Structural noise and coherent backscattering modelled with the ATHENA 2D finite elements code

Sharfine Shahjahan , Fabienne Rupin , Thierry Fouquet , Alexandre Aubry , Arnaud Derode (1)

1 LOA - Laboratoire Ondes et Acoustique (UMR 7587)

The ability to detect and characterize flaws is a key element in the structural integrity and safety program of nuclear operators. Ultrasonic propagation in coarse grain steels is hampered by ultrasonic wave attenuation and high backscattered noise leading to a decrease of the detection and characterisation capabilities of common ultrasonic testing techniques. Nevertheless, this structural noise can be considered as a fingerprint of the material as it contains information about its microstructure. Accurate interpretation of experimental data necessitates an accurate comprehension of complex phenomena that occurs in multiple scattering media and thus robust scattering models. In particular, numerical models can offer the opportunity to realise parametric studies on controlled microstructures. However, the ability of the model to simulate the propagation in complex media has to be validated. In this study, the finite element code ATHENA 2D developed by EDF R&D is coupled with a Voronoï tessellation description of the medium. Two different microstructural descriptions of a statistically isotropic bulk material were simulated. The structural noise was characterised by observing the coherent backscattering enhancement (a typical signature of multiple scattering), and by the singular values of the response matrix of the medium. These results were compared to experimental data carried out on nickel based alloys (Inconel 600®).

Mots clés: multiple scattering; NDT; coherent backscattering; numerical

Domaines: Acoustique [physics.class-ph]

Sharfine Shahjahan, Fabienne Rupin, Thierry Fouquet, Alexandre Aubry, Arnaud Derode. Structural noise and coherent backscattering modelled with the ATHENA 2D finite elements code. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810833⟩