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Battocchio, Giovanni, Niels Kristian Madsen, and Ove Christiansen. "Density matrices and iterative natural modals in vibrational structure theory." Molecular Physics 115, no. 1-2 (November 2, 2016): 228–40. http://dx.doi.org/10.1080/00268976.2016.1243263.

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Grigorev, Alexey, Alexey Lysenko, Igor Kochegarov, Vladimir Roganov, and Jurijs Lavendels. "Determination of Vibrational Displacement Measurement Error Based on the Blurring Analysis of a Round Mark Image." Applied Computer Systems 23, no. 2 (December 1, 2018): 150–60. http://dx.doi.org/10.2478/acss-2018-0019.

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Abstract The relevance and nature of a new technology for measurement of vibrational displacement of a material point through normal toward the object plane are stated in the article. This technology provides registration and processing of images of a round mark or a matrix of round marks, which are applied to the surface of a control object. A measuring signal here is the module of radius increment of the round mark image at vibrational blurring of this image. The method for calculation of the given error of measurements, as a function of a number of pixels of the round mark image, has been developed and proven in the present research. The results of pilot studies are given. Linearity of transformation of the measured size into a measuring signal has been proven. The conditions of a technical compromise between the field of view area of a recording device during distribution measurement of vibrational displacements along the surface of a control object, and the accuracy of this measurement are determined. The results are illustrated with numerical examples of calculations of the given error of measurements in the set field of view and the one at the given maximum set error of measurements.
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Choi, Dong-Soo, and Sang-Youn Kim. "Transparent Film-Type Vibrotactile Actuator Array and Its Haptic Rendering Using Beat Phenomenon." Sensors 19, no. 16 (August 9, 2019): 3490. http://dx.doi.org/10.3390/s19163490.

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The most important thing in a thin and soft haptic module with an electroactive polymer actuator array is to increase its vibrotactile amplitude and to create a variety of vibrotactile sensations. In this paper, we introduce a thin film-type electroactive polymer actuator array capable of stimulating two types of human mechanoreceptors simultaneously, and we present a haptic rendering method that maximizes the actuators’ vibrational force without improving the array’s haptic performance. The increase in vibrational amplitude of the soft electroactive polymer actuator array is achieved by creating a beat vibration, which is an interference pattern of two vibrations with slightly different frequencies. The textures of a target object are translated into haptic stimuli using the proposed method. We conducted qualitative and quantitative experiments to evaluate the performance of the proposed rendering method. The results showed that this method not only amplifies the vibration’s amplitude but also haptically simulates various objects’ surfaces.
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Sun, Miao Zhong, Chuan Wang, and Yuan Li Xu. "Fault Diagnosis of Grinding Machine Using Choi-Williams Distribution Based on COM Module Technology." Applied Mechanics and Materials 226-228 (November 2012): 572–75. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.572.

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In this paper, a time-frequency analytic system is implemented by using mixed programming of Matlab and Delphi languages based on COM (Component Object Model）module technology. Matlab possesses many signal analytic functions and Delphi has a friendly visual programming environment. These two advantages are fully combined in the mixed programming. This system can be easily upgraded to expand new analytic functions with help of COM module technology. Fault diagnosis of a grinding machine is carried out by using this system. A same vibrational signal sampled from the machine is analyzed in turn by three methods in this system that are Fast Fourier Transform(FFT), Wigner-Ville Distribution(WVD) and Choi-Williams Distribution(CWD). Comparing with the three results, it shows that CWD can get best diagnostic information and validity of the estimation on the instantaneous frequency of a signal. Success of the mixed programming is presented meantime.
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Naduty, Vladimir, Anastasia Loginova, and Vitaliy Sukharev. "DETERMINATION OF DEPENDENCE OF OPERATING INDICATORS OF TWO-SHAFT CENTRIFUGAL MODULE ON VARIABLE PARAMETERS." Vibrations in engineering and technology, no. 2(97) (August 27, 2020): 15–21. http://dx.doi.org/10.37128/2306-8744-2020-2-2.

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The article presents the results of studies of a new design of a two-shaft centrifugal vibration module, which was created on the basis of the modernization of a two-shaft disintegrator. A distinctive feature of this design is the presence of an additional device that provides the operation of vibrational classification by size of the crushed rock mass directly in the grinding chamber. This eliminates its regrinding and increases the performance of the module. Since structural changes were introduced into the previously existing disintegrator design and new technological operations were added, a set of studies was carried out to determine the performance and expended drive power of the module, depending on the most influential operating parameters and rock mass characteristics. The main variable parameters were adopted: the number of revolutions of the beater shaft in the grinding chamber, the frequency and amplitude of oscillations of the grinding chamber, the size and strength of the crushed rock mass, and the effect of the screening process of the finished size class in the grinding chamber on the productivity and power consumption of the drive was established. It has been established that the efficiency of rock mass screening in a centrifugal vibration module is within 60 ÷ 70% depending on the separation size class and the density of the processed rock mass, as well as on the content of the finished size class in its loading. In this case, the performance of the module increases by 20%, and with the use of vibration excitation of the grinding chamber - by 25 ÷ 30%. The obtained experimental dependences of these values on variable parameters are presented in the form of graphs with their further identification by regression models, which will allow us to determine its main structural and power parameters when designing the parametric series of the module (based on the initial requirements). The results of studies of the experimental model of the module showed the effectiveness of the modernization and allow us to recommend it for wide industrial use.
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Hammer, T. "Investigation of XeCl vibrational and quenching kinetics: Measurements of gain and laser spectra in a discharge-pumped oscillator module." Applied Physics B Photophysics and Laser Chemistry 56, no. 5 (May 1993): 243–48. http://dx.doi.org/10.1007/bf00325211.

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Liu, Yaolong. "Study on the vibrational comfort of aircraft in formation flight." Aircraft Engineering and Aerospace Technology 92, no. 8 (July 27, 2020): 1307–16. http://dx.doi.org/10.1108/aeat-12-2018-0311.

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Purpose The purpose of this paper is to investigate the passenger comfort changes due to the wake turbulence impact from the formation flight (FF) leading aircraft, which can be a showstopper for the real application of FF to airliners. Design/methodology/approach Taking advantage of the overall aircraft design and optimization framework, as well as the module for FF assessment, the comfort level has been quantified for aircraft in solo flight and in FF according to ISO 2631–1 specifications concerning vibration total value. Findings The results showed that atmospheric turbulence intensity is the dominant factor in determining the passenger ride quality in comparison to the impact of formation wake flow. According to the preliminary results of this study, passengers seated away from the aircraft mass center encounter larger discomfort. In comparison to mass center, seats away from mass center also experience slightly stronger discomfort due to FF. The current simulation results show that FF is feasible without remarkably degrading passenger comfort level, which agrees well with the flight test results. Practical implications As passenger comfort is crucial for civil transport application of FF, the study carried out within this manuscript can give a preliminary indication to the showstopper of FF real-world application. Originality/value The proposed strategy can provide quantitative values for judging the possible drawbacks of FF, i.e. passenger comfort issues as mentioned in the literature. On the other hand, the aircraft level study based on reliable data and methods can give important insight for this interesting topic and further help the real-world application of FF for commercial aircraft. In addition, it can serve as preliminary studies for further design and operation modifications for aircraft in FF.
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Verma, V., D. Chionis, A. Dokhane, and H. Ferroukhi. "MODELLING AND ANALYSIS OF FUEL ASSEMBLY VIBRATIONAL MODES IN PWRS USING SIMULATE-3K." EPJ Web of Conferences 247 (2021): 21008. http://dx.doi.org/10.1051/epjconf/202124721008.

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Some of the KWU pre-KONVOI PWRs operating across Europe saw a systematic increase in the neutron noise levels over several cycles in the last decade, and subsequently, core internals’ movements, especially vibrations of fuel assemblies with specific designs were identified as one of the plausible causes. Therefore, it is important to develop computational methods that can allow to investigate and predict the reactor noise response to fuel assemblies vibrations. To this aim, the 3D nodal reactor dynamics code SIMULATE-3K is used at PSI with a special module called the ‘assembly vibration model’ that imitates time-dependent motions of fuel assemblies by dynamically modifying the water-gaps surrounding the laterally moving fuel assemblies. The varying water-gaps are represented by the variation in the corresponding two-group macroscopic cross sections generated using the lattice code CASMO-5 in 2D. The studies conducted so far to assess the methodology for full core noise simulations were based on assuming vibrations of a clamped-free cluster of fuel assemblies that are unsupported from both ends. However, as this represents a non-physical movement, further developments were made at PSI to allow simulating more realistic movements of fuel assemblies such as the cantilevered mode vibration. The updated methodology, along with evaluations of the simulated noise response to realistic vibration modes, is presented in this paper. Results show that, as expected, the radial and axial neutron noise behaviour follow the vibration pattern of the imposed time-dependent axial functions corresponding to the natural oscillation modes of the fuel assemblies, thereby providing confidence in the application of the developed methodology for numerical neutron noise analyses of the PWR cores.
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Naduty, Vladimir, Anastasia Loginova, and Vitaliy Sukharev. "THE RESULTS OF STUDIES OF THE DEPENDENCE OF THE PERFORMANCE OF THE VIBRATING TWO-SHAFT CENTRIFUGAL MODULE ON THE MODE AND DESIGN PARAMETERS." Vibrations in engineering and technology, no. 3(94) (November 26, 2019): 5–10. http://dx.doi.org/10.37128/2306-8744-2019-3-1.

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The article presents a new design of a vibrating twin-shaft centrifugal module designed for grinding and classification of rock mass. In this design, in addition to grinding, the operation of classification or screening of the crushed mass was added, which does not allow its regrinding and increases the productivity of the device. This is achieved by installing in the bottom of the chamber grinding mesh with cells in accordance with the required class size. At the same time, the classification process is intensified by the presence of vibration from vibration exciters fixed on the camera body and the installation of the camera on elastic supports. The reciprocating horizontal vibrations of the chamber with a given amplitude and frequency contribute to the segregation of the crushed rock mass in the bed by size, which positively affects the efficiency of classification and grinding. The presence of vibration helps to unload the oversize product from the grinding chamber. Also, the article considers experimental studies performed on a vibrational two-shaft centrifugal module to determine the dependence of the performance of a given design on five variable factors: rotor shaft revolutions (n, rpm), size of the loaded rock mass (Δ, mm), rock mass strength (σ, kg/mm2), camera vibration frequency (ω, rpm) and its vibration amplitude (A, mm). Studies have shown the efficiency and increased productivity of the new design in relation to a centrifugal disintegrator without a classification grid and vibration. The results of the work allow us to recommend the design under study for the manufacture of an experimental sample according to the given initial requirements, and the established dependences (Q = f (n, Δ, σ, ω, A) make it possible to develop a mathematical model of the grinding process in this setup to calculate the required parameters.
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Dissertations / Theses on the topic "Modèle vibrationnel"

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Souhabi, Jihane. "Réexamen du comportement vibrationnel des alliages modèles GaAs(1-x)Px et Si(1-x)Gex : modèle de percolation et calculs ab initio." Thesis, Metz, 2010. http://www.theses.fr/2010METZ025S/document.

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Le schéma générique de percolation 1-liaison→2-TO mis au point sur site pour la compréhension de base des spectres de vibration (Raman et infrarouge - IR) des alliages semiconducteurs aléatoires usuels, i.e., s’inscrivant dans la structure zincblende, qui a récemment supplanté le modèle standard 1-liaison→1-TO dit MREI [modified-random-element-isodisplacement, (Chang, et al., 1971)] mis au point dans les années soixante, est ici confronté au modèle à clusters (Verleur, et al., 1966), consacré par l’usage pour la discus-sion des spectres de vibration de ces alliages zincblende particuliers, présumés non aléatoires, qui montrent évidemment plus d’un mode phonon par liaison dans leur spectres de vibration. En fait, nous montrons que les spectres de réflectivité IR pionniers de l’alliage GaAs1-xPx représenta-tif de cette dernière classe de comportement, i.e. ceux-là mêmes qui ont motivé le développement du modèle à clusters dans les années soixante, trouvent une explication naturelle dans le cadre du modèle de percolation sur la base d’une substitution As ↔ P parfaitement aléatoire, sans aucun paramètre ajustable. L’alliage GaAs1-xPx et ses semblables se trouvent ainsi réhabilités en tant que systèmes aléatoires vis-à-vis de leurs propriétés vibrationnelles. Du même coup, la classification admise des spectres de vibration des alliages semiconducteurs à structure zincblende, basée sur les modèles MREI-Clusters, en quatre sous-types distincts, se trouve totalement unifiée dans le cadre de notre modèle de percolation. Dans un second temps nous explorons dans quelle mesure une extension du schéma de percolation de la structure zincblende vers la structure diamant, peut aider à comprendre la nature mystérieuse du comportement Raman de l’alliage aléatoire représentatif Si1-xGex. Il s’avère qu’une simulation satisfaisante des spectres Raman de Si1-xGex d’ores et déjà existants dans la littérature peut être accomplie, sans autre para-mètre ajustable que l’efficacité Raman de la liaison mixte Si-Ge, dans le cadre d’une version générique 1-liaison→N-mode du schéma de percolation, où N indique une sensibilité à l’environnement local des liaisons Ge-Ge (N=1, insensibilité), Si-Si (N=2, sensibilité à l’environnement premiers-voisins) et Si-Ge (N=3, sen-sibilité à l’environnement seconds-voisins). Des différences notables entre les schémas de percolation de GaAs1-xPx et de Si1-xGex sont attribuées à la différence de nature de la relaxation du réseau dans les cristaux à structure zincblende et diamant (inversion de l’ordre des branches au sein du triplet Si-Ge) et à la dispersion spectaculaire des modes Ge-Ge (antiparallélisme de la branche unique Ge-Ge) et Si-Si (inversion de l’ordre des branches au sein du doublet Si-Si), qui vient s’ajouter à l’effet de contrainte locale, habituellement seul pris en compte pour les alliages zincblende déjà examinés. L’assignation des branches phonons individuelles au sein de chaque schéma de percolation, i.e. GaAs1-xPx ou Si1-xGex, est réalisé par voie ab initio en se focalisant sur les modes de vibration des liaisons en stretching pur le long de motifs d’impuretés prototypes choisis quasi-linéaires de manière à rester dans l’esprit de l’approximation de la chaîne linéaire (ACL) sur laquelle est basé le modèle phénoménologique de percolation
The 1-bond → 2-TO percolation generic scheme proposed for the basic understanding of the vibra-tion spectra (Raman and Infrared –IR) of usual random semiconductor alloys with zincblende structure, which has recently challenged the standard MREI (modified-random-element-isodisplacement) model with the 1-bond→1-TO behavior, (Chang et Mitra, 1971) developped in the sixties, is here confronted to the cluster model (Verleur et Barker, 1966) which has been accepted through use for the study of the vibration spectra of these particular zincblende alloys, which obviously exhibit more than one phonon mode per bond in their vibration spectra. In fact, the IR reflectivity spectra of GaAs1-xPx, the representative alloy of the last class, i.e. those very ones which motivated the developpement of the cluster model in the sixties, find a natural explanation in the scope of the percolation model on the basis of a perfect random substitution As ↔ P, with no adjusta-ble parameter. With this, GaAs1-xPx and its like are rehabilitated as random alloys in principle, and further, the percolation paradigm generalizes to all types and subtypes of the traditional four-type classification of phonon mode behavior of semiconductor alloys, based on the MREI and cluster models. In a second stage, we investigate to which extent an extension of the percolation scheme to the di-amond structure may help to understand the mysterious nature of the Raman behavior of the representative Si1-xGex alloy. We realize that a good simulation of the Si1-xGex Raman spectra already existing in the literature can be obtained with no adjustable parameter but the Raman efficiency of the Si1-xGex bond within a generic 1-bond→N-TO version of the percolation model, where N indicates a sensitivity to the local environment of the Ge-Ge (N=1 non sensitive), Si-Si (N=2, sensitive to the first neighbor environment) and Si-Ge (N=3, sensitive to the second neighbor environment) bonds. Some differences between the GaAs1-xPx and Si1-xGex percolation patterns are attributed to the different natures of the lattice relaxation in the zincblende and di-amond structures (inversion of the order of like branches in the Si-Ge triplet) and to the spectacular disper-sion of the Ge-Ge like modes (anti parallelism of the unique Ge-Ge branch) and Si-Si (inversion of the order of like branches in the Si-Si doublet), which add to the local constraint effect, the only one usually taken into account in the zincblende alloys examined so far. The assignment of the individual phonons branches in each percolation scheme, i.e. GaAs1-xPx or Si1-xGex, is achieved via home-made ab initio phonon calculations with a focusing on bond-stretching along prototype impurity motives designed as quasi linear so as to be remain in with the spirit of the linear chain approximation on which the percolation model is based
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Obiajunwa, Eusebius. "Contribution à l'étude de transition de forme par diffusion inélastique : application aux isotopes de samarium et de germanium." Paris 11, 1987. http://www.theses.fr/1987PA112227.

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Les isotopes stables, pairs de samarium et de germanium ont été étudiés par le processus de diffusion inélastique de protons (Ep = 24 MeV) et d’apha (Eα= 36 MeV) 148-154 Sm(p,p’) ; 150-152 Sm(α,α’) ; 70-74 Ge(α,α’). Les cibles métalliques, très minces, enrichies et auto-supportées sont utilisées avec les faisceaux de protons et d'alpha, de haute qualité fournis par l'accélérateur Tandem van de Graaff d'Orsay. Les particules diffusées sont analysées en quantités de mouvement par le spectromètre magnétique, split-pole et sont localisées par un ensemble de détecteurs à haute résolution dans le plan focal du spectromètre. Les divers modèles collectifs nucléaires vibrationnel harmonique (VM) et anharmonique (AVM), rotationnel symétrique (SRM) et asymétrique (ARM), rotation-vibrationnel (RVM) et le modèle des bosons en interaction (IBM), utilisés dans les analyses des données expérimentales sont présentés. Les données expérimentales concernant les premiers niveaux des noyaux 148-150 Sm sont analysées dans le cadre de VM au second ordre. Les états multiphonons (1-,5-,3-) de ces noyaux sont étudiés pour la première fois. Ces analyses révèlent qu'il est nécessaire de tenir compte d'effet d'anharmonicité dans ces noyaux en particulier pour les états multiphonons. Quant aux noyaux 152-154Sm, les données concernant les premiers niveaux de la bande fondamentale (0+,2+,4+,6+) sont analysées dans le cadre de SRM. Ces niveaux et les niveaux (1-,3-,5-) bandes vibrationnelles octupolaires, kπ =0- pour les deux noyaux, sont pour la première fois, analysés simultanément et d'une façon cohérente, dans le cadre de RVM. Dans le cas de la diffusion inélastique 70-74 Ge (α,α'), les données pour les premiers niveaux de ces noyaux sont analysées dans le cadre des modèles VM, AVM et ARM. L'AVM donne une meilleure description globale des premiers niveaux de ces trois noyaux. Une méthode plus rigoureuse et cohérente de traiter l'effet d'anharmonicité dans les noyaux vibrationnels est présentée, en partant de l'Hamiltonien de Brink et Kerman ; les résultats obtenus par cette méthode sont très encourageants. L'application d'IBM aux analyses des données de diffusion inélastique est aussi présentée
The stable even samarium and germanium isotopes have been studied by means of inelastic proton (Ep = 24 MeV) and aloha (Eα= 36 MeV) scattering: 148-154 Sm(p,p’) 150-152 Sm(α,α’) ; 70-74 Ge(α,α’). Enriched self-supporting, thin metallic targets are used with high quality proton and alpha beams furnished by the Orsay Tandem Van de Graaff accelerator. The scattered particles were momentum analysed by a split-pole magnetic spectrometer and were detected by an ensemble of position-sensitive, high resolution detecter placed at the focal plane of the spectrometer. The various collective nuclear models: vibrations harmonic (VM) and anharmonic (AVM), rotationnal symmetric (SRM)and asymmetric (ARM), rotation-vibration (RVM), and interacting bosons model (IBM), used in the analysis of the experimental data are presented. The data for the low-lying levels of 148-150 Sm are analysed in the frame-work of the second order VM. The multiple-phonon states (1-,5-,3-) are studied for the first time in these nuclei. These analyses revealed that effects of anharmonicity should be considered especially for the multiphonon states. The data for the low-lying members of the ground states band (0+,2+,4+,6+) of 152-154Sm are analysed in the frame-work of SRM. The ground-state band and the octupole-vibrationnal band KIT= 0, (1-,3-,5-), of these two nuclei are for the first time, analysed simultaneous and in a coherent fashion, in the frame-work of the RVM. In the case of the inelastic 70-74 Ge (α,α'), experiments, the data for the low-lying states are analysed in the frame-work of the ARM, VM and AVM. The AVM is found to give a better description of the low-lying states of these three nuclei. A more rigorous and coherent method of treating the anharmonicity in vibrationnal nuclei is presented, starting from the Hamiltonien of Brink and Kerman ; the results obtained by this method is very encouraging. The application of the IBM to the analysis of inelastic scattering data is presented
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Binauld, Quentin. "Modélisation et simulation du rayonnement dans les jets de moteurs à propergol solide à haute altitude." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLC090/document.

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Le rayonnement dans les jets issus de moteurs à propergol solide constitue un phénomène essentiel à l’estimation des flux aux parois et à la prédiction de la signature radiative des engins. A haute altitude, de l’ordre de 100 km, ces jets sont caractérisés par des écoulements compressibles diphasiques, à fort aspect raréfié dans certaines régions, compos ´es de particules d’alumine et de gaz de combustion. Le transfert radiatif y joue un rôle important dans la mesure où il influence fortement le refroidissement et le changement de phase des particules. Afin de simuler numériquement les jets et leur rayonnement, différents modèles ont été développés. Le rayonnement des gaz a été pris en compte à l’aide de modèles statistiques à bandes étroites. Le phénomène de surfusion qui régit le changement de phase de l’alumine et les champs de température associés aux différentes tailles de particules, a été pris en compte. Enfin, une méthode de splitting des puissances radiatives a été mise en œuvre afin de permettre le couplage entre le rayonnement et l’écoulement dans des milieux en des ‘équilibre thermique gaz/particules. Ces modèles ont été implémentes dans une plateforme de calcul, permettant de coupler un solveur fluide utilisant une approche Navier-Stokes, un solveur eulérien pour traiter la phase dispersée et un solveur radiatif qui utilise une méthode de Monte Carlo. L’outil numérique développe a été partiellement validé en comparant nos résultats aux mesures obtenues dans le cadre de l’expérience BSUV2. Dans les conditions de cette expérience, le rayonnement des particules est prédominant mais la contribution des gaz s’avère non négligeable. Des simulations sous différentes hypothèses ont permis de mettre en évidence le rôle primordial du transfert radiatif, couplé au phénomène de surfusion, dans l’établissement des champs de température des particules. La dernière partie de ces travaux s’est attachée à l’étude du déséquilibre vibrationnel de la phase gazeuse et de son impact sur le rayonnement dans les jets. Il est montré que le gel partiel des niveaux de vibration de la molécule CO2 durant la détente du jet peut augmenter de façon significative son rayonnement
Radiation from solid propellant rocketplumes is important for the prediction of thermalfluxes on vehicle walls and of plume signature. Athigh altitudes, of approximately 100 km, those plumesare characterized by two-phase compressible flows,highly rarefied in some regions, composed of aluminaparticles and exhaust combustion gases. Radiativetransfer plays an important role in the cooling and thephase change of the particles.In order to carry out numerical simulations of rocketplumes and their radiation, several models have beendeveloped. The radiation of the gas phase is takeninto account using statistical narrow bands models.The supercooling phenomenon has been modeled todeal with the phase change of alumina and to obtaincorrect temperature fields for the different size classesof particles. Finally, a splitting method of the radiativepower has been established to enable the couplingbetween radiation and the flow field under gas/particlethermal non-equelibrium. These models have beenimplemented in a calculation platform, enabling tocouple a Navier-Stokes solver for the gas phase, anEulerian solver dealing with the dispersed phase anda radiative solver based on a Monte Carlo method.The developed numerical tool has been partly validatedcomparing our results with the measurementsobtained during the BSUV2 experiment. In the conditionsof this experiment, particle radiation is shownto be predominant but the contribution of the gasphase is found to be non-negligible. Simulations underdifferent hypotheses have put the emphasis onthe importance of radiative transfer, coupled with thesupercooling phenomenon, for an accurate evaluationof particle temperature fields.The last part of this work focuses on the study ofgas vibrational non-equilibrium and its impact on radiationfrom high altitude plumes. It is shown thatthe slow deexcitation of vibrational levels of the CO2molecule during the plume expansion may increasesignificantly its radiation
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Marques, Luís Silvino Alves. "Modélisation et caractérisation de décharges radiofréquence à couplage capacitif dans l'hydrogène." Paris 11, 2005. http://www.theses.fr/2005PA11A002.

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Le travail presente traite de la modelisation et de la caracterisation de decharges radiofrequence (rf dans l'hydrogene. Le reacteur utilise possede une symetrie cylindrique et ses deux electrodes, paralleles, permettent un couplage capacitif au plasma. Dans un premier temps, un modele bi-dimensionnel elabore (qui decrit la dynamique des electrons et des ions h+, h2+, h3+ et h- dans le reacteur) y est couple de faÇon auto-coherente a un modele collisionnel-radiatif homogene (qui inclut une description complete de la cinetique vibrationnelle et atomique de l'hydrogene). L'etude de la decharge y est menee sur une gamme etendue de frequences d'excitation, de pressions du gaz et de tensions rf appliquees. Un bon accord est observe entre les previsions du modele et les mesures experimentales du potentiel plasma et de la puissance electrique couplee au plasma. En ce qui concerne les valeurs de densite electronique et de tension d'auto-polarisation, l’accord n'est que qualitatif - les valeurs calculees par le modele etant sous-estimees par rapport aux resultats experimentaux. Cet ecart ne peut cependant pas s'expliquer completement par le choix du schema cinetique mais plus vraisemblablement par celui de la description homogene adoptee pour le transport des neutres. Dans un deuxieme temps, afin de clarifier cet aspect, un modele hydrodynamique, exploitant les equations de navier stokes, y est developpe pour le gaz et couple a un module de transport reactif de masse multi-composants. Ce modele innovateur devant pouvoir etre utilise
This work presents the modelling and the characterization of capacitively-coupled radio- frequency discharges in hydrogen, produced within a cylindrical parallel-plate reactor. The discharge characterization covered a wide range of excitation frequencies (13,56-80. 0 mhz). Gas pressures (0. 2 - 6 torr) and applied rf voltages (50-800 v), and used a state of art two-dimensional fluid model (to describe the dynamics of electrons, positive ions h+, h2+, h3+ and negative ion h- in the reactor), self-consistently coupled to a homogeneous collisional-radiative model for hydrogen (including a very complete kinetic scheme involving vibrationally excited molecular species and electronically excited atomic species). There is a good agreement between calculated results and experimental measurements for the coupled electrical power and the plasma potential. However, model predictions for the electron density and the self-bias voltage show only a qualitative agreement with experiment, with calculated values understimated with respect to measurements. This qualitative disagreement is only slightly dependent of the kinetic scheme adopted, and probably is a direct consequence of the homogenous model describing the transport of neutral species. To clarify this, a two-dimensional hydrodynamic gas model is developed based on the navier-stokes equation system plus a multicomponent reactive mass transport module. This innovative model is the key part of a powerful predictive tool, to be used in the optimisation of plasma reactors for material processing
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Habka, Sana. "Spectroscopie optique des paires d'ions : De la caractérisation des modèles en phase gazeuse à l'identification des paires d'ions en solution." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS227/document.

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Les appariements d’ions sontomniprésents dans la nature, des océans auxaérosols, et passant par les organismes vivants.Les paires d’ions présentes dans les solutionsriches en ions y jouent un rôle crucial, notammentdans le déroulement des mécanismes réactionnelschimiques et biochimiques. En dépit de leurimportance, la caractérisation expérimentale despaires en solution reste problématique en raison dela coexistence de plusieurs types. Ainsi, le premierobjectif de ce travail est de développer uneapproche originale en phase gazeuse, pour l’étudedes paires d’ions modèles entre un groupementcarboxylate et un cation alcalin, illustrant le typed’appariement observé dans le milieu biologique.Ces premières études sont menées à l’aide d’uneapproche de spectroscopie IR et UV sélective enconformation, combinée à des calculs au niveauchimie quantique sur des modèles de formulegénérale (C6H5-(CH2)n-COO-, M+; M = Li, Na, K,Rb, Cs et n ≤ 4). L’appariement entre les ions a étéainsi caractérisé sur l’ensemble de ces systèmes, etune compétition entre les interactions cation-anionet cation-π a été observée pour les systèmes de plusgrande taille.Dans un second temps, une étude théorique estdéveloppée dans l’objectif de proposer un spectrethéorique pour chaque type de paires, et de leconfronter aux spectres expérimentaux en solutionde la littérature. L’approche repose sur le calcul dela signature vibrationnelle de paires (CH3-COO-,M+; M = Li, Na) et de l’anion libre, entouréssuccessivement de molécules d’eau explicitesdécrites au niveau chimie quantique, puis auniveau champ de force et enfin par un modèle desolvant continu.Cet apport original pour l’étude des paires d’ionsneutres ouvre la voie vers une meilleurecaractérisation de ces paires dans les solutions électrolytiques
Ion pairs are ubiquitous in nature andwere documented in sea waters, aerosols andliving organisms, thus they play a crucial role inmany chemical and biochemical mechanisms.Although many experimental approaches aimedat identifying these ion pairs in solutions, theyfailed in characterizing their microscopicproperties, mainly due to the coexistence of manytypes of pairs in solution. This original study aimsto identify the structural properties of ion pairmodels in the gas phase that depicts theinteraction between carboxylate group and alkalication, largely present in biological media.Model systems (M+, C6H5(CH2)nCOO-, M = Li,Na, K, Rb, Cs and n ≤ 4) were the subject of thefirst studies conducted using gas phaseconformational selective IR and UV spectroscopycombined to quantum chemistry calculations.Among the identified structures, we found asecondary interaction between the cation andphenyl ring (cation-π interaction) for systems witha flexible carbon chain, which led us to study thecompetition between cation-anion and cation-πinteractions.The second study developed focused mainly oncharacterizing ion pairs (M+, CH3COO-; M = Li,Na) and free anion in solution, where the firstsolvation layer were described at the quantumlevel, followed by a solvent continuum. Thus thevibrationnal signatures proposed for theseaggregates were compared to solution spectra inlitterature, thus offering a reliable structuralassignement.This study on neutral ion pairs paves way to a betterunderstanding of ion pairing and offers a uniqueapproach to adress the structural characterization ofthese systems in solution
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Hermet, Patrick. "Modélisation de la dynamique vibrationnelle des oligothiophènes." Montpellier 2, 2004. http://www.theses.fr/2004MON20168.

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O'Neill, Martin P. "Vibrational analyses of unrestrained large skeletal structures." Thesis, University of Surrey, 1989. http://epubs.surrey.ac.uk/847864/.

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The modal characteristics of large skeletal structures (LSS) made from tubes of graphite reinforced Poly (Ether Sulphone) (PES), a high technology thermoplastic composite material, have been investigated. These large skeletal structures are intended for application in land-mobile communications networks and would be positioned at geosynchronous equatorial orbit (GEO). Experimental modal surveys of a number of skeletal configurations have been conducted under simulated unrestrained conditions, and have involved the prior commissioning of the modal survey apparatus used in their examination. The surveys have been performed in tandem with analogous natural frequency extractions from the structures' analytical models using the finite element (FE) method. The skeletal structures were fabricated using either the graphite reinforced PES material or perspex plastic, and formed representative sub-structures of candidate LSS configurations. The structures' geometries ranged in complexity from sparsely configured composite systems to a perspex platform-based bank of reflector arrays, and allowed the evolution of both local and global modal behaviour in these skeletal systems to be observed in detail. It has been found that the modal behaviour of predominantly uniaxially reinforced PES composite, in the state of uniaxial stress to which it will be subjected as a component of multi-bay LSS configurations, can be accurately described using an isotropic approximation for its material characteristics. Additionally, it has been found that the use of perspex plastic as a material for modelling representative multi-bay sub-structures of composite LSS is justified in consideration of the eventual stress environments to which the composite material will be subjected in LSS systems. Following this, a series of analytical parametric studies has been performed on a number of concept composite LSS suitable for use in a data-relay capacity at GEO. It has been found that the modal frequencies developed by these configurations are comparable to the published frequencies of similar skeletal structures intended for use at these orbits. It has also been established that the testing of a reduced modelling of the LSS can be highly instructive as to the general trends in modal behaviour developed by the large skeletal structures in orbit.
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Lucas, Geoffrey Iain Mechanical &amp Manufacturing Engineering Faculty of Engineering UNSW. "Vibrational characteristics of structures with uncertainty." Publisher:University of New South Wales. Mechanical & Manufacturing Engineering, 2008. http://handle.unsw.edu.au/1959.4/41274.

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This thesis is concerned with the prediction of the vibro-acoustic response of structures with uncertain properties in the mid frequency region. The motivation for this research is the growing need of engineers to understand the responses of a group of similar structures ranging from vehicles, aircraft and aerospace structures, to household whitegood appliances. These structures are complex in geometry and may possess variability in their material or geometric properties, as well as variation arising from the assembly and manufacturing processes. Small variations can have a significant effect on a dynamic response of a structure, and the effect of structural uncertainties increases as the frequency increases. Deterministic modelling techniques such as finite element analysis are only suitable to model complex structures at low frequencies. Furthermore, FEA cannot easily account for uncertainty or randomness in structural parameters. High frequency dynamic predictive techniques such as Statistical Energy Analysis can account for structural uncertainty but is limited to structures with high modal density. There exists a frequency range between the two methods in which neither technique can be applied with great confidence. The objective of this thesis is to investigate predictive techniques for mid frequency vibration analysis of dynamic systems with structural uncertainties. The first part of this work is to numerically characterise the effect of a range of uncertainties on the modal statistics of structures. The degree of uncertainty required to achieve universality of the statistical properties is investigated. This is achieved by examining the modal statistics of dynamic systems with a range of uncertainty, corresponding to uncertainty due to mass and stiffness perturbations, uncertainty at the boundaries of a structure, uncertainty in the coupling between structures, uncertainty in the material properties of a structure and uncertainty in the geometry of a structure. Several structures are examined corresponding to a plate with masses and/or linear springs added at random locations, a plate with torsional springs attached at random locations along its boundary edges, two plates coupled by linear springs at random locations, a mass-loaded coupled L-shaped plate, a mass-loaded frame-plate structure, and a plate with varying Young's modulus, density and thickness. The natural frequencies of the aforementioned structures have been derived using either the Lagrange-Rayleigh-Ritz technique, finite element analysis, or the use of interval analysis in conjunction with FEA. The natural frequency statistics of structures with uncertain properties are observed using two statistical measures; the statistical overlap factor and the probability density function of the spacing between successive natural frequencies. The statistical overlap factor is defined by the variation in a natural frequency from its mean value measured across an ensemble of nominally identical structures with uncertainty. For a single ensemble member, the probability density function of the spacing between successive natural frequencies is compared to a Rayleigh distribution of the mean frequency spacing. A Rayleigh distribution of modal spacings is a feature of the universality exhibited by structures with uncertainty. To further investigate the effect of structural uncertainty on the vibrational characteristics of structures, the interval analysis is applied to finite element models of a plate with uncertainty in its material properties and dimensions. Using this method, the Young's modulus, density and thickness of a rectangular plate were set to vary by a small amount within predefined bounds. Using finite element equations, the natural frequencies and modeshapes of the structure were then determined in terms of the Young's modulus, density and plate thickness. For the mass and spring loaded plates, the springs were shown to affect the lower order modes while the masses had a significant effect on the higher order modes. As the frequency increased, only a small amount of perturbation was sufficient to affect the natural frequencies of a structure. Using the interval analysis method, the variation of the natural frequencies from their deterministic value increased as the frequency increased. An ergodic hypothesis was used to examine the responses statistics of structures with uncertainty. Three structures have been computationally studied corresponding to two plates coupled by springs, an L-shaped plate and a frame plate structure. Uncertainty has been generated for the two coupled plates by locating the springs randomly across the surface of the two plates. For the L-shaped plate and a frame plate structure, uncertainty was generated by randomly positioning small masses across the plates. Using the ergodic hypothesis, the frequency averaged response on one member of an ensemble is compare with the ensemble averaged response. It was found that the ensemble averaged response was well predicted by a frequency averaged response of a single ensemble member. The width of the frequency averaging band was shown to have a large influence on the quality of the match between the frequency and ensemble averaged responses. Results were significantly improved using a frequency averaging bandwidth which varies proportionally to frequency. Finally, experiments have been conducted on an L-shaped plate, a frame plate structure and a vehicle to validate the computational results for the natural frequency and response statistics.
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Vorobiev, Anatoliy. "Thermal vibrational convection in near-critical fluids." Toulouse 3, 2003. http://www.theses.fr/2003TOU30205.

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Asarar, Kate. "Predicting comfort in autonomous driving from vibration measurements using machine learning models." Thesis, KTH, Fordonsdynamik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299355.

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Highly automated driving is approaching reality at a high speed. BMW is planningto put its first autonomous driving vehicle on the road already by 2021. The path torealising this new technology is however, full of challenges. Not only the transverseand longitudinal dynamic vehicle motion play an important role in experiencedcomfort but also the requirements and expectations of the occupants regarding thevertical dynamic vibration behaviour. Especially during long trips on the motorwaywhere the so far active driver becomes the chauffeured passenger, who reads, worksor sleeps in his newly gained time. These new use-cases create new requirements forthe future design of driving comfort which are yet to be fully discovered.This work was carried out at the BMW headquarters and had the aim to usedifferent machine learning models to investigate and identify patterns between thesubjective comfort values reported by participants in a study, on a comfort scale of 1-7 and the mechanical vibrations that they experienced, measured inm/s2. The datawas collected in a previous independent study and statistical methods were used toinsure the quality of the data. A comparison of the ISO 2631-1 comfort ratings andthe study’s findings is done to understand the need for a more sophisticated model to predict comfort in autonomous driving. The work continued by investigating different dimensionality reduction methods and their influence on the performance of the models. The process used to build, optimise and validate neural networks and other models is included in the method chapter and the results are presented. The work ends with a discussion of both the prediction results and the modelsre-usability. The machine learning models investigated in this thesis have shown great po-tential for detecting complex pattern that link feelings and thoughts to mechanical variables. The models were able to predict the correct level of comfort with up to50% precision when trying to predict 6 or 7 levels of comfort. When divided into high versus low discomfort, i.e. predicting one of two comfort levels, the models were able to achieve a precision of up to 75.4%.Excluded from this thesis is the study of differences in attentive vs inattentive state when being driven in an autonomous driving vehicle. It became clear shortly before the start of this work, that the experiment that yielded the data used for it failed to find a statistically significant difference between the two states.
Självkörande bilar är snart inte längre en dröm utan en mycket sann verklighet. År 2021 planerar BMW att släppa ut sin första autonoma bil på vägarna. Dock är vägen till att förverkliga denna nya teknik full av utmaningar. Utöver den tvärgående och längsgående dynamiska styrningen av fordonet, så spelar även passagerarens förväntningar på det vertikala dynamiska vibrationsbeteendet en växande roll. Speciellt under långa resor på motorvägen där den för nuvarande aktiva föraren blir passagerare, som läser, arbetar eller sover under sin nyvunna tid. De nya användarsenarierna ställer i sin tur nya krav på bilens komfort. Krav som inte har blivit hittills utförligt undersäkta, fastän de kan komma att spela en stor roll i teknikens framgång.Detta examensarbete genomfördes hos BMW:s huvudkontor i Tyskland och hade som mål att undersöka olika maskininlärningsmodeller och deras förmåga att identifiera mönster mellan de subjektiva komfortvärden som rapporterats av deltagarna i en studie, givna på skala 1-7, och de mekaniska vibrationerna som de upplevde mätta i m/s^2. Uppgifterna samlades in i en tidigare oberoende studie. Statistiska metoder användes för att säkerställa datakvaliteten. I detta arbeter har en jämförelse mellan ISO 2631-1-komfortbedömningar och undersökningsresultaten gjorts för att förstå behovet av en mer sofistikerad komfortstandard för att objektifera komfort i självkörande bilar. Arbetet fortsatte med att undersöka olika metoder för att minska datadimensionerna och deras inflytande på modellernas prestanda. Processen som används för att bygga, optimera och validera neurala nätverk och andra modeller är inkluderad i metoddelen och resultaten är presenterade och förklarade därefter. Arbetet avslutas med en diskussion kring både resultatets validitet och modellernas användbarhet.De maskininlärningsmodeller som undersöktes i detta examensarbete har visat stor potential för att upptäcka komplexa mönster som kopplar känslor och tankar till mekaniska variabler. Modellerna kunde förutsäga rätt komfortnivå med upp till 50% precision när 6 eller 7 nivåer av komfort användes. Vid uppdelning i hög mot låg komfort, dvs att kunna förutsäga en av två komfortnivåer, kunde modellerna uppnå en precision på upp till 75.4%.
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Books on the topic "Modèle vibrationnel"

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Advanced vibration analysis. Boca Raton, FL: CRC/Taylor & Francis, 2007.

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Modeling and control in vibrational and structural dynamics: A differential geometric approach. Boca Raton, FL: Taylor & Francis, 2011.

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Kelly, S. Graham. Advanced Vibration Analysis. Taylor & Francis Group, 2006.

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Baer, Tomas, and William L. Hase. Unimolecular Reaction Dynamics. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195074949.001.0001.

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This book provides a penetrating and comprehensive description of energy selected reactions from a theoretical as well as experimental view. Three major aspects of unimolecular reactions involving the preparation of the reactants in selected energy states, the rate of dissociation of the activated molecule, and the partitioning of the excess energy among the final products, are fully discussed with the aid of 175 illustrations and over 1,000 references, most from the recent literature. Examples of both neutral and ionic reactions are presented. Many of the difficult topics are discussed at several levels of sophistication to allow access by novices as well as experts. Among the topics covered for the first time in monograph form is a discussion of highly excited vibrational/rotational states and intramolecular vibrational energy redistribution. Problems associated with the application of RRKM theory are discussed with the aid of experimental examples. Detailed comparisons are also made between different statistical models of unimolecular decomposition. Both quantum and classical models not based on statistical assumptions are described. Finally, a chapter devoted to the theory of product energy distribution includes the application of phase space theory to the dissociation of small and large clusters. The work will be welcomed as a valuable resource by practicing researchers and graduate students in physical chemistry, and those involved in the study of chemical reaction dynamics.
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United States. National Aeronautics and Space Administration., ed. Automation based on knowledge modeling theory and its applications in engine diagnostic systems using space shuttle main engine vibrational data. [Washington, DC: National Aeronautics and Space Administration, 1995.

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Nitzan, Abraham. Chemical Dynamics in Condensed Phases. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780198529798.001.0001.

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This text provides a uniform and consistent approach to diversified problems encountered in the study of dynamical processes in condensed phase molecular systems. Given the broad interdisciplinary aspect of this subject, the book focuses on three themes: coverage of needed background material, in-depth introduction of methodologies, and analysis of several key applications. The uniform approach and common language used in all discussions help to develop general understanding and insight on condensed phases chemical dynamics. The applications discussed are among the most fundamental processes that underlie physical, chemical and biological phenomena in complex systems. The first part of the book starts with a general review of basic mathematical and physical methods (Chapter 1) and a few introductory chapters on quantum dynamics (Chapter 2), interaction of radiation and matter (Chapter 3) and basic properties of solids (chapter 4) and liquids (Chapter 5). In the second part the text embarks on a broad coverage of the main methodological approaches. The central role of classical and quantum time correlation functions is emphasized in Chapter 6. The presentation of dynamical phenomena in complex systems as stochastic processes is discussed in Chapters 7 and 8. The basic theory of quantum relaxation phenomena is developed in Chapter 9, and carried on in Chapter 10 which introduces the density operator, its quantum evolution in Liouville space, and the concept of reduced equation of motions. The methodological part concludes with a discussion of linear response theory in Chapter 11, and of the spin-boson model in chapter 12. The third part of the book applies the methodologies introduced earlier to several fundamental processes that underlie much of the dynamical behaviour of condensed phase molecular systems. Vibrational relaxation and vibrational energy transfer (Chapter 13), Barrier crossing and diffusion controlled reactions (Chapter 14), solvation dynamics (Chapter 15), electron transfer in bulk solvents (Chapter 16) and at electrodes/electrolyte and metal/molecule/metal junctions (Chapter 17), and several processes pertaining to molecular spectroscopy in condensed phases (Chapter 18) are the main subjects discussed in this part.
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Darrigol, Olivier. Theories of Heat: Some Background. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198816171.003.0002.

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This is a condensed history of thermodynamics and kinetic-molecular theory in Boltzmann’s times and earlier. In the second half of the nineteenth century, there was a widely shared belief in the kinetic-molecular nature of heat. This belief extended to the generally educated public, thanks to popular accounts such as John Tyndall’s Heat considered as a mode of motion (1863). There still was no consensus on the precise form of this motion. For instance, many French physicists persisted in favoring Ampère’s old vibrational picture. Also, there was no consensus on the fruitfulness of the kinetic-molecular theories. Most physicists did not need more than macroscopic thermodynamics, and there were voices, toward the end of the century, to denounce the disproportion between the difficulty of the kinetic-molecular theories and the amount of usable results. Boltzmann had to face such criticism although he was not alone in his quest for a comprehensive kinetic-molecular view of nature.
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Book chapters on the topic "Modèle vibrationnel"

1

Jacobs, M. H. G., and H. A. J. Oonk. "307 Towards Vibrational Models." In Equilibrium Between Phases of Matter, 145–90. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-1948-4_7.

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Picquart, Michel. "Vibrational Spectroscopy of Biological Membrane Models." In Developments in Mathematical and Experimental Physics, 125–34. Boston, MA: Springer US, 2003. http://dx.doi.org/10.1007/978-1-4615-0207-4_12.

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Vasilevskiy, M. I., and O. V. Baranova. "Vibrational Properties of a Clustered Linear Atomic Chain with Substitutional Impurities." In Cluster Models for Surface and Bulk Phenomena, 631–40. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4684-6021-6_50.

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Handke, Mirosław, Włodzimierz Mozgawa, and Magdalena Rokita. "Vibrational Spectroscopy of Borogermanate Glasses as Models for Aluminosilicate Glasses." In Progress in Fourier Transform Spectroscopy, 515–17. Vienna: Springer Vienna, 1997. http://dx.doi.org/10.1007/978-3-7091-6840-0_126.

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Aguirre, M., I. Urresti, F. Martinez, G. Fernandez, and S. Cogan. "Vibrational Model Updating of Electric Motor Stator for Vibration and Noise Prediction." In Model Validation and Uncertainty Quantification, Volume 3, 283–93. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-54858-6_28.

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Roberts, Thomas, and Phillip J. Cornwell. "An Investigation of Vibrational Characteristics of Lap Joints Using Experimental and Analytical Methods." In Topics in Modal Analysis & Testing, Volume 8, 9–24. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-47717-2_2.

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Useche, Jairo, and Alexander Narvaez. "Vibrational Response of Elastic Membranes Coupled to Acoustic Fluids Using a BEM–BEM Formulation." In Topics in Modal Analysis I, Volume 7, 333–40. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-04753-9_34.

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Walter, R. F. "Comparison of Vibrational Kinetics Models for the Combustion-Driven CO2 Gasdynamic Laser." In Gas Flow and Chemical Lasers, 307–12. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-71859-5_47.

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Ortiz, Jonel, Giuliana Davis, Kevin Troyer, and Paul Heyliger. "The Influence of Edge Boundary Conditions and Cracks on Vibrational Modes of Multilayer Ceramic Capacitors." In Topics in Modal Analysis & Testing, Volume 9, 79–89. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-74700-2_9.

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Eliseev, Sergey Viktorovich, and Andrey Vladimirovich Eliseev. "Construction of Mathematical Models of Mechanical Vibrational Systems: Additional Couplings and Equivalent Transformations." In Studies in Systems, Decision and Control, 121–206. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-31295-4_4.

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Conference papers on the topic "Modèle vibrationnel"

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Baumruk, V., J. Kapitán, V. Kopecký, P. Bouř, P. Maloň, V. K. Vaidyan, and V. S. Jayakumar. "Raman Optical Activity of Biomolecules: From Simple Models to Complex Systems." In PERSPECTIVES IN VIBRATIONAL SPECTROSCOPY: Proceedings of the 2nd International Conference on Perspectives in Vibrational Spectroscopy (ICOPVS 2008). AIP, 2008. http://dx.doi.org/10.1063/1.3046219.

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Gautam, Rekha, Jennifer Herington, Naoko Brown, Wilson Adam, Jackson H. Rogers, Jen Bateman, Christine O'Brien, Jeff Reese, and Anita Mahadevan-Jansen. "Comparing cervical maturation in preterm and term birth mouse models with Raman spectroscopy (Conference Presentation)." In Biomedical Vibrational Spectroscopy 2020: Advances in Research and Industry, edited by Wolfgang Petrich and Zhiwei Huang. SPIE, 2020. http://dx.doi.org/10.1117/12.2551333.

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Wasilewski, Maciej, and Dominik Pisarski. "Adaptive optimal control algorithm for vibrational systems under nonlinear friction." In 2017 22nd International Conference on Methods and Models in Automation and Robotics (MMAR). IEEE, 2017. http://dx.doi.org/10.1109/mmar.2017.8046807.

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Candy, J. V., L. M. Stoops, S. N. Franco, and M. C. Emmons. "Modal Frequency Tracking of an Unknown Vibrational System." In 2018 OCEANS - MTS/IEEE Kobe Techno-Ocean (OTO). IEEE, 2018. http://dx.doi.org/10.1109/oceanskobe.2018.8558788.

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Onipede, Oladipo, Ilya Avdeev, Amir Khalilollahi, and Lisa Buziewicz. "Vibrational Characteristics of Micro Beams." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-79560.

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Several high frequency MEMS devices such as resonators and filters can be modeled as electrostatically driven micro-beams. While their static structural response depends solely on the magnitude of the applied voltage and their elastic stiffness, their dynamic response also depends on their mass, damping properties and the applied voltage frequency. In designing these devices, critical parameters must include the maximum voltage, voltage frequency and the natural frequency of the system. Even though the electrostatic force developed by the voltage is non-linear, the system can be modeled as a harmonic system due to the periodic nature of the response. Results from a non-linear structural-electrostatic dynamic model show the importance of the dynamic properties and the non-linear electrostatic force. The results show significantly lower limiting voltages, especially when the driving voltage is close to the natural frequency of the system. The effect of damping is also addressed.
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Cammi, R., George Maroulis, and Theodore E. Simos. "On the Vibrational Effective Polarizabilities Calculation from Cavity Models." In COMPUTATIONAL METHODS IN SCIENCE AND ENGINEERING: Advances in Computational Science: Lectures presented at the International Conference on Computational Methods in Sciences and Engineering 2008 (ICCMSE 2008). AIP, 2009. http://dx.doi.org/10.1063/1.3225405.

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Korpics, Natalie S., and Reid A. Berdanier. "Consideration of Simplified Structural Models for Turbine Vane Modal Analysis." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-15806.

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Abstract Modal analysis of jet engine hardware is a necessary analytical tool utilized by engineers to understand and predict the vibrational risks to the system. Whereas blades and disks are critically analyzed due to their failure modes and effects, turbine vanes also need to be evaluated with respect to their design modal criteria to minimize potential risks to the engine. Although full hoop models of the entire system are most accurate, the time required for modeling and solution processing is typically prohibitive. Through cyclic symmetry and the use of commercial contact techniques, an analytical model may be created that provides the behavior of the entire system with a fraction of the computing time. However, methods for model simplification, including vane-only models, have not been addressed, and the potential for simplified models to accurately predict system modes is of particular interest. Accordingly, this paper studies the finite element modeling procedures for turbine vane modal analysis using multiple contact methods and cyclic symmetry applied to a turbine vane. An emphasis is placed on evaluating vane-only modeling techniques and an abbreviated turbine casing model. Additional comparisons with a traditional assembly model assess finite element model solution accuracy and efficiency. Ultimately, formal recommendations are offered for structural modeling of turbine vanes, including assessments of accuracy, reduction of frequency prediction capability, and computational efficiency gain.
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Sadeghi, Reza, Firooz Bakhtiari-Nejad, and Taha Goudarzi. "Vibrational Analysis of Human Femur Bone." In ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-85114.

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Femur bone is the longest and largest bone in the human skeleton. This bone connects the pelvic bone to the knee and carries most of the body weight. The static behavior of femur bone has been a center of investigation for many years while little attention has been given to its dynamic and vibrational behavior, which is of great importance in sports activities, car crashes and elderly falls. Investigation of natural frequencies and mode shapes of bone structures are important to understand the dynamic and vibrating behaviors. Vibrational analysis of femoral bones is presented using finite element method. In the analysis, the bone was modeled with isotropic and orthotropic mechanical properties. The effect of surrounding bone muscles has also been accounted for as a viscoelastic medium embedding the femur bone. Natural frequencies extracted considering the effects of age aggravated by weakening the elastic modulus and density loss. The effects of real complex bone geometry on natural frequencies are studied and are compared with a simple circular cross-sectional model.
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Stepanov, N. F., and Alexei A. Buchachenko. "Theoretical models of vibrational predissociation for van der Waals complexes." In High Resolution Molecular Spectroscopy: 11th Symposium and School, edited by Alexander I. Nadezhdinskii, Yu V. Ponomarev, and Leonid N. Sinitsa. SPIE, 1994. http://dx.doi.org/10.1117/12.166234.

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Elkin, P. M., L. M. Babkov, T. V. Bezrodnaya, G. A. Puchkovskaya, and M. D. Elkin. "Structural-dynamic models and vibrational spectra of nitrobenzene and nitropyridines." In Saratov, Russia, edited by Vladimir L. Derbov, Leonid A. Melnikov, and Lev M. Babkov. SPIE, 2005. http://dx.doi.org/10.1117/12.636984.

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Reports on the topic "Modèle vibrationnel"

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Lehman, S., J. Candy, M. Converse, and K. Fisher. Vibrational Energy Harvesting Using a Cantilever Model. Office of Scientific and Technical Information (OSTI), July 2021. http://dx.doi.org/10.2172/1814093.

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Candy, J. V., J. E. Case, K. A. Fisher, P. Kumar, P. K. Singh, D. E. Bower, K. L. Eves, B. R. Illingsworth, and M. C. Emmons. Modal Frequency Identification of Vibrational Response Measurements: Simulation/Experiment/Validation. Office of Scientific and Technical Information (OSTI), September 2018. http://dx.doi.org/10.2172/1497977.

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Rice, Betsy M., John Grosh, and Donald L. Thompson. Vibrational Mode Selectivity in the Unimolecular Decomposition of CH2NNO2. Fort Belvoir, VA: Defense Technical Information Center, May 1995. http://dx.doi.org/10.21236/ada294300.

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Candy, J. V., S. N. Franco, M. C. Emmons, I. M. Lopez, and R. A. Fellini. MODAL CLASSIFICATION: Processing and Anomaly Detection in a Noisy Vibrational Environment. Office of Scientific and Technical Information (OSTI), December 2016. http://dx.doi.org/10.2172/1497270.

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Daw, Murry. First-Principles Calculation of Vibrational Mode Lifetimes in Complex Materials. Office of Scientific and Technical Information (OSTI), July 2019. http://dx.doi.org/10.2172/1571761.

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Candy, J. V., J. Case, K. E. fisher, D. Bower, B. Illingsworth, and M. C. Emmons. Modal Frequency Identification of a Cylindrical Object from Noisy Vibrational Response Measurements. Office of Scientific and Technical Information (OSTI), May 2018. http://dx.doi.org/10.2172/1497275.

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Ali, A. W. The Harmonic and Anharmonic Models for Vibrational Relaxation and Dissociation of the Nitrogen Molecule. Fort Belvoir, VA: Defense Technical Information Center, December 1986. http://dx.doi.org/10.21236/ada177453.

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Marshalek, E. R. Theoretical studies in nuclear structure. [Self-consistent cranking model for anharmonic collective vibrational states]. Office of Scientific and Technical Information (OSTI), December 1992. http://dx.doi.org/10.2172/6609040.

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Yau, Waifan. Spatially resolved localized vibrational mode spectroscopy of carbon in liquid encapsulated Czochralski grown gallium arsenide wafers. Office of Scientific and Technical Information (OSTI), April 1988. http://dx.doi.org/10.2172/5398032.

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Mork, Steven M., C. C. Miller, and Laura A. Philips. High Resolution Spectroscopy of 1,2-Difluoroethane in a Molecular Beam: A Case Study of Vibrational Mode-Coupling. Fort Belvoir, VA: Defense Technical Information Center, May 1992. http://dx.doi.org/10.21236/ada251286.

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