Characterization of the contact between solids by laser-generated interface waves

Tony Valier-Brasier , Thomas Dehoux , Bertrand Audoin

Laser Ultrasonic techniques provide a powerful tool for the remote analysis of adhesion mechanisms at imperfect interfaces. However, the sensitivity of interface waves to the quality of interface is not very well known. In this context, the aim of this work is to study the influence of the contact between solids half-spaces on laser-generated interface waves. The mechanical boundary conditions at the interface between the solid half-spaces are described by a spring model, implying a discontinuity of the displacement fields across the interface and involving tangential and normal spring constants. To identify the relative amplitudes of the different types of interface waves (skimming, leaky Rayleigh and Stoneley waves), a semi-analytical time-model is derived. In addition, the dispersion curves for the interface waves are calculated to interpret the results of the time-model. The results demonstrate the influence of the boundary conditions on the attenuation of the leaky Rayleigh wave and on the existence of the Stoneley wave, which should prove to be a powerful tool for the inspection of contacting interfaces. Moreover, characteristic frequencies depending on normal and tangential springs constants are highlighted, suggesting a scaled behaviour of the interface waves.

Mots clés: Interface waves; Laser Ultrasonic

Domaines: Acoustique [physics.class-ph]

Tony Valier-Brasier, Thomas Dehoux, Bertrand Audoin. Characterization of the contact between solids by laser-generated interface waves. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810877⟩