Implémentation de l’imagerie ultrasonore multi-éléments de pièces complexes à l’aide d’un bras robotisé

Abstract

In industry, many mechanical parts need to be regularly inspected because maintaining their structural integrity is critical, as failures can have serious financial or, worse still, human consequences. Various nondestructive testing techniques have therefore been developed for this purpose. It is often necessary to obtain subsurface information of the components to be inspected. Ultrasonic or X-ray inspections are widely used for this purpose. Ultrasounds have the advantage of being risk-free for human health and more flexible than X-Rays because it involves more compact and usually portable devices. In addition, advanced ultrasound imaging techniques using multi-element probes enable increasingly accurate images to be obtained, such as the Total Focusing Method (TFM), which is becoming the gold standard in this field. However, when it comes to inspecting parts with complex geometries, such as pipe connections or forged parts, inspections have to be carried out in immersion or using a wedge that conforms to the surface. Ultrasound passes through two different propagation media and is refracted and deflected at the interface. As a result, it is difficult to properly configurate the ultrasonic inspection of complex parts so that it is reliable and repeatable although it is necessary to detect all the defects that they may contain. Indeed, a slight variation in the position of the probe relative to the part can drastically change the result of the ultrasound imaging. It may therefore be worthwhile to carry out these inspections in a robotic cell to obtain complete control over the orientation and position of the probe. In order to define this position, numerical simulations can be used, which have already been developed for several decades in the field of ultrasonic inspection. In this thesis, we propose to implement simulations in the case of multi-element ultrasonic imaging of complex parts. A finite element method will be used to model the response of defects of any shape. The disadvantage of this method is its long computation time, which is critical for multi-element simulations where the number of simulations that must be carried out is equal to the number of emitters in the probe. We will therefore choose POGO, a finite element calculation software implemented on graphics processors that is fully configurable and much faster than those using the central processor. In addition, a hybrid simulation method will be set up to use finite elements only in the area with potential defects and analytical calculations for the rest of the ultrasonic propagation. Finally, the simulated TFM images will be compared with experimental TFM images in simple configurations to begin with, and then in the case of a nozzle welded to a pipe containing known defects.

Date	22 Nov 2023
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Pierre Bélanger (Supervisor)