Vincent TOURNAT

Nonlinear waves and Acoustics 

Nonlinear elastic waves in architected and flexible elastic metamaterials 

Audible sound metamaterials 

Rotating-square structures, flexible soft-solid architected materials, LEGO structures, soliton propagation, waves in bistable material, elastic vector solitons, displacement-rotation modes of propagation, amplitude gaps, soliton collision... 

Coda wave interferometry for the NDT of concrete 

Multiple scattered fields, nonlinear effects with coda waves, monitoring of the damage level in complex structures, numerical modelling of coda waves in cracked elastic media... 

Nonlinear acoustic methods for nondestructive evaluation of materials  

Elastic wave interaction with cracks, internal contacts, nonlinear resonance methods, modelling of hysteresis for elastic waves, slow dynamics, ... 

Picosecond laser ultrasonics of microstructures 

Ultrasonic waves in micro-structures, thin films, microspheres, non contact generation and detection of ultrasounds and hypersounds, non destructive testing... 

Nonlinear photo-thermo-acoustic processes, laser ultrasonics characterization of cracks and materials 

Nonlinear processes in the photo-thermo-acoustic processes of laser generation, interaction with cracks, laser ultrasonic crack imaging and characterization, laser ultrasonics non destructive testing of composite materials, kissing bonds, zero group velocity (ZGV) Lamb modes... 

Picosecond laser ultrasonics in materials under high static pressures 

Study of water ice at several GPa static pressures, diamand anvil cell, evaluation of elastic properties, time domain Brillouin scattering, depth-profiling at the microscale... 

Nonlinear acoustics and ultrasonics for non destructive testing 

Laser ultrasonics 

Metamaterials for sound absorption : "metaporous" materials 

Acoustic porous materials with embedded scatterers and resonators, sub-wavelength absorption, total absorption, perfect absorption, critical coupling, acoustic metamaterial panels... 

Audible frequency range acoustic metamaterials and phononic crystals 

Waves in tubes loaded with Helmholtz resonators, acoustic channel lattices, slow sound, nonlinear regime of propagation, origami-inspired reconfigurable waveguides, phononic crystals for air-borne sound, acoustic panels and walls with periodic rods, perforated bamboos, wave guiding... 

Guided waves along the free surface of granular media  

Elastic modes of propagation in vanishing pressure granular packings, acoustics at the jamming transition, waves in graded layers, acousto-elasticity at low confining pressures in granular media, analogue modelling in geophysics, influence of fluid pore pressure, seismic refraction at the lab scale... 

Linear and nonlinear acoustics of loose granular packings 

Acoustic probing and characterization of avalanche precursors, acoustic probing of the compaction process, dynamics of single precursors, influence of the contact cohesion, ultrasonic probing of elastic properties of powders, influence of grain shapes and packing polydispersity on the elastic properties probed with ultrasounds, ... 

Nonlinear acoustics of confined granular packings 

Nonlinear coda waves, clapping contacts, hysteresis, self-demodulation effect, nonlinear effects, shear to longitudinal nonlinear mode conversion... 

Acoustics of granular phononic crystals and granular metamaterials 

Waves in periodic arrangements, chains in 1D, membranes in 2D, or 3D structures of spherical beads, rotational modes of propagation, nonlinear propagation, Hertzian and hysteretic nonlinearities, granular wave devices for sound control, non-reciprocal transmission devices ("diode"), topological waves ... 

Acoustics of granular media 

Research Topics