City Research Online

Abstract

The development of broad-band, ultrasonic, Rayleigh wave transducers, and their use in measuring the dimensions of simulated cracks (with dimensions of the order of a millimetre) are described. The method, the generation of the cepstra of signals reflected from the defect, removes the problem of variation in the coupling of the transducer to the testpiece. It also increases the resolution to its limit, this limit being defined by the highest frequency the surface will allow to propagate with acceptable’ attenuation. It is shown theoretically how the angle of the crack to the surface may be determined, and the possibilities of obtaining other important crack parameters are discussed. With existing transducers the minimum crack depth that can be measured is approximately 1 ½ mm.

Publication Type:	Thesis (Doctoral)
Subjects:	Q Science > QC Physics
Departments:	School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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