Eigenfrequency maximisation by using irregular lattice structures
In conclusion, we show that irregular lattice structures have a high potential to manipulate the eigenfrequencies of lightweight structures. (Source: Journal of Sound and Vibration)
Source: Journal of Sound and Vibration - October 22, 2019 Category: Physics Source Type: research

Prediction of wheel squeal noise under mode coupling
Publication date: Available online 22 October 2019Source: Journal of Sound and VibrationAuthor(s): Paul A. MeehanAbstractWheel squeal vibration and noise amplitude under the effects of mode coupling and rising and falling creep behavior is investigated and predicted using an efficient analytical model. Based on previous research, a simplified modal dynamics model for wheel squeal noise amplitude is enhanced to include two coupled modes. Closed form analytical solutions for the vibration and squeal noise amplitude are determined under combined squeal mechanisms of full sliding falling friction and mode coupling. The analyti...
Source: Journal of Sound and Vibration - October 22, 2019 Category: Physics Source Type: research

On the numerical simulations of amplitude-adaptive impact dampers
Publication date: Available online 21 October 2019Source: Journal of Sound and VibrationAuthor(s): Tunc Yüzbasioglu, Jimmy Aramendiz, Alexander FidlinAbstractTwo impact dampers are analysed and compared with respect to their effectiveness for vibration reduction. Estimations of nonlinear system behaviour are derived using only well-known solutions for a linear dynamic vibration absorber. Critical parameter values separating domains with qualitatively different system behaviours are found. Using numerical simulations, the estimations are verified and the influence of each system parameter on the vibration amplitudes is...
Source: Journal of Sound and Vibration - October 22, 2019 Category: Physics Source Type: research

Model order reduction for temperature-dependent nonlinear mechanical systems: A multiple scales approach
Publication date: Available online 18 October 2019Source: Journal of Sound and VibrationAuthor(s): Shobhit Jain, Paolo TisoAbstractThe thermal dynamics in thermo-mechanical systems exhibits a much slower time scale compared to the structural dynamics. In this work, we use the method of multiple scales to reduce the thermo-mechanical structural models with a slowly-varying temperature distribution in a systematic manner. In the process, we construct a reduction basis that adapts according to the instantaneous temperature distribution of the structure, facilitating an efficient reduction in the number of unknowns. As a proof...
Source: Journal of Sound and Vibration - October 19, 2019 Category: Physics Source Type: research

The statistical errors in the estimated correlation function matrix for operational modal analysis
This article focuses on the statistical errors due to this estimation process and the effect it has on the envelope and zero crossings of the estimated correlation function matrix. It is proven that the estimated correlation function matrix is a Gaussian stochastic process. Furthermore, it is proven that the envelope of the modal correlation function matrix is Rice distributed. This causes the tail region of the correlation function to become erroneous - called the noise tail. The zero crossings are unbiassed, but the random error related to the crossings increases fast in the noise tail. The theory is tested on a simulate...
Source: Journal of Sound and Vibration - October 19, 2019 Category: Physics Source Type: research

A stochastic Functional Model based method for random vibration based robust fault detection under variable non–measurable operating conditions with application to railway vehicle suspensions
Publication date: Available online 18 October 2019Source: Journal of Sound and VibrationAuthor(s): T.-C.I. Aravanis, J.S. Sakellariou, S.D. FassoisAbstractThe problem of random vibration based robust fault detection under variable and non–measurable Environmental and Operating Conditions (EOCs) is considered, and a novel stochastic Functional Model (FM) based method is postulated. It is a data–driven method, of the Statistical Time Series (STS) type, and aims at overcoming the well known drawbacks of available methods by achieving high detection performance while eliminating their drawbacks, such as the need fo...
Source: Journal of Sound and Vibration - October 19, 2019 Category: Physics Source Type: research

On the application of bi-orthogonality relations for analysis of linear dynamic systems
Publication date: Available online 17 October 2019Source: Journal of Sound and VibrationAuthor(s): Lasse S. Ledet, Sergey V. SorokinAbstractThis paper derives a new class of modal decompositions of Somigliana's identities for a certain class of problems displaying symmetry and uniformity such as, for instance, elastic vibration problems including the effect of fluid loading. The decompositions are shown to lead to a number of new analytical results relating to homogeneous and inhomogeneous boundary value problems in whichever realm of physics, for example, free and forced vibration problems in a bounded domain, and also to...
Source: Journal of Sound and Vibration - October 19, 2019 Category: Physics Source Type: research

Contact mechanics and friction processes in ultrasonic wire bonding - Basic theories and experimental investigations
Publication date: Available online 17 October 2019Source: Journal of Sound and VibrationAuthor(s): Yangyang Long, Jens Twiefel, Jörg WallaschekAbstractEven though ultrasonic (US) wire bonding has been a popular interconnection technique in electronic packaging industry for decades, the contact and friction conditions during the bonding processes have not been well understood. In this work, the relative motion at the wire/substrate interface and the tool/wire interface, and the influences of oxides and microwelds on the friction at the wire/substrate interface are brought together to systematically and comprehensively ...
Source: Journal of Sound and Vibration - October 19, 2019 Category: Physics Source Type: research

Dynamic buckling of functionally graded graphene nanoplatelets reinforced composite shallow arches under a step central point load
Publication date: Available online 17 October 2019Source: Journal of Sound and VibrationAuthor(s): Zhicheng Yang, Airong Liu, Jie Yang, Jiyang Fu, Bin YangAbstractThis paper presents dynamic buckling analysis for a functionally graded graphene nanoplatelets reinforced composite (FG-GPLRC) arch subjected to a step central point load at its center. The arch is composed of multiple composite layers reinforced with graphene nanoplatelets (GPLs) which are evenly distributed in each layer while the GPL weight fraction changes from layer to layer along the thickness direction. The effective materials properties are predicted by H...
Source: Journal of Sound and Vibration - October 19, 2019 Category: Physics Source Type: research

Robust uncertainty quantification in structural dynamics under scarse experimental modal data: A Bayesian-interval approach
Publication date: Available online 17 October 2019Source: Journal of Sound and VibrationAuthor(s): Maurice Imholz, Matthias Faes, Dirk Vandepitte, David MoensAbstractThe accurate prediction of the dynamic behaviour of a complex component or system is often difficult due to uncertainty or scatter on the physical parameters in the underlying numerical models. Over the past years, several non-deterministic techniques have been developed to account for these model inaccuracies, supporting an objective assessment of the effect of these uncertainties on the dynamic behaviour. Still, also these methods require a realistic quantif...
Source: Journal of Sound and Vibration - October 19, 2019 Category: Physics Source Type: research

Evaluating reduced order models of curved beams for random response prediction using static equilibrium paths
Publication date: Available online 17 October 2019Source: Journal of Sound and VibrationAuthor(s): C.I. Van Damme, M.S. Allen, J.J. HollkampAbstractThin curved structural components are susceptible to dynamic snap-through when subjected to the high amplitude aerodynamic loading that is present in extreme environments. In order to estimate the life of the structures, time simulations must extend over many seconds so that the statistical response due to the random loading environment can be adequately characterized. In order to compute the geometrically nonlinear response of these structures in a reasonable time, Reduced Ord...
Source: Journal of Sound and Vibration - October 17, 2019 Category: Physics Source Type: research

Noise radiated from a periodically stiffened cylindrical shell excited by a turbulent boundary layer
Publication date: Available online 17 October 2019Source: Journal of Sound and VibrationAuthor(s): Laurent Maxit, Oriol Guasch, Valentin Meyer, Mahmoud KarimiAbstractThis work proposes a semi-analytical method to model the vibroacoustic behavior of submerged cylindrical shells periodically stiffened by axisymmetric frames and excited by a homogeneous and fully developed turbulent boundary layer (TBL). The process requires the computation of the TBL wall-pressure cross spectral density function and the sensitivity functions for stiffened cylindrical shells. The former is deduced from an existent TBL model and the latter are...
Source: Journal of Sound and Vibration - October 17, 2019 Category: Physics Source Type: research

Interferences in the re-emission field of multimodal leaky lamb waves propagating in an immersed plate: Analytical modelling, simulation and experimentation
Publication date: Available online 15 October 2019Source: Journal of Sound and VibrationAuthor(s): Pierre Kauffmann, Marie-Aude Ploix, Jean-François Chaix, Cécile Gueudre, Gilles Corneloup, François BaqueAbstractThe transmission and re-emission of energy by leaky Lamb waves from an immersed plate is being studied in the case of multi-modal propagation. When more than two Lamb modes propagate together, interferences can be generated in the re-emitted field. The latter have to be well understood and mastered because they can distort the diagnosis of a Non-Destructive Testing of an immersed plate. They ar...
Source: Journal of Sound and Vibration - October 16, 2019 Category: Physics Source Type: research

Demodulation technique to identify nonlinear characteristics of vibro-acoustic NDT measurements
Publication date: Available online 15 October 2019Source: Journal of Sound and VibrationAuthor(s): A. Carcione, P. Blanloeuil, M. VeidtAbstractA novel approach for nonlinear ultrasonics is presented which uses the demodulated response of a nonlinear vibro-acoustic response signal. The demodulation process is similar to quadrature demodulation process used in telecommunications. It is shown that the demodulation method provides an alternative approach for the analysis of nonlinear behavior compared to the analysis of frequency spectra or other techniques. The proposed method suggests that a representative reconstruction of ...
Source: Journal of Sound and Vibration - October 16, 2019 Category: Physics Source Type: research

A step excitation optimization method for intensive modal identification of cable net structures
Publication date: Available online 15 October 2019Source: Journal of Sound and VibrationAuthor(s): Xintao Wang, Hua DengAbstractCompared with the direct force measurement of cables, dynamic modal testing is more economic and applicable in engineering for monitoring the stiffness change of cable net structures caused by pretension deviation. Normally, it is sufficient to detect the variation of structural key stiffness by testing a few modes (target modes) that are, however, likely located in the region of dense modes. To effectively evaluate the stiffness of an existing cable net structure, the identification accuracy of t...
Source: Journal of Sound and Vibration - October 16, 2019 Category: Physics Source Type: research

Single-camera single-axis vision method applied to measure vibrations
Publication date: Available online 14 October 2019Source: Journal of Sound and VibrationAuthor(s): Thomas Durand-Texte, Manuel Melon, Elisabeth Simonetto, Stéphane Durand, Marie-Héléne MouletAbstractIncreased interest has been witnessed for full-field techniques measuring vibrations. 3D vision methods coupled to two high-speed cameras have proven to be a valid solution to measure 3D displacements, notably with the Stereo Digital Image Correlation (SDIC) tools. The now conventional pseudo-stereo system with a single high-speed camera and a four-mirror adapter, generating two virtual cameras, may also be...
Source: Journal of Sound and Vibration - October 16, 2019 Category: Physics Source Type: research

Active nonlinear control of a stroke limited inertial actuator: Theory and experiment
Publication date: Available online 12 October 2019Source: Journal of Sound and VibrationAuthor(s): M. Dal Borgo, M. Ghandchi Tehrani, S.J. ElliottAbstractThis paper presents a theoretical and experimental study of a stroke limited inertial actuator when used for active vibration control. The active control system under investigation consists of the inertial actuator attached to a flexible structure, a collocated vibration sensor and a velocity feedback controller (VFC). Controlling low frequency motions or large amplitude vibrations requires a very long stroke for the proof mass. However, a physical limitation of inertial ...
Source: Journal of Sound and Vibration - October 13, 2019 Category: Physics Source Type: research

A wave-based optimization approach of curved joints for improved defect detection in waveguide assemblies
Publication date: Available online 11 October 2019Source: Journal of Sound and VibrationAuthor(s): Denis Vivien, Jean-Mathieu MencikAbstractA wave-based numerical approach is proposed for the detection of defects in waveguide assemblies with curved joints. Within this framework, the wave finite element (WFE) method is used. It provides an efficient numerical means for computing waves in one-dimensional periodic structures (waveguides), and assessing the reflection and transmission coefficients of waves around defects and curved joints. A so-called apparent reflection matrix of the defects, which takes into account the infl...
Source: Journal of Sound and Vibration - October 13, 2019 Category: Physics Source Type: research

Two constant amplitude pulses’ input shaper to maneuver an attitude of precise-oriented flexible spacecraft
Publication date: Available online 11 October 2019Source: Journal of Sound and VibrationAuthor(s): Setyamartana Parman, Tiauw Hiong Go, TuwosoAbstractThis paper proposes an integrated feed-forward input shaper for flexible spacecraft maneuvering involving coupled roll and yaw motion interactions. The shaper affects both the roll and yaw inputs, and each individual input consists of two constant amplitude pulses. The cross-contribution of the roll and yaw inputs is considered in the formulation of the residual roll and yaw oscillation constraints. The resulting shaped roll and yaw inputs are then applied to several maneuver...
Source: Journal of Sound and Vibration - October 13, 2019 Category: Physics Source Type: research

Extracting torsional band gaps and transient waves in phononic crystal beams: Method and validation
Publication date: Available online 11 October 2019Source: Journal of Sound and VibrationAuthor(s): Kuo-Chih Chuang, Zhi-Wen Yuan, Y.Q. Guo, Xu-Feng LvAbstractDue to an absence of proper measuring techniques, torsional waves/vibrations in one-dimensional phononic crystals (PCs) or elastic metamaterials are usually theoretically or numerically studied without experimental validations. This work proposes a measurement method capable of extracting torsional band gaps and transient torsional waves from the total responses of PC and metamaterial beams. Specifically, a pair of point-wise self-demodulated fiber Bragg grating (SFBG...
Source: Journal of Sound and Vibration - October 13, 2019 Category: Physics Source Type: research

Rainbow metamaterials for broadband multi-frequency vibration attenuation: Numerical analysis and experimental validation
In this study, we propose a ‘rainbow’ metamaterial to achieve broadband multi-frequency vibration attenuation. The rainbow metamaterial is constituted of a Π-shaped beam partitioned into substructures by parallel plates insertions with two attached cantilever-mass acting as local resonators. Both resonators inside each substructure can be non-symmetric such that the metamaterial can have multi-frequency bandgaps. Furthermore, these cantilever-mass resonators have a progressively variant design along the beam, namely rainbow-shaped, for the purpose of achieving broader energy stop bands. Π-shaped beams par...
Source: Journal of Sound and Vibration - October 13, 2019 Category: Physics Source Type: research

Potential well hopping and performance of ocean energy harvesters
Publication date: Available online 10 October 2019Source: Journal of Sound and VibrationAuthor(s): Dane Sequeira, Brian P. MannAbstractThis paper examines a gimballed horizontal pendulum and studies how it can be used to harvest energy from ocean waves. The system's behavior is analyzed under both static and dynamic scenarios. Threshold escape behavior for parametrically excited systems with a time dependent term in the potential energy function is discussed and a criterion is proposed for predicting escape events. Performance metrics are identified to quantify and compare different responses. Numerical and experimental st...
Source: Journal of Sound and Vibration - October 11, 2019 Category: Physics Source Type: research

Dispersion analysis in ballasted railway tracks and Anderson localization in granular media
Publication date: Available online 10 October 2019Source: Journal of Sound and VibrationAuthor(s): L. de Abreu Corrêa, R. Cottereau, B. FaureAbstractThis paper analyzes the dynamic behavior of a randomly-heterogeneous continuum model of a ballasted railway track through the numerical construction of dispersion curves along the axis of the track. At intermediate frequencies (50–100 Hz), the dispersion curves display a strong decrease of the group velocity. At higher frequencies (above 100 Hz), the wave are strongly localized and cannot propagate along the track. This behavior is coherent with experimental ob...
Source: Journal of Sound and Vibration - October 11, 2019 Category: Physics Source Type: research

Corrigendum to “Local bending stiffness identification of beams using simultaneous Fourier-series fitting and shearography” [J. Sound Vib. 443 (2019) 764–787]
Publication date: Available online 10 October 2019Source: Journal of Sound and VibrationAuthor(s): Filip Zastavnik, Rik Pintelon, Mathias Kersemans, Wim Van Paepegem, Lincy Pyl (Source: Journal of Sound and Vibration)
Source: Journal of Sound and Vibration - October 11, 2019 Category: Physics Source Type: research

Comments on “Free vibration of functionally graded beams and frameworks using the dynamic stiffness method [J. Sound Vib. 422(2018) 34–47]”
Publication date: Available online 9 October 2019Source: Journal of Sound and VibrationAuthor(s): A.A. Popov (Source: Journal of Sound and Vibration)
Source: Journal of Sound and Vibration - October 10, 2019 Category: Physics Source Type: research

Comments on the validity of transfer matrix based models for the prediction of the effect of curved sound packages
Publication date: Available online 6 October 2019Source: Journal of Sound and VibrationAuthor(s): Kamal Kesour, Luca Alimonti, Noureddine AtallaAbstractIn this paper, the validity of using the Transfer Matrix Method (TMM) to account for the effect of practical curved sound packages (i.e. spring-mass treatment) in vibroacoustic systems is assessed. For this purpose, a sub-structuring method that employs a Patch Transfer Functions (PTF) approach is used to efficiently couple standard Finite Element Method (FEM) of the structure and the acoustic cavity with the sound package model. Three models of the noise control treatment ...
Source: Journal of Sound and Vibration - October 7, 2019 Category: Physics Source Type: research

Forced vibration analysis of Timoshenko double-beam system under compressive axial load by means of Green's functions
Publication date: Available online 4 October 2019Source: Journal of Sound and VibrationAuthor(s): X. Zhao, B. Chen, Y.H. Li, W.D. Zhu, F.J. Nkiegaing, Y.B. ShaoAbstractAs typical and significant structural elements, double-beam systems widely exist in practical engineering applications such as some subgrades and highway bridges. This paper focuses on presenting the closed-form solutions of the forced transverse vibration of a coupled Timoshenko double-beam system under compressive axial load. The solutions are generalized and can be suitable for any boundary conditions. The present model is generalized and can be reduced t...
Source: Journal of Sound and Vibration - October 6, 2019 Category: Physics Source Type: research

Generalized Transfer Matrix Method for periodic planar media
Publication date: Available online 4 October 2019Source: Journal of Sound and VibrationAuthor(s): A. Parrinello, G.L. Ghiringhelli, N. AtallaAbstractSound transmission through infinite planar multilayered structures characterized by in-plane periodicity is accurately and efficiently predicted by exploiting free wave propagation and Bloch modes. A through-thickness transfer matrix is derived for each layer by manipulating the dynamic stiffness matrix related to a finite element model of a unit cell. The transfer matrices of all the layers composing the structure account for the Bloch modes generated in heterogeneous layers....
Source: Journal of Sound and Vibration - October 6, 2019 Category: Physics Source Type: research

Commentary on, “Discussion on ‘Free vibration of functionally graded beams and frameworks using the dynamic stiffness method’ by Banerjee et al., Journal of Sound and Vibration 442 (2018) 34–47.”
Publication date: Available online 4 October 2019Source: Journal of Sound and VibrationAuthor(s): J.R. Banerjee, A. Ananthapuvirajah (Source: Journal of Sound and Vibration)
Source: Journal of Sound and Vibration - October 6, 2019 Category: Physics Source Type: research

Nonlinear vibrations of a coupled beam-arch bridge system
Publication date: Available online 4 October 2019Source: Journal of Sound and VibrationAuthor(s): Vladimir Stojanović, Marko D. Petković, Dunja MilićAbstractA characteristic engineering example of the model presented in this paper, which consists of a viscoelastically and nonlinearly coupled beam-arch system, can be found in the physical model of a bridge. Here, the beam analogue of von Kármán's nonlinear strain-displacement relationships is used. After that the p-version of the finite element method is employed for the coupled system's geometrically nonlinear responses. In order to investigate the feature...
Source: Journal of Sound and Vibration - October 4, 2019 Category: Physics Source Type: research

The estimation of the pressure pulsation damping coefficient of a nozzle
Publication date: Available online 3 October 2019Source: Journal of Sound and VibrationAuthor(s): Przemysław Młynarczyk, Piotr CyklisAbstractThe attenuation of pressure pulsation in volumetric compressor manifolds is a result of three factors: anti-resonance, viscosity and vorticity. Two main methods are considered as the standard approach for the estimation of the element influence on pressure pulsations: a one-dimensional real time-space domain solution and a distributed acoustic impedance model (Helmholtz) approach solved in a complex domain. In both cases, only two types of pressure attenuation may be estimated: reso...
Source: Journal of Sound and Vibration - October 3, 2019 Category: Physics Source Type: research

Bandlimited force identification based on sinc-dictionaries and Tikhonov regularization
Publication date: Available online 1 October 2019Source: Journal of Sound and VibrationAuthor(s): Li Wang, Jike Liu, Zhong-Rong LuAbstractA bandlimited force identification approach is proposed in this paper. It consists of two main ingredients. On the one hand, the sinc-dictionaries are established for bandlimited force representation. This motivates from the sampling formula that a bandlimited signal can be well interpolated by sinc functions. It is also noteworthy that using the sinc-dictionaries, the amount of variables is dramatically reduced. On the other hand, the Tikhonov regularization is introduced to circumvent ...
Source: Journal of Sound and Vibration - October 3, 2019 Category: Physics Source Type: research

Processing time-series of randomly forced self-oscillators: The example of beer bottle whistling
We present a model-based, output-only parameter identification method for self-sustained oscillators forced by dynamic noise, which we illustrate experimentally with a simple aeroacoustic setup: a turbulent jet impinging a beer bottle and producing a distinct whistling tone in a finite range of jet angles and jet velocities. Given a low-order model of the system, the identification is based on analyzing stationary time series of a single key observable: the acoustic pressure fluctuations inside the bottle. Noting that this observable exhibits all the characteristics of weakly non-linear self-oscillations, we choose as a mi...
Source: Journal of Sound and Vibration - September 29, 2019 Category: Physics Source Type: research

Railway track degradation: The contribution of a spatially variant support stiffness - Global variation
Publication date: Available online 28 September 2019Source: Journal of Sound and VibrationAuthor(s): Mehran Sadri, Tao Lu, Michaël SteenbergenAbstractThe effect of large-scale variation in the support stiffness on railway track degradation is studied using a frequency-domain approach. The model used can deal with parametric excitation due to both the discrete sleeper spacing and arbitrary large-scale spatial track non-uniformity. Adopted stiffness profiles are based on realistic datasets in the literature. The sensitivity to degradation is assessed by quantifying the energy dissipation in the substructure over the inf...
Source: Journal of Sound and Vibration - September 29, 2019 Category: Physics Source Type: research

On the use of active and reactive input power in topology optimization of one-material structures considering steady-state forced vibration problems
Publication date: Available online 28 September 2019Source: Journal of Sound and VibrationAuthor(s): Olavo M. Silva, Miguel M. Neves, Arcanjo LenziAbstractAs studied by the authors in a previous work, applying topology optimization to minimize overall dynamic response of structures under time-harmonic loads may present serious drawbacks. It happens e.g. for an excitation frequency above the first resonance of the initial design, especially when the objective is to obtain one-material structures. Essential part of these drawbacks is due to the use of dynamic quantities that present strong influence of local responses, with ...
Source: Journal of Sound and Vibration - September 29, 2019 Category: Physics Source Type: research

A compressive-sensing-based method for radial mode analysis of aeroengine fan noise
Publication date: Available online 28 September 2019Source: Journal of Sound and VibrationAuthor(s): Huanxian Bu, Xun Huang, Xin ZhangAbstractA couple of new mode detection methods are proposed in this paper to enable effective and efficient radial mode analysis of in-duct tonal sound fields by utilizing compressive sensing. The first method uses a compressive-sensing-based azimuthal mode detection and an inverse-method-based radial mode decomposition. The second method employs the compressive sensing directly from an in-duct sound propagation model. Prediction error analysis of the two techniques is numerically performed ...
Source: Journal of Sound and Vibration - September 29, 2019 Category: Physics Source Type: research

Active vibration control unit with a flywheel inertial actuator
Publication date: Available online 27 September 2019Source: Journal of Sound and VibrationAuthor(s): Aleksander Kras, Paolo GardonioAbstractThis paper presents simulation and experimental results on the implementation of a velocity feedback control unit with a new flywheel inertial actuator, which can be used to reduce flexural vibration of distributed structures. The actuator incorporates a classical coil–magnet linear transducer and a flywheel element such that both linear and rotational inertia effects are generated by the moving components of the actuator. The additional rotational inertia effect shifts to lower ...
Source: Journal of Sound and Vibration - September 29, 2019 Category: Physics Source Type: research

On the sound field from a source moving above non-locally reacting grounds
Publication date: Available online 26 September 2019Source: Journal of Sound and VibrationAuthor(s): Y. Wang, K.M. Li, D. Dragna, P. Blanc-BenonAbstractEquation Chapter 1 Section 1This paper investigates the sound fields generated by a source moving horizontally at a constant speed above a non-locally reacting flat ground. The present study offers an extension of an earlier study that focused on sound fields owing to a moving source above a locally reacting ground. However, a locally reacting ground model may not be sufficient for many acoustic “soft” grounds such as snow-covered ground or a layer of sound-abso...
Source: Journal of Sound and Vibration - September 27, 2019 Category: Physics Source Type: research

Methods for evaluating in-duct noise attenuation performance in a muffler design problem
In this study, methods for evaluating the noise attenuation performance of a muffler in a muffler design problem are investigated, and a proper evaluation method is suggested for actual noise reduction in a duct when an optimally designed muffler is mounted on a duct. Mathematical expressions of the transmission loss, insertion loss, and level difference for a simple expansion chamber muffler are developed from basic acoustic equations. The effects of the locations of the measurement points, tailpipe length, and impedance at the end of the duct on the noise attenuation performance calculated using the three evaluation meth...
Source: Journal of Sound and Vibration - September 27, 2019 Category: Physics Source Type: research

On the formation of complex modes in non-proportionally damped systems
Publication date: Available online 26 September 2019Source: Journal of Sound and VibrationAuthor(s): Can Nerse, Semyung WangAbstractIn the classical studies of non-proportionally damped systems, the resulting complex modal parameters are obtained by solving the generalized eigenvalue problem. In the present study, we propose a unique method to obtain complex modes for discrete and continuous systems. Based on a wave analogy, the difference between a complex mode and a real normal mode is represented by the summation of patterns that propagate from the boundaries. Owing to the spatial non-proportionality of the damping, the...
Source: Journal of Sound and Vibration - September 27, 2019 Category: Physics Source Type: research

Prediction and uncertainty quantification of structure-borne sound radiation into a diffuse field
Publication date: Available online 24 September 2019Source: Journal of Sound and VibrationAuthor(s): Edwin P.B. Reynders, Pengchao Wang, Cédric Van hoorickx, Geert LombaertAbstractWhen predicting the radiation of structure-borne sound into a room, it is often assumed that the generated sound field is diffuse. A diffuse field is by definition a random field, composed of a large number of statistically independent plane waves, the spatial phase of which is uniformly distributed and independent from the amplitude. It may represent the sound field of a conceptual ensemble of rooms with the same modal density and total a...
Source: Journal of Sound and Vibration - September 26, 2019 Category: Physics Source Type: research

Wavelet analysis of multiple tonal phenomena generated from a simplified nose landing gear and a ring cavity
Publication date: Available online 24 September 2019Source: Journal of Sound and VibrationAuthor(s): Ling Li, Peiqing Liu, Yu Xing, Hao GuoAbstractDiscrete tones exist in the airframe noise spectra. For landing gear components, some cavities may generate multiple tones. The tonal frequencies can be accurately predicted and two different tonal noise generation mechanisms have been already proposed, namely fluid-acoustic feedback loop and acoustic resonance. However, the inherent temporal features and the relationships between multiple tones are rarely researched. This paper introduces the continuous wavelet transform method...
Source: Journal of Sound and Vibration - September 26, 2019 Category: Physics Source Type: research

Time-frequency damage index of Broadband Lamb wave for corrosion inspection
Publication date: Available online 25 September 2019Source: Journal of Sound and VibrationAuthor(s): Jiadong Hua, Xuwei Cao, Yinggang Yi, Jing LinAbstractThe method based on Lamb wave shows great potential for structural health monitoring (SHM) and nondestructive testing (NDT). Damage index (DI) is a series of features extracted from Lamb wave signal that can be linked with damage, which can serve as an indicator to depict the damage. Conventional DIs including time-of-flight, amplitude change and signal difference coefficient are extracted from narrowband Lamb wave. However, time-of-flight needs prior knowledge of accurat...
Source: Journal of Sound and Vibration - September 26, 2019 Category: Physics Source Type: research

Foundations of Vibroacoustics by Colin Hansen. CRC Press (2018)
Publication date: 22 December 2019Source: Journal of Sound and Vibration, Volume 463Author(s): Dhanesh N. Manik (Source: Journal of Sound and Vibration)
Source: Journal of Sound and Vibration - September 26, 2019 Category: Physics Source Type: research

Multipole orthogonal beamforming combined with an inverse method for coexisting multipoles with various radiation patterns
Publication date: Available online 23 September 2019Source: Journal of Sound and VibrationAuthor(s): Xingjian Pan, Haijun Wu, Weikang JiangAbstractIdentification of sources with non-uniform radiation patterns is attracting considerable attention these years. A multipole beamforming algorithm combined with an inverse method, is proposed to detect coexisting multipoles with various radiation patterns. Positions and strengths of sources are estimated first. The sound field of each source is represented by the eigenvector of the cross-spectral matrix of microphone array signals. Source directivity is removed by the normalizati...
Source: Journal of Sound and Vibration - September 24, 2019 Category: Physics Source Type: research

Investigation of the causes behind the vibrations of a high-speed solid-rotor induction motor
Publication date: Available online 24 September 2019Source: Journal of Sound and VibrationAuthor(s): Sabin Sathyan, Anouar Belahcen, Antti Lehikoinen, Ugur Aydin, Fredrik BoxbergAbstractThis paper analyzes the causes of vibrations in a solid-rotor induction motor (SRIM) through electromagnetic Finite Element (FE) simulations and laboratory measurements. The computed results are compared with vibration measurements, and the electromagnetic causes of vibrations were discovered, including the fault related reasons. The machine under investigation is a 300 kW, 60 000 rpm, three-phase SRIM for industrial air compression. ...
Source: Journal of Sound and Vibration - September 24, 2019 Category: Physics Source Type: research

Efficiency of vibrational energy dissipation by tuned rolling-cylinder dampers
Publication date: Available online 21 September 2019Source: Journal of Sound and VibrationAuthor(s): Ryota Tsuda, Masato SaekiAbstractThe damping efficiency of a tuned rolling-cylinder damper in a horizontally vibrating system under sinusoidal excitation was investigated experimentally and analytically. The damper is an auxiliary system and consists of some rotary bodies placed on a circular arc surface attached to the primary system. The friction force between rotary bodies is a source of energy dissipation of the auxiliary system. In an experimental approach, the effects of the size of rotary bodies, the number of rotary...
Source: Journal of Sound and Vibration - September 23, 2019 Category: Physics Source Type: research

Numerical prediction of passenger cabin noise due to jet noise by an ultra–high–bypass ratio engine
Publication date: Available online 20 September 2019Source: Journal of Sound and VibrationAuthor(s): Christopher Blech, Christina K. Appel, Roland Ewert, Jan W. Delfs, Sabine C. LangerAbstractWithin the framework of the Collaborative Research Center 880, future civil transportation aircraft are investigated. One major aim is a drastic reduction of the noise emission to the ground and an appropriate noise immission into the passenger cabin. The latter forms the focus of this contribution with the aim to ensure an equal or lower noise level in the cabin for new aircraft configurations. Numerical methods are applied to establ...
Source: Journal of Sound and Vibration - September 21, 2019 Category: Physics Source Type: research

Energy transfer by a secondary acoustic source through Friction-Induced Vibrations: A power flow analysis
Publication date: Available online 20 September 2019Source: Journal of Sound and VibrationAuthor(s): Soizic Terrien, Lucas Frache, Eric Chatelet, Francesco MassiAbstractFriction Induced Vibrations occur in many different contexts, from automotive industry to musical instruments, and are often investigated for their detrimental effects such as surface damage and dynamical instabilities. In this article, a mechanical device exploits Friction Induced Vibrations to transfer energy in a structure from a primary ambient low-frequency vibrational field towards a secondary acoustic field with a higher and wider frequency content. ...
Source: Journal of Sound and Vibration - September 21, 2019 Category: Physics Source Type: research

Secondary source and error sensing strategies for the active control of sound transmission through a small opening
Publication date: Available online 21 September 2019Source: Journal of Sound and VibrationAuthor(s): Congxin Zhang, Ming Qin, Haishan Zou, Xiaojun QiuAbstractThe openings of an enclosure allow natural ventilation and light ingress but also act as a point of entry for noise of the whole structure. In this paper, the active control of the sound transmitted through a small opening in a wall formed by two infinitely-large baffles is investigated up to 4 kHz. Based on an analytical model developed with the modal expansion method, the effects of different secondary source and error sensor strategies are compared numerically fo...
Source: Journal of Sound and Vibration - September 21, 2019 Category: Physics Source Type: research