Marc Pachebat - Academia.edu (original) (raw)

Papers by Marc Pachebat

Research paper thumbnail of Toward an active anechoic room

Le Centre pour la Communication Scientifique Directe - HAL - Diderot, Sep 7, 2014

International audienc

Research paper thumbnail of Simulation of the TBL Induced Vibrations of a Plate Using Virtual Sources

Finding an alternative to common test means (reverberant chamber, wind tunnel facilities, in-situ... more Finding an alternative to common test means (reverberant chamber, wind tunnel facilities, in-situ measurements, etc.) is of particular interest to the transportation industry (automobile, aeronautics , etc.) for the reproduction of the vibroacoustic response of structures under random excitations such as the diffuse acoustic field or the turbulent boundary layer. In this paper a method of achieving this goal using a single acoustic source and the synthetic array principle is proposed. To assess the validity of this method, an academic case study consisting of a simply supported thin aluminum plate under turbulent boundary layer excitation is presented. The vibroacoustic response of the plate is determined with the proposed process and compared to results from random vibration theory and direct measurements in an anechoic wind tunnel facility. This comparison shows good agreement between the proposed approach and both the theoretical and wind tunnel results.

Research paper thumbnail of Comparaison de techniques d'absorption vibro-acoustiques

Cette étude propose la conception d'un banc d'essai servant à la caractérisation d'ab... more Cette étude propose la conception d'un banc d'essai servant à la caractérisation d'absorbeurs vibro-acoustiques. Ce banc est conçu sur la propriété d'un tube de Kundt court permettant le travail en basses fréquences (en-dessous de la première fréquence de résonance du tube). Une méthode de mesure ne (méthode à deux microphones surdéterminée) est mise en place an d'extraire les paramètres acoustiques souhaités de l'absorbeur et in ne proposer un bilan énergétique résultant et sa répartition spectrale (fréquence d'excitation et ses harmoniques)

Research paper thumbnail of Identification parcimonieuse d'un système non-linéaire en régime forcé : mesure, transformée de Hilbert-Huang et a priori

National audienceOn présente dans cette communication une amélioration de la transformée de Hilbe... more National audienceOn présente dans cette communication une amélioration de la transformée de Hilbert-Huang par ajout d'information a priori. Son application au mouvement fortement non-linéaire d'une membrane faiblement tendue révèle que la dynamique de la membrane change au cours d'un cycle forcé

Research paper thumbnail of Comparison between methods to characterize the acoustical properties of musical toneholes

Research paper thumbnail of Vibroacoustic Testing of Panels Under a Turbulent Boundary Layer Excitation Using a Space-Time Spectral Synthesis Approach

Research paper thumbnail of Characterization of open woodwind toneholes by the tube reversed method

The Journal of the Acoustical Society of America, 2021

Research paper thumbnail of Une cabine acoustique pour la restitution contrôlée des basses et très basses fréquences (3Hz-300Hz) : qualification, identification acoustique et premier exemple de contrôle

Research paper thumbnail of Synthesis of the Vibroacoustic Response of a Panel under Diffuse Acoustic Field using the Synthetic Array Principle

Research paper thumbnail of Experimental evidence of simultaneous amplitude reduction of two acoustic modes under quasiperiodic excitation by a single nonlinear membrane

Research paper thumbnail of Device and method of attenuation of sound

The invention particularly relates to an attenuating device for attenuating acoustic waves genera... more The invention particularly relates to an attenuating device for attenuating acoustic waves generated by a source (1) emitting acoustic waves with frequencies between f1 and f2 and whose pressure levels range between n1 and n2, the attenuating device comprising at least one absorber (11) comprising at least one acoustic nonlinear membrane; - the attenuation device being configured so that the first face (13) of the absorber (11) is in acoustic communication with the source (1); - the attenuation device comprises at least one coupling element (16) of the second face (14) with the source (1), the coupling element (16) being configured to transmit to the second face (14) of acoustic function of the acoustic waves emitted by the source (1), whose phase and / or amplitude leads to a differential pressure of the acoustic waves incident on respectively the first and second face at the same time. The invention also includes a system and method for sound attenuation.

Research paper thumbnail of Recherches et Musiques au Laboratoire de Mécanique et d'Acoustique

Research paper thumbnail of Reproduction of the vibroacoustic response of panels under stochastic excitations using the source scanning technique

Journal of Sound and Vibration, 2021

OpenStreetMap (OSM), with its global coverage and Open Database License, has recently gained popu... more OpenStreetMap (OSM), with its global coverage and Open Database License, has recently gained popularity. Its quality is adequate for many applications, but since it is crowd-sourced, errors remain an issue. Errors in associated tags of the road network, for example, are impacting routing applications. Particularly road classification errors often lead to false assumptions about capacity, maximum speed, or road quality, possibly resulting in detours for routing applications. This study aims at finding potential classification errors automatically, which can then be checked and corrected by a human expert. We develop a novel approach to detect road classification errors in OSM by searching for disconnected parts and gaps in different levels of a hierarchical road network. Different parameters are identified that indicate gaps in road networks. These parameters are then combined in a rating system to obtain an error probability to suggest possible misclassifications to a human user. The methodology is applied to an exemplar case for the state of New South Wales in Australia. The results demonstrate that (1) more classification errors are found at gaps than at disconnected parts, and (2) the gap search enables the user to find classification errors quickly using the developed rating system that indicates an error probability. In future work, the methodology can be extended to include available tags in OSM for the rating system. The source code of the implementation is available via GitHub.

Research paper thumbnail of Nonlinear targeted energy transfer of two coupled cantilever beams coupled to a bistable light attachment

Journal of Sound and Vibration, 2016

Research paper thumbnail of On the Use of P-U Probes for Measuring the Transitory Near Acoustic Field

Research paper thumbnail of Vibro-acoustic response of a stiffened panel under synthetized space-time random excitations

Research paper thumbnail of Low frequency coupling and mode interference in an inhomogeneous lattice of finite length

The propagation through a lattice made with two waveguides periodically coupled by perforations i... more The propagation through a lattice made with two waveguides periodically coupled by perforations is studied at low-frequencies. A degree of inhomogeneity is introduced with parametrically opened diaphragms inserted into one waveguide of the lattice. Analytical results obtained thanks to the fourth-order transfer matrix formalism illustrate three physical phenomena. The first phenomena is the effect of the perforations, the second is the effect of the inhomogeneity of the lattice, and the third is the effect of the interference between propagating modes when the system have finite length. These results give analytical expressions for the insertion loss, the characteristic impedance or propagation constants, that can be of practical interest for understanding and designing non local acoustic treatments for automotive and turbofan engines. The cases of a strongly inhomogeneous lattice and almost homogeneous lattice and their transition to homogeneous and branched resonator cases are dis...

Research paper thumbnail of Comportement Des Materiaux Absorbants Dans Les Champs Acoustiques Intenses ; Modelisation De Traitements Acoustiques Reactifs a Reaction Non Locale Dans Les Conduits

Ce travail s'inscrit dans la recherche de traitements acoustiques passifs de conception nouve... more Ce travail s'inscrit dans la recherche de traitements acoustiques passifs de conception nouvelle, permettant une reduction accrue des nuisances sonores des reacteurs d'avions (traitements acoustiques de paroi) ou des moteurs thermiques automobiles (silencieux) par exemple. La premiere partie du memoire presente l'etude du comportement des materiaux poreux dans les champs acoustiques intenses, lorsque le squelette poreux peut etre considere comme rigide. Deux dispositifs experimentaux ont ete mis au point. Le premier permet la mesure de la resistance au passage de l'air. en fonction du nombre de Reynolds d'un ecoulement a travers un echantillon (Loi de Darcy non lineaire). Deux comportements non lineaires distincts ainsi qu'un nombre de Reynolds critique sont mis en evidence experimentalement pour chaque echantillon. Le second dispositif permet la mesure des coefficients de reflexion et de transmission acoustiques des memes echantillons, inseres dans un condui...

Research paper thumbnail of Le pompage énergétique par absorbeur non-linéaire bi-stable : prédiction de la transition chaotique de l’absorbeur par analyse de Mel’nikov

Research paper thumbnail of Caractérisation expérimentale d’un banc de mesures acoustique pour absorbeurs linéaires et non linéaires à basse fréquence et fort niveau : méthodes à un et plusieurs microphones

Cette etude experimentale est realisee dans un tube de Kundt court ou des mesures de pression son... more Cette etude experimentale est realisee dans un tube de Kundt court ou des mesures de pression sont effectuees au moyen de quatre microphones. La plage frequentielle va de 10 a 200 Hz pour de forts niveaux allant jusqu’a 300 Pa. Une methode qui permet de determiner l’impedance et le coefficient de reflexion d’une terminaison inconnue est presentee. Cette methode necessite la connaissance de quatre terminaisons inconnues et d’au moins une mesure de pression. Une validation des impedances estimees est effectuee avec plusieurs microphones puis une terminaison inconnue. Le coefficient de reflexion d’une membrane visco-elastique non lineaire est determine. Le comportement d’un absorbeur non lineaire est alors mis en evidence.

Research paper thumbnail of Toward an active anechoic room

Le Centre pour la Communication Scientifique Directe - HAL - Diderot, Sep 7, 2014

International audienc

Research paper thumbnail of Simulation of the TBL Induced Vibrations of a Plate Using Virtual Sources

Finding an alternative to common test means (reverberant chamber, wind tunnel facilities, in-situ... more Finding an alternative to common test means (reverberant chamber, wind tunnel facilities, in-situ measurements, etc.) is of particular interest to the transportation industry (automobile, aeronautics , etc.) for the reproduction of the vibroacoustic response of structures under random excitations such as the diffuse acoustic field or the turbulent boundary layer. In this paper a method of achieving this goal using a single acoustic source and the synthetic array principle is proposed. To assess the validity of this method, an academic case study consisting of a simply supported thin aluminum plate under turbulent boundary layer excitation is presented. The vibroacoustic response of the plate is determined with the proposed process and compared to results from random vibration theory and direct measurements in an anechoic wind tunnel facility. This comparison shows good agreement between the proposed approach and both the theoretical and wind tunnel results.

Research paper thumbnail of Comparaison de techniques d'absorption vibro-acoustiques

Cette étude propose la conception d'un banc d'essai servant à la caractérisation d'ab... more Cette étude propose la conception d'un banc d'essai servant à la caractérisation d'absorbeurs vibro-acoustiques. Ce banc est conçu sur la propriété d'un tube de Kundt court permettant le travail en basses fréquences (en-dessous de la première fréquence de résonance du tube). Une méthode de mesure ne (méthode à deux microphones surdéterminée) est mise en place an d'extraire les paramètres acoustiques souhaités de l'absorbeur et in ne proposer un bilan énergétique résultant et sa répartition spectrale (fréquence d'excitation et ses harmoniques)

Research paper thumbnail of Identification parcimonieuse d'un système non-linéaire en régime forcé : mesure, transformée de Hilbert-Huang et a priori

National audienceOn présente dans cette communication une amélioration de la transformée de Hilbe... more National audienceOn présente dans cette communication une amélioration de la transformée de Hilbert-Huang par ajout d'information a priori. Son application au mouvement fortement non-linéaire d'une membrane faiblement tendue révèle que la dynamique de la membrane change au cours d'un cycle forcé

Research paper thumbnail of Comparison between methods to characterize the acoustical properties of musical toneholes

Research paper thumbnail of Vibroacoustic Testing of Panels Under a Turbulent Boundary Layer Excitation Using a Space-Time Spectral Synthesis Approach

Research paper thumbnail of Characterization of open woodwind toneholes by the tube reversed method

The Journal of the Acoustical Society of America, 2021

Research paper thumbnail of Une cabine acoustique pour la restitution contrôlée des basses et très basses fréquences (3Hz-300Hz) : qualification, identification acoustique et premier exemple de contrôle

Research paper thumbnail of Synthesis of the Vibroacoustic Response of a Panel under Diffuse Acoustic Field using the Synthetic Array Principle

Research paper thumbnail of Experimental evidence of simultaneous amplitude reduction of two acoustic modes under quasiperiodic excitation by a single nonlinear membrane

Research paper thumbnail of Device and method of attenuation of sound

The invention particularly relates to an attenuating device for attenuating acoustic waves genera... more The invention particularly relates to an attenuating device for attenuating acoustic waves generated by a source (1) emitting acoustic waves with frequencies between f1 and f2 and whose pressure levels range between n1 and n2, the attenuating device comprising at least one absorber (11) comprising at least one acoustic nonlinear membrane; - the attenuation device being configured so that the first face (13) of the absorber (11) is in acoustic communication with the source (1); - the attenuation device comprises at least one coupling element (16) of the second face (14) with the source (1), the coupling element (16) being configured to transmit to the second face (14) of acoustic function of the acoustic waves emitted by the source (1), whose phase and / or amplitude leads to a differential pressure of the acoustic waves incident on respectively the first and second face at the same time. The invention also includes a system and method for sound attenuation.

Research paper thumbnail of Recherches et Musiques au Laboratoire de Mécanique et d'Acoustique

Research paper thumbnail of Reproduction of the vibroacoustic response of panels under stochastic excitations using the source scanning technique

Journal of Sound and Vibration, 2021

OpenStreetMap (OSM), with its global coverage and Open Database License, has recently gained popu... more OpenStreetMap (OSM), with its global coverage and Open Database License, has recently gained popularity. Its quality is adequate for many applications, but since it is crowd-sourced, errors remain an issue. Errors in associated tags of the road network, for example, are impacting routing applications. Particularly road classification errors often lead to false assumptions about capacity, maximum speed, or road quality, possibly resulting in detours for routing applications. This study aims at finding potential classification errors automatically, which can then be checked and corrected by a human expert. We develop a novel approach to detect road classification errors in OSM by searching for disconnected parts and gaps in different levels of a hierarchical road network. Different parameters are identified that indicate gaps in road networks. These parameters are then combined in a rating system to obtain an error probability to suggest possible misclassifications to a human user. The methodology is applied to an exemplar case for the state of New South Wales in Australia. The results demonstrate that (1) more classification errors are found at gaps than at disconnected parts, and (2) the gap search enables the user to find classification errors quickly using the developed rating system that indicates an error probability. In future work, the methodology can be extended to include available tags in OSM for the rating system. The source code of the implementation is available via GitHub.

Research paper thumbnail of Nonlinear targeted energy transfer of two coupled cantilever beams coupled to a bistable light attachment

Journal of Sound and Vibration, 2016

Research paper thumbnail of On the Use of P-U Probes for Measuring the Transitory Near Acoustic Field

Research paper thumbnail of Vibro-acoustic response of a stiffened panel under synthetized space-time random excitations

Research paper thumbnail of Low frequency coupling and mode interference in an inhomogeneous lattice of finite length

The propagation through a lattice made with two waveguides periodically coupled by perforations i... more The propagation through a lattice made with two waveguides periodically coupled by perforations is studied at low-frequencies. A degree of inhomogeneity is introduced with parametrically opened diaphragms inserted into one waveguide of the lattice. Analytical results obtained thanks to the fourth-order transfer matrix formalism illustrate three physical phenomena. The first phenomena is the effect of the perforations, the second is the effect of the inhomogeneity of the lattice, and the third is the effect of the interference between propagating modes when the system have finite length. These results give analytical expressions for the insertion loss, the characteristic impedance or propagation constants, that can be of practical interest for understanding and designing non local acoustic treatments for automotive and turbofan engines. The cases of a strongly inhomogeneous lattice and almost homogeneous lattice and their transition to homogeneous and branched resonator cases are dis...

Research paper thumbnail of Comportement Des Materiaux Absorbants Dans Les Champs Acoustiques Intenses ; Modelisation De Traitements Acoustiques Reactifs a Reaction Non Locale Dans Les Conduits

Ce travail s'inscrit dans la recherche de traitements acoustiques passifs de conception nouve... more Ce travail s'inscrit dans la recherche de traitements acoustiques passifs de conception nouvelle, permettant une reduction accrue des nuisances sonores des reacteurs d'avions (traitements acoustiques de paroi) ou des moteurs thermiques automobiles (silencieux) par exemple. La premiere partie du memoire presente l'etude du comportement des materiaux poreux dans les champs acoustiques intenses, lorsque le squelette poreux peut etre considere comme rigide. Deux dispositifs experimentaux ont ete mis au point. Le premier permet la mesure de la resistance au passage de l'air. en fonction du nombre de Reynolds d'un ecoulement a travers un echantillon (Loi de Darcy non lineaire). Deux comportements non lineaires distincts ainsi qu'un nombre de Reynolds critique sont mis en evidence experimentalement pour chaque echantillon. Le second dispositif permet la mesure des coefficients de reflexion et de transmission acoustiques des memes echantillons, inseres dans un condui...

Research paper thumbnail of Le pompage énergétique par absorbeur non-linéaire bi-stable : prédiction de la transition chaotique de l’absorbeur par analyse de Mel’nikov

Research paper thumbnail of Caractérisation expérimentale d’un banc de mesures acoustique pour absorbeurs linéaires et non linéaires à basse fréquence et fort niveau : méthodes à un et plusieurs microphones

Cette etude experimentale est realisee dans un tube de Kundt court ou des mesures de pression son... more Cette etude experimentale est realisee dans un tube de Kundt court ou des mesures de pression sont effectuees au moyen de quatre microphones. La plage frequentielle va de 10 a 200 Hz pour de forts niveaux allant jusqu’a 300 Pa. Une methode qui permet de determiner l’impedance et le coefficient de reflexion d’une terminaison inconnue est presentee. Cette methode necessite la connaissance de quatre terminaisons inconnues et d’au moins une mesure de pression. Une validation des impedances estimees est effectuee avec plusieurs microphones puis une terminaison inconnue. Le coefficient de reflexion d’une membrane visco-elastique non lineaire est determine. Le comportement d’un absorbeur non lineaire est alors mis en evidence.