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Title: Spatial Distribution of Acoustic Radiation Force for Non-Contact Modal Excitation
In modal testing, a common excitation method is a transducer in mechanical contact with the object under test. However, for some structures it is desirable to excite vibrations without physical contact. One promising excitation technique is the acoustic radiation force. However, a challenge in using this technique is that the acoustic radiation force is spread out over a finite-diameter focal region. We describe a method to directly measure the spatial distribution of this force. An ultrasound transducer emitted sine waves with frequencies of, for example f1 = 600.610 kHz and f2 = 600 kHz; the resulting radiation force had a component at the difference frequency f1-f2 = 610 Hz. A MicroAcoustic Instruments BAT6 ultrasound transducer was focused to an approximately 2 mm diameter spot on a 19.6 by 8.1 by 0.37 mm clamped-free brass cantilever with a 610 Hz fundamental frequency. A vibrometer measured the response as this focus spot traversed the edge of the cantilever. This enabled determination of the distribution of the acoustic radiation force being delivered by the transducer. This may be helpful in future studies that involve modeling the force applied to a structure using the acoustic radiation force.  more » « less
Award ID(s):
1300591
PAR ID:
10036798
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
Topics in Modal Analysis & Testing, Volume 10
Volume:
10
Page Range / eLocation ID:
155-162
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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