Passive guided wave tomography for corrosion monitoring under varying environmental conditions

Tom Druet (1) , Axel Thomas (1) , Arnaud Recoquillay (1) , Yann Gélébart (2) , Etienne Martin (3) , Bastien Chapuis (1)

1 LSPM (CEA, LIST) - Laboratoire Systèmes et Photonique pour le Monitoring (CEA, LIST)
2 EDF R&D - EDF R&D
3 EDF Ceidre TEGG

Abstract conference The detection and quantification of defects in pipes by non-destructive testing techniques plays a crucial role in several industries (petrochemical and nuclear in particular). Once a defect is detected, assessing its severity enables to schedule maintenance appropriately, hence reducing rupture or leakage risks. Structural Health Monitoring (SHM) is an approach that consists in instrumenting a structure with permanent sensors to monitor its health status throughout its life. Guided elastic waves are particularly suitable for SHM applications on thin structures (such as plates, tubes or tanks) thanks to their ability to propagate over long distances and their high sensitivity. Our group works since several years on an original SHM approach for the detection and quantification of corrosion in pipes called "guided waves passive tomography". This technology is based on the combination of guided elastic wave tomography algorithms and a passive method such as the so-called ambient noise cross-correlation. It allows to obtain absolute and precise maps of the thickness of an area surrounded by a distribution of sensors without emitting waves, simply by analyzing the elastic noise that exists naturally in the pipe (due to vibrations, turbulences of the moving fluid, etc.). The type of corrosions imaged by this technique are thickness losses on extended areas of size often higher than the centimeter. We will present recent advances in the technology, in particular the capacity of the tomography algorithms to work in an 'absolute' mode, i.e. without a baseline, thanks to an automatic calibration using solely the data of the current acquisition. This makes the diagnosis very robust to environmental fluctuations and inherent variabilities in the structure. Experimental validations of the method will be presented and results on the method's robustness to temperature variations will be shown through acquisitions carried out in a climatic chamber over a wide range of temperatures. Abstract article : This paper presents a study of guided wave tomography for corrosion monitoring under varying environmental conditions. Guided wave tomography can be computed in an 'absolute' mode thanks to an automatic calibration using solely the data of the current acquisition. This is interesting because no baseline is needed. In particular, this paper studies the capacity of absolute tomography algorithms to be robust to temperature fluctuations. Experimental validations of the method are presented and results on the method's robustness to temperature variations are shown through acquisitions carried out in a climate chamber over a wide range of temperatures.

Domaines: Acoustique [physics.class-ph]

Tom Druet, Axel Thomas, Arnaud Recoquillay, Yann Gélébart, Etienne Martin, et al.. Passive guided wave tomography for corrosion monitoring under varying environmental conditions. 2nd International Conference on Non-Destructive Examination in Nuclear (NDE in Nuclear 2023), Jun 2023, Sheffield, United Kingdom. 28283 (6 p.), ⟨10.58286/28283⟩. ⟨cea-04189381⟩