A miniaturized acoustic vector sensor with PIN-PMN-PT single crystal cantilever beam accelerometers

Abstract

Directional sound detection using vector sensors rather than large hydrophone arrays is highly advantageous for target detection in SONAR. However, developing highly sensitive and compact vector sensors for use in a system whose size is limited has been a challenging issue. In this paper, we describe a miniaturized acoustic vector sensor with piezoelectric single crystal accelerometers for the application in towed line arrays. A mass-loaded cantilever beam accelerometer with a [011] poled PIN-PMN-PT single crystal shows a better signal-to-noise ratio compared to accelerometers with other piezoelectric materials because of its superior piezoelectric properties in the 32 direction. We suggested a sufficiently compact vector sensor by using a cylindrical hydrophone with 10 mm in diameter as a housing of the single crystal accelerometers. Two single crystal accelerometers were orthogonally mounted inside the cylindrical hydrophone to detect direction of sound in the transverse plane of the line array. The receiving voltage sensitivity of the accelerometers and hydrophone was −199 and −196 dB, respectively, at 3 kHz. The directional cardioid beams generated by summing the omnidirectional beam from the hydrophone and the dipole beam from the accelerometers were validated over the entire operating frequency.

The Use of a PVDF Array to Measure the Stress Field Inside an Elastic Material

“…Without the thorough understanding of the working mechanisms of embedded PVDF, its output lacks a clear physical meaning. Therefore, in many current applications, embedded PVDF can only be used as an auxiliary to other sensors [ 10 , 11 ], and its output can only be analyzed qualitatively [ 12 ]. This difficulty in interpreting the output of embedded PVDF sensors has limited its use as a sensor.…”

Theoretical and Experimental Studies on Sensitivity and Bandwidth of Thickness-Mode Driving Hydrophone Utilizing A 2-2 Piezoelectric Single Crystal Composite

“…In recent studies [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ], relaxor-PT single crystals such as Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMN-PT) and Pb(Zn 1/3 Nb 2/3 )O 3 -PbTiO 3 (PZN-PT) have been investigated as active materials for composites. Single crystals exhibit superior piezoelectric properties compared to PZT ceramics; for example, they have piezoelectric coefficients d over 1500 pC/N and electromechanical coupling factors k 33 around 0.90 [ 27 , 28 , 29 ]. Therefore, it is expected that single crystals can further improve the sensitivity, source level, and frequency bandwidth when used as the active material of the composite.…”