Tomographie ultrasonore tridimensionnelle de composants mécaniques

International audienceNon-destructive testing techniques now enables to represent the response of the objects in the form of an image, in particular in ultrasonics. In the case of ultrasound, this image consists in a presentation of the amplitudes or time of flight of the waves in the material. Ultrasonic imaging thus allows the objects to be represented in the form of a projection parallel or perpendicular to the surface of the material, as in B-scan used in medicine. Tests carried out to date in various laboratories as well as CETIM show that it is now possible to perform 2D or 3D ultrasonic tomography as in X-ray tomography, More, such type of reconstruction is applicable in guided wave tomography for plate imaging. So, ultrasonic tomography gives us an access to mechanical properties of the material under scan. The communication will consist in describing the problem of the ultrasound tomographic control by reconstruction, and to position this method in relation to the existing processing methods (Full Matrix capture, FTP). Analogies with the x-rays, and the particularities of the ultrasound reconstruction, will be explained, highlighting the advantages and limitations of each method. Results obtained by CETIM in low frequency imaging of a pipe section content will be presented, first in term of density. More, the tomographies performed showed that the time-of-flight reconstruction enables to monitor the evolution of volume temperature distribution of a flow circulating in the same pipe. First results obtained by CETIM in guided wave ultrasonic tomography of pipe walls will be presented too. Finally, the major potential applications of reconstruction tomography will be discussed, as well as the latches to be lifted in order to allow industrialization of this process, while considering the three-dimensional ultrasonic imagery in the context of the development of digital and computer technologies