High-frequency asymptotics in mathematical modelling of non-destructive testing
by
Larissa Fradkin
Centre for Waves and Fields, South Bank University, London
Coauthors: Dmitri Gridin, Victor Zalipaev

A wide range of mathematical models have been used in NDT (non-destructive testing) modelling ultrasonic pulse propagation and scattering, both direct numerical and approximate analytic. Our Centre specialises in models based on high-frequency asymptotics. We have described the structure of the time-harmonic near field of the circular compressional transducer directly coupled to homogeneous and isotropic solid, both its geometrical regions and boundary layers in between. Pulse propagation, rectangular transducers and transducers of complex apodisation have been also modelled using this approach. We have now developed a similar asymptotic model for simulating the scattered pulses in the near field of an elliptic crack embedded in an isotropic and homogeneous elastic space for an obliquely incident compressional plane wave. The high-frequency models elucidate the physics of the problem and give explicit dependence on model parameters, thus allowing an easy prediction of amplitudes and shapes of the scattered pulses. The corresponding asymptotic codes are hundreds to thousands times faster than the direct numerical codes, and practically just as accurate.

Date received: August 20, 1999

Copyright © 1999 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cadl-05.