Guided ultrasonic waves in the cylindrical layer-substrate structures. Application to the control of the massive machine elements with cylindrical cavities

This paper presents a study of the ultrasonic wave propagation in a cylindrical layer-substrate structure of an infinite length. We determine the dispersion curves of the structure, the displacements field in the structure and the impact of the contact quality between the layer and the substrate. The industrial application aimed by our study is the control of the massive machine elements with cylindrical cavities coated and exposed to corrosion. The obtained results show that some modes of propagation are insensitive to the layer thickness. Therefore, these modes can be generated during the ultrasonic control of the layer. In addition, for the dimensions considered here, the second mode of propagation is the most adapted for the detection of defects in the vicinity of the internal layer wall. In addition, our study shows the possibility of characterization of the quality of contact between the layer and the substrate from the analysis of dispersion curves of the structure.