scholarly journals Effect of Concave Stave on Class I Barrel-Stave Flextensional Transducer

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1258
Author(s):  
Duo Teng ◽  
Xiaoyong Liu ◽  
Feng Gao
Keyword(s):  
Finite Element ◽  
Resonance Frequency ◽  
Low Frequency ◽  
Acoustic Energy ◽  
Class I ◽  
Small Range ◽  
Transformation Behavior ◽  
Mechanical Transformation ◽  
Source Level ◽  
Flextensional Transducer

To meet the requirements of low frequency, high power, small size and light weight, a type of Class I barrel-stave flextensional transducer employing improved concave stave is presented. As the key component of flextensional transducer, concave stave plays an important role in vibrating efficiently to radiate acoustic energy. The structure of concave stave has a great effect on its behavior. In this paper, the main parameters of concave stave are discussed, especially the effect of radius on flextensional transducer. Both concave stave and transducer are analyzed through finite element method, including mechanical transformation behavior of concave stave and performances of flextensional transducer. On the basis of finite element design, five prototypes employing concave staves with different radii are manufactured and measured. The simulations and tests reveal that concave stave can affect performances of flextensional transducer. A larger radius of concave stave will result in a greater amplification of vibration and a lower resonance frequency of transducer. This can be a feasible way to optimize the resonance frequency or source level of flextensional transducer through adjusting the radius of concave stave in a small range. According to the electrical and acoustical tests, our Class I barrel-stave flextensional transducer is capable of being used as underwater low-frequency small-size projector.

scholarly journals Finite element analysis of double resonance bender disk low frequency transducer

2019 ◽  
Vol 283 ◽  
pp. 05008
Author(s):  
Wei Lu ◽  
Yu Lan ◽  
Tianfang Zhou
Keyword(s):  
Finite Element ◽  
Resonance Frequency ◽  
Double Resonance ◽  
Low Frequency ◽  
Mass System ◽  
First Order ◽  
Metal Disc ◽  
Bending Mode ◽  
Frequency Transducer ◽  
Hollow Metal

A bender disk transducer can generate low-frequency sound in a small size and light weight. But traditional bender disk transducer only works at single frequency by using first order bending mode and emits moderate levels of power. In this work, a double resonance bander disk low frequency transducer is investigated by using finite element model. The double resonance bender disk transducer consists of two segmented 3-3 mode piezoelectric ceramic disk on the both side of hollow metal disc, which could generate larger displacement in order to increase power radiation. A simple elastic mass system placed inside the hollow metal disc is introduced in the system to produce other lower resonance modes. Through the FEM calculations, it is found that the transmitting voltage response (TVR) of bender disk transducer could enhance 4dB in the first order bending mode resonance frequency, which is compared with traditional bender disk transducer with the same size. The TVR of lower resonance mode which is produced by additional central simple support elastic mass system in segmented bender disk transducer is more than 130dB. Through the optimization of finite element simulation, a double resonance bender disk transducer is designed, and its resonance frequency is 600Hz and 1kHz, respectively. The value of TVR is 130dB and 134dB corresponding to two resonance frequency. The double resonance bender disk transducer is compact dimension, low weight and it is a high performance low frequency transducer.

scholarly journals Mathematical and laboratory modeling of resonant impact on the spike for the purpose of grain selection

2020 ◽  
Vol 210 ◽  
pp. 05017
Author(s):  
Arkady Soloviev ◽  
Andrey Matrosov ◽  
Ivan Panfilov ◽  
Besarion Meskhi ◽  
Oleg Polushkin ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Resonance Frequency ◽  
High Frequency ◽  
Low Frequency ◽  
Element Model ◽  
Laboratory Modeling ◽  
Full Scale Experiment ◽  
High Frequency Vibrations ◽  
Scale Experiment

Mathematical and computer finite element model in the ACELAN package of resonant impact on a spike was developed and a full-scale experiment was carried out. Two installations are considered, one based on a cantilever, the free end of which acts on the spike, and the second is a semi-passive round bimorph. Excitation of vibrations is carried out using an actuator based on piezoceramic elements. In the first installation, low-frequency vibrations of the stem with a spike are excited and the resonance frequency is determined at which only an spike with grain performs intense vibrations. The second installation is designed to excite high-frequency vibrations at which resonant movements of the grains themselves arise. The purpose of both installations is to separate the grain from the spike using resonance phenomena.

Finite Element Analysis of Flextensional Transducer with Slotted Shell

2012 ◽  
Vol 187 ◽  
pp. 151-154
Author(s):  
Si Chen ◽  
Yu Lan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Resonant Frequency ◽  
Low Frequency ◽  
Maximum Size ◽  
Voltage Response ◽  
Element Analysis ◽  
Finite Element Software ◽  
Acoustic Transducer ◽  
Flextensional Transducer

The study of low frequency, small size transducer was an important aspect for the development of the underwater acoustic transducer. The Class Ⅳ flextensional transducer was a typical low frequency, high-power and small size transducer. For decreasing its resonant frequency in the case of small size, a flextensional transducer with slotted shell was analyzed using finite element software ANSYS. A comparison between the flextensioanl transducer with slotted shell and the Class Ⅳ flextensional transducer was made. The maximum size of the shell is 200mm. The transmitting voltage response of the transducer reaches to 131dB with resonant frequency 600Hz in water. The transducer could radiate at low frequency with small size of the shell.

scholarly journals Estimation of the Noise Source Level of a Commercial Ship Using On-Board Pressure Sensors

2021 ◽  
Vol 11 (3) ◽  
pp. 1243
Author(s):  
Hongseok Jeong ◽  
Jeung-Hoon Lee ◽  
Yong-Hyun Kim ◽  
Hanshin Seol
Keyword(s):  
Noise Source ◽  
Pressure Sensors ◽  
Low Frequency ◽  
Frequency Resolution ◽  
Source Strength ◽  
Recording Time ◽  
Source Level ◽  
The One ◽  
Hydrophone Array ◽  
Good Agreement

The dominant underwater noise source of a ship is known to be propeller cavitation. Recently, attempts have been made to quantify the source strength using on-board pressure sensors near the propeller, as this has advantages over conventional noise measurement. In this study, a beamforming method was used to estimate the source strength of a cavitating propeller. The method was validated against a model-scale measurement in a cavitation tunnel, which showed good agreement between the measured and estimated source levels. The method was also applied to a full-scale measurement, in which the source level was measured using an external hydrophone array. The estimated source level using the hull pressure sensors showed good agreement with the measured one above 400 Hz, which shows potential for noise monitoring using on-board sensors. A parametric study was carried out to check the practicality of the method. From the results, it was shown that a sufficient recording time is required to obtain a consistent level at high frequencies. Changing the frequency resolution had little effect on the result, as long as enough data were provided for the one-third octave band conversion. The number of sensors affected the mid- to low-frequency data.

Collective oscillations in bubble clouds

2011 ◽  
Vol 680 ◽  
pp. 114-149 ◽  
Author(s):  
ZORANA ZERAVCIC ◽  
DETLEF LOHSE ◽  
WIM VAN SAARLOOS
Keyword(s):  
Frequency Response ◽  
Acoustic Field ◽  
Low Frequency ◽  
Acoustic Energy ◽  
Viscous Damping ◽  
Edge States ◽  
Bubble Cloud ◽  
Collective Oscillations ◽  
The Individual ◽  
Bubble Oscillations

In this paper the collective oscillations of a bubble cloud in an acoustic field are theoretically analysed with concepts and techniques of condensed matter physics. More specifically, we will calculate the eigenmodes and their excitabilities, eigenfrequencies, densities of states, responses, absorption and participation ratios to better understand the collective dynamics of coupled bubbles and address the question of possible localization of acoustic energy in the bubble cloud. The radial oscillations of the individual bubbles in the acoustic field are described by coupled linearized Rayleigh–Plesset equations. We explore the effects of viscous damping, distance between bubbles, polydispersity, geometric disorder, size of the bubbles and size of the cloud. For large enough clusters, the collective response is often very different from that of a typical mode, as the frequency response of each mode is sufficiently wide that many modes are excited when the cloud is driven by ultrasound. The reason is the strong effect of viscosity on the collective mode response, which is surprising, as viscous damping effects are small for single-bubble oscillations in water. Localization of acoustic energy is only found in the case of substantial bubble size polydispersity or geometric disorder. The lack of localization for a weak disorder is traced back to the long-range 1/r interaction potential between the individual bubbles. The results of the present paper are connected to recent experimental observations of collective bubble oscillations in a two-dimensional bubble cloud, where pronounced edge states and a pronounced low-frequency response had been observed, both consistent with the present theoretical findings. Finally, an outlook to future possible experiments is given.

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