Ushakov,V.M.; Shcherbinskii, V.G.; Kraskovskii, A.S.; Mirgazov,
VA. Optimization of the p a r a m e t e r s of inclined transducers with matched layers on the basis of c o m p u t e r experiments Soviet Journal of Nondestructive Testing, Vol. 25, No. 8, pp. 541-546 (Apr.
1990) The author present the results obtained by the method of computer experiments carried out to optimize the amplitude-frequency characteristic (AFC), the pulse time, the transformation coefficient at the frequency of the maximum of the AFC of inclined transducers with matching four-wave layers. Recommendations for producing these converters are given. 43971 Mayev,R.G.; Kolosov, O.V.; Atayev, K.A.; Levin, V.M. T h e investigation of local piezoelectric properties of piezoelectric t r a n s d u c e r s by acoustic microscopy Proceeding of the IEEE 1988 Ultrasonics Symposium, Chicago, (United States), 2-5 Oct. 1988. Vol. 2, pp. 775-777. Edited by B. R McAvoy. IEEE (1989) ISSN 0090-5607. Local piezoelectric properties of piezoelectric trausducers have been studied by the transmission acoustic microscopy methods at a frequency of 450 MHz with a resolution of 3 m u m . Unidimontional profiles and grey-scale acoustic images of microstrncture have been obtained. The experimental data have beea interpreted form the theoretical viewpoint. It has been proven that acoustic microscopy can he used for investigation of non-mechanical characteristics of specimen. 43968 Davids, D.A.; Chizhik, D.; Bertoni, H.L. Measured characteristics of an acoustic microscope having a bow-tie transducer Proceeding of the IEEE 1988 Ultrasonics Symposium, Chicago, (United States), 2-5 Oct. 1988. Vol. 2, pp. 763-766. Edited by B. R McAvoy. IEEE (1989) ISSN 0090-5607. The bow-tie transducer was conceived as providing a way to achieve angular resolution in the measurement of the Rayleigh wave velocity on anisotmpic substrates, while retaining the lateral resolution of the spherical point focus lens. However, agreement with the generally accepted velocity variation is poor. It is proposed that diffraction effects in the lens rod result in Rayleigh waves being excited with significant amplitude in directions on the object surface that lie outside the sector of the bow-tie. Spatial resolution was also examined in the directions along and across the bow tie, and was found to he similar for both cases. 43966 Sugawara, Y.; Kushibiki, J.; Chubachi. N. Performance of concave t r a n s d u c e r s in acoustic m i ~ e a c o p y Proceeding of the IEEE 1988 Ultrasonics Symposium, Chicago, (United States), 2-5 Oct. 1988. Vol. 2, pp. 751-756. Edited by B. R McAvoy. IEEE (1989) ISSN 0090-5607. Performance of scanning reflection acoustic microscope system using concave transducers has been investigated numerically and experimentally. V(z) characteristics which contains information of leaky surface acoustic waves (LSAWs) at the water/sample boundary is useful to analyze the performance of the system. In this paper, numerical analyses of V(z) curves are made through the transfer function of the system using a concave transducer based on the field theory, taking a fused q u a ~ as a typical sample. It is revealed the that the amplitude response of V(z) curve contains a rapid periodic variation in the defocus region, which is not dix~tly related to the propagation properties of LSAW, while the phase response of V(z) curve depends strongly on the propagation properties of LSAW. 43892 Gruber, G.; Hamlin, D. Imaging the interaction of multibeam/muitlmode ultrasonic transducers with m a n u f a c t u r i n g a n d service-induead flaws Proceedings of the 15th Annual Review of Progress in Quantitative Nondestructive Evaluation, La Jolla, California (USA), 31 Jul. - 5 Aug. 1988. Vol. 8B, pp. 2267-2273. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1989). ISBN 0-306-43209-9. In this paper, the three-step approach to the ultrasonic evalnatiou of flaweA reactor pressure vessel components (i.e., flaw detection, identification, and sizing) are discussed in relation to fatigue cracks, slag inclusions, incomplete fusion flaws, and porosity clusters. The emphasis is on flaw identification (cracks vs. benign flaws) which must take place before estimating the depth of the flaw. The composite pulse patterns obtained with four multibeam/multimode SLIC transducers for two model flaws (a side-milled notch and a side- drilled hole) and two real flaws (fatigue crack and slag inclusion) are imaged in a B-scan format. The color-graphic displays of the data acquired during remote transducer scanning with a four-charmel Enhanced Data Acquisition System (EDAS) instrument made it possible for the traditionally trained ultrasonic examiners to fully characterize a material discontinuity in near real time. 43690 Sandhu,J.S.; Thomas, R.E.; Jensen, C. Acoustographic evaluation of ultrasonic t r a n s d u c e r s Review of Progress in Quantitative Nondeslructive Evaluation, Vol. 8A. Edited by D. O. Thompson and D.E. Chimenti, pp. 951-958. Plenum Press (1989) ISBN 0 306 43209 9 In this paper, we discuss the application of Acoustography for evaluating the acoustic field characteristics of ultrasonic transducers. Acoustography offers some unique advantages over other field characterizatiou methods and offers the potential for enhancing the current state-of-the-art of transducer characterization. 43684 Gruber, G.; Mueller, T. Modeling the Interaction of multibeam/multimode ultrasonic trans.
ducers with fatigue cracks in cladded reactor pressure vessels
Review of Progress in Quantitative Nondestructive Evaluation, Vol. 8A. Edited by D. O. Thompson and D.E. Chimenti, pp. 1075-1082. Plenum Press (1989) ISBN 0 306 43209 9 The novel SLIC transducers which simultaneously use Shear and Longitudinal waves for material Inspection and flaw Characterization have recently been qualified in conjunction with satellite-pulse flight time measurement techniques on over fifty fatigue cracks in cladded test blocks. However, a computer modeling capability to aid the ultrasonic examiner in the interpretation of the data was not available during the qualification trials. 43663 Lal,R.; Das-Gupta, D.K. Characterization of ultrasonic transducers IEEE Transactions on Electrical Insulation, Vol. 24, No. 3, pp. 473- 480 (Jun. 1989) A systematic approach in the design and evaluation of high-freqnency piezoelectric transducers is presented. The transducers, prior to manufacture, may he modeled to generate an optimum response for a given specification. The design parameters may be adjusted until a physically realizable model of the transducer is achieved. This model of the transducer may then he constructed and characterised both in the time and frequency domains, and, the results compared with theoretical predictions. Furthermore, the acoustic output parameters as required by current international standard could then be estimated from data obtained by poise-intensity integral measurements. Results for three ultrasonic transducers are presented to illustrate the procedures involved and to highlight the limitation of such ponderations. 43602 Toda,D.; Sawaguchi, A. T h e performance of a leaky surface acoustic wave t r a n s d u c e r consisting of PVDF and fused quartz Acoustical Imaging, Vol. 17. Edited by H. Shimizu, N. Chubachi, and J Kushibiki. pp. 393-401 Plenum Press, (1989) ISBN 0306431505 The structure of a PVDF/interdigital transducer/fused quartz plate is analyzed numerically to understand the transducer performance including the phase velocity and efficiency for the acoustic beam radiation into water in comparison with the characteristics in a structure incorporating a piezoelectric ceramic plate instead of PVDF. The zeroth-order mode has a large transducer efficiency, although the electromechanical coupling constant is small. 43598 Wang,L.; Wei, Y. A mechanical.scanning ultrasonic t r a n s d u c e r for QNDT imaging Acoustical Imaging, Vol. 17. Edited by H. Shimizu, N. Chubachi, and J Kushibiki. pp. 587-6596 Plenum Press, (1989) ISBN 0306431505 Presented in this paper are theoretical studies and research work about an ultrasonic transducer which has short pulse response and can scan over a wide range automatically as well. A design approach to the short pulse Iransducer, the approach of matching strong damping backing, is pot forward, which can well solve the contradiction between efficiency and short pulse response or fi~lUency bandwidth that exists in conventional ultrasonic transducers. A stntcture of a rotating mechanical fan-scanning ultrasonic transducer is given. A software package for radiation field calculations and designs of the transducers is developed. Based on theoretical studies, with the help of the approach, a short pulse mechanical scanning ultrasonic transducer is designed and manufactured. Measurement results about the characteristics of the transducer are given and discussed. 43402 Zhang, S.Y.; Kreier, P.; Gamper, T.; Edelmann, X. Sound field characteristics of transmitter receiver longitudinal angle beam transducers Reliability in Non-Destructive Testing, Froce~ings of the 27th Annual British Conference on Non-Destructive Testing, Portsmouth (United Kingdom), 12-15 Sep. 1988. pp. 375-383. Edited by C. Brook and P.D. Hanstead. Pergamon Press, 1989. Theoretical calculations of the longitudinal and transverse wave sound field distribution of the transmitter/receiver longitudinal angle beam transducers are presented. The position of the "focal point" can be estimated from the curve of receiving amplitude and the distance of the sound path. Changing of effective angle in steel with increasing sound path is taken into conalderatiou for various transducer parameters. The comparison of the theoretical cu~es with mmm~mem results indicates that the theoretical model is reasonable. The fiat surface end cylindrical surface (adaption to curvature of component) are considered in the calculations.
Wormley,S.I.; Newberry, B.P.; Hughes, M.S.; Hsu, D.K.; Thompson, D.O.
Application of Gauss-Hermite beam model to the design of ultrasonic probes Review of Progress in Quantitative Nondestructive Evaluation, Vol. 8A. Edited by D.C. Thompson and D.E. Chimenti, pp. 835-842. Plenum Press (1989), ISBN 0 306 43209 9 Work is cun~ntly underway to develop and test prototypic ultrasonic insmunentation that will produce unipolar stress pulses in a pulse- echo mode, The insffument will be used to detect and characterize flaws in materials and for the measurement of material properties importantin material processing applicatious. In conjunction with this work, a Gauss-Hermite Beam Model is used to predict the response of various transducer element geometries to maintain the unipolas response over a longer pmpegntion distance. 43347 Bennink,D.D.; Pate, A.L. Ultrasonic transducer calibration for reciproclty.lmsed m e a s u r e m e n t
models Review of Progress in Quantitative Nondestructive Evaluation, Vol. 8A.
N D T & E International Volume 25 Number 3 1992