Vibro-Acoustic of Structures

The "Vibro-acoustics" research operation brings together a set of activities whose objective is to contribute to the development and application of methods for modeling and experimental characterization of systems in which coupling mechanisms between mechanical vibrations and acoustic fields are involved.

The competences developed in the research operation cover analytical (modal or wave), numerical (finite and boundary elements) and experimental methods in vibro-acoustics (inverse methods, acoustic imaging). The themes concerned are divided into three axes: experimental methods, vibration and/or acoustic reduction devices under lightening constraints, analysis of wave couplings. 

Experimental methods

• Development of imaging methods
  
  • Acoustic/vibratory imaging by holography or beamforming,
  • Measurement of full field vibrations (ultra-fast optical holography, thermal camera).
• Development of post-processing methods
  • Vibration inverse problem by the Force Analysis Technique or the Corrected version (FAT, CFAT),
  • Identification of acoustic wall pressures due to turbulent flows,
  • Identification of structural parameters, detection of defects.

Vibration and/or acoustic reduction devices under lightening constraints

• Exploitation of original physical phenomena
  • Vibration attenuation by periodization effects,
  • Vibration reduction by Acoustic Black Hole effect (ABH),
  • Dissipation of vibratory energy by non-linear phenomena (friction, micro-impacts ...),
  • Semi-passive control using piezoelectric patches.
• Integration mixing different physical phenomena (ABH, damping, periodization)
  • Enhanced black holes (with piezoelectric and thermal active systems),
  • Elaboration of design rules under lightening constraints,
  • Meta-plate development,
  • Insertion of lightweight granular materials, ABH, porous materials,…

Analysis of wave couplings

• Fluid-structure couplings
  
  • Vibro-acoustics of industrials ducts,
  • Vibro-acoustics of complex industrial structures,
  • Vibro-acoustics of wooden buildings,
• 3D vibration wave coupling
  • Coupling between in-plane and out-of-plane movements,
  • Control of the effects at the interfaces. 
• Opto-mechanical coupling
  • Reduction of parametric instabilities in the gravitational wave detectors of the LIGO project.