DocumentCode :
982741
Title :
Disposable PVDF ultrasonic transducers for nondestructive testing applications
Author :
Brown, Lewis F. ; Mason, Joel L.
Author_Institution :
Dept. of Electr. Eng., South Dakota State Univ., Brookings, SD, USA
Volume :
43
Issue :
4
fYear :
1996
fDate :
7/1/1996 12:00:00 AM
Firstpage :
560
Lastpage :
568
Abstract :
Disposable ultrasonic contact transducers have been constructed with inexpensive PVDF films for nondestructive testing (NDT) applications. This paper reports the temperature-dependent ultrasonic performance of commercial polyvinylidene fluoride (PVDF) films and PVDF sensors. PVDF film was evaluated for its material properties of interest for ultrasonic transducer performance including the relative dielectric constant /spl epsi//sub r/, dielectric loss tangent tan /spl delta//sub e/, electromechanical coupling constant k/sub t/, mechanical quality factor Q/sub m/, and acoustic impedance Z. Disposable PVDF transducers were then coupled to both low and high acoustic impedance test panels and their ultrasonic insertion loss/sensitivity and frequency bandwidth measured as a function of temperature in both the pulse-echo and pitch-catch modes. The results yielded center frequencies in the 3.5-16 MHz range, with -6-dB fractional bandwidths for some of the transducers exceeding 100%. The temperature dependence of the transducers´ performance is reported for the -40 to 80/spl deg/C range and shows an approximate linear decrease in center frequency and increase in fractional bandwidth with increasing temperature. These measured results are compared with predictions from computer simulations based on Mason´s model. These tests showed that the same disposable transducers can be used for both ultrasonic and acoustic emission sensing NDT applications. This paper summarizes the quantitative ultrasonic and vibration sensing performance for all of the disposable PVDF film transducers which were tested.
Keywords :
acoustic emission testing; acoustic impedance; dielectric losses; echo; permittivity; polymer films; ultrasonic materials testing; ultrasonic transducers; -40 to 80 degC; 3.5 to 16 MHz; Mason´s model; PVDF ultrasonic transducers; acoustic emission sensing; acoustic impedance; center frequency; dielectric loss tangent; electromechanical coupling constant; fractional bandwidths; frequency bandwidth; insertion loss; mechanical quality factor; nondestructive testing; pitch-catch mode; polyvinylidene fluoride; pulse-echo mode; relative dielectric constant; temperature-dependent ultrasonic performance; ultrasonic emission sensing; Acoustic pulses; Acoustic testing; Acoustic transducers; Bandwidth; Dielectric loss measurement; Frequency; Impedance; Nondestructive testing; Temperature sensors; Ultrasonic transducers;
fLanguage :
English
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
Publisher :
ieee
ISSN :
0885-3010
Type :
jour
DOI :
10.1109/58.503716
Filename :
503716
Link To Document :
بازگشت