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>

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 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.

scholarly journals Low Cost Frictional Seismic Base-Isolation of Residential New Masonry Buildings in Developing Countries: A Small Masonry House Case Study

2017 ◽  
Vol 11 (1) ◽  
pp. 1026-1035 ◽  
Author(s):  
Ahmad Basshofi Habieb ◽  
Gabriele Milani ◽  
Tavio Tavio ◽  
Federico Milani
Keyword(s):  
Finite Element ◽  
Seismic Vulnerability ◽  
Base Isolation ◽  
Low Cost ◽  
Element Model ◽  
Shaking Table ◽  
Fe Model ◽  
Isolation System ◽  
Finite Element Software ◽  
Non Linear

Introduction:An advanced Finite Element model is presented to examine the performance of a low-cost friction based-isolation system in reducing the seismic vulnerability of low-class rural housings. This study, which is mainly numerical, adopts as benchmark an experimental investigation on a single story masonry system eventually isolated at the base and tested on a shaking table in India.Methods:Four friction isolation interfaces, namely, marble-marble, marble-high-density polyethylene, marble-rubber sheet, and marble-geosynthetic were involved. Those interfaces differ for the friction coefficient, which was experimentally obtained through the aforementioned research. The FE model adopted here is based on a macroscopic approach for masonry, which is assumed as an isotropic material exhibiting damage and softening. The Concrete damage plasticity (CDP) model, that is available in standard package of ABAQUS finite element software, is used to determine the non-linear behavior of the house under non-linear dynamic excitation.Results and Conclusion:The results of FE analyses show that the utilization of friction isolation systems could much decrease the acceleration response at roof level, with a very good agreement with the experimental data. It is also found that systems with marble-marble and marble-geosynthetic interfaces reduce the roof acceleration up to 50% comparing to the system without isolation. Another interesting result is that there was little damage appearing in systems with frictional isolation during numerical simulations. Meanwhile, a severe state of damage was clearly visible for the system without isolation.

Thermal Stress Analysis of the Die during High Pressure Casting

2014 ◽  
Vol 915-916 ◽  
pp. 1074-1077
Author(s):  
Wu Hu ◽  
Ming Long Kang ◽  
Jian Min Zeng
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Die Casting ◽  
The Other ◽  
Air Cooling ◽  
Pressure Casting ◽  
Cooling Channel ◽  
Finite Element Software ◽  
Efficient Measure ◽  
Pressure Die Casting

The distribution of temperatures and stresses in the die during high pressure die casting are computed through commercially finite element software developed by Wincast team, Germany. The deformation of the die during its continual running is predicted under the conditions without and with air cooling. The simulated results show that the regions of die, which contact with the casting, is subjected to compressed stresses and the other regions of the die subjected to tensile stresses. Compressed stresses are changed steeply from tensile to compress on the boundary between the casting and the inner cavity walls, which will results in hot-fatigue in those regions of the die. Setting cooling channel within the die is an efficient measure for eliminating hot-fatigue and prolonging life of the die.

Optimization Dressing Method of Amplitude Transformer Based on Finite Element

2013 ◽  
Vol 278-280 ◽  
pp. 315-318
Author(s):  
Ming Li Zhao ◽  
Bo Zhao ◽  
Yu Qing Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Resonant Frequency ◽  
Structural Parameters ◽  
Low Cost ◽  
Dressing Method ◽  
Finite Element Software ◽  
System Vibration ◽  
Vibration Performance ◽  
Element Method

The node position of amplitude transformer was determined by the finite element method, and the flange was designed at the nod position for conveniently installation. By the finite element software, the amplitude transformer with flange was optimized and dressed, and its structural parameters were determined. During the actual manufacturing process, it was used impedance analyzer to test its vibration performance, the testing results show that this system vibration performance is good, its resonant frequency is 34.771kHz, anti-resonant frequency is 35.008kHz. The above-mentioned results are very much coincided with the system natural frequency of 34.893kHz which is drew by finite element method. Compared to the traditional dressing this method has many advantages such as convenience, green, environmental protection, low cost and others.

Mechanism of band gaps in self-similar triangular lattice with Koch fractal

2021 ◽  
pp. 1-17
Author(s):  
Pengcheng Zhao ◽  
Cheng Zhao ◽  
Kai Zhang ◽  
Zichen Deng
Keyword(s):  
Finite Element ◽  
Triangular Lattice ◽  
Vibration Suppression ◽  
Low Frequency ◽  
Band Gaps ◽  
Band Edge ◽  
Periodic Lattice ◽  
Finite Element Software ◽  
Iteration Number ◽  
Koch Fractal

Abstract Fractal lattice is a kind of lattices with multifunctional physical characteristics and superior mechanical properties. The wave propagation of the triangular lattice with Koch fractal is calculated by the finite element method and Bloch theorem. The effects of the iteration number on the band gaps and the band edge modes are studied. The finite element software was used to simulate the dynamic response of the triangular lattice with Koch fractal for verifying the vibration suppression performance. The results show that the triangular lattice with Koch fractal can produce multiple and low-frequency band gaps. As an increase of the iteration number, the band gap gradually shifts to a lower frequency. By comparing and analyzing the band edge modes and the eigenmodes of Koch fractal, the mechanisms of the band gaps within the low-frequency ranges are analyzed and discussed in detail. Additionally, the band edge modes exhibit similar vibration modes. Finally, the simulation results of the finite lattice verify the broadband vibration suppression performance of the triangular lattice with Koch fractal. This work provides insights into the lattice dynamic behavior adjusted by Koch fractal, which is beneficial to the periodic lattice for suppressing vibration in engineering applications.

Combustion System Development and Testing for MAN’s New Industrial Gas Turbines MGT 6100 and MGT 6200

2014 ◽  
Author(s):  
Frank Reiss ◽  
Sven-Hendrik Wiers ◽  
Ulrich Orth ◽  
Emil Aschenbruck ◽  
Martin Lauer ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Test Facility ◽  
Combustion System ◽  
Test Rig ◽  
Low Emission ◽  
Pressure Test ◽  
Industrial Gas Turbines ◽  
And Performance

This paper describes the development and test results of the low emission combustion system for the new industrial gas turbines in the 6–7 MW class from MAN Diesel & Turbo. The design of a robust combustion system and the achievement of very low emission targets were the most important design goals of the combustor development. During the design phase, the analysis of the combustor (i.e. burner design, air distribution, liner cooling design) was supported with different CFD tools. This advanced Dry Low Emission can combustion system (ACC) consists of 6 cans mounted externally on the gas turbine. The behavior and performance of a single can sector was tested over a wide load range and with different boundary conditions; first on an atmospheric test rig and later on a high pressure test rig with extensive instrumentation to ensure an efficient test campaign and accurate data. The atmospheric tests showed a very good performance for all combustor parts and promising results. The high pressure tests demonstrated very stable behavior at all operation modes and very low emissions to satisfy stringent environmental requirements. The whole operation concept of the combustion system was tested first on the single-can high pressure test bed and later on twin and single shaft gas turbines at MAN’s gas turbine test facility. During the engine tests, the can combustors demonstrated the expected combustion performance under real operation conditions. All emissions and performance targets were fully achieved. On the single shaft engine, the combustors were running with single digit ppm NOx levels between 50% and 100% load. The validation phase and further optimization of the gas turbines and the engine components are ongoing. The highlights of the development process and results of the combustor and engine tests will be presented and discussed within this paper.

scholarly journals Ambient Vibration Testing of a Pedestrian Bridge Using Low-Cost Accelerometers for SHM Applications

Smart Cities ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 20-30 ◽  
Author(s):  
Azam Ali ◽  
Talha Sandhu ◽  
Muhammad Usman
Keyword(s):  
Finite Element ◽  
System Identification ◽  
Damage Detection ◽  
Low Cost ◽  
Ambient Vibration ◽  
Mode Shapes ◽  
Pedestrian Bridge ◽  
Finite Element Software ◽  
Ambient Vibration Testing ◽  
Good Comparison

Damage detection and structural health monitoring have always been of great importance to civil engineers and researchers. Vibration-based damage detection has several advantages compared to traditional methods of non-destructive evaluation, such as ground penetrating radar (GPR) or ultrasonic testing, since they give a global response and are feasible for large structures. Damage detection requires a comparison between two systems states, the baseline or “healthy state”, i.e., the initial modal parameters, and the damaged state. In this study, system identification (SI) was carried out on a pedestrian bridge by measuring the dynamic response using six low-cost triaxial accelerometers. These low-cost accelerometers use a micro-electro-mechanical system (MEMS), which is cheaper compared to a piezoelectric sensor. The frequency domain decomposition algorithm, which is an output-only method of modal analysis, was used to obtain the modal properties, i.e., natural frequencies and mode shapes. Three mode shapes and frequencies were found out using system identification and were compared with the finite element model (FEM) of the bridge, developed using the commercial finite element software, Abaqus. A good comparison was found between the FEM and SI results. The frequency difference was nearly 10%, and the modal assurance criterion (MAC) of experimental and analytical mode shapes was greater than 0.80, which proved to be a good comparison despite the small number of accelerometers available and the simplifications and idealizations in FEM.

Low Cost Diffuser Based Micropump Using Pinch Actuation

2011 ◽  
Vol 422 ◽  
pp. 397-400 ◽  
Author(s):  
Pei Song Chee ◽  
Ruzairi Abdul Rahim ◽  
U. Hashim ◽  
Rashidah Arsat ◽  
Pei Ling Leow
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Spin Coating ◽  
Low Cost ◽  
Low Frequency ◽  
Hot Embossing ◽  
Element Analysis ◽  
Construction Parameter

Planar pinch micropump with the integration of two diffuser valve elements has been reported. The fabrication of the micropump is carried out by utilizing simple hot embossing technique for microdiffuser imprinting and spin coating for membrane construction. Parameter of diffuser design is optimized via finite element analysis (FEA). The experiment result shows that the pump works well at low frequency of 29 Hz.

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