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Ultrasonic spectral analysis for nondestructive evaluation
102
Ultrasonic Spectral Analysis for Nondestructive Evaluation, by Dale W. Fitting and Laszlo Adler, Plenum, New York, 1981. ISBN 0-306-40804-2, ix + 354 pages, 98 illustrations, 14 tables, hard cover $45.00 (plus 20% outside of the U.S. and Canada). "Since m a n y material properties manifest themselves as amplitude or phase changes in ultrasonic waves used to interrogate a specimen, ultrasonic spectroscopy has proven to be quite v a l u a b l e . " . . . . " t h a t hoary old perennial, frequency spectrum analysis appears y e t again . . . . no d o u b t motivated by a hope t h a t someone will, at last, find a use for it in defect characterisation." These two quotations -- the first from the introduction of Fitting and Adlers' book, the other from a review by a prominent British engineer of a recently published book of NDT techniques -- serve to illustrate shades of opinion regarding the usefulness of ultrasonic spectroscopy. Close examination of the choice of the above words, as emphasised by the (reviewers) italics, does perhaps hint at the consensus of current feeling as to the most fruitful areas to which ultrasonic frequency analysis may be applied. However, it is u n d o u b t e d l y true that some of the bad press the subject has received has in part been due to unforseen difficulties encountered in taking a well established technique and applying it to a new field. Fitting and Adlers' book is an invaluable aid in understanding and overcoming these problems and will be of particular benefit to investigators new to the field. The book begins with a concise review of the historical development of the subject and continues with a chapter giving a detailed description of ultrasonic spectroscopic instrumentation using a system model to introduce the treatment. Topics covered include the transmitting and receiving transducers and associated electronic instrumentation, such as wide-band receivers and analogue gates. The electrical and mechanical coupling of the transducers is discussed at some length and the effects of diffraction on the shape of the ultrasonic pulses propagated by them is mentioned. This last topic is of particular relevance to defect characterisation: its treatment could perhaps have been improved by a discussion of how the transmit--receive mode response is affected by diffraction. In addition, greater emphasis on diffraction effects in solids rather than in fluids would have been useful for NDT in general. The final part of the chapter describes analogue and digital spectrum analysers, the latter giving useful insight into the problem of.handling sampled data. Chapter 3 is devoted to an extensive, though somewhat uncritical, review of the literature of both the t h e o r y and application of ultrasonic spectroscopy in materials evaluation. A feature is the inclusion of the replies to a questionnaire sent to over one h u n d r e d practitioners in the field. These form a detailed survey of the current state of the art of ultrasonic spectroscopy. The book concludes with an excellent abstracted bibliography listing over 300 relevant papers. J.P. WEIGHT
Ultrasonic Spectral Analysis for Nondestructive Evaluation, by Dale W. Fitting and Laszlo Adler, Plenum, New York, 1981. ISBN 0-306-40804-2, ix + 354 pages, 98 illustrations, 14 tables, hard cover $45.00 (plus 20% outside of the U.S. and Canada). "Since m a n y material properties manifest themselves as amplitude or phase changes in ultrasonic waves used to interrogate a specimen, ultrasonic spectroscopy has proven to be quite v a l u a b l e . " . . . . " t h a t hoary old perennial, frequency spectrum analysis appears y e t again . . . . no d o u b t motivated by a hope t h a t someone will, at last, find a use for it in defect characterisation." These two quotations -- the first from the introduction of Fitting and Adlers' book, the other from a review by a prominent British engineer of a recently published book of NDT techniques -- serve to illustrate shades of opinion regarding the usefulness of ultrasonic spectroscopy. Close examination of the choice of the above words, as emphasised by the (reviewers) italics, does perhaps hint at the consensus of current feeling as to the most fruitful areas to which ultrasonic frequency analysis may be applied. However, it is u n d o u b t e d l y true that some of the bad press the subject has received has in part been due to unforseen difficulties encountered in taking a well established technique and applying it to a new field. Fitting and Adlers' book is an invaluable aid in understanding and overcoming these problems and will be of particular benefit to investigators new to the field. The book begins with a concise review of the historical development of the subject and continues with a chapter giving a detailed description of ultrasonic spectroscopic instrumentation using a system model to introduce the treatment. Topics covered include the transmitting and receiving transducers and associated electronic instrumentation, such as wide-band receivers and analogue gates. The electrical and mechanical coupling of the transducers is discussed at some length and the effects of diffraction on the shape of the ultrasonic pulses propagated by them is mentioned. This last topic is of particular relevance to defect characterisation: its treatment could perhaps have been improved by a discussion of how the transmit--receive mode response is affected by diffraction. In addition, greater emphasis on diffraction effects in solids rather than in fluids would have been useful for NDT in general. The final part of the chapter describes analogue and digital spectrum analysers, the latter giving useful insight into the problem of.handling sampled data. Chapter 3 is devoted to an extensive, though somewhat uncritical, review of the literature of both the t h e o r y and application of ultrasonic spectroscopy in materials evaluation. A feature is the inclusion of the replies to a questionnaire sent to over one h u n d r e d practitioners in the field. These form a detailed survey of the current state of the art of ultrasonic spectroscopy. The book concludes with an excellent abstracted bibliography listing over 300 relevant papers. J.P. WEIGHT