Jean-Philippe Groby
Researcher at CNRS/Chargé de Recherche CNRS since 2009.
Habilitation à Diriger des Recherches.
Chair of the Technical Committee «Acoustic Materials»of the European Acoustics Association (EAA).
Chair of the DENORMS network.
Mailing address: Laboratoire d'Acoustique de l'Université du Mans (LAUM), UMR6613 CNRS,
Avenue Olivier Messiaen,
F-72085 LE MANS Cedex 9 France.
Phone: +33 2 43 83 36 70
French citizen
Born, 16th August 1979
Image Groby3b

Image new Analytical modeling of one-dimensional resonant asymmetric and reciprocal acoustic structures as Willis materials, New J. Phys., 23: 053020 by J.-P. Groby, M. Malléjac, A. Merkel, V. Romero-García, V. Tournat, D. Torrent, and J. Li

Abstract: As building blocks of acoustic metamaterials, resonant scatterers have demonstrated their ability to modulate the effective fluid parameters, which subsequently possess extreme properties such as negative bulk modulus or negative mass density. Promising applications have been shown such as extraordinary absorption, focusing, and abnormal refraction for instance. However, acoustic waves can be further controled in Willis materials by harnessing the coupling parameters. In this work, we derive the closed forms of the effective parameters from the transfer matrix in three asymmetric and reciprocal one-dimensional resonant configurations and exhibit the differences in terms of coupling coefficients. The way in which Willis coupling occurs in spatially asymmetric unit cells is highlighted. In addition, the analysis shows the absence of odd Willis coupling for reciprocal configurations. These effective parameters are validated against experimental and numerical results in the three configurations. This article paves the way of a novel physical understanding and engineering use of Willis acoustic materials.
Read more on Publications item.

Image new Natural sonic crystal absorber constituted of seagrass (Posidonia Oceanica) fibrous spheres, Sci. Rep., 11: 711, 2021, by L. Barguet, V. Romero-García, N. Jiménez, L. M. Garcia-Raffi, V. J. Sánchez-Morcillo, and J.-P. Groby

Abstract: We present a 3-dimensional fully natural sonic crystal composed of spherical aggregates of fibers (called Aegagropilae) resulting from the decomposition of Posidonia Oceanica. The fiber network is first acoustically characterized, providing insights on this natural fiber entanglement due to turbulent flow. The Aegagropilae are then arranged on a principal cubic lattice. The band diagram and topology of this structure are analyzed, notably via Argand representation of its scattering elements. This fully natural sonic crystal exhibits excellent sound absorbing properties and thus represents a sustainable alternative that could outperform conventional acoustic materials.
Read more on Publications item.

Image new-animated-gif-icon Virtual visit of the temporary exhibition Acoustics and Beyond at the University of Coimbra's Museum of Science, 21 Feb.- 31 Oct. 2020.

Job opportunity:
Image new-animated-gif-icon Two year post-doc position on the design of reconfigurable acoustic metasurfaces for room acoustics funded by the ANR-RGC METARoom (ANR-18-CE08-0021) project.

jean-phi 2021-06-02