scholarly journals Dynamics Analysis on Piezoelectric Laminated Vibrator and Optimization of PZT Position

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Caiqi Hu ◽  
Xiaoqi Hu ◽  
Jing Ji ◽  
Jude Liu ◽  
Shengduo Li
Keyword(s):  
Electromechanical Coupling ◽  
Vibration Mode ◽  
Coupling Effect ◽  
Ritz Method ◽  
Admissible Function ◽  
Coefficient Matrix ◽  
Functional Variation ◽  
Linear Superposition ◽  
Piezoelectric Vibrator ◽  
Admissible Functions

Piezoelectric laminated structure is widely used as actuator’s drive part. The different position of PZT on a piezoelectric vibrator causes different incentive effects. Therefore, seeking an optimal PZT position is of great significance to improve actuator’s drive forces and electromechanical conversion efficiency. In this research, the optimization of PZT position was studied using the approximate solution of piezoelectric vibrator mode shape with mutation sections. The vibration mode function was expressed as a linear superposition of the admissible function according to Rayleigh Ritz method. Then solving of functional variation was converted into the solving of the coefficient matrix of the admissible function by Hamilton’s principle. Through analyzing the forms of admissible functions, the admissible functions that satisfied the boundary conditions of displacement were chosen. For a given vibrator, approximate function for natural frequency and vibration mode was calculated in given admissible functions. Calculated values and experimental results were compared. Results showed that the more items an admissible function sequence had the closer the calculated results were to the experimental values. The errors of calculations were analyzed based on the selection of admissible functions and electromechanical coupling effect. Optimization of PZT position was achieved by analyzing the mode forces of the piezoelectric laminated vibrator.

Distributed Modal Signals of Conical Shells Based on Flexoelectric Effect

2012 ◽  
Author(s):  
H. Li ◽  
S. D. Hu ◽  
H. S. Tzou
Keyword(s):  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Ritz Method ◽  
Strain Component ◽  
Conical Shells ◽  
Total Signal ◽  
Flexoelectric Effect ◽  
Bending Strain ◽  
Spatially Distributed ◽  
Strain Components

Flexoelectricity is known as the electromechanical coupling effect between the strain gradient and the polarization. It is the only contribution of polarization from inhomogeneous mechanical deformation in nonpiezoelectric materials. Conical shells are commonly used as injectors, sprays and rocket nozzles, etc, which are generally clamped at the minor end and free at the major end when mounted. In this study, a flexoelectric layer is laminated on conical shells with clamped-free boundary conditions (BCs) to monitor the natural modal signal distributions. The direct flexoelectric effect defined in a tri-orthogonal coordinate system is presented first, followed by the sensing mechanism of a generic flexoelectric sensor patch. The mode shape functions of conical shells obtained by using the Rayleigh-Ritz method are briefly reviewed. The spatially distributed microscopic sensing signal with respect to position coordinates is evaluated in detail to reveal the modal signal distributions. Due to the gradient effect, the bending strain component is the only contribution to the total sensing signal. The total signal consists of two components resulting from the two bending strain components: circumferential bending strains and longitudinal bending strains. Analytical results show that, the flexoelectric sensing signal induced by the circumferential bending strain is the dominant contribution to the total signal for lower order modes. The optimal location of flexoelectric sensors is discussed for selected vibration modes.

An hourglass-type electromagnetic isolator with negative resistance electromagnetic shunt circuit

2020 ◽  
Vol 64 (1-4) ◽  
pp. 549-556
Author(s):  
Yajun Luo ◽  
Linwei Ji ◽  
Yahong Zhang ◽  
Minglong Xu ◽  
Xinong Zhang
Keyword(s):  
Vibration Isolation ◽  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Negative Resistance ◽  
Isolation System ◽  
Amplitude Vibration ◽  
Vibration Responses ◽  
The Stability ◽  
Isolation Performance ◽  
Shunt Circuit

The present work proposed an hourglass-type electromagnetic isolator with negative resistance (NR) shunt circuit to achieve the effective suppression of the micro-amplitude vibration response in various advanced instruments and equipment. By innovatively design of combining the displacement amplifier and the NR electromagnetic shunt circuit, the current new type of vibration isolator not only can effectively solve the problem of micro-amplitude vibration control, but also has significant electromechanical coupling effect, to obtain excellent vibration isolation performance. The design of the isolator and motion relationship is presented firstly. The electromechanical coupling dynamic model of the isolator is also given. Moreover, the optimal design of the NR electromagnetic shunt circuit and the stability analysis of the vibration isolation system are carried out. Finally, the simulation results about the transfer function and vibration responses demonstrated that the isolator has a significant isolation performance.

Free vibration analysis of three-layer thin cylindrical shell with variable thickness two-dimensional FGM middle layer under arbitrary boundary conditions

2021 ◽  
pp. 109963622110204
Author(s):  
Xue-Yang Miao ◽  
Chao-Feng Li ◽  
Yu-Lin Jiang ◽  
Zi-Xuan Zhang
Keyword(s):  
Cylindrical Shell ◽  
Boundary Conditions ◽  
Volume Fraction ◽  
Ritz Method ◽  
Admissible Function ◽  
Free Vibration Analysis ◽  
Middle Layer ◽  
Two Dimensional ◽  
Arbitrary Boundary ◽  
Arbitrary Boundary Conditions

In this paper, a unified method is developed to analyze free vibrations of the three-layer functionally graded cylindrical shell with non-uniform thickness. The middle layer is composed of two-dimensional functionally gradient materials (2D-FGMs), whose thickness is set as a function of smooth continuity. Four sets of artificial springs are assigned at the ends of the shells to satisfy the arbitrary boundary conditions. The Sanders’ shell theory is used to obtain the strain and curvature-displacement relations. Furthermore, the Chebyshev polynomials are selected as the admissible function to improve computational efficiency, and the equation of motion is derived by the Rayleigh–Ritz method. The effects of spring stiffness, volume fraction indexes, configuration on of shell, and the change in thickness of the middle layer on the modal characteristics of the new structural shell are also analyzed.

scholarly journals Independent coordinate coupling method for vibration analysis of a functionally graded carbon nanotube–reinforced plate with central hole

2019 ◽  
Vol 11 (8) ◽  
pp. 168781401987292 ◽  
Author(s):  
Yan Guo ◽  
Yanan Jiang ◽  
Bin Huang
Keyword(s):  
Carbon Nanotube ◽  
Volume Fraction ◽  
Ritz Method ◽  
Matching Condition ◽  
Functionally Graded ◽  
Central Hole ◽  
Lagrange’S Equation ◽  
Reinforced Plate ◽  
Distribution Type ◽  
Admissible Functions

In this article, the free vibration of a functionally graded carbon nanotube–reinforced plate with central hole is investigated by means of the independent coordinates-based Rayleigh–Ritz method. For the proposed method, the kinematic and potential energies are substituted into Lagrange’s equation in order to obtain the equation of motion. However, the total energies are computed by the difference of energies between the hole domain and the plate domain. By applying the displacement matching condition at the hole domain, two coordinate systems are coupled. For the Rayleigh–Ritz method, the mode shape functions of uniform beams are assumed as admissible functions. By this method, convergent results can be obtained with certain number of terms of admissible functions. The present results clearly reflect the effects of the carbon nanotube distribution type, carbon nanotube volume fraction, hole size, and boundary condition on the nondimensional natural frequencies. The provided results show that the present method is efficient in studying the vibration problems of functionally graded carbon nanotube–reinforced plate with central hole.

Electromechanical Coupling and Signal Distribution of a Circular Cylindrical Shell Coupled With Segmented Sensors

2008 ◽  
Author(s):  
Shih-Lin Huang ◽  
Chin-Chou Chu ◽  
Chien C. Chang ◽  
H. S. Tzou
Keyword(s):  
Cylindrical Shell ◽  
Large Scale ◽  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Circular Cylindrical Shell ◽  
Open Circuit ◽  
Signal Generation ◽  
Signal Distribution ◽  
Shear Design ◽  
Spatially Distributed

The direct piezoelectric effect has long been recognized as an effective electromechanical coupling effect applied to designs of various transducers. Conventional sensor design usually follows three design principles: 1) the tension/compression design, 2) the bending or flexible design and 3) the shear design. These are mostly point-type transducers monitoring responses of discrete locations and, thus, they are not suitable to dynamic spatial monitoring of large-scale distributed structures, such as shells and plates. Accordingly, distributed designs and configurations, such as the segmentation and shaping techniques, have been proposed and evaluated in the last two decades. This study is to evaluate electromechanical coupling and signal generations of a coupled piezoelectric/elastic circular shell structure. A generic open-circuit signal equation of electromechanical coupling and signal generation is presented first, followed by a simplification to signal generation of a circular cylindrical shell case. The total signal generation and its contributing components are analyzed in the modal domain. Spatially distributed modal signals of various shell modes are calculated and the spatial signal distribution illustrates distinct modal characteristics resulting from microscopic modal strain behaviors. Thus, the optimal sensor location(s) for specific shell modes can be identified from the modal signal distribution plots.

The Effect of Drain/Gate Bias on Electromechanical Coupling Effect in Accelerometer Based on MESFET

2011 ◽  
Vol 11 (2) ◽  
pp. 384-388 ◽  
Author(s):  
Chenyang Xue ◽  
Zhenxin Tan ◽  
Weili Shi ◽  
Jun Liu ◽  
Binzhen Zhang ◽  
...  
Keyword(s):  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Gate Bias

Experimental and theoretical analysis in impedance-based structural health monitoring with varying temperature

2010 ◽  
Vol 10 (6) ◽  
pp. 573-585 ◽  
Author(s):  
Naserodin Sepehry ◽  
Mahnaz Shamshirsaz ◽  
Ali Bastani
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Electrical Impedance ◽  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Physical And Mechanical Properties ◽  
Measurement Tool ◽  
Temperature Dependent ◽  
Structural Health ◽  
Aluminum Alloy 2024

In the recent years, the piezoelectric wafer active sensors (PWASs) are increasing as a measurement tool in structural health monitoring techniques. In impedance-based structural health monitoring (ISHM) method, the electrical impedance of a PWAS bonded to the structure is measured and served as a defect detection index of the structure. The principle of this method is based on the electromechanical coupling effect of PWAS materials. As any change in the structure will lead to a change in mechanical impedance of structure, the electrical impedance of PWAS could sense this change by the electromechanical coupling effect of PWAS. Since the physical and mechanical properties of PWAS materials are temperature-dependent, so the electrical impedance of PWAS will change with varying temperature. Consequently, the changes in environmental or service temperatures could be detected in ISHM method as a defect. In this article, in order to consider the temperature dependency of PWAS material properties, a temperature-dependent model is developed for a PWAS bonded to an Euler Bernoulli cantilever beam. An aluminum (alloy 2024) beam was examined experimentally by ISHM method in order to validate the proposed model. The comparison of theoretical and experimental results demonstrates a good improvement in ISHM modeling where temperature variation is present.

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