Acoustic emission transducer «DISM»
A new construction of bandwidth acoustic emission transducer with a service band from 200 kHz to 1200 kHz has been designed at the Bakul institute for superhard materials of National academy of sciences (NAS).
The damping of the rear side of a piezoplate – a sensible element of the acoustic emission transducer, is applied in the design of the transducer.
An original material, consisting of WC and TiNi particles, fastened by an epoxy resin with a hardener is used as a damper.
The composition of the damper is selected in such a way that its acoustic impedance is equal to that of piezo-ceramics and the damping properties are maximal because of the TiNi martensite transformation with an energy absorption. Because of this the damping properties have been increased by 1.5-2.0 times.
In total, this allowed the substantional decreasing of resonance peaks, elimination of parasite return signals from the rear side of the plate and from the case of the transducer as well as decreasing the irregularity of the amplitude-frequency characteristic (AFC) from 23 dB to 8.5 dB.
An original charging amplifier of the acoustic emission signal with a differential current inputs, which realizes an optimal circuit of the transducer connection and a preamplification at a minimum relation of “signal-nose” has been designed jointly which the National Aviation University (NAU) for the matching of the transducers with an electronic equipment.
The system of the graduation (calibration) of the acoustic emission transducers which permits one to efficiently study the amplitude-frequency characteristics of the acoustic emission transducers and to certificate their characteristics has been developed.
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Input resistance, Ohm – 2.3-1011 Band, MHz – 0.3-1.2 Irregular AFC, dB – 8.5 Sensitivity, mV/m·s-2 – 125 Capacity, nF – 1.45
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Reference:
04074, Kyiv-74, 2, Avtozavodskaya, st.
Phone: 8(044) 430-82-45
E-male: ldevin@ism.kiev.ua
Head of the laboratory, doctor of technical sciences, professor Devin L.N.