Showing papers on "Sound transmission class published in 2014"
TL;DR: The acoustic analog of the Zeeman effect in a subwavelength meta-atom consisting of a resonant ring cavity biased by a circulating fluid is introduced, producing giant acoustic nonreciprocity in a compact device.
Abstract: Acoustic isolation and nonreciprocal sound transmission are highly desirable in many practical scenarios. They may be realized with nonlinear or magneto-acoustic effects, but only at the price of high power levels and impractically large volumes. In contrast, nonreciprocal electromagnetic propagation is commonly achieved based on the Zeeman effect, or modal splitting in ferromagnetic atoms induced by a magnetic bias. Here, we introduce the acoustic analog of this phenomenon in a subwavelength meta-atom consisting of a resonant ring cavity biased by a circulating fluid. The resulting angular momentum bias splits the ring’s azimuthal resonant modes, producing giant acoustic nonreciprocity in a compact device. We applied this concept to build a linear, magnetic-free circulator for airborne sound waves, observing up to 40-decibel nonreciprocal isolation at audible frequencies.
840 citations
TL;DR: In this article, sound transmission through double shells, lined with poroelastic material in the presence of external mean flow, is studied, where the porous material is modeled as an equivalent fluid because shear wave contributions are known to be insignificant.
83 citations
TL;DR: In this paper, an analytical study on the vibro-acoustic and sound transmission loss characteristics of functionally graded material (FGM) plates using a simple first-order shear deformation theory is presented.
71 citations
TL;DR: In this article, a mixture of 70% metakaolin and 30% blast furnace slag powders is used as the raw material in the production of inorganic polymeric foams (IPF) with various densities ranging from 0.4 to 1.0 ǫg/cm3 and different thicknesses of 6, 10 and 14 cm using a mechanical foaming method.
67 citations
TL;DR: In this paper, the authors report theoretically and numerically on the sound transmission loss performance through a thick plate-type acoustic metamaterial made of spring-mass resonators attached to the surface of a homogeneous elastic plate.
Abstract: We report theoretically and numerically on the sound transmission loss performance through a thick plate-type acoustic metamaterial made of spring-mass resonators attached to the surface of a homogeneous elastic plate. Two general analytical approaches based on plane wave expansion were developed to calculate both the sound transmission loss through the metamaterial plate (thick and thin) and its band structure. The first one can be applied to thick plate systems to study the sound transmission for any normal or oblique incident sound pressure. The second approach gives the metamaterial dispersion behavior to describe the vibrational motions of the plate, which helps to understand the physics behind sound radiation through air by the structure. Computed results show that high sound transmission loss up to 72 dB at 2 kHz is reached with a thick metamaterial plate while only 23 dB can be obtained for a simple homogeneous plate with the same thickness. Such plate-type acoustic metamaterial can be a very effective solution for high performance sound insulation and structural vibration shielding in the very low-frequency range.
55 citations
49 citations
TL;DR: In this paper, a vibroacoustic finite element model was used to simulate sound production and sound beam formation in the bottlenose dolphin (Tursiops truncatus), based on computed tomography scans from live and postmortem dolphins.
Abstract: Psychoacoustic laboratory studies with live dolphins require considerable resources and are essential for assessing the validity of our models. Computerized numerical modelling methods are a reasonable approach to simulate the vibroacoustic functions of the dolphin biosonar apparatus. In order to validate this approach, we chose a vibroacoustic finite element model to simulate sound production and sound beam formation in the bottlenose dolphin (Tursiops truncatus), based on computed tomography scans from live and postmortem dolphins. The right and left dorsal bursae were assumed to be potential sound sources. The simulations confirm several hypotheses: (1) the shape of the skull plays a role in the formation of the sound transmission beam; (2) the melon appears to concentrate the acoustic energy by a factor of four in the transmitted beam; (3) focusing the sound beam apparently occurs in a series of stages that include contributions from the skull, nasal diverticula, melon and connective tissue structures...
47 citations
TL;DR: A computational model was developed and validated by comparing its predictions with results from animal and human experiments which involved applying acoustic excitation to the anterior chest, while detecting skin vibrations at the posterior chest, and predicted wave patterns inside the chest.
Abstract: Chest physical examination often includes performing chest percussion, which involves introducing sound stimulus to the chest wall and detecting an audible change. This approach relies on observations that underlying acoustic transmission, coupling, and resonance patterns can be altered by chest structure changes due to pathologies. More accurate detection and quantification of these acoustic alterations may provide further useful diagnostic information. To elucidate the physical processes involved, a realistic computer model of sound transmission in the chest is helpful. In the present study, a computational model was developed and validated by comparing its predictions with results from animal and human experiments which involved applying acoustic excitation to the anterior chest, while detecting skin vibrations at the posterior chest. To investigate the effect of pathology on sound transmission, the computational model was used to simulate the effects of pneumothorax on sounds introduced at the anterior chest and detected at the posterior. Model predictions and experimental results showed similar trends. The model also predicted wave patterns inside the chest, which may be used to assess results of elastography measurements. Future animal and human tests may expand the predictive power of the model to include acoustic behavior for a wider range of pulmonary conditions.
38 citations
TL;DR: In this article, the sound transmission through an infinite multilayer cylinder composed of orthotropic skins and an isotropic polymer core is calculated analytically, and the results are compared with results published recently in the literature.
38 citations
TL;DR: In this article, the authors proposed a nonparametric stochastic model for the sound transmission through a wall in between two rooms, in which the rooms are modeled in a very efficient and non-parametric way, as in statistical energy analysis.
38 citations
TL;DR: In this article, the dispersion characteristics of two dimensional composite orthotropic structures are predicted using a Wave Finite Element method using a polynomial eigenvalue problem, the solutions of which correspond to the propagation constants of the waves travelling within the structure.
TL;DR: On page 516 of this issue, Fleury et al. (1), taking inspiration from a natural electromagnetic phenomenon, designed and demonstrated an engineered structure that allows one-way transmission of sound waves.
Abstract: Structures that admit flow in only one direction are commonplace—consider one-way streets, insect traps, and the staple of the police procedural story, the one-way mirror. However, creating a device that allows waves to pass in only one direction, termed an isolator, is challenging because of the inherently symmetric physics of wave phenomena. On page [516][1] of this issue, Fleury et al. ( 1 ), taking inspiration from a natural electromagnetic phenomenon, designed and demonstrated an engineered structure that allows one-way transmission of sound waves.
[1]: /lookup/doi/10.1126/science.1246957
TL;DR: In this paper, a structural-acoustic coupling model of an elastically restrained double-panel structure with an acoustic cavity having arbitrary impedance on sidewalls around the cavity is developed in which the two dimensional (2D) and three dimensional (3D) modified Fourier series are used to represent the displacement of the panels and the sound pressure inside the cavity, respectively.
TL;DR: In this article, an experimental work on active control of sound transmission through a restricted opening bottom hinged window is presented, where the active control is configured to cancel the pressure at the aperture using a single-input single-output feed-forward adaptive system.
TL;DR: In this paper, a coupled finite element/boundary element method (FEM/BEM) for control of noise radiation and sound transmission of vibrating structure by passive piezoelectric techniques is presented.
Patent•
13 Mar 2014TL;DR: Active acoustic pyrometry-based gas flow temperature measurement is incorporated into the combustion monitoring and control system by addition of an acoustic transmitter or acoustic transceiver that transmits a sound wave in a line-of-sight with a plurality of acoustic sensors, such as dynamic pressure sensors as discussed by the authors.
Abstract: Active acoustic pyrometry-based gas flow temperature measurement, such as for monitoring of gas turbine combustors, including industrial gas turbine (IGT) combustors is incorporated into the combustion monitoring and control system by addition of an acoustic transmitter or acoustic transceiver that transmits a sound wave in a line-of-sight with a plurality of acoustic sensors, such as dynamic pressure sensors. For temperature measurement, in some embodiments sound transmission time-of-flight that is directed generally transverse the gas flow path is measured by the controller and correlated with gas flow temperature along the line-of-sight. In other embodiments line-of-sight correlated gas flow temperatures in up and down stream planar paths are interpolated. In an integrated thermoacoustic pressure-based sensor and monitoring/control system embodiment, the controller determines absolute active path temperatures with acoustic transmission and time-of-flight analysis techniques.
TL;DR: Three different predictive methods based on wave descriptions of the acoustic field are presented and used to calculate transmission and radiation properties of typical rail and aerospace structures and can be used to effectively support decision making in the design process of trains and aircraft.
Patent•
16 Dec 2014TL;DR: Active acoustic velocity and pyrometry-based gas flow velocity and temperature measurement for monitoring of gas turbine combustors, including industrial gas turbine (IGT) combustors is incorporated into the combustion monitoring and control system by addition of an acoustic transmitter or acoustic transceiver that transmits a sound wave in a line-of-sight with a plurality of acoustic sensors, such as dynamic pressure sensors as mentioned in this paper.
Abstract: Active acoustic velocity and pyrometry-based gas flow velocity and temperature measurement, such as for monitoring of gas turbine combustors, including industrial gas turbine (IGT) combustors is incorporated into the combustion monitoring and control system by addition of an acoustic transmitter or acoustic transceiver that transmits a sound wave in a line-of-sight with a plurality of acoustic sensors, such as dynamic pressure sensors. For velocity measurement, sound transmission time-of-flight that is directed generally along the gas flow path is measured by the controller and correlated with gas flow velocity along the line-of-sight. Similarly, sound transmission time-of-flight is correlated with temperature along the line-of-sight. Path(s) of acoustic transmission serve as velocity or velocity/absolute temperature measurement. In an integrated thermoacoustic pressure-based sensor and monitoring/control system embodiment, the controller correlates velocity and, if desired, absolute active path temperatures with acoustic transmission and time-of-flight analysis techniques.
TL;DR: The proposed virtual panel considers an aperture as an equivalent structural component, which can be integrated with the solid/flexible structure to form a unified compound interface, thus providing an efficient and versatile tool to tackle system complexities when using sub-structuring techniques.
Abstract: Modeling sound transmission among acoustic media through mixed separations, consisting of both rigid/flexible structures with apertures, is a challenging task. The coexistence of both structural and acoustic transmission paths through the same coupling surface adds system complexities, hampering the use of existing sub-structuring modeling techniques when the system configuration becomes complex. In the present work, a virtual panel treatment is proposed to model thin apertures involved in such complex vibroacoustic systems. The proposed virtual panel considers an aperture as an equivalent structural component, which can be integrated with the solid/flexible structure to form a unified compound interface. This allows handling the entire compound interface as a pure structural element, thus providing an efficient and versatile tool to tackle system complexities when using sub-structuring techniques. The accuracy and convergence of the method are investigated and validated, and the effective thickness range allowing for the virtual panel treatments is determined. The capability and the flexibility of the proposed formulation are demonstrated through several numerical examples, with underlying physics being explored.
Patent•
18 Mar 2014
TL;DR: In this paper, a point cloud representation of an acoustic environment is used to calculate its acoustics from the interior information obtained from the depth camera, which is suitable for run-time applications since it is not based on an audible excitation that can disturb running audio.
Abstract: The invention provides a method for generating an output indicative of acoustical sound transmission in a room. By using e.g. a point cloud representation of an acoustic environment, it is possible to calculate its acoustics from the interior information obtained from the depth camera. This approach is suitable e.g. for run-time applications since it is not based on an audible excitation that can disturb running audio. Also, the point-cloud model can be updated in real time according to the scene changes detected by depth-camera. This allows efficient acoustical simulation of dynamic, interactive environments. Although only geometrical information of a room is provided, high amount of surface details leaves possibility for implementation of material recognition algorithms that involve semantic mapping. This can provide information of reflective properties of surfaces or objects at a point level. Also, a high amount of details allows a good approximation of complex geometries, e.g. porous materials, and rough surfaces, thus a more natural simulation of wave phenomena like diffraction and scattering is possible.
TL;DR: In this article, three extensions of the Transfer Matrix Method (TMM) are discussed for the modeling of the transmission loss of sandwich-composite panels, and a wave based model is recalled and used to derive a simpler model based on identifying effective properties of an equivalent orthotropic panel.
TL;DR: In this article, the effect of modal coupling on low frequency impact sound transmission through rectangular homogeneous concrete floors and floating floors has been investigated, and experimental results have been used to identify the main factors affecting low frequency sound transmission.
Patent•
04 Apr 2014TL;DR: In this paper, a real-time, continuous measurements of the composition and other properties of individual phases of petroleum, water and gas mixtures during the oil production process, without requiring test separators, test lines, with associated valving and instrumentation, are described.
Abstract: Methods for real-time, continuous measurements of the composition and other properties of individual phases of petroleum, water and gas mixtures during the oil production process, without requiring test separators, test lines, with associated valving and instrumentation, are described. Embodiments of the present invention direct ultrasonic sound transmission (12, 24) through a flowing multiphase fluid (20) in three frequency ranges: low frequencies, gas bubble resonance frequencies, and high frequencies, wherein certain sound propagation measurements, including sound speed, sound attenuation and sound scattering, are made in one or more of the three separate frequency regions, from which the multiphase composition and other properties are extracted without having to separate the multiphase fluid or the gas from the flowing stream.
TL;DR: In this paper, a triangular lattice two-dimensional sonic crystal made of rods in a triangular cross-section was used as a frequency selective acoustic diode operating at a frequency of 8950 Hz.
TL;DR: In this paper, the authors proposed a weighted normalised loudness level difference (Lnor,w) method to calculate the airborne sound insulation between rooms to determine the quality of sound protection.
TL;DR: In this article, the authors compared various decentralised control strategies, including structural and acoustic actuator-sensor configuration designs, to reduce noise transmission through a double panel structure based on identical control stability indexes.
TL;DR: This role is investigated via a 2D axisymmetric finite element model of a silicon earplug coupled to an artificial skin to better understand the role of each part of the earplug/ear canal system and how the energy circulates within the domains.
Abstract: Acoustical test fixtures (ATFs) are currently used to measure the attenuation of the earplugs. Several authors pointed out that the presence of an artificial skin layer inside the cylindrical ear canal of the ATFs strongly influenced the attenuation measurements. In this paper, this role is investigated via a 2D axisymmetric finite element model of a silicon earplug coupled to an artificial skin. The model is solved using COMSOL Multiphysics (COMSOL®, Sweden) and validated experimentally. The model is exploited thereafter to better understand the role of each part of the earplug/ear canal system and how the energy circulates within the domains. This is investigated by calculating power balances and by representing the mechanical and acoustical fluxes in the system. The important dissipative role of the artificial skin is underlined and its contribution as a sound transmission pathway is quantified. In addition, the influence of both the earplug and the artificial skin parameters is assessed via sensitivities analyses performed on the model.
TL;DR: In this article, a study on the acoustic behavior of double-walled panels, with sandwiched layer of porous materials is presented within Classical Laminated Plate Theory (CLPT) for laminated composite panels.
Abstract: A study on the acoustic behavior of double-walled panels, with sandwiched layer of porous materials is presented within Classical Laminated Plate Theory (CLPT) for laminated composite panels. For this purpose, equations of wave propagation are firstly extracted based on Biot's theory for porous materials, then the transmission loss (TL) of the structure is estimated in a broadband frequency. Secondly, TL coefficient of the structure is determined using Statistical Energy Analysis (SEA). In the next step, accuracy of the solution is shown with comparing the data obtained from these two presented models as well as the experimental results available in literature. Finally, the effects of parameters on sound transmission loss of double porous composite panels, especially at a high frequency range, are discussed. In addition, the results show that maximum sound energy is transferred through the waves frame (structure born) due to the porous layer bonded between the two composite panels. Therefore, material parameters that are principally related to solid phase of the foam such as Poisson's ratio, bulk density and bulk Young's modulus, have the most significant effects on the transmission loss. Meanwhile, the impacts of composite material panels and composite plies arrangement on sound transmission loss structures have been addressed in this paper.
Patent•
09 Apr 2014
TL;DR: In this article, a converter transformer operating state on-line audio analyzing and monitoring system belongs to the field of monitoring devices, which consists of a sound collection unit, a sound transmission unit, an analysis unit, and an analysis result comparison and analysis unit.
Abstract: A converter transformer operating state on-line audio analyzing and monitoring system belongs to the field of monitoring devices. The system comprises a sound collection unit, a sound transmission unit, a sound analysis unit, a historical sound library, and an analysis result comparison and analysis unit, which are sequentially connected. The sound collecting unit collects actual operating sounds of a converter transformer and converts the sounds into electrical signals. The sound transmission unit transmits the electrical signals converted from the collected actual operating sounds of the converter transformer to the sound analysis unit. The sound analysis unit conducts audio decomposition of the electrical signals converted from the collected actual operating sounds of the converter transformer and forms typical amplitude and frequency curves of the converter transformer on different operating conditions. The historical sound library stores the typical amplitude and frequency curves of the converter transformer on different operating conditions for comparison and comparative analysis. The analysis result comparison and analysis unit is used for analysis and comparison of newly collected audios of the converter transformer, analysis and comparison of historical sounds, and automatic alarming when the collected operating sounds of the converter transformer is abnormal.