Effects of electrodes and electrical connections of piezoelectric layers on dynamic characteristics of radially polarized multilayer piezoelectric cylindrical transducers

2018 ◽  
Vol 30 (1) ◽  
pp. 63-81 ◽  
Author(s):  
Jianjun Wang ◽  
Donghuan Liu ◽  
Weijie Li ◽  
Peijun Wei ◽  
Lihua Tang
Keyword(s):  
Dynamic Characteristics ◽  
Structural Characteristics ◽  
Smart Devices ◽  
Underwater Sound ◽  
Element Analysis ◽  
Resonance Frequencies ◽  
Piezoelectric Layers ◽  
Cylindrical Transducer ◽  
Electrical Connections ◽  
Radially Polarized

Piezoelectric cylindrical transducer is a type of excellent smart devices that can generate radial sound radiation due to its unique structural characteristics and has been widely used for ultrasonic and underwater sound applications. In the design of a piezoelectric cylindrical transducer, especially with the multilayer structure, the electrodes and electrical connections of piezoelectric layers are two key factors affecting the device performance but have not been well evaluated, which result in the inaccurate prediction of dynamic characteristics. This work establishes the exact theoretical models for radially polarized multilayer piezoelectric cylindrical transducers by taking into account the electrodes and electrical connections of piezoelectric layers. Based on the plane stress assumption, the dynamic solutions of the models are derived. Analytical expressions of electric impedances are also derived to obtain the resonance frequencies. In addition, the analytical solutions are validated using the special example in the earlier work and comparing them with the finite element analysis results. Subsequently, the effects of the electrodes and electrical connections of piezoelectric layers on the dynamic characteristics of the transducer are analyzed and discussed. The results show that the electrode thickness, the electrode type, and the parallel and series connections significantly affect the transducer’s performance, thus providing useful guidelines in the design of piezoelectric cylindrical transducers. This work contributes to an overall analysis on the dynamic characteristics of the radially polarized multilayer piezoelectric cylindrical transducers, which is very helpful to improve the performance of two-dimensional emitter and receiver in underwater sound and ultrasonic applications.

Experimental validation of axially polarized multilayer piezoelectric composite cylindrical transducers with adjustable multifrequency

2021 ◽  
pp. 1045389X2110530
Author(s):  
Lei Qin ◽  
Jianjun Wang ◽  
Weijie Li ◽  
Peijun Wei ◽  
Lihua Tang
Keyword(s):  
Dynamic Characteristics ◽  
Theoretical Models ◽  
Piezoelectric Composite ◽  
The Novel ◽  
Impedance Spectra ◽  
Underwater Sound ◽  
Resonance Frequencies ◽  
Piezoelectric Layers ◽  
Ultrasonic Radiator ◽  
Elastic Layers

The axially polarized multilayer piezoelectric composite cylindrical transducers with adjustable multifrequency capability have been proposed by adjusting the external electric resistance and the ratio of piezoelectric layer numbers between the actuator part and the sensor part, which have promising potential in designing the novel cymbal transducer for underwater sound projector and ultrasonic radiator applications. In the previous studies, the multilayer models were established to guide the design of the transducers with arbitrary layer number, and analyzed the dynamic characteristics theoretically. In this work, an experimental study is performed to validate the theoretical models and predictions. Piezoelectric rings with multiple concentric annular electrodes are designed to characterize the multilayer piezoelectric composite cylindrical transducers. The top surface of the piezoelectric rings is divided into two separate parts. One part is covered by multiple concentric annular electrodes, corresponding to the piezoelectric layers, and the other part is uncovered, corresponding to the elastic layers. Four prototypes are fabricated and each consists of four concentric annular electrodes. The impedance spectra are measured by the impedance analyzer to obtain the resonance and anti-resonance frequencies. Effects of two adjusting methods on the dynamic characteristics are evaluated experimentally. The experimental results basically coincide with the theoretical ones. This comprehensive experimental work assures the feasibility of using axially polarized multilayer piezoelectric composite cylindrical transducers with adjustable multifrequencies and confirms the benefit of the developed theoretical models for guiding the fabrication and optimization of this type of transducers.

scholarly journals Finite Element Analysis of Dynamic Characteristics and Bending Stiffness for Cross Laminated Timber Floor Panels with and without Openings

2021 ◽  
Vol 72 (4) ◽  
pp. 373-379
Author(s):  
Ljiljana Kozarić ◽  
Smilja Bursać ◽  
Martina Vojnić Purčar ◽  
Miroslav Bešević ◽  
Žikica Tekić
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Structural Characteristics ◽  
Longitudinal Direction ◽  
Bending Stiffness ◽  
Full Potential ◽  
Element Analysis ◽  
Cross Laminated Timber ◽  
Additional Service ◽  
Floor System

The aim of this paper is to present numerical investigations of dynamic characteristics and bending stiffness for cross laminated timber floor panels with and without service openings. Five-layer panels with the outer layers oriented in the longitudinal direction of the panel have been analyzed. In order to explore the full potential of this floor system using a limited number of measurements and structural tests, models based on the finite element method have been proposed, validated against experimental results and then used to investigate the effect of opening position in the floor on main structural performance parameters. The results showed that, when the need for additional service opening appears, a slight decrease of the main structural characteristics of the cross laminated timber floor panels is achievable with an adequate geometrical position of the opening in the floor.

On-Site Experimental Testing to Study the Vibration of Composite Floors

2014 ◽  
Vol 601 ◽  
pp. 231-234
Author(s):  
Cristian Lucian Ghindea ◽  
Dan Cretu ◽  
Monica Popescu ◽  
Radu Cruciat ◽  
Elena Tulei
Keyword(s):  
Dynamic Characteristics ◽  
Experimental Testing ◽  
Concrete Slab ◽  
Human Perception ◽  
Experimental Tests ◽  
International Standards ◽  
Structural Element ◽  
Element Analysis ◽  
Floor Slabs ◽  
Composite Floors

As a general trend, in order to reduce material consumption or to reduce the mass of the structures, composite floor slabs solutions are used to achieve large spans floor slabs. This solutions led to floors sensitive to vibrations induced generally by human activities. As a verification of the design concepts of the composite floors, usually, it is recommended a further examination of the floor after completion by experimental tests. Although the experimental values of the dynamic response of the floor are uniquely determined, the processing can take two directions of evaluation. The first direction consist in determining the dynamic characteristics of the floor and their comparison with the design values. Another way that can be followed in the processing of the experimental results is to consider the human perception and comfort to the vibration on floors. The paper aims to present a case study on a composite floor, with steel beams and concrete slab, tested on-site. Both aspects of data processing are analyzed, in terms of the structural element, and in terms of the effect on human perception and comfort. Experimentally obtained values for the dynamic characteristics of the floor are compared with numerical values from finite element analysis, while the second type of characteristic values are compared with various human comfort threshold values found in international standards.

The Method for Determining the Vibration-Damping Elements for the Mechanical System to Obtain the Desired Amplitude Value

2014 ◽  
Vol 657 ◽  
pp. 644-648 ◽  
Author(s):  
Andrzej Dymarek ◽  
Tomasz Dzitkowski
Keyword(s):  
Mechanical System ◽  
Dynamic Characteristics ◽  
Vibration Reduction ◽  
Mechanical Systems ◽  
Vibration Damping ◽  
Displacement Velocity ◽  
Synthesis Methods ◽  
Resonance Frequencies

The paper presents the use of synthesis methods to determine the parameters of passive vibration reduction in mechanical systems. Passive vibration reduction in a system is enabled by units called dampers whose values are determined on the basis of the method formulated and formalized by the authors. The essence of the method are, established at the beginning of a task, dynamic characteristics in the form of the resonance and anti-resonance frequencies, and amplitudes of displacement, velocity or acceleration of vibration.

Uvula Dynamic Characteristics

2013 ◽  
Author(s):  
A. M. Al-Jumaily ◽  
S. Ashaat ◽  
B. A. Martin ◽  
R. Heinzer ◽  
J. Haba Rubio ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Structural Model ◽  
Fluid Layer ◽  
Structural Characteristics ◽  
Upper Airway ◽  
Mode Shapes ◽  
Tissue Elasticity ◽  
Upper Airways ◽  
Obstructive Sleep ◽  
Mri Scans

The airway binary fluid layer and the structural characteristics of the upper airways have significant influence on the activity of the airway muscles by changing airway compliance and collapsibility during obstructive sleep apnea trauma. The uvula plays an important role in the collapse process. Using MRI scans, this paper develops a structural model for the uvula and determines its dynamic characteristics in terms of natural frequencies and mode shapes as a preliminary process to determine optimum conditions to therapeutically relieve upper airway obstruction. The effect of the variation of tissue elasticity due to water content is elaborated on.

Dynamic Analysis of Large-Scale Power House

2012 ◽  
Vol 446-449 ◽  
pp. 837-840
Author(s):  
Yu Zhao ◽  
Shu Fang Yuan ◽  
Jian Wei Zhang
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Large Scale ◽  
Three Dimensional ◽  
Dynamic Responses ◽  
Dynamic Loads ◽  
Element Analysis ◽  
Power House ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The underwater structure of power house is major structure under the dynamic loads of unit. The vibration problem is very common in operation. So the structures should have sufficient stiffness to resist dynamic loads of unit. This paper establishes three-dimensional finite element models with finite element analysis software—ANSYS. Dynamic characteristics of the power house and dynamic responses of structure under earthquake are analyzed. The results of the computation show that fluid-solid coupling may be ignored when studying dynamic characteristics of structures of the underground power house.

scholarly journals Dynamic characteristics of triaxial active control magnetic bearing with asymmetric structure

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 9-13 ◽  
Author(s):  
Atsushi Nakajima ◽  
Katsuhiro Hirata ◽  
Noboru Niguchi ◽  
Masayuki Kato
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Active Control ◽  
Dynamic Characteristics ◽  
Negative Pressure ◽  
Axial Direction ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Asymmetric Structure ◽  
Element Analysis

Abstract Supporting forces of magnetic bearings are lower than those of mechanical bearings. In order to solve these problems, this paper proposes a new three-axis active control magnetic bearing (3-axis AMB) with an asymmetric structure where its rotor is attracted only in one axial direction due to a negative pressure of fluid. Our proposed 3-axis AMB can generate a large suspension force in one axial direction due to the asymmetric structure. The performances of our proposed 3-axis AMB are computed through 3-D finite element analysis.

Modeling and electromechanical performance analysis of frequency-variable piezoelectric stack transducers

2020 ◽  
Vol 31 (6) ◽  
pp. 897-910
Author(s):  
Jianjun Wang ◽  
Shuyuan Cai ◽  
Lei Qin ◽  
Donghuan Liu ◽  
Peijun Wei ◽  
...  
Keyword(s):  
Experimental Study ◽  
Performance Analysis ◽  
Analytical Solution ◽  
Resonance Frequency ◽  
Analytical Model ◽  
Dynamic Characteristics ◽  
Active Element ◽  
Underwater Sound ◽  
Layer Number ◽  
Electromechanical Performance

An exact analytical model of frequency-variable piezoelectric stack transducers is proposed, and their dynamic characteristics are studied in this article. Based on the linear piezoelasticity theory, the dynamic analytical solution is first derived, and then its correctness is validated by comparing it with the results of a special example in the previous literature and the ones of the experimental study. The effects of the tuning resistance and the layer number of the active element on the dynamic characteristics are discussed. Numerical results show that tuning the resistance and the layer number of the active element can enable the multi-frequency characteristics of the piezoelectric stack transducers. A proper layer number of the active element can minimize the short-circuited resonance frequency and the open-circuited anti-resonance frequency. These findings provide guidelines to design and optimize the piezoelectric stack transducers, which have promising potential in developing the multi-frequency Langevin transducers for some underwater sound and ultrasonic applications, such as ultrasonic cleaning, ultrasonic chemistry, and sonar radiators.

Finite Element Analysis for Wave Spring of Multi-Disc Wet Clutch Based on ANSYS

2013 ◽  
Vol 419 ◽  
pp. 203-208
Author(s):  
Ying Yu ◽  
Yao Run Peng ◽  
Shi Xin Lan ◽  
Ping Zhou
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Characteristics ◽  
Response Speed ◽  
Wave Number ◽  
Element Analysis ◽  
Wet Clutch ◽  
Relationship Of ◽  
Deformation Relationship

Wave spring is a key component of multi-disc wet clutch and the response speed and running quality of multi-disc wet clutch is affected by its characteristics. This paper analyses the theoretical calculation of load-deformation relationship of wave spring. The load-deformation relationship of wave spring is obtained by ANSYS10.0 software according to its structural characteristics and actual boundary condition and compared with the calculated results based on different methods and the measured value, and then study the effect of the wave number on the load-deformation relationship of wave spring. The results show that the calculated value of finite element analysis (FEM) is closer to the measured value and the FEM has more advantages on simulation of the working performance of wave spring.

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