The Effect of Beam Divergence on the Ultrasonic Attenuation Measurement

概要

論文の詳細を見る
One of the effects which cause error in attenuation measurement of ultrasonic pulses transmitted in a specimen from a piezoelectric transducer is beam divergence. H. Seki, et al. and A.E. Lord, Jr., have derived approximated formulas of sound pressure by using Bessel's functions and evaluated this effect in the case where a circular transmitter and a similar receiver are set coaxially on a parallel specimen.In order to extend the evaluation of error due to beam divergence in other cases, a method of numerical integration to calculate particle velocity and to integrate it in the receiving area is formulated so as to fit the computations on a digital computer, and the apparent attenuation when the circular receiver is not coaxial with the transmitter is calculated. Then the attenuation of pulsed 2 and 5MHz signals travelling in a parallel steel specimen of 76mm in thickness, is measured by means of X-cut quartz transducers of 20mm in diameter, changing their relative positions, and the result shows a good agreement of ±1.5dB with the numerical computations.
公益社団法人計測自動制御学会の論文