Letteratura scientifica selezionata sul tema "Acoustic-elastic coupling"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Consulta la lista di attuali articoli, libri, tesi, atti di convegni e altre fonti scientifiche attinenti al tema "Acoustic-elastic coupling".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Articoli di riviste sul tema "Acoustic-elastic coupling":
1
Shin, Ye Jeong, Hong Min Seung e Joo Hwan Oh. "Fluid-like elastic metasurface". Applied Physics Letters 122, n. 10 (6 marzo 2023): 101701. http://dx.doi.org/10.1063/5.0139336.
Abstract (sommario):
What makes elastic waves different from other waves is the existence of various wave modes and coupling between these modes. Accordingly, the manipulation of elastic waves suffers from many limitations due to mode coupling, which is an inherent complex physical property of elastic waves. In this study, we propose fluid-like elastic metasurfaces that act as an acoustic (fluid) surface to perfectly eliminate mode coupling. Because longitudinal and shear waves are decoupled, only reflected longitudinal (or shear) waves exist when longitudinal (or shear) waves are incident. Using a strip-type unit cell, elastic metasurfaces mimicking acoustic hard-wall and soft-wall were designed and realized. In addition, numerical analysis and experiments were conducted to prove the validity of the designed unit cells. This study presents a more versatile metasurface by solving the mode coupling of solid elastic waves. In addition, two types of designed fluid-like metasurfaces are expected to be utilized in further studies considering the opposite phase shift characteristic.
2
Chaplain, Gregory J., Dan Moore, Ian Hooper, Alastair Hibbins, John Sambles e Timothy Starkey. "Beyond-nearest-neighbour metamaterials". Journal of the Acoustical Society of America 154, n. 4_supplement (1 ottobre 2023): A156. http://dx.doi.org/10.1121/10.0023108.
Abstract (sommario):
Engineering the dispersion of acoustic or elastic waves using coupling terms that spatially reach beyond the immediate local environment, or unit cell, is an “emerging topic” in Metamaterial design. In this talk, we present experimental studies in acoustic and elastic systems that realize beyond-nearest-neighbour coupling to introduce dispersion relations with extrema within the first Brilloun Zone. In acoustics, we use mixed waveguide-surfacewave coupling, while in elasticity we develop an elastic scaffold (made from meccano) with reconfigurable coupling elements and demonstrate the effects of structural symmetries on these exotic dispersion relations. Applications to enhanced energy harvesting structures are presented by leveraging zero-group-velocity modes.
3
Gao, Longfei, e David Keyes. "Explicit coupling of acoustic and elastic wave propagation in finite-difference simulations". GEOPHYSICS 85, n. 5 (1 settembre 2020): T293—T308. http://dx.doi.org/10.1190/geo2019-0566.1.
Abstract (sommario):
We present a mechanism to explicitly couple the finite-difference discretizations of 2D acoustic and isotropic elastic-wave systems that are separated by straight interfaces. Such coupled simulations allow for the application of the elastic model to geological regions that are of special interest for seismic exploration studies (e.g., the areas surrounding salt bodies), with the computationally more tractable acoustic model still being applied in the background regions. Specifically, the acoustic wave system is expressed in terms of velocity and pressure while the elastic wave system is expressed in terms of velocity and stress. Both systems are posed in first-order forms and are discretized on staggered grids. Special variants of the standard finite-difference operators, namely, operators that possess the summation-by-parts property, are used for the approximation of spatial derivatives. Penalty terms, which are also referred to as the simultaneous approximation terms, are designed to weakly impose the elastic-acoustic interface conditions in the finite-difference discretizations and couple the elastic and acoustic wave simulations together. With the presented mechanism, we are able to perform the coupled elastic-acoustic wave simulations stably and accurately. Moreover, it is shown that the energy-conserving property in the continuous systems can be preserved in the discretized systems with carefully designed penalty terms.
4
Cui, Huaifeng, Rufu Hu e Nan Chen. "Modelling and analysis of acoustic field in a rectangular enclosure bounded by elastic plates under the excitation of different point force". Journal of Low Frequency Noise, Vibration and Active Control 36, n. 1 (marzo 2017): 43–55. http://dx.doi.org/10.1177/0263092317693488.
Abstract (sommario):
The coupled acoustic field of fully elastic plate model is described by the modal analysis method. The acoustic potential energy resonance peaks of the fully elastic plate model are significantly more than that of the one elastic plate model due to the influence of the vibration of multi elastic plates. The acoustic field characteristics of the fully elastic plate model are analyzed when the primary excitation source is applied on the different elastic plates. The results show that the coupled acoustic field of the fully elastic plate model is dominated by the structural mode of the elastic plate with primary excitation, and the acoustic mode of the enclosure, and the structural-acoustic coupling between the plate and the enclosure; the structure modes of the other elastic plates have less effects on the acoustic field in the enclosure except the first ones of them.
5
Dong, Kaiyuan, Yiwen Lv, Peng Wang, Wei Cheng e Han Li. "Acoustic properties of underwater acoustic metamaterials based on multi-physical field coupling model". Journal of Physics: Conference Series 2713, n. 1 (1 febbraio 2024): 012006. http://dx.doi.org/10.1088/1742-6596/2713/1/012006.
Abstract (sommario):
Abstract In this paper, according to the internal structure of underwater acoustic metamaterial, a multi-physical field coupling model of underwater acoustic metamaterial is established by using finite element analysis. Based on the model, the influence of typical underwater acoustic metamaterial structure and material parameters on sound absorption performance is studied. The results show that increasing the height or radius of the local resonance mass unit in the metamaterial is beneficial to improve the low frequency sound absorption performance. With the increase of the distance between mass elements and the thickness of elastic material, the acoustic absorption performance increases first and then decreases. Increasing the elastic modulus of elastic material of the local resonance unit or matrix will lead to the decrease of low frequency sound absorption performance of the material and the improvement of high frequency sound absorption performance. Increasing the loss factor of elastic material of the local resonance unit or matrix material can broaden the sound absorption band. These rules can provide guidance for the design of underwater acoustic metamaterials.
6
Norris, Andrew N., e Douglas A. Rebinsky. "Acoustic coupling to membrane waves on elastic shells". Journal of the Acoustical Society of America 95, n. 4 (aprile 1994): 1809–29. http://dx.doi.org/10.1121/1.408688.
7
Yoon, Gil Ho. "Unified Analysis with Mixed Finite Element Formulation for Acoustic-Porous-Structure Multiphysics System". Journal of Computational Acoustics 23, n. 01 (16 febbraio 2015): 1550002. http://dx.doi.org/10.1142/s0218396x15500022.
Abstract (sommario):
This research aims to develop a novel unified analysis method for an acoustic-porous-structure multiphysics interaction system when the porous medium is modeled by the empirical Delany–Bazley formulation. Multiphysics analysis of acoustic structure interaction is commonly performed by solving the linear elasticity and Helmholtz equations separately and enforcing a mutual coupling boundary condition. If the pressure attenuation from a porous material is additionally considered, the multiphysics analysis becomes highly intricate, because three different media (acoustic, porous, and elastic structures) with different governing equations and interaction boundary conditions should be properly formulated. To overcome this difficulty, this paper proposes the application of a novel mixed formulation to consider the mutual coupling effects among the acoustic, fibrous (porous), and elastic structure media. By combining the mixed finite element formulation with the Delany–Bazley formulation, a multiphysics simulation of sound propagation considering the coupling effects among the three media can be easily conducted. To show the validity of the present unified approach, several benchmark problems are considered.
8
Di Bartolo, Leandro, Rosário Romão Manhisse e Cleberson Dors. "Efficient acoustic-elastic FD coupling method for anisotropic media". Journal of Applied Geophysics 174 (marzo 2020): 103934. http://dx.doi.org/10.1016/j.jappgeo.2019.103934.
9
Hsiao, Fu-Li, Ying-Pin Tsai, Wei-Shan Chang, Chien-Chang Chiu, Bor-Shyh Lin e Chi-Tsung Chiang. "Photo-Elastic Enhanced Optomechanic One Dimensional Phoxonic Fishbone Nanobeam". Crystals 12, n. 7 (23 giugno 2022): 890. http://dx.doi.org/10.3390/cryst12070890.
Abstract (sommario):
We investigated the strength of acousto-optical (AO) interaction in one-dimensional fishbone silicon nanobeam computationally. The structure can generate phononic and photonic band gaps simultaneously. We use defect cavity optical mode and slow light mode to interact with acoustic defect modes. The AO coupling rates are obtained by adding the optical frequency shifts, which result from photo-elastic effect and moving-boundary effect disturbances. The AO coupling rates are strongly dependent on the overlap of acoustic and optical mode distribution. The strength of AO interaction can be enhanced by choosing certain acoustic defect modes that are formed by the stretching of wings and that overlap significantly with optical fields.
10
MAR-OR, ASSAF, e DAN GIVOLI. "A FINITE ELEMENT STRUCTURAL-ACOUSTIC MODEL OF COUPLED MEMBRANES". Journal of Computational Acoustics 12, n. 04 (dicembre 2004): 605–18. http://dx.doi.org/10.1142/s0218396x04002407.
Abstract (sommario):
A simple model displaying structural-acoustic behavior is considered. The model comprises of two parallel infinitely-long flat membranes lying on elastic foundations and the acoustic medium separating them. The structural-acoustic coupling manifests itself in that a vibrational excitation of one of the membranes triggers vibrations in the other. The governing equations are stated, and the associated finite element formulation is constructed. The model is then analyzed numerically and its vibrational properties are investigated. The proposed model is especially simple, being two-dimensional and involving a small number of parameters, but at the same time it brings to light some important features associated with structural-acoustic coupling. Therefore it may serve as a benchmark for evaluating structural-acoustic numerical schemes and as an educational tool for studying structural-acoustic coupling in a simple context.
Tesi sul tema "Acoustic-elastic coupling":
1
Nassor, Alice. "Domain decomposition method for acoustic-elastic coupled problems in time-domain. Application to underwater explosions". Electronic Thesis or Diss., Institut polytechnique de Paris, 2023. http://www.theses.fr/2023IPPAE015.
Abstract (sommario):
Ce travail étudie les approches globales en temps de décomposition de domaine pour résoudre des problèmes transitoires d'interaction fluide-structure. Afin de déterminer un algorithme optimal, nous étudions dans un premier temps la solvabilité des problèmes élastodynamiques et acoustiques transitoires avec des conditions aux frontières de type Robin et de Neumann. Nous énonçons des résultats de solvabilité, en soulignant les différentes régularités espace-temps des solutions. Nous étudions également la solvabilité du problème couplé élastodynamique-acoustique transitoire. Puis en nous basant sur ces résultats mathématiques, nous proposons ensuite un algorithme itératif global en temps basé sur les conditions aux limites de type Robin pour le problème couplé et prouvons sa convergence.Ces résultats sont ensuite mis en oeuvre pour coupler deux méthodes numériques efficaces. La réponse du fluide en temps discret est obtenue à l'aide d'une approche Z-BEM qui combine (i) une méthode d'éléments de frontière (BEM) accélérée par la méthode des matrices hiérarchiques dans le domaine de Laplace et (ii) une quadrature de convolution. La réponse de la structure est modélisée à l'aide de la méthode des éléments finis. Nous développons de cette manière une méthode numérique de couplage itérative globale en temps à convergence garantie, permettant en outre d'utiliser deux méthodes numériques distinctes de manière non intrusive.Plusieurs améliorations sont ensuite proposées: une méthode d'accélération de convergence est mise en œuvre et une approximation à haute fréquence est proposée pour améliorer l'efficacité de la Z-BEM. On propose ensuite un deuxième couplage itératif global-en-temps basé sur une interface acoustique-acoustique, dont la convergence est également démontrée. Ce couplage permet ensuite d'introduire des effets non linéaires dus au phénomène de cavitation pour préciser le modèle fluide. La Z-BEM est enfin adaptée en utilisant la méthode des images pour permettre la prise en compte d'une surface libre.Cette méthode est appliquées à des problèmes à dynamique rapide de dispersion d'ondes de choc acoustiques par des structures élastiques immergées et permet de simuler des configurations réalistes rencontrées dans l'industrie navaleThis work addresses global-in-time domain decomposition approaches for the numerical solution of transient fluid-structure interaction problems. To determine an optimal algorithm, we first study the solvability for the transient acoustic and elastodynamic problems with Robin and Neumann boundary conditions. We state solvability results along with the different space-time regularities of the solutions. We also study the solvability for the transient coupled elastodynamic-acoustic problem. Using on these mathematical results we then propose a global-in-time iterative algorithm based on Robin boundary conditions for the coupled elastodynamicacoustic problem and we prove its convergence.These results are leveraged to design a computational methodology by coupling two efficient numerical methods. The fluid response is formulated in the discrete-time domain, using a Z-BEM approach that combines (i) a boundary element method (BEM) accelerated with hierarchical matrix implemented in the Laplace domain and (ii) a convolution quadrature method. The structure response is modelled using the finite elements method. We thus propose a global-in-time iterative coupling with guaranteed convergence, which enables the use of two distinct numerical methods in a non-intrusive manner.Several improvements are then explored: an acceleration method is implemented and a high-frequency approximation is proposed to improved the Z-BEM efficiency. A second iterative global-in-time coupling based on an acoustic-acoustic interface is then proposed and its convergence is also proved. This coupling enables the addition of non linear effects due to the cavitation phenomenon to derive a more realistic fluid model. The Z-BEM is lastly adapted using the method of images to take a free surface into account.This method is applied on fast-time problems of acoustic shock wave scattering by submerged elastic structures and enables to simulate realistic configurations from naval industry
2
Hepburn, Carolyna. "Dynamic interplay between the magnetization and surface acoustic waves in magnetostrictive Fe1-xGax thin films". Electronic Thesis or Diss., Paris 6, 2017. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2017PA066622.pdf.
Abstract (sommario):
Récemment, beaucoup d'efforts ont été consacrés au contrôle de l'aimantation dans les nanostructures par d'autres moyens qu'un champ magnétique externe. En effet, le but est de miniaturiser les dispositifs et il est difficile d'imposer un champ magnétique présentant de faibles dimensions latérales. D'autre part, les ondes de spin ouvrent actuellement de nouvelles perspectives dans le traitement de l'information. Les avantages qu'elles présentent sont les suivants: longueurs d'onde nanométriques, à comparer à celles des ondes électromagnétiques dans la même gamme de fréquences (GHz-THz), et absence de chauffage par effet Joule. Une possibilité de contrôle réside dans l'utilisation d'ondes acoustiques de surface pour induire la dynamique de l'aimantation ou pour contrôler les ondes de spin. En d'autres termes le contrôle de l'aimantation s’exerce alors via une déformation dynamique. Ceci est rendu possible grâce à une propriété fondamentale des corps magnétiques, le couplage magnéto-élastique, c'est-à-dire le couplage entre aimantation et déformation. Cette thèse porte sur la phénoménologie de l'interaction magnéto-élastique dans les couches minces épitaxiées magnétostrictives de Fe0.8Ga0.2. Nous avons effectué une étude expérimentale systématique des interactions magnéto-élastiques dans des films minces de différentes épaisseurs et structures magnétiques. Nous avons aussi développé deux modèles phénoménologiques, pour interpréter nos expériences. Nous obtenons le résultat important suivant: il est possible d'extraire, d'une étude acoustique, les constantes magnéto-élastiques ainsi que les constantes d'anisotropie magnétique. La thèse a aussi une forte composante technologique. Un des buts était d'exciter efficacement des ondes acoustiques de surface dans la gamme de fréquences de quelques GHz (1-5 GHz) sur substrat piézoélectrique de GaAs dans le but d'observer l'interaction résonante avec les ondes de spin thermiques. Nous avons aussi cherché à exciter des ondes de spin, dans des couches minces épitaxiées, avec des antennes RF afin d'observer l'interaction résonante. Nous présentons des expériences préliminaires sur cette interaction, qui ont été réalisées en diffusion Brillouin (BLS) et en diffusion micro Brillouin, en collaboration avec le laboratoire GHOST à Pérouse, en ItalieRecently, lot of efforts have been devoted to control the magnetization in nanostructures by means other than external magnetic field to achieve device miniaturization, as it is difficult to handle the magnetic field at low lateral dimensions. On the other hand, a new road emerged towards the wave based computing by employing spin waves (SWs). The advantages, that SWs offer for the data processing are nm wavelength as compared to the electromagnetic waves in the same frequency range (GHz-THz) and the absence of Joule heating. A possibility exists to use Surface Acoustic Waves (SAWs), in other words, dynamic strain, to induce magnetization dynamics or to control spin waves. This is possible due to a very fundamental property of magnetic bodies, the magneto-elastic coupling, that is when magnetization orientation and strain are coupled. This thesis focuses on the phenomenology of the magneto-elastic interaction in thin epitaxied films of magnetostrictive Fe0.8Ga0.2. We performed a systematic experimental study of the magneto-elastic interactions in thin films of different thicknesses and magnetic structures. We also developed two phenomenological models in order to interpret our results. An important result of this study is that we are able to extract the magneto-elastic and the magnetic anisotropy constants by acoustic means. The thesis has also a strong technological component. One aim was to efficiently excite surface acoustic waves in GHz frequency range (1-5 GHz) on GaAs piezoelectric substrates in order to observe the resonant interaction with thermal spin waves. We also managed to excite spin waves in thin epitaxied magnetostrictive layers, using RF antennas. We report preliminary measurements on this interaction that were performed with Brillouin light scattering (BLS) and micro BLS techniques in collaboration with the GHOST laboratory in Perugia, Italy
3
Hepburn, Carolyna. "Dynamic interplay between the magnetization and surface acoustic waves in magnetostrictive Fe1-xGax thin films". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066622/document.
Abstract (sommario):
Récemment, beaucoup d'efforts ont été consacrés au contrôle de l'aimantation dans les nanostructures par d'autres moyens qu'un champ magnétique externe. En effet, le but est de miniaturiser les dispositifs et il est difficile d'imposer un champ magnétique présentant de faibles dimensions latérales. D'autre part, les ondes de spin ouvrent actuellement de nouvelles perspectives dans le traitement de l'information. Les avantages qu'elles présentent sont les suivants: longueurs d'onde nanométriques, à comparer à celles des ondes électromagnétiques dans la même gamme de fréquences (GHz-THz), et absence de chauffage par effet Joule. Une possibilité de contrôle réside dans l'utilisation d'ondes acoustiques de surface pour induire la dynamique de l'aimantation ou pour contrôler les ondes de spin. En d'autres termes le contrôle de l'aimantation s’exerce alors via une déformation dynamique. Ceci est rendu possible grâce à une propriété fondamentale des corps magnétiques, le couplage magnéto-élastique, c'est-à-dire le couplage entre aimantation et déformation. Cette thèse porte sur la phénoménologie de l'interaction magnéto-élastique dans les couches minces épitaxiées magnétostrictives de Fe0.8Ga0.2. Nous avons effectué une étude expérimentale systématique des interactions magnéto-élastiques dans des films minces de différentes épaisseurs et structures magnétiques. Nous avons aussi développé deux modèles phénoménologiques, pour interpréter nos expériences. Nous obtenons le résultat important suivant: il est possible d'extraire, d'une étude acoustique, les constantes magnéto-élastiques ainsi que les constantes d'anisotropie magnétique. La thèse a aussi une forte composante technologique. Un des buts était d'exciter efficacement des ondes acoustiques de surface dans la gamme de fréquences de quelques GHz (1-5 GHz) sur substrat piézoélectrique de GaAs dans le but d'observer l'interaction résonante avec les ondes de spin thermiques. Nous avons aussi cherché à exciter des ondes de spin, dans des couches minces épitaxiées, avec des antennes RF afin d'observer l'interaction résonante. Nous présentons des expériences préliminaires sur cette interaction, qui ont été réalisées en diffusion Brillouin (BLS) et en diffusion micro Brillouin, en collaboration avec le laboratoire GHOST à Pérouse, en ItalieRecently, lot of efforts have been devoted to control the magnetization in nanostructures by means other than external magnetic field to achieve device miniaturization, as it is difficult to handle the magnetic field at low lateral dimensions. On the other hand, a new road emerged towards the wave based computing by employing spin waves (SWs). The advantages, that SWs offer for the data processing are nm wavelength as compared to the electromagnetic waves in the same frequency range (GHz-THz) and the absence of Joule heating. A possibility exists to use Surface Acoustic Waves (SAWs), in other words, dynamic strain, to induce magnetization dynamics or to control spin waves. This is possible due to a very fundamental property of magnetic bodies, the magneto-elastic coupling, that is when magnetization orientation and strain are coupled. This thesis focuses on the phenomenology of the magneto-elastic interaction in thin epitaxied films of magnetostrictive Fe0.8Ga0.2. We performed a systematic experimental study of the magneto-elastic interactions in thin films of different thicknesses and magnetic structures. We also developed two phenomenological models in order to interpret our results. An important result of this study is that we are able to extract the magneto-elastic and the magnetic anisotropy constants by acoustic means. The thesis has also a strong technological component. One aim was to efficiently excite surface acoustic waves in GHz frequency range (1-5 GHz) on GaAs piezoelectric substrates in order to observe the resonant interaction with thermal spin waves. We also managed to excite spin waves in thin epitaxied magnetostrictive layers, using RF antennas. We report preliminary measurements on this interaction that were performed with Brillouin light scattering (BLS) and micro BLS techniques in collaboration with the GHOST laboratory in Perugia, Italy
4
Parpiiev, Tymur. "Ultrafast magneto-acoustics in magnetostrictive materials". Thesis, Le Mans, 2017. http://www.theses.fr/2017LEMA1044/document.
Abstract (sommario):
Avec l’avènement du laser femtoseconde il est devenu possible de mesurer comment la démagnétisation femtoseconde peut permettre de sonder l’interaction d’échange dans les métaux ferromagnétiques. La démagnétisation induite par laser d’un matériau avec un fort couplage magnéto-élastique amène à la relaxation des contraintes mécaniques, générant ainsi des ondes acoustiques longitudinales (L) et transversales (T). Dans ce travail de thèse, la génération d’impulsions acoustiques picosecondes T par le mécanisme de démagnétostriction dans des matériaux fortement magnétostrictifs est traitée analytiquement et montrée expérimentalement dans le cas d’un alliage de Terfenol. En premier lieu, nous avons développé un modèle phénoménologique de magnétostriction directe dans un film monocristallin de Terfenol. Les expériences pompe-sonde linéaire MOKE résolues en temps montrent que la relaxation transitoire des contraintes magnéto-élastiques du film amène à l’excitation d’ondes GHz acoustiques L at T. Ces résultats sont la première observation expérimentale de l’excitation d’ondes acoustiques transversales picoseconde par mécanisme de démagnétostriction induit par laser. En second lieu, nous avons analysé le processus d’interaction d’ondes acoustiques L avec l’aimantation d’un film mince de Terfenol. L’onde acoustique picoseconde produit un changement de magnétisation du film et induit la conversion de modes acoustiques. C’est une autre voie de génération d’ondes acoustiques T que nous avons mis en évidence. La gamme de fréquence des impulsions générées est liée à l’échelle de temps de démagnétisation, qui corresponds à quelques centaines de GHz - 1 THzWith the advent of femtosecond lasers it became possible to measure how femtosecond optical demagnetization can probe the exchange interaction in ferromagnetic metals. Laser-induced demagnetization of materials with strong magneto-elastic coupling should lead to the release of its build-in strains, thus to the generation of both longitudinal (L) and shear (S) acoustic waves. In this thesis, generation of shear picosecond acoustic pulses in strongly magnetostrictive materials such as Terfenol is processed analytically and shown experimentally. In case of Terfenol with strong magneto-crystalline anisotropy, laser induced demagnetostriction is responsible for S excitation. First, the phenomenological model of direct magnetostriction in a Terfenol monocrystalline film is developed. The shear strain generation efficiency strongly depends on the orientation of the film magnetization. Time-resolved linear MOKE pump-probe experiments show that transient laser-induced release of the magnetoelastic strains lead to the excitation of GHz L and S acoustic waves. These results are the first experimental observation of picosecond shear acoustic wave excitation by laser-induced demagnetostriction mechanism. Second, the interaction of an optically generated L acoustic pulse with the magnetization of a Terfenol thin film is reported. Arrival of the picosecond strain wave alters a change of its magnetization and leads to acoustic mode conversion, which is another pathway of shear acoustic wave generation. The frequency bandwidth of the generated acoustic pulses matches the demagnetization timescale and lies in the range of several hundreds of GHz, close to 1 THz
5
Yevstafyev, Oleksandr. "Instabilité explosive des ondes magneto-élastiques". Phd thesis, Ecole Centrale de Lille, 2011. http://tel.archives-ouvertes.fr/tel-00607191.
Abstract (sommario):
Les instabilités paramétriques non linéaires (NL) ont été observées sur les ondes magnéto-élastiques dans le cas d'un couplage de trois quasi-phonons sous pompage électromagnétique. La théorie en prédit une dynamique supercritique explosive, mais limitée expérimentalement par le décalage de fréquence dû aux fortes nonlinéarités. La dynamique supercritique des instabilités paramétriques NL est étudiée dans deux matériaux antiferromagnétiques "plan facile" (AFEP): l'hématite α-Fe2O3 et le borate de fer FeBO3. Ces matériaux possèdent une très grande NL acoustique effective en raison du couplage magnéto-élastique élevé. Les mécanismes de limitation de la dynamique explosive ont été analysés à l'aide de l'approximation anharmonique. La compensation du décalage fréquentiel NL par une modulation de phase singulière du pompage a été proposée et théoriquement vérifiée, puis utilisée pour l'observation expérimentale de la dynamique supercritique explosive des excitations de trois quasi-phonons dans les résonateurs magnéto-élastiques. Les études sur FeBO3 ont été réalisées dans la gamme de température 77 K - 293 K où les paramètres magnéto-élastiques du cristal varient de façon significative. Un modèle fortement non linéaire des excitations de trois quasi-phonons dans les AFEPs a été développé. Les simulations numériques sont en accord avec les résultats expérimentaux. Les études théoriques de couplage de trois ondes magnéto-élastiques progressives ont été effectuées sur la base de modèles théoriques prenant en compte la non-linéarité cubique des cristaux AFEP réels. Les simulations numériques prévoient un comportement explosif et une localisation spatiale des triades générées
Capitoli di libri sul tema "Acoustic-elastic coupling":
1
deGroot-Hedlin, Catherine, e John Orcutt. "T-phase Observations in Northern California: Acoustic to Seismic Coupling at a Weakly Elastic Boundary". In Monitoring the Comprehensive Nuclear-Test-Ban Treaty: Hydroacoustics, 513–30. Basel: Birkhäuser Basel, 2001. http://dx.doi.org/10.1007/978-3-0348-8270-5_5.
2
Eberle, Sarah. "FEM-BEM Coupling of Wave-Type Equations: From the Acoustic to the Elastic Wave Equation". In Trends in Mathematics, 109–24. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-47174-3_7.
3
Bentarki, Houda, Abdelkader Makhoute e Tőkési Karoly. "Signatures of the Mode Symmetries in Sapphire PhoXonic Cavities". In Advances in Systems Analysis, Software Engineering, and High Performance Computing, 108–17. IGI Global, 2023. http://dx.doi.org/10.4018/979-8-3693-0497-6.ch007.
Abstract (sommario):
The acousto-optic couplings mechanisms are investigated theoretically in photonic and phononic crystals with simultaneous band gaps. The authors have focused on the acousto-optic couplings inside a phoXonic cavity by taking into account two coupling mechanisms, the photo elastic effect and effect of movement of the interfaces. They discuss the symmetry of modes to distinguish those that don't interfere in an efficient way. They calculate the modulation of the frequency of the photonic mode during a period of acoustic oscillations with a finite element method (FE) (COMSOL®Multiphysics). The two mechanisms presented in the numerical calculations produce additive or subtractive effects in total acousto-optical coupling while depending on whether they are in phase or out of phase.
4
"8. Coupling of acoustic and elastic waves in phononic crystals". In Phononic Crystals, 255–71. De Gruyter, 2020. http://dx.doi.org/10.1515/9783110641189-008.
Atti di convegni sul tema "Acoustic-elastic coupling":
1
Krenz, Lukas, Carsten Uphoff, Thomas Ulrich, Alice-Agnes Gabriel, Lauren S. Abrahams, Eric M. Dunham e Michael Bader. "3D acoustic-elastic coupling with gravity". In SC '21: The International Conference for High Performance Computing, Networking, Storage and Analysis. New York, NY, USA: ACM, 2021. http://dx.doi.org/10.1145/3458817.3476173.
2
Nesemann, L. "Numerical Acoustic-elastic Coupling and Curved Boundaries for RTM". In 76th EAGE Conference and Exhibition 2014. Netherlands: EAGE Publications BV, 2014. http://dx.doi.org/10.3997/2214-4609.20141185.
3
Bartolo*, Leandro Di, Ana Paula Gomes Vieira, Cleberson Dors e Webe João Mansur. "Memory optimized acoustic-elastic FD coupling for offshore seismic simulations". In SEG Technical Program Expanded Abstracts 2015. Society of Exploration Geophysicists, 2015. http://dx.doi.org/10.1190/segam2015-5905882.1.
4
Di Bartolo, Leandro, Cleberson Dors e Webe João Mansur. "An efficient and simple acoustic-elastic FD coupling for offshore seismic simulations". In SEG Technical Program Expanded Abstracts 2012. Society of Exploration Geophysicists, 2012. http://dx.doi.org/10.1190/segam2012-1320.1.
5
Filipe, M., e T. Ha-Duong. "A Coupling of FEM-BEM for Elastic Structure in a Transient Acoustic Field". In ASME 1995 Design Engineering Technical Conferences collocated with the ASME 1995 15th International Computers in Engineering Conference and the ASME 1995 9th Annual Engineering Database Symposium. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/detc1995-0393.
Abstract (sommario):
Abstract We propose in this paper a space-time variational formulation for the scattering problem of transient acoustic waves in a fluid medium with a submerged elastic object. The problem is first reduced to a coupling problem between partial differential equations and boundary integral equations and an energy formula given in terms of the unknowns of this coupling problem. The variational formulation follows then. A space-time finite element method based on this formulation gives rise to a time-stepping scheme with both volume and surface spatial elements as variables.
6
Shepard, W. Steve, Kenneth A. Cunefare e Jerry H. Ginsberg. "Identifying Critical Elastic Scales in Structural-Acoustic Models". In ASME 1995 Design Engineering Technical Conferences collocated with the ASME 1995 15th International Computers in Engineering Conference and the ASME 1995 9th Annual Engineering Database Symposium. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/detc1995-0415.
Abstract (sommario):
Abstract The level of detail required for accurate structural acoustic modeling of fluid loaded structures remains an issue of significant debate. Analytical solutions are rarely available, and discrete numerical solutions are typically too complex for ready extraction of physical understanding. In addition, numerical techniques introduce their own explicit scales, through the minimum mesh dimension. However, the wavenumber based formulation of the surface variational principle describes the surface pressure and displacement as a comparatively small set of interacting waves. Coupling the SVP with distributed methods of representing structural attachment features provides a means to introduce, control and investigate features of differing scales. We present here a technique for assessing the critical resolution scales for a fluid loaded two-dimensional plate. For feature attachments, we consider a line-mass elastically suspended by a line-spring from the wetted plate. We then use a spatial expansion for the elastic attachment to the wetted plate. The excitation applied to the plate is taken as a concentrated harmonic force. With the excitation held fixed, the influence of the scale of the feature spatial representation on the radiated power is assessed.
7
Willemsen, Bram, e Alison Malcolm. "Coupling a local elastic solver to a background acoustic model to estimate phase variation". In SEG Technical Program Expanded Abstracts 2016. Society of Exploration Geophysicists, 2016. http://dx.doi.org/10.1190/segam2016-13867595.1.
8
Muhlestein, Michael B., Benjamin M. Goldsberry, Caleb F. Sieck e Michael R. Haberman. "Analytical and Numerical Investigation of Scattering From Bianisotropic Acoustic Media". In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-72672.
Abstract (sommario):
Scattering from fluid domains with dissimilar material properties is of foundational importance to many application areas in acoustics and elastic wave propagation. For example, biomedical ultrasound and sonar both make use of acoustic field scattering for localization, imaging, and identification of objects. The theory of acoustic scattering from fluid and elastic materials is well established and has been validated with numerical and physical experiments. Recent work in acoustic and elastic meta-materials has shown that materials with subwavelength asymmetry have a macroscopic response characterized by a scalar bulk modulus, a tensorial mass density, and a vector that couples the pressure-strain relationship with the momentum density-particle velocity relationship. This type of constitutive behavior is the acoustic analogue of bianisotropy in electromagnetism and has come to be known as Willis coupling in acknowledgement of the first description of this material response by J.R. Willis [Willis, Wave Motion 3, pp. 111 (1981)]. We present a theoretical description of acoustic scattering of a plane wave incident upon a cylinder exhibiting weak Willis coupling using a perturbation approach. The scattered field depends upon the orientation of the Willis coupling vector and is therefore anisotropic despite the symmetry of the geometry. The analytical model is validated through comparison with a finite element-based numerical experiment where the bianisotropic material response is introduced using a weak formulation of the constitutive equations.
9
Yang, Mingsui, Yanting Ai e Song Xiang. "Coupling of FEM and Exterior/Interior Acoustic Field with BEM and Numerical Simulation of Vibro-Acoustic Response of Elastic Target". In 2010 International Conference on Measuring Technology and Mechatronics Automation (ICMTMA 2010). IEEE, 2010. http://dx.doi.org/10.1109/icmtma.2010.534.
10
Botelho, Rui M. "Computing Resonant Frequencies and Coupled Mode-Shapes of Structural-Acoustic Systems Using the Finite Element Method". In ASME 2008 Noise Control and Acoustics Division Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/ncad2008-73017.
Abstract (sommario):
This paper examines numerical techniques to compute the resonant frequencies and coupled mode-shapes of general structural-acoustic systems using the finite element method. This information is useful in quantifying the key frequencies and vibration patterns of elastic structures coupled to bounded or unbounded acoustic fluid volumes. This paper reviews and evaluates three finite element solution techniques that deal with the computational difficulties encountered in structural-acoustic eigen-analysis. One of the difficulties stems from the fluid-structure coupling in the finite element equations, which depending on the variable used to discretize the acoustic fluid, either introduces non-symmetric area coupling terms in the mass and stiffness matrices or adds symmetric area coupling terms in the damping matrix. The other difficulty is related to the application of a radiation boundary condition in those structural-acoustic problems involving unbounded acoustic domains. The radiation boundary condition introduces damping terms in the finite element equations that lead to a complex eigen-analysis to determine the resonant frequencies and coupled mode-shapes. The finite element techniques evaluated in this paper consist of subspace projection employing an augmented-symmetric form of the fluid-structure equations as well as new extensions of component mode synthesis (CMS). Basic examples of simplified structural-acoustic systems are used to compare the solution accuracy between the three finite element techniques. Examples consist of simplified one-dimensional (1-D) and two-dimensional (2-D) elastic structures coupled to closed and open acoustic spaces.