Response of acoustic imaging systems using convergent leaky waves to cylindrical flaws

Date

1989-9

Author

Günalp, Nilgün
Atalar, Abdullah

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A theoretical study of imaging systems utilizing focused leaky surface acoustic waves (SAWs), and their response to certain kind of defects is presented. In particular, circular cylindrical inhomogeneities with axes perpendicular to the surface are considered. The scattering of the SAW from this cylinder is formulated with some approximations. The surface wave incident on the inhomogeneity is initially found as an angular spectrum of plane waves. However, to apply the boundary conditions at the cylindrical surface, the incident field has to be transformed into a superposition of cylindrical waves. Similarly, the scattered field, which is found in the form of outgoing cylindrical SAWs, is converted back to a plane wave spectrum. A formula is obtained for the transducer output voltage in terms of the position and the radius of the cylinder, and it is suitable for computer evaluation. By considering various locations for the cylinder, the sensitivity of the system around the focal point is studied. By comparing the output voltages for cylinders of different radii, the sensitivity of the system to the size of the inhomogeneity is examined. The numerical results are in agreement with the experimental observations.

Subject Keywords

Acoustics, Acoustic imaging, Surface acoustic waves, Sawing machines, Acoustic scattering, Voltage, Focusing, Acoustic waves, Boundary conditions, Surface waves, Transducers

URI

https://hdl.handle.net/11511/52154

Journal

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control

DOI

https://doi.org/10.1109/58.31794

Collections

Department of Electrical and Electronics Engineering, Article

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Citation Formats

N. Günalp and A. Atalar, “Response of acoustic imaging systems using convergent leaky waves to cylindrical flaws,” IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, pp. 507–516, 1989, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/52154.