Characterisation of ultrasonic structural noise in multiple scattering media using phased arrays

Thomas Bedetti (1) , Vincent Dorval (2) , Frédéric Jenson (1) , Arnaud Derode (3)

1 LMC (CEA, LIST) - Laboratoire Méthodes CND (CEA, LIST)
2 LSMA (CEA, LIST) - Laboratoire Simulation et Modélisation Acoustique (CEA, LIST)
3 IL - Institut Langevin - Ondes et Images (UMR7587)

The ultrasonic inspection of multiple scattering media gives rise to structural noise which makes it difficult to detect potential damage or crack inside the component. In order to predict the performances of ultrasonic inspection over such complex media, scattering models can be used. Such models rely on specific key parameters describing the multiple scattering process, which can be determined by specific measurements and post-processing techniques. Such experiments were carried out on stainless steel plates using linear phased-arrays. They consist in recording the response matrix constituted by impulse responses between all the elements of the array. By conducting post-processing on this matrix, we measure the elastic mean free path le and the correlation distance dc of the recorded noise. Additionally, the dynamic behaviour of the coherent backscattering effect was studied in order to measure the diffusion constant D. Plane-wave beamforming has been applied to the response matrix to improve the angular resolution and the signal-to-noise ratio of the backscattered intensity. Details of postprocessing techniques will be shown.

Keywords: Multiple scattering; Linear phased arrays; Ultrasound

Domains: Acoustics [physics.class-ph]; Modeling and Simulation

Thomas Bedetti, Vincent Dorval, Frédéric Jenson, Arnaud Derode. Characterisation of ultrasonic structural noise in multiple scattering media using phased arrays. Journal of Physics: Conference Series, 2013, 457, pp.012003. ⟨10.1088/1742-6596/457/1/012003⟩. ⟨cea-01820756⟩