scholarly journals Research and Fabrication of Broadband Ring Flextensional Underwater Transducer

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1548
Author(s):  
Jiuling Hu ◽  
Lianjin Hong ◽  
Lili Yin ◽  
Yu Lan ◽  
Hao Sun ◽  
...  
Keyword(s):  
High Speed ◽  
Structural Parameters ◽  
Low Frequency ◽  
Flexural Vibration ◽  
Underwater Acoustic Communication ◽  
Voltage Response ◽  
Water Tank ◽  
Spherical Cap ◽  
Finite Element Software ◽  
Underwater Transducer

At present, high-speed underwater acoustic communication requires underwater transducers with the characteristics of low frequency and broadband. The low-frequency transducers also are expected to be low-frequency directional for realization of point-to-point communication. In order to achieve the above targets, this paper proposes a new type of flextensional transducer which is constructed of double mosaic piezoelectric ceramic rings and spherical cap metal shells. The transducer realizes broadband transmission by means of the coupling between radial vibration of the piezoelectric rings and high-order flexural vibration of the spherical cap metal shells. The low-frequency directional transmission of the transducer is realized by using excitation signals with different amplitude and phase on two mosaic piezoelectric rings. The relationship between transmitting voltage response (TVR), resonance frequency and structural parameters of the transducer is analyzed by finite element software COMSOL. The broadband performance of the transducer is also optimized. On this basis, the low-frequency directivity of the transducer is further analyzed and the ratio of the excitation signals of the two piezoelectric rings is obtained. Finally, a prototype of the broadband ring flextensional underwater transducer is fabricated according to the results of simulation. The electroacoustic performance of the transducer is tested in an anechoic water tank. Experimental results show that the maximum TVR of the transducer is 147.2 dB and the operation bandwidth is 1.5–4 kHz, which means that the transducer has good low-frequency, broadband transmission capability. Meanwhile, cardioid directivity is obtained at 1.4 kHz and low-frequency directivity is realized.

Covert Underwater Acoustic Communication System Using Parametric Array

2019 ◽  
Vol 53 (1) ◽  
pp. 20-26 ◽  
Author(s):  
Anbang Zhao ◽  
Yue Cheng ◽  
Tiansi An ◽  
Juan Hui
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Low Frequency ◽  
Nonlinear Behavior ◽  
Beam Width ◽  
Point Of View ◽  
Underwater Acoustic Communication ◽  
Water Tank ◽  
Narrow Beam ◽  
Underwater Acoustic ◽  
Parametric Array

AbstractA novel and efficient covert underwater acoustic (UWA) communication scheme using an acoustic parametric array and orthogonal frequency division multiplexing (OFDM) system is presented. The proposed system is robust and can easily be implemented in the ocean environment. The system is also very useful in military applications where the secrecy of transmission signal and location of the transmitter are extremely important. The paper exploits the difference frequency generated by the acoustic parametric array due to the nonlinear behavior of an underwater medium. Besides the lightness and compactness, the parametric array also possesses the advantage of being low-frequency, broadband, highly directive, and narrow beam with no side lobes. The narrow beam width also helps to secure the data from a spatial point of view. Experiments have been performed in a water tank, and the results are presented to show the effectiveness of the proposed scheme.

scholarly journals Metal Ceramic Segmented Ring Transducer under Deep Submergence Conditions

2017 ◽  
Vol 67 (6) ◽  
pp. 612
Author(s):  
Subash Chandrabose M R ◽  
Shan Victor Pereira ◽  
Jayakumar B ◽  
Ebenezer D. D.
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Low Cost ◽  
Low Frequency ◽  
Test Facility ◽  
Voltage Response ◽  
Performance Parameters ◽  
Finite Element Software ◽  
Pressure Test ◽  
Metal Ceramic

<p class="p1">Segmented ring transducers are widely used for low frequency, broadband, deep submergence applications. These transducers can be made out of piezoceramic wedges or slabs and metallic wedges. Higher diameter, low frequency transducers are generally made out of piezoceramic slabs and metal wedges due to ease of manufacture and low cost. In this paper, metal ceramic segmented ring transducers are modelled using ATILA, a finite element software for the design of underwater transducers. Transducer variants were modelled with different wedge and piezoceramic materials. Transducers modelled were manufactured, assembled and tested. Various stages of manufacture like piezoceramic stacking, transducer assembly, pre-stressing with fibre winding, and encapsulation are explained. Acoustic performances of the transducers manufactured were measured in an open tank and inside a pressurised vessel from 10 bar to 70 bar. Performance parameters like resonance frequency, transmitting voltage response and directivity were measured. Results indicate that the transducer has usable bandwidth of about two octaves and stable response. One of the transducers was also tested in a high pressure test facility at 600 bar to check its pressure withstanding capability.</p>

scholarly journals Numerical Design of Sound-Insulating Material with Combined Cavities of Mixed Sizes

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Xu-wen Wang ◽  
Shao-wei Li ◽  
Wei Cheng ◽  
Jing-rui Li ◽  
Zhi Fang ◽  
...  
Keyword(s):  
Transmission Loss ◽  
Structural Parameters ◽  
Low Frequency ◽  
Sound Transmission ◽  
Sound Transmission Loss ◽  
Analysis Model ◽  
Insulating Material ◽  
Compression Performance ◽  
Finite Element Software ◽  
Pressure Resistance

In view of the low-frequency acoustic insulation performance and poor pressure resistance of a single cavity at present, finite element software COMSOL is used to establish an analysis model to calculate the sound transmission loss (TL) and compression performance of the sound-insulating material with combined cone cavities. The effectiveness of the numerical method is validated by comparing with the experimental results, and influence of the structural parameters of the cone cavity, the perforation, and the mixed cavity shape on the sound transmission loss is investigated.

Local Optimization Analysis of Bailey Beam Bracket Based on Multiscale Model

2019 ◽  
Vol 815 ◽  
pp. 229-234
Author(s):  
Qin Tian ◽  
Cheng Hao Hang ◽  
Zi Xin Wan ◽  
Yun Peng Zou
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Structural Parameters ◽  
Bending Moment ◽  
Element Model ◽  
Railway Bridge ◽  
High Speed Railway ◽  
Finite Element Software ◽  
Steel Cushion ◽  
Structural Measure

In the construction of high-speed railway bridge, the stress of Bailey beam is much higher than that of other parts due to the large local compressive stress and bending moment at the fulcrum. To solve this problem, this paper proposes a structural measure of adding double I-steel cushion between Bailey beam and top beam to alleviate the larger stress at the fulcrum and make the support more uniform. Based on the Bailey beam support system of cast-in-situ high-speed railway bridge of Lianshui County super large bridge, the multi-scale finite element model of Bailey beam support is established by ABAQUS general finite element software, and the influence law of structural parameters of double-jointed I-steel cushion on support stress is analyzed. The research shows that the rigidly of the double-jointed I-beam cushion should not be too large or too small. When the length is appropriate, it can effectively alleviate the problem of excessive stress at the fulcrum of Bailey beam, and is a safe, economical and simple new structural measure.

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 Tunable Low Frequency Band Gap and Waveguide of Phononic Crystal Plates with Different Filling Ratio

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 828
Author(s):  
Shaobo Zhang ◽  
Jiang Liu ◽  
Hongbo Zhang ◽  
Shuliang Wang
Keyword(s):  
Band Gap ◽  
Composite Structure ◽  
Structural Parameters ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Filling Ratio ◽  
Height Ratio ◽  
Road Vehicles ◽  
Aluminum Base ◽  
Gap Width

Aiming at solving the NVH problem in vehicles, a novel composite structure is proposed. The new structure uses a hollow-stub phononic-crystal with filled cylinders (HPFC) plate. Any unit in the plate consists of a lead head, a silicon rubber body, an aluminum base as outer column and an opposite arranged inner pole. The dispersion curves are investigated by numerical simulations and the influences of structural parameters are discussed, including traditional hollow radius, thickness, height ratio, and the new proposed filling ratio. Three new arrays are created and their spectrum maps are calculated. In the dispersion simulation results, new branches are observed. The new branches would move towards lower frequency zone and the band gap width enlarges as the filling ratio decreases. The transmission spectrum results show that the new design can realize three different multiplexing arrays for waveguides and also extend the locally resonant sonic band gap. In summary, the proposed HPFC structure could meet the requirement for noise guiding and filtering. Compared to a traditional phononic crystal plate, this new composite structure may be more suitable for noise reduction in rail or road vehicles.

Sign in / Sign up

Export Citation Format

Share Document