Hangzhou Applied Acoustics Research Institute

Hangzhou, China

Hangzhou Applied Acoustics Research Institute

Hangzhou, China
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Wang S.,Hangzhou Applied Acoustics Research Institute
Journal of Computational Acoustics | Year: 2016

This paper investigates the prediction of the far-field performances of high frequency projectors using the second source array method (SSAM). The far-field parameters can be calculated accurately using the complex acoustic pressure data of two very close parallel planes which lie in the near-field region of the projector. The paper simulates the feasibility of predicting the far-field parameters such as transmitting voltage response and the far-field directivity pattern. The predicting results are compared with that calculated using boundary element method (BEM). It shows very good agreement between the two methods. A planar high frequency projector is measured using the near-field method. In order to verify the predicting results, the far-field measurement is performed for the same projector. The comparison of the results shows that the near-field method is capable to precisely predict the far-field parameters of the projector. © 2017 © IMACS


Wang S.,Hangzhou Applied Acoustics Research Institute | Chen Y.,Hangzhou Applied Acoustics Research Institute
Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future | Year: 2016

Optical method has been used in the calibration of hydrophones for many years. It is an absolute method for the calibration of free-field sensitivity of hydrophones. Usually, the calibration is carried out in an open water tank. In this paper, the calibration of a B&K8105 and TC4033 hydrophones in a closed acoustic vessel were described. The comparison results between the optical method and the reciprocal method were given and good agreements were achieved. It showed that the optical method had potential applications for the calibration of hydrophones in a pressure vessel in future. © 2016, German Acoustical Society (DEGA). All rights reserved.


Liu J.,Hangzhou Applied Acoustics Research Institute
2016 IEEE/OES China Ocean Acoustics Symposium, COA 2016 | Year: 2016

Over the past several years, Hangzhou Applied Acoustics Research Institute(HAARI) has developed the ring transducer, including the air-backed ring transducer(ABRT) and free-flooded ring transducer(FFRT). A previous paper [1] described a kind of transmit-receive air-backed ring transducer with radially poled ceramic. This paper reports on our successful efforts to develop a broadband segmented free-flooded ring transducer with a circumferentially poled ceramic. Broadband response is achieved by coupling the cavity resonance mode and the circumferential resonance mode. The maximum diameter of the transducer is 90mm (without mounting base). As a transmit-receive transducer, the maximum of the Transmitting Voltage Response (TVR) is 141.3 dB//μPa@1m/V, @12.8kHz. The frequency band with transmitting response decreasing 3dB is from 9.6kHz to 18.4kHz. The maximum of the Receiving Voltage Response (RVS)in free field is -179 dB//V/μPa, @13.2kHz. The frequency band width receiving response decreasing 3.3dB is from 8.6kHz to 18.8kHz. The transducer shows great promise as a broadband, high efficiency, high-power underwater acoustic transceiver for deep water applications in excess of several thousand meters and with an omi-directionally beam pattern in horizon. © 2016 IEEE.


Yang Y.,Hangzhou Applied Acoustics Research Institute | Jiao J.,Hangzhou Applied Acoustics Research Institute
2016 IEEE/OES China Ocean Acoustics Symposium, COA 2016 | Year: 2016

The sounding method and accuracy of multi-beam bathymetric sonars are being continuously researched, and many traditional multi-beam bathymetric algorithms have been proposed, such as: the Energy Centre method, the WMT method, the BDI method, etc. Some of these methods have a high precision of sounding in the mirror area, while some have a high precision of sounding in the non- mirror area. If we combine these methods and apply them to high-frequency shallow-water multi-beam sonar, the precision of sounding reaches a satisfactory level. Besides the sounding precision, the sounding resolution (the number of sounding points) is also an important indicator for multi-beam bathymetric sonar. The sounding resolution of a traditional bathymetric algorithm mainly depends on the number of pre-formed beams, which restricts the improvement of sounding resolution. In this paper, differential phase technology will be applied to broadband multi-beam bathymetric sonar, which not only ensures the accuracy of sounding, but also greatly improves the sounding resolution by dozens of times or even a hundred times as compared to a traditional bathymetric algorithm. Hence, more detailed acoustic images can be obtained without increasing the frequency of multi-beam bathymetric sonar. This is possible by using differential phase technology for underwater topography, which is advantageous for small target detection. The paper also analyzes various important factors which affect the differential phase technique, such as additive noise, baseline de-correlation and beam footprint of the seabed. In addition, it also gives the theoretical curve of sounding accuracy changing with the signal pulse width, SNR, grazing angle and other factors. Finally, we find that even under high SNR conditions, differential phase technology is still able to maintain a good sounding performance, even when we reduce the number of received array elements. This lays a good foundation for studying low frequency multi-beam bathymetric sonar. © 2016 IEEE.


Zhang K.,Hangzhou Applied Acoustics Research Institute
Proceedings of the 2015 Symposium on Piezoelectricity, Acoustic Waves and Device Applications, SPAWDA 2015 | Year: 2015

There are many advantages of broadband transducers, such as reducing of signal distortion, widening the security about information transmission, reducing the ratio of false codes. The use of eight 33 mode single crystal pieces, a thin light beryllium alloy head mass and a thick heavy tungsten alloy tail mass can expand the bandwidth of the middle-frequency transducer. The one-fourth finite element model of transducer was set up with ANSYS software and the structure of the transducer was optimized. A final transducer was designed, fabricated and measured, and its longitudinal size is about 21mm. The bandwidth of the transducer is 17 kHz-120 kHz, in which the ripple of the transmitting voltage response does not exceed ±5dB. There are several conclusions from the research: the bandwidth of tonpilz transducers can be expanded by the use of single crystal pieces, beryllium alloy head mass and tungsten alloy tail mass; and it gives a method to achieve the broad-band projecting performance of middle-frequency transducers. © 2015 IEEE.


Bai L.-L.,Hangzhou Applied Acoustics Research Institute
Proceedings of the 2012 Symposium on Piezoelectricity, Acoustic Waves and Device Applications, SPAWDA 2012 | Year: 2012

According to Berktay the far-field solution of parametric array, self-demodulatory sound pressure is proportional to squared of envelope function to the second derivative of the time. The excitation input signals of parametric array were designed and analyzed. A parameter array is measured under the different excitation signals. The results show that: (1) When the input signals is single-sideband amplitude modulatory signal the harmonic distortion of the sound field is relatively small compared to the double sideband amplitude modulated signal and the difference frequency wave acoustic source level is higher; (2) The difference frequency wave source level will increase rapidly with increase of input power of the parametric array. But too much power may cause the power amplifier to produce nonlinear, thus the harmonic amplitude increase and the conversion efficiency will be lower. © 2012 IEEE.


Zheng Z.-Y.,Hangzhou Applied Acoustics Research Institute
Proceedings of the 2012 Symposium on Piezoelectricity, Acoustic Waves and Device Applications, SPAWDA 2012 | Year: 2012

The equivalent circuit model of piezoelectric ceramic pillar transducer with matching layer material is proposed, and the applicability of this model in the U-shape transducer array is discussed. The vibration character and directivity pattern of the transducer are analyzed by the finite element method. The manufactured U-shape transducer array has verified feasibility of the piezoelectric ceramic pillar transducer with matching layer design. The broadband and high power density characters of such design are suitable for high frequency broadband acoustic emission with special directivity. © 2012 IEEE.


Zhang K.,Hangzhou Applied Acoustics Research Institute
Proceedings of the 2012 Symposium on Piezoelectricity, Acoustic Waves and Device Applications, SPAWDA 2012 | Year: 2012

There many advantages of broadband transducers, such as reducing of signal distortion, widening the security about information transmission, reducing the ratio of false codes. The combine of piezoelectric pillars and dual matching layers can expand the bandwidth of the high-frequency transducer. The one-eighth finite element model of transducer was set up with ANSYS software and the structure of the transducer was optimized. A final transducer was designed, which used the first thickness mode, the second thickness mode and the third thickness mode. The bandwidth of the transducer is 47kHz-159kHz, in which the ripple of the transmitting voltage response does not exceed ±3dB. There are several conclusions from the research: the bandwidth of pillar transducers can be expanded by the first thickness mode, the second thickness mode and the third thickness mode, and it gives a method to achieve the broad-band projecting performance of high-frequency transducers. © 2012 IEEE.


Xu X.-R.,Hangzhou Applied Acoustics Research Institute
Proceedings of the 2012 Symposium on Piezoelectricity, Acoustic Waves and Device Applications, SPAWDA 2012 | Year: 2012

In this paper, a new structure with a perforated electrode design in free-flooded 33-mode ring transducer is proposed. The FEM is utilized to simulate the performance of the transducer, and several design parameters are optimized to achieve higher output power over a wider bandwidth. The tested performance of the manufactured transducers verify the validity of the design. The influence of different shape openings of transducer on its performance is also studied experimentally. © 2012 IEEE.


Zhang K.,Hangzhou Applied Acoustics Research Institute
Proceedings of the 2014 Symposium on Piezoelectricity, Acoustic Waves and Device Applications, SPAWDA 2014 | Year: 2014

There are many advantages of 1-3 piezocomposite transducers, such as lighter weight, lower specific acoustic impedance. The matching layer is commonly used to expand the bandwidth of composite transducers. The finite element modal of transducer was set up with ANSYS software and the structure of the transducer was optimized. A final 1-3 piezocomposite transducer was designed, which used the first thickness mode, the first lateral mode and the third thickness mode. The bandwidth of the transducer is 120kHz-470kHz, in which the ripple of the transmitting voltage response does not exceed ±5dB. There are several conclusions from the research: the bandwidth of 1-3 piezocomposite transducers can be expanded by the first thickness mode, the first lateral mode and the third thickness mode, and it gives a method to achieve the broad-band projecting performance of high-frequency transducers. © 2014 IEEE.

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