| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Tournat, Vincent
French National Centre for Scientific Research
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (20/20 displayed)
- 2024Automated discovery of reprogrammable nonlinear dynamic metamaterialscitations
- 2024Sono-Activated RAFT Ab Initio Emulsion Polymerization of Methyl Methacrylate: Toward an Exogenous Initiator-Free and Surfactant-Free Processcitations
- 2021Analytical modeling of one-dimensional resonant asymmetric and reciprocal acoustic structures as Willis materialscitations
- 2020Guided transition waves in multistable mechanical metamaterialscitations
- 2020Imaging grain microstructure in a model ceramic energy material with optically generated coherent acoustic phononscitations
- 2020Imaging grain microstructure in a model ceramic energy material with optically generated coherent acoustic phononscitations
- 2020Nondestructive evaluation of structural adhesive bonding using the attenuation of zero-group-velocity Lamb modescitations
- 2020Cumulative fatigue damage in thin aluminum films evaluated non-destructively with lasers via zero-group-velocity Lamb modescitations
- 2019Three-dimensional imaging of inhomogeneities in transparent solids compressed in a DAC by time-domain Brillouin scattering
- 2019Three-dimensional imaging of inhomogeneities in transparent solids compressed in a DAC by time-domain Brillouin scattering
- 2019Elastic anisotropy and single-crystal moduli of solid argon up to 64 GPa from time-domain Brillouin scatteringcitations
- 2017Beam shaping to enhance zero group velocity Lamb mode generation in a composite plate and nondestructive testing applicationcitations
- 2016Small-Scale Seismic Monitoring of Varying Water Levels in Granular Mediacitations
- 2016Monitoring of autogenous crack healing in cementitious materials by the nonlinear modulation of ultrasonic coda waves, 3D microscopy and X-ray microtomographycitations
- 2014Small crack detection in cementitious materials using nonlinear coda wave modulationcitations
- 2012Study of stress-induced velocity variation in concrete under direct tensile force and monitoring of the damage level by using thermally-compensated Coda Wave Interferometrycitations
- 2012Elastic waves in phononic granular membranes
- 2011Experimental Evidence of Rotational Elastic Waves in Granular Phononic Crystalscitations
- 2010Nonlinear Biot waves in porous media with application to unconsolidated granular mediacitations
- 2003Effet non linéaire d'auto-démodulation d'amplitude dans les milieux granulaires: théories et expériences
Places of action
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thesis
Effet non linéaire d'auto-démodulation d'amplitude dans les milieux granulaires: théories et expériences
Abstract
Nonlinear acoustics methods have demonstrated a high sensitivity to the presence of structural defects in solids and are now used with the purpose of nondestructive testing for damaged materials.<br /><br />In this thesis, operation of the parametric antenna in unconsolidated granular materials is studied. The parametric antenna, widely used in underwater acoustics, involves a nonlinear acoustic effect that can be interpreted as an amplitude self-demodulation or as a difference frequency generation phenomenon : from the emission of intense waves, composed of several neighbouring high frequencies (around 100 kHz), waves of lower frequencies (1-10 kHz) are generated by nonlinear effect in the medium of propagation. The main interests of this method are i) the possible high directivity of the low frequency radiation, useful for selective testing, ii) the energy conversion towards low frequency waves which propagate easier than high frequency waves in highly absorbing or scattering media.<br /><br />First, two models of parametric antenna are developed to take into account absorption, scattering, or dispersion phenomena, as well as evanescent feature of the waves. Experiments in disordered packings of glass beads, in qualitative agreement with theoretical predictions are performed and interpreted.<br /><br />Second, parametric antenna with shear waves is operated for the first time, and produce a low frequency demodulated longitudinal signal. This nonlinear dilatancy phenomenon is tested in different experimental configurations. The demodulated longitudinal signal amplitude as a function of the shear waves amplitude is initially quadratic and then exhibit a transition to a 3/2 power law dependence. It is demonstrated that the clapping phenomenon, i.e. the opening and closing of the contacts under acoustic action, is responsible for this transition. The localization of this transition enables to characterize qualitatively the distribution of the contacts static strains in the medium bulk, especially in the weak contacts region.<br /><br />Finally, the rotation of the shear waves polarization is a convenient mean to characterize the anisotropy of the nonlinear parameter of the medium. Such anisotropy is present in granular media when, for instance, an uniaxial static force is applied on the whole material, and creates a network of force chains that are preferentially oriented along the apply static force.