Jean-Louis Guyader

Jean-Louis Guyader
Institut National des Sciences Appliquées de Lyon | INSA Lyon · Laboratory of Vibrations and Acoustics (LVA - EA 677)

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306
Publications
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Publications

Publications (306)
Article
This paper presents an analytical study of the acoustic radiation modeling of a finite cylindrical shell with infinite rigid extensions. An infinite fluid at rest surrounds the shell, which contains a flowing fluid and excited by a harmonic driving force. The external pressure is calculated with a single layer integral equation, while the internal...
Article
MODal ENergy Analysis (MODENA) was previously developed in the same framework as Statistical Energy Analysis (SEA) and Statistical modal Energy distribution Analysis (SmEdA) methods. It deals with energy exchanges between weakly coupled subsystems in vibro-acoustics. However, unlike SEA, MODENA is not a statistical method as it is based on determin...
Preprint
Full-text available
In this article, an improvement of [1] is proposed, in order to identify the flexural and shear complex moduli of a sandwich beam by simply measuring the displacement field. The method described here involves a correction of finite the difference scheme 5
Article
In substructuring approaches in the field of acoustics, subdomains are mostly characterized by impedance or mobility at their interfaces with other subdomains. This allows handling large systems broken down into smaller, easier to solve subdomains and reaching higher frequency ranges. When a subdomain is characterized by experiments, the impedances...
Article
Full-text available
This paper addresses the problem of estimating the local viscoelastic parameters of sandwich beams. An original procedure involving an inverse vibratory method (Force Analysis Technique) and the Timoshenko beam theory is detailed and applied experimentally on a sample presenting a honeycomb core. The major philosophy relies in considering multi-lay...
Article
Full-text available
Vibro-acoustic simulation in the mid-frequency range is of interest for automotive and truck constructors. The dissipative treatments used for noise and vibration control such as viscoelastic patches and acoustic absorbing materials must be taken into account in the problem. The Statistical modal Energy distribution Analysis (SmEdA) model consists...
Poster
Full-text available
De nombreux travaux dans la littérature se sont concentrés sur la modélisation vibro-acoustique de coques cylindriques raidies immergées, du fait des nombreuses applications industrielles, en particulier dans le domaine aéronautique ou naval. Cependant, peu d’études prennent en compte des structures internes non-axisymétriques. En effet, des struct...
Article
A method for reconstructing and separating vibratory field on a plate-like structure is presented. The method, called “Structural Holography” is derived from classical Near-field Acoustic Holography (NAH) but in the vibratory domain. In this case, the plate displacement is measured on one-dimensional lines (the holograms) and used to reconstruct th...
Article
This paper presents the theoretical framework of the virtual acoustic volume concept and two related inverse Patch Transfer Functions (iPTF) identification methods (called u-iPTF and m-iPTF depending on the chosen boundary conditions for the virtual volume). They are based on the application of Green's identity on an arbitrary closed virtual volume...
Article
The source field reconstruction aims at identifying the excitation field measuring the response of the system. In Near-field Acoustic Holography, the response of the system (the radiated acoustic pressure) is measured on a hologram using a microphones array and the source field (the acoustic velocity field) is reconstructed with a back-propagation...
Conference Paper
A perfect diffuse acoustic field is theoretically required when performing measurements that make use of a reverberant room. From an experimental point of view, completely diffuse conditions are impossible to reach and ensuring an as effective as possible sound diffusion in the room becomes of crucial practical importance. The diffusivity indicator...
Article
Statistical modal Energy distribution Analysis (SmEdA) approach was developed to enlarge the application field of Statistical Energy Analysis (SEA) when equipartition of modal energies is not achieved. SmEdA gives more precise results than standard SEA when compared to exact energy response of a deterministic system in the case of low modal overlap...
Article
Full-text available
This article presents the modeling of a MEMS microphone with an original architecture formed of mechanical structures moving in the plane of the substrate. On the contrary of most microphones generally constituted of an oscillating membrane, some transducers developed by the CEA-LETI with M&NEMS technology use micro beams moving in the plane of the...
Article
Full-text available
An as diffuse as possible acoustic field is pursued when performing measurements that make use of a reverberant room. The diffusivity descriptors that are commonly used to qualify the actual sound field in such a room are calculated in the room volume, away from boundaries. This is somewhat contradictory with the fact that for sound insulation and...
Conference Paper
Full-text available
L’étude du rayonnement acoustique des coques cylindriques raidies a fait l’objet de nombreux travaux car elles sont d’un grand intérêt pour les industriels des secteurs naval et aéronautique. Cependant peu d’attention a été portée aux effets liés à la présence de structures fixées rigidement à l’intérieur de la coque, telles que des planchers, des...
Article
Full-text available
The vibroacoustic behavior of axisymmetric stiffened shells immersed in water has been intensively studied in the past. On the contrary, little attention has been paid to the modeling of these shells coupled to non-axisymmetric internal frames. Indeed, breaking the axisymmetry couples the circumferential orders of the Fourier series and considerabl...
Article
Full-text available
Substructuring approaches are nowadays widely used to predict numerically the vibroacoustic behavior of complex mechanical systems. Some of these methods are based on admittance or mobility frequency transfer functions at the coupling interfaces. They have already been used intensively to couple subsystems linked by point contacts and enable to sol...
Conference Paper
In this paper, a generalization of the estimate local method named GELM is proposed in which a new semi analytical approach is presented to solve the free motion equation of a multi-span bridge. By the superposition of wavenumbers with the corresponding beam mode shape, the bi-dimensional equation of the plate which was used to model the roadway br...
Conference Paper
Full-text available
Numerical models of periodically stiffened axisymmetric submerged shells impinged by an acoustic plane wave have been developed in order to study the scattered pressure by this target. Along with experimental results, they show that Bragg, Bloch-Floquet and helical waves can be observed. Nevertheless, the influence of added non-axisymmetric interna...
Article
Full-text available
Abstract The irrotational part of the structural intensity for flexural wave motion in plate-like structures is calculated from measurement data of kinematic quantities, such as out-of-plane velocities, by a new method that makes use of a test functional series expansion. The computation of the structural intensity and its irrotational part, which...
Article
Full-text available
A damage identification method named virtual vibration deflection (VVD) was developed, the principle of which was formulated based on the “weak” modality of the pseudo-excitation (PE) approach previously established. In essence, VVD is based on locating structural damage within a series of “sub-regions” divided from the entire structure under inspe...
Conference Paper
Full-text available
Numerical methods are nowadays widely used to predict the vibroacoustic behavior of mechanical systems. Nevertheless, when the system is complex as for instance in the aerospace or naval industry, it is practically impossible to solve for the problem at once, more particularly at medium or high frequencies. That is why substructuring approaches hav...
Conference Paper
Full-text available
This work aims at analyzing structures by mean of an inverse vibratory method consisting in an evolution of the Force Analysis Technique. The latter developed by Pézerat et al. firstly allowed localization and quantification of vibratory sources from measurement of the displacement field. In 2012 Ablitzer et al. improved the procedure for character...
Article
Many methods to detect, quantify, or reconstruct acoustic sources exist in the literature and are widely used in industry (near-field acoustic holography, inverse boundary element method, etc.). However, the source identification in a reverberant or nonanechoic environment on an irregularly shaped structure is still an open issue. In this context,...
Article
Full-text available
The acoustic detection of defects or leaks inside a cylindrical shell containing a fluid is of prime importance in the industry, particularly in the nuclear field. This paper examines the beamforming technique which is used to detect and locate the presence of an acoustic monopole inside a cylindrical elastic shell by measuring the external shell v...
Article
Nowadays, the need of source identification methods is still growing and application cases are more and more complex. As a consequence, it is necessary to develop methods allowing us to reconstruct sound fields on irregularly shaped sources in reverberant or confined acoustic environment. The inverse Patch Transfer Functions (iPTF) method is suitab...
Article
Full-text available
This paper presents a method of determining an appropriate equation of motion of two-dimensional plane structures like membranes and plates from vibration response measurements. The local steady-state vibration field is used as input for the inverse problem that approximately determines the dispersion curve of the structure. This dispersion curve i...
Article
A damage characterization framework based on the “pseudo-excitation” (PE) approach has recently been established, aimed at quantitatively identifying damage in beam-, plate-, and shell-like structural components. However, it is envisaged that the effectiveness of the PE approach can be restricted in practical implementation, due to the involvement...
Article
Full-text available
Transient sonar detection systems have been developed over the last decades, and hence transient noise emissions from ship have become a matter of concern for acoustic discretion. One step towards the mitigation of transient noise emissions from ships consists in the accurate localization and identification of the noise sources. We use in this pape...
Poster
Full-text available
Numerical methods are nowadays widely used to predict the vibroacoustic behavior of mechanical systems. Nevertheless, when the system is complex as for instance in the aerospace or naval industry, it is practically impossible to solve for the problem at once, more particularly at medium or high frequencies. That is why sub-structuring approaches ha...
Article
The identification of excitations on plates by an inverse method using local Finite Element modeling is studied. A dynamic condensation is proposed in order to eliminate Degrees Of Freedom not directly measurable like rotations. Before the condensation, the Craig–Bampton method can be optionally used to reduce the model (decrease of both computatio...
Conference Paper
Full-text available
Transient sonar detection systems have been developed over the last decades, and hence transient noise emissions from ships have become a matter of concern for acoustic discretion. A step towards the mitigation of transient noise emissions consists in the accurate localization and identification of the noise sources. We propose in this paper to app...
Article
Full-text available
While the structural-acoustic coupling between flexible structures and closed acoustic cavities has been extensively studied in the literature, the modeling of structures coupled through open cavities, especially connected in cascade, is still a challenging task for most of the existing methods. The possible presence of micro-perforated panels (MPP...
Article
Full-text available
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 techniqu...
Conference Paper
Full-text available
De nos jours, les systèmes de détection acoustique utilisés dans la lutte sous-marine sont capables d’analyser les bruits transitoires. Il est donc nécessaire pour l’industriel de maitriser la discrétion acoustique dans ce domaine. Afin de définir une méthodologie qui permettra de spécifier des exigences sur les matériels sources de bruit transitoi...
Article
This article presents the modeling of aM EMS microphone with an original architecture formed of mechanical structures moving in the plane of the substrate. On the contrary of most microphones generally constituted of an oscillating membrane, some transducers developed by the CEA-LETI with M&NEMS technology use micro beams moving in the plane of the...
Conference Paper
Full-text available
Statistical modal Energy distribution Analysis (SmEdA) can be used to model a fluid-structure-problem based on modal information of the uncoupled-subsystems. Recently the method has been extended to include the effect of a dissipative treatment (i.e. damping or absorbing material). In this paper, SmEdA is tested on a steel plate with/without dampin...
Article
Interfacial debonding in multilayered engineering structures can jeopardize the structural integrity without timely awareness. By reconstructing the distribution of interfacial forces and canvassing local perturbance to the structural dynamic equilibrium, an identification approach for interfacial debonding between different structural components w...
Conference Paper
Full-text available
Measuring the vibro-acoustic response of structures subjected to a turbulent boundary layer (TBL) excitation in operating conditions remains an open issue for experimenters. Generally, in situ measurements, e.g. flight tests, underwater measurements and wind tunnel measurements are carried out, although they require expensive facilities. As an alte...
Article
Full-text available
Statistical modal Energy distribution Analysis (SmEdA) can be used as an alternative to Statistical Energy Analysis for describing subsystems with low modal overlap. In its original form, SmEdA predicts the power flow exchanged between the resonant modes of different subsystems. In the case of sound transmission through a thin structure, it is well...
Conference Paper
Full-text available
This paper describes the conception, designs consideration and fabrication process of a novel MEMS microphone. The presented microphone not only uses a new architecture, the sensitive part being beams moving within the plane of the substrate, but also uses an innovative detection means with Silicon piezo-resistive nanogauges. Modelization will cons...
Article
Full-text available
The aim of this work consists in evaluating and analyzing vibrations and radiated pressure from a fluid loaded structure excited by a transient mechanical source. The time signature can be estimated from a discrete inverse Fourier transform of the Frequency Response Functions (FRF) of the considered system. In order to validate the numerical proces...
Article
Full-text available
Energy methods like Statistical Energy Analysis (SEA) or Statistical modal Energy distribution Analysis (SmEdA), based on the well-known equations of two coupled oscillators, are both limited when non-resonant contributions of modes are not negligible (typically in the case of cavity/structure/cavity coupling). In SEA, this non-resonant contributio...
Article
Previously, an inverse damage characterization framework was proposed by quantifying the perturbation to local dynamic equilibrium of a beam-like structure, showing advantages in some aspects over the traditional global vibration-based and local guided-wave-based methods. Residing on the plate theory, this framework was expanded to a two-dimensiona...
Conference Paper
Full-text available
Vibroacoustic systems, involving cascade structures mutually coupled through partially open/close acoustic cavities, are commonly seen in various applications. The modeling of such systems is challenging since the two adjacent acoustic domains separated by the partial partition are connected both structurally and acoustically, where the continuity...
Article
Full-text available
An additive damping treatment is an effective tool to control the dynamic response of built-up structures, and it is widely utilized through industrial applications. By applying a viscoelastic layer on a given structure, the vibratory energy is dissipated through shear and in-plane motions at the layer interface. Modeling the effect of such a treat...