ULTRASONIC POINT-SOURCE POINT-RECEIVER MEASUREMENTS IN THIN SPECIMENS

被引:28
作者
VEIDT, M [1 ]
SACHSE, W [1 ]
机构
[1] CORNELL UNIV,DEPT THEORET & APPL MECH,ITHACA,NY 14853
关键词
D O I
10.1121/1.410104
中图分类号
O42 [声学];
学科分类号
070206 ; 082403 ;
摘要
This paper reports on the application of the ultrasonic point-source/point-receiver technique (PS/PR) to thin, anisotropic specimens. By using a scanned source and viewing a large number of signals measured at adjacent source/receiver configurations, one obtains a so-called scan image which represents the detailed spatial and temporal characteristics of the elastic wave field in a specimen. The measurement system uses either a focused, pulsed laser beam operating as a dipole source or a small aperture, piezoceramic shear transducer serving as a monopolar source. Detection of the signals is with a sensitive piezoceramic sensor that responds to the lateral or shear motions of the specimen surface. Scan images were obtained in a Silicon wafer whose thickness was 625 mu m and in one- or two-ply, unidirectional graphite/epoxy laminates whose thicknesses were approximately 145 and 275 mu m, respectively. The experimental data are analyzed using a simple plane-wave, plane-stress model that describes the propagation of quasilongitudinal and quasitransverse membrane wave in the plane of the plate. Good agreement is obtained between the experimental and theoretical group velocity curves of the membrane waves in the laminates. It is shown that the measured group velocity data of different wave modes can be inverted to recover the elastic constants of a material with excellent reliability and accuracy. The measurement system was also used to map out the group velocities in branches comprising the cuspidal region of the quasi-transverse group velocity curve.
引用
收藏
页码:2318 / 2326
页数:9
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