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.

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.

Gear transmission error outside the normal path of contact due to corner and top contact

1999 ◽  
Vol 213 (4) ◽  
pp. 389-400 ◽  
Author(s):  
R. G. Munro ◽  
L Morrish ◽  
D Palmer
Keyword(s):  
Dynamic Test ◽  
Theoretical Models ◽  
Transmission Error ◽  
Helical Gear ◽  
Gear Transmission ◽  
The Novel ◽  
Transmission Systems ◽  
Helical Gears ◽  
Tooth Stiffness ◽  
Top Contact

This paper is devoted to a phenomenon known as corner contact, or contact outside the normal path of contact, which can occur in spur and helical gear transmission systems under certain conditions. In this case, a change in position of the driven gear with respect to its theoretical position takes place, thus inducing a transmission error referred to here as the transmission error outside the normal path of contact (TEo.p.c). The paper deals with spur gears only, but the results are directly applicable to helical gears. It systematizes previous knowledge on this subject, suggests some further developments of the theory and introduces the novel phenomenon of top contact. The theoretical results are compared with experimental measurements using a single flank tester and a back-to-back dynamic test rig for spur and helical gears, and they are in good agreement. Convenient approximate equations for calculation of TEo.p.c suggested here are important for analysis of experimental data collected in the form of Harris maps. This will make possible the calculation of tooth stiffness values needed for use in theoretical models for spur and helical gear transmission systems.

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.

scholarly journals Topological Network Properties of Fractal-Like Metallic Nanoparticle Patterns and Their Effects on Optical Resonances

2018 ◽  
Vol 8 (8) ◽  
pp. 1310
Author(s):  
Naoya Kihara ◽  
Osamu Sakai
Keyword(s):  
Unit Length ◽  
Theoretical Models ◽  
Topological Properties ◽  
Metallic Nanoparticle ◽  
Diffusion Limited Aggregation ◽  
Complex Network Theory ◽  
Geometrical Properties ◽  
Optical Resonances ◽  
Resonance Frequencies ◽  
Network Topologies

Fractal-like nanoparticle two-dimensional patterns forming in diffusion-limited aggregation show variant spatial patterns. However, they have invariant statistical properties in their network topologies, even though their formation is completely in self-assembled processes. One of the outputs from these topological properties is optical resonances at invariant frequencies, which is a required feature of a metamaterial alternative. Fractal-like metallic patterns studied here in both experiments and theoretical models exhibit similar resonance frequencies in the infrared-ray range, and they depend on the unit length of nanoparticles composing arbitrary fractal-like structures. The scheme of analysis applied here using complex network theory does not only reveal the topological properties of the nanoparticle network, but points out their optical and possibly other physical potentials arising from their geometrical properties.

scholarly journals Breach of Contact: An Intercultural Reading of China Miéville's 'The City and The City'

2014 ◽  
Vol 11 (2) ◽  
Author(s):  
Barbara Elizabeth Hanna ◽  
Peter Cowley
Keyword(s):  
Theoretical Models ◽  
The Other ◽  
Intercultural Training ◽  
The Novel ◽  
Intercultural Encounters ◽  
Training Courses ◽  
City States ◽  
City Relations ◽  
The City ◽  
Two Populations

China Miéville’s 2009 'Weird' detective novel The City and The City is a tale of two city states, culturally distinct, between which unpoliced contact is forbidden. While residents of each city can learn about the other’s history, geography, politics, see photographs and watch news footage of the other city, relations between the two are tightly monitored and any direct contact requires a series of protocols, some of which might seem reasonable, or at least familiar: entry permits, international mail, international dialing codes, intercultural training courses. What complicates these apparently banal measures is the relative positioning of the two cities, each one around, within, amongst the other. The two populations live side by side, under a regime which requires ostentatious and systematic disregard or 'unnoticing' of the other in any context but a tightly regulated set of encounters. For all that interculturality is endemic to everyday life in the 21st century, what is striking is that critical and popular uptake of this novel so frequently decries the undesirability, the immorality even, of the cultural separation between the two populations, framing it as an allegory of unjust division within a single culture, and thus by implication endorsing the erasure of intercultural difference. We propose an alternative reading which sees this novel as exploring the management of intercultural encounters, and staging the irreducibility of intercultural difference. We examine how the intercultural is established in the novel, and ask how it compares to its representations in prevalent theoretical models, specifically that of the Third Place.

scholarly journals A critical review of reduced one-dimensional beam models of piezoelectric composite beams

2019 ◽  
Vol 30 (8) ◽  
pp. 1148-1162 ◽  
Author(s):  
Luca Luschi ◽  
Giuseppe Iannaccone ◽  
Francesco Pieri
Keyword(s):  
Three Dimensional ◽  
Beam Width ◽  
Composite Beams ◽  
Piezoelectric Composite ◽  
Beam Equation ◽  
Transverse Stress ◽  
One Dimensional ◽  
Piezoelectric Energy ◽  
Wide Range ◽  
Piezoelectric Layers

Simplified one-dimensional models for composite beams with piezoelectric layers, which are intrinsically three-dimensional structures, are important for many applications, including piezoelectric energy harvesters. To reduce the dimensionality of the system, assumptions on the stress/strain state in the transverse direction are typically made. The most common are those of null transverse stress, used for narrow beams, null transverse deformation, used for wide beams, and continuous interface strain, suited for thin piezoelectric layers (we call this assumption thin film continuous). We show that the models based on these assumptions are often used uncritically for beam geometries for which large errors may result. In particular, null transverse stress fails even for narrow beams if the thickness is much smaller than the beam width. We give clear geometric criteria that, for any geometry, allow the selection of the most accurate model among the three. We also develop a single, unified beam equation encompassing the three models and compare the analytical results from this equation with finite element simulations over a wide range of beam lengths, widths, and layer thicknesses. The selection criteria and the unified beam equation form a valuable tool for fast and accurate design of composite piezoelectric beams.

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.

Non-Invasive Methods of Delamination Monitoring in Multi-Layer Structures

2012 ◽  
Vol 518 ◽  
pp. 238-245 ◽  
Author(s):  
Joanna Iwaniec ◽  
Marek Iwaniec
Keyword(s):  
Dynamic Characteristics ◽  
Health Monitoring ◽  
Critical Condition ◽  
Measurement Techniques ◽  
Adhesive Force ◽  
Structural Defects ◽  
The Novel ◽  
Non Invasive ◽  
Delamination Detection ◽  
Layer Structures

In the paper there are discussed the most interesting methods dedicated to frescos structural health monitoring. In the further part two methods and devices for fresco delamination detection developed by authors are presented. In order to enable future automation of developed measurement techniques and autonomic detection of fresco structural defects, the novel measures quantifying the probability of critical condition appearance (the lack of adhesive force) were introduced. Finally, the results of measurements of dynamic characteristics of healthy and delaminated structures are presented.

Identification of the Dynamic Characteristics of Long Annular Seals Using a Time Domain Technique

1998 ◽  
Vol 120 (3) ◽  
pp. 705-712 ◽  
Author(s):  
M. Ismail ◽  
R. D. Brown
Keyword(s):  
Dynamic Characteristics ◽  
Time Domain ◽  
Theoretical Models ◽  
Rotational Frequency ◽  
Singular Value Decomposition Method ◽  
Damping Coefficients ◽  
Theoretical Predictions ◽  
The Time Domain ◽  
Value Decomposition ◽  
Annular Seals

This paper describes experimental results from a research program aimed at a study of the static and dynamic characteristics of liquid long annular seals. A seal test rig permits the identification in the time domain of mass, stiffness, and damping coefficients using a least-squares technique based on the singular value decomposition method. The experimental method relies on the forced excitation of a flexibly supported stator by two hydraulic shakers. The forcing signal is composed from a small number of frequencies which are not related to the rotational frequency of the rigid shaft rotating inside the stator. The test data consisting of two inertia, four stiffness, and four damping coefficients is compared with theoretical predictions based on two theoretical models: (i) the model of Black et al. (1971 and 1981) and (ii) the model of Childs and Kim (1985).

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