Search

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study proposed a vibration analysis employing the substructure elimination and binding method to evaluate the bending vibration of beams. Modal analysis is commonly used for vibration analysis. In modal analysis, it is imperative to obtain highly precise results with fewer degrees of freedom. Thus, to reduce the required degrees of freedom, we proposed the substructure change and elimination methods. Because these methods obtain the desired structure by changing or eliminating certain regions of the original structure, these methods necessitate only a superposition of the eigenmodes of the original structure. Despite no major problems in the substructure elimination method, the precision of the substructure change method decreased owing to the non-smoothness of the shear force etc. at the interface. In addition, a recent study revealed the possibility of analyzing the coupled vibration of a beam using the substructure elimination method with fewer degrees of freedom. In this method, both ends of a beam are eliminated and the coupling with the other structures at the new boundaries were formulated. Owing to the eigenfunctions exhibiting phase variations at the new boundaries, arbitrary amplitudes and phases can be expressed with fewer degrees of freedom at the new boundaries. However, beams are often coupled to other structures other than that at their ends. Despite the long-standing establishment of the analysis method for this case, the precision of this conventional method decreases because of the discontinuity or non-smoothness of the shear force etc., similar to the substructure change method. Thus, this study proposed a method to set a virtual elimination region at the interface and bind the two ends of the virtual elimination region. The virtual elimination region smoothly connected the discontinuities and non-smooth points. Further, we proposed an analytical model for this method, and an equation of motion for a minute fraction was formulated. In addition, modal analysis was applied to the derived equation of motion. Furthermore, simulations revealed that the length of the virtual elimination region must be set to three to four times the wavelength of the highest eigenmode of the original beam. Moreover, to investigate the advantage of precision, the simulation results obtained using the proposed method were compared with those obtained without installing the virtual elimination regions based on the exact solutions.

Copyright of Journal of the Japan Society for Abrasive Technology is the property of Japan Society for Abrasive Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aiming at the complex mechanical characteristics of the curvic coupling in the aero-engine rotor under operation condition, the contact stiffness model of the curvic coupling under the bending vibration is proposed to study the law of stiffness loss of the curvic coupling and the dynamic characteristics of the rotor with the curvic coupling under the bending vibration. Based on the Hertz contact theory and the elastic-plastic contact theory, an analytical model for the contact stiffness of the three-dimensional curvic coupling is established considering the complex geometric characteristics of the curvic coupling. And the law of stiffness loss of the curvic coupling under the bending vibration is studied. Then, a finite element model of the rotor system is proposed and the dynamic characteristics of the rotor system is analyzed. The results are tested and verified. The results show that the stiffness loss of the curvic coupling under the bending vibration is increased and the critical speed of the rotor is decreased caused by the increased stiffness loss. The contact stiffness model and research conclusions proposed in this paper provide an important theoretical basis for the design and dynamic characteristics analysis of modern aero-engine rotor systems.

In this study, aluminum alloy specimens were subjected to bending vibrations at different vibration frequencies near the first resonance frequency in order to investigate the vibration changes associated with crack propagation. Bending displacement, crack length, and strains at several parts of the specimen were measured during the bending vibration tests. As a result, it was confirmed that when the vibration frequency was lower than the initial first resonance frequency, the vibration amplitude increased with the crack length, and when the vibration frequency was higher than the initial first resonance frequency, the vibration amplitude decreased with an increase in the crack length. This is due to the decrease in the first resonance frequency due to the material damage. The relationship between the change of bending displacement amplitude and the crack length during vibration of the specimens can be organized using the slope (dΔεx2/dfv) of the relationship between the strain range and the vibration frequency for the undamaged specimen. This might be due to the strong correlation between the decrease in the first resonance frequency and the crack size when the crack initiation location is limited in the material. Moreover, based on the relationship between the change of bending displacement amplitude and the crack length, the stress intensity factor range (ΔK) was estimated by incorporating the load change into the crack length. By using the modified ΔK, the crack growth rate during bending vibration could be predicted.

This article presents the mathematical modelling and nonlinear dynamics of beam with three-dimensional tip mass undergoing large deformation in lateral and transverse directions. The beam is modelled as Euler–Bernoulli having large radius of curvature considering longitudinal, lateral, transverse as well as torsional deformations. The governing equations of motion and linearly coupled boundary conditions assimilating the moments and shear forces dues to three-dimensional tip mass are derived using Hamilton's principle. The transcendental eigen-frequency equation and subsequently, the eigen-functions are obtained by free vibration analysis for beam with and without torsional deformation. In addition, the investigation of nonlinear behaviors of the system under combined external excitation and inherently present internal resonance conditions between lateral and transverse motions are explored. The inextensibility condition is used to define longitudinal deformation in terms of lateral and transverse deformations leading to highly nonlinear governing equations of motion. The Galerkin's method is exploited for discretization using the obtained modal parameters and method of multiple scale is used to obtain the steady state solutions under combined resonance conditions. The spring softening behavior due to cubic nonlinearities exhibiting multi-valued solutions and multi-jump phenomenon are investigated. The system exhibits peculiar combination of pitchfork and saddle-node bifurcations in frequency response of system due to parametric variation of system attributes which have not been visible in previous studies. The obtained linear as well as nonlinear results have been compared with the existing results as well as numerical simulations. The outcomes of the present work shall enhance the ability of prediction and control of catastrophic failure of the base excited beam with three-dimensional tip mass. [ABSTRACT FROM AUTHOR]

In this study, a vibration analysis method is presented based on the substructure elimination method for a Bernoulli-Euler beam. Vibration analysis using modal analysis is effective for reducing the degrees of freedom and enables the analysis of a beam on which actuators and sensors are installed. When mechanical impedances are installed at the boundaries or the beam is coupled to other structures, a free-free beam is employed for conventional modal analysis using continuous functions. However, conventional modal analysis provides inaccurate simulation results when the coupled mechanical impedances considering the characteristic impedances of the beam are large. To address this issue, the modal analysis of a beam using the substructure elimination method was proposed in this study. Because the substructure elimination method for beams was only briefly reported on by the first author, several problems currently exist. To solve these problems, a substructure elimination method is proposed using a simply supported beam in addition to a guided-guided beam. Additionally, a new formulation method based on constraint conditions was proposed as a versatile method for setting arbitrary boundary conditions. The appropriate length, line density, and bending stiffness of the elimination regions, and the highest order of the eigenmode, were determined through simulations. The effectiveness of the proposed method was then verified by comparing the simulation results of the proposed method and exact solutions obtained using the boundary conditions. Based on a comparison with the simulation results of conventional modal analysis using a free-free beam, the precision of the proposed method is significantly higher than that of conventional modal analysis.

In order to simplify the motor structure, to reduce the difficulty of rotor pre-pressure application and to obtain better output performance, a new internal cone type rotating traveling wave ultrasonic motor is proposed. The parametric model of the internal cone type ultrasonic motor was established by the ANSYS finite element software. The ultrasonic motor consists of an internal cone type vibrator and a tapered rotor. The dynamic analysis of the motor vibrator is carried out, and two in-plane third-order bending modes with the same frequency and orthogonality are selected as the working modes. The other advantages of this motor are that pre-pressure can be imposed by the weight of the rotor. The prototype was trial-manufactured and experimentally tested for its vibration characteristics and output performance. When the excitation frequency is 22260.0 Hz, the pre-pressure is 0.1 N and the peak-to-peak excitation voltage is 300 V, the maximum output torque of the prototype is 1.06 N·mm, and the maximum no-load speed can reach 441.2 rpm. The optimal pre-pressure force under different loads is studied, and the influence of the pre-pressure force on the mechanical properties of the ultrasonic motor is analyzed. It is instructive in the practical application of this ultrasonic motor. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to present applications and design elements of scale models of the carbody of railway vehicles integrated in experimental laboratory systems to verify the effectiveness of the methods to reduce vertical bending vibration of the carbody. In the first part of the paper, some applications of such experimental systems are presented, which include different scale models of the railway vehicle carbody. In the second part of the paper, the structure and dimensioning elements of a new demonstrative experimental system, specially designed by the authors of the present paper for testing the functionality of an original method of reducing the vertical bending vibrations of the carbody of railway vehicles, are presented. This method is based on an innovative approach that involves the use of a passive system consisting of two bars rigidly mounted on the longitudinal beams of the carbody underframe, having the role of opposing the bending of the carbody. The main element of the demonstrative experimental system is the scale model of the vehicle carbody, reduced to a beam, on which the two bars, called anti-bending bars, are mounted. For the dimensioning of the experimental model of the carbody and the anti-bending bars, original methodologies are developed in which several conditions are involved. In the case of the dimensioning of the experimental model of the carbody, the conditions refer to the convenient adoption of the scaling factor of the dimensions of the real carbody from the perspective of the practical realization of the experimental model of the carbody, ensuring the buckling stability of the demonstrative experimental system, achieving natural frequency of the vertical bending of the real carbody and avoiding the interference of the bounce vibration with the vertical bending vibration of the demonstrative experimental model of the carbody. The dimensions of the anti-bending bars are established from the condition that the vertical bending frequency of the experimental model of the carbody is outside the range of sensitivity of the human body to vertical vibration. Additionally, the natural frequency of the vertical bending vibration of the anti-bending bars must be chosen to avoid interference with the vertical bending vibration of the experimental model of the carbody. The effectiveness of the anti-bending bars in reducing the vertical bending vibration of the experimental model of the carbody is investigated with the help of numerical simulation results developed based on an original theoretical model of the experimental model of the carbody with anti-bending bars. [ABSTRACT FROM AUTHOR]

Rectangular double-laminated piezoelectric elements are widely used in low frequency transducers. At present, most of these piezoelectric elements use a piezoelectric ceramic laminated structure. In this work, the bending vibration properties of double-laminated piezoelectric ceramic elements with different transverse dimensions were analyzed by the finite element method. It was found that there was a strong transverse mechanical coupling, and the transverse dimensions had a great effect on the bending vibration. To suppress the transverse mechanical coupling effect, a double-laminated piezoelectric element based on a 2-2 piezoelectric composite was designed. The simulation results show that the bending vibration performance of the double-laminated composite element is not affected by the transverse size. The 2-2 piezoelectric composite double-laminated and ceramic elements were prepared. In addition, simulation and experimental results indicate that the transverse mechanical coupling of the bending vibration of the piezoelectric composite double-laminated element is effectively suppressed, the vibration frequency is reduced by about 100 Hz, and the vibration displacement is increased by 2.2 times, in comparison with the piezoelectric ceramic double-laminated element. [ABSTRACT FROM AUTHOR]

In this work, a new type of double-harmonic piezoelectric composite laminated structure is designed. Two bending vibration frequencies are generated by designing the structure with non-equal length and non-equal width, and the response is relatively consistent at the frequency point of the double-harmonic vibration. Firstly, the finite element software ANSYS is used to establish the simulation model of double-harmonic piezoelectric composite lamination. Two bending vibration frequencies are generated by using the non-equal length structure design, and the variation law of the conductance curve with the laminated structure is analyzed. Then, according to this law, the structure is optimized, and a non-equal width structure is further proposed in this work. Different double-harmonic piezoelectric composite laminations are prepared for comparison. The simulation and experimental results show that the value of the corresponding conductance curve at the two vibration frequency points can be increased or reduced by changing the lamination width. Then, the same conductance peak can be obtained to have a relatively consistent response at the double-harmonic frequency point. This will provide a good choice for expanding the transducer bandwidth and developing the broadband energy collector. [ABSTRACT FROM AUTHOR]

A simplified analytical method for analyzing the dynamic behavior of the intermittently welded stiffened plate is newly proposed. The plate and stiffener are considered as individual beams, and the influence of the longitudinal internal shear force per unit length at the stiffener-to-plate junction of a continuously welded stiffened plate is considered. The whole span of an intermittently welded stiffened plate is divided into welded and non-welded segments. The intermittently welded stiffened plate is changed into equivalent continuously welded one, and a model for the bending vibration analysis of the intermittently welded stiffened plate is developed. The governing equation for the bending vibration analysis of the intermittently welded stiffened plate by the influence function method is formulated and a practical approach is newly developed to solve the governing equation for the bending vibration analysis of the intermittently welded stiffened plate. The numerical calculation for bending vibration analysis of the intermittently welded stiffened plate is carried out. A comparison of results from the proposed method with the finite element analysis results is carried out to demonstrate the validity of the proposed method. • A simplified method for analyzing the dynamic behavior of the intermittently welded stiffened plate and an evaluating method for its stiffness are presented. • The intermittently welded stiffened plate is changed into equivalent continuously welded one, and a model for the bending vibration analysis of the intermittently welded stiffened plate is developed. • The governing equation for the bending vibration analysis of the intermittently welded stiffened plate by the influence function method is formulated. The evaluation criterion for the stiffness of the intermittently welded stiffened plate is defined. • The bending vibration analysis of the intermittently welded stiffened plate is carried by the developed method, and a comparison of results with the finite element analysis results is made for validation. [ABSTRACT FROM AUTHOR]

In this work, a cylindrical lead-free rotary-linear ultrasonic motor was attached to piezoelectric plates of MnO2-doped (Ba0.97Ca0.03)(Ti0.96Sn0.005Hf0.035)O3 ceramics using the first bending vibration to pull a thread output shaft of the interior of a stator. The effect of the proposed ceramics' d33 and Qm values are the key factors for ultrasonic motors. Therefore, MnO2-doped (Ba0.97Ca0.03)(Ti0.96Sn0.005Hf0.035)O3 lead-free piezoelectric ceramics with high values of d33 = 230 pC/N, Qm = 340.8 and a good temperature stability of their dielectric and piezoelectric properties are suitable for application to linear piezoelectric motors. The structure of the linear piezoelectric motor was simulated and fabricated by Finite Element Analysis. The characteristics of linear piezoelectric motors were also studied. The output characteristics of the lead-free piezoelectric motor were a left-pull velocity = 3.21 mm/s, a right-pull velocity = 3.39 mm/s, an up-pull velocity = 2.56 mm/s and a force >2 N at 39.09 kHz for an input voltage of approximately 200 Vp-p (peak to peak). These results are comparable to those for a lead-based piezoelectric motor that uses PZT-4 ceramics. The proposed lead-free piezoelectric motors were successfully fabricated and used to pull a 0.5 mL commercial insulin syringe. [ABSTRACT FROM AUTHOR]

This paper presents the results of studies on the analytical dependence between the value of a longitudinal distributed load and the frequency of free vibrations in a uniform rod. Based on the exact solution of the corresponding differential equation, a method for calculating vibrations in rod structures, while considering their dead weight, is implemented. The method algorithm is shown using the example of a rod with both ends clamped. This article contains graphs and analytical formulas for displaying dependencies. A table is provided that contains all the necessary coefficients to perform similar calculations for other boundary conditions. These results allow the physical and mechanical characteristics of a system to be used to determine the natural frequency of rod structures without using approximate methods.

Abstract This study examines the effect of shear and rotatory inertia on the accuracy of the vibration method with additional mass (VAM). Bending vibration tests were performed for rectangular bars with a width of 30 mm, thicknesses ranging from 5 to 60 mm, and a length of 300 mm, small round bars with diameters in the range of 6–36 mm, and lengths of 150–300 mm, and cross beams for timber guardrails with and without a concentrated mass under a free–free condition. The estimation accuracy of the VAM and the effect of shear and rotatory inertia increased and decreased, respectively, as the length/thickness ratio of the rectangular bar and length/diameter ratio of the round bar increased. The estimation accuracy of the VAM decreased with an increase in the effect of shear and rotatory inertia, and it could be corrected. The range of the effect of shear and rotatory inertia for the sufficient estimation accuracy of the VAM was obtained.

Microcystis aeruginosa, as a typical alga, produces microcystin with strong liver toxicity, seriously endangering the liver health of human and animals. Inhibiting the bloom of the Microcystis aeruginosa in lakes becomes a significant and meaningful work. Ultrasonic cavitation is currently considered to be the most environmentally friendly and effective method for the removal of Microcystis aeruginosa. However, the commercialized ultrasonic algae removal systems require multi-Langevin transducers to achieve omnidirectional ultrasonic irradiation due to the single irradiation direction of the Langevin transducer, resulting in the complex design and high energy consumption. To achieve a low-cost, simple structure, and high-efficiency algae removal system, a novel omnidirectional ultrasonic cavitation removal system for Microcystis aeruginosa is proposed. The proposed system is major composed of a novel omnidirectional ultrasonic transducer, which generates the omnidirectional ultrasonic irradiation by its shaking-head motion coupled by two orthogonal bending vibration modes. Modal simulation, sound field simulation, and cavitation bubble radius simulation are first carried out to optimize the geometric sizes of the proposed transducer and verify the correctness of the omnidirectional ultrasonic irradiation principle. Then the vibration characteristics of the transducer prototype are measured by vibration tests and impedance tests. Finally, the feasibility and effectiveness of the proposed omnidirectional ultrasonic removal system for Microcystis aeruginosa are evaluated through the algae removal experiments. The experimental results exhibit that the algal cells damaged by ultrasonic irradiation from the proposed system do not have the ability to self-repair. In addition, the algal removal rates reached 55.41% and 72.97% after 30 min of ultrasonic treatment when the corresponding ultrasonic densities are 0.014 W/mL and 0.021 W/mL, respectively. The proposed omnidirectional ultrasonic algae removal system significantly simplifies the configuration and reduces energy consumption, presenting the potential promise of algae removal and environmental protection.

The purpose of this paper is to present applications and design elements of scale models of the carbody of railway vehicles integrated in experimental laboratory systems to verify the effectiveness of the methods to reduce vertical bending vibration of the carbody. In the first part of the paper, some applications of such experimental systems are presented, which include different scale models of the railway vehicle carbody. In the second part of the paper, the structure and dimensioning elements of a new demonstrative experimental system, specially designed by the authors of the present paper for testing the functionality of an original method of reducing the vertical bending vibrations of the carbody of railway vehicles, are presented. This method is based on an innovative approach that involves the use of a passive system consisting of two bars rigidly mounted on the longitudinal beams of the carbody underframe, having the role of opposing the bending of the carbody. The main element of the demonstrative experimental system is the scale model of the vehicle carbody, reduced to a beam, on which the two bars, called anti-bending bars, are mounted. For the dimensioning of the experimental model of the carbody and the anti-bending bars, original methodologies are developed in which several conditions are involved. In the case of the dimensioning of the experimental model of the carbody, the conditions refer to the convenient adoption of the scaling factor of the dimensions of the real carbody from the perspective of the practical realization of the experimental model of the carbody, ensuring the buckling stability of the demonstrative experimental system, achieving natural frequency of the vertical bending of the real carbody and avoiding the interference of the bounce vibration with the vertical bending vibration of the demonstrative experimental model of the carbody. The dimensions of the anti-bending bars are established from the condition that the vertical bending frequency of the experimental model of the carbody is outside the range of sensitivity of the human body to vertical vibration. Additionally, the natural frequency of the vertical bending vibration of the anti-bending bars must be chosen to avoid interference with the vertical bending vibration of the experimental model of the carbody. The effectiveness of the anti-bending bars in reducing the vertical bending vibration of the experimental model of the carbody is investigated with the help of numerical simulation results developed based on an original theoretical model of the experimental model of the carbody with anti-bending bars.

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the bending vibration characteristics of the piezoelectric composite double laminated vibrator are studied by simulation and experiment. Firstly, the bending vibration characteristics of a 2-2 piezoelectric composite double laminated vibrator under free and fixed boundary conditions are simulated by the finite element analysis software. Results show that the vibrator has a pure bending vibration mode in the frequency band of 2–4.6 kHz. Then, two types of a 2-2 piezoelectric composite double laminated vibrator are prepared by using epoxy resin and silicone rubber. The test results show that the resonance frequencies of the free and fixed boundaries are ~4.5 and 2.5 kHz, respectively. The vibrator has relatively pure bending vibration characteristics, especially the silicone rubber vibrator, which has lower resonance frequency, higher electromechanical coupling coefficient and larger bending vibration displacement; thus, the 2-2 piezoelectric composite double laminated vibrator is a better choice for the fabrication of a low-frequency transducer. [ABSTRACT FROM AUTHOR]

This paper presents a short review of numerical methods used for lateral vibration analysis in the case of straight Euler and Timoshenko beams. A particular integral method is described with more details. This approximate integral method is based on the use of flexibility influence functions (Green’s functions). It leads to a matrix formulation and to an eigenvalue problem for vibration analysis. The presented approach is able to estimate separately the shear effects and the rotary inertia effects and also the combined effects. Simple numerical examples are also presented for comparisons with analytical and finite elements results. The results show good agreement.

Rectangular double-laminated piezoelectric elements are widely used in low frequency transducers. At present, most of these piezoelectric elements use a piezoelectric ceramic laminated structure. In this work, the bending vibration properties of double-laminated piezoelectric ceramic elements with different transverse dimensions were analyzed by the finite element method. It was found that there was a strong transverse mechanical coupling, and the transverse dimensions had a great effect on the bending vibration. To suppress the transverse mechanical coupling effect, a double-laminated piezoelectric element based on a 2-2 piezoelectric composite was designed. The simulation results show that the bending vibration performance of the double-laminated composite element is not affected by the transverse size. The 2-2 piezoelectric composite double-laminated and ceramic elements were prepared. In addition, simulation and experimental results indicate that the transverse mechanical coupling of the bending vibration of the piezoelectric composite double-laminated element is effectively suppressed, the vibration frequency is reduced by about 100 Hz, and the vibration displacement is increased by 2.2 times, in comparison with the piezoelectric ceramic double-laminated element.

The topic of reducing structural vibrations in the case of flexible carbodies of railway vehicles has been intensively studied, but it is still an active research topic thanks to the importance of the perspective of improving the ride comfort. However, no study has been identified in the specialty literature to feature the contribution of the vibration structural modes upon the vibration behaviour of the railway vehicle carbody. The structural vibration modes of the flexible carbodies are particularly complex; however, the first vertical bending mode holds great significance in terms of the ride comfort. This paper analyses the influence of the first vertical bending mode on the vibration behaviour in three reference points of the railway vehicle carbody in correlation with the carbody flexibility, the vehicle velocity and the suspension damping. This study relies on comparisons between the results of the numerical simulations obtained for a 'flexible carbody' type model of the vehicle and the ones obtained for a 'rigid carbody' type model. The first part of this study analyses the characteristics of the vertical vibrations behaviour of the flexible carbody based on the dynamic response of the vehicle and expressed as the acceleration power spectral density. In the second part, the influence of the vertical bending on the vertical vibrations level of the carbody is analysed using the root mean square of the vertical acceleration. [ABSTRACT FROM AUTHOR]

This paper presents the results of studies on the analytical dependence between the value of a longitudinal distributed load and the frequency of free vibrations in a uniform rod. Based on the exact solution of the corresponding differential equation, a method for calculating vibrations in rod structures, while considering their dead weight, is implemented. The method algorithm is shown using the example of a rod with both ends clamped. This article contains graphs and analytical formulas for displaying dependencies. A table is provided that contains all the necessary coefficients to perform similar calculations for other boundary conditions. These results allow the physical and mechanical characteristics of a system to be used to determine the natural frequency of rod structures without using approximate methods. [ABSTRACT FROM AUTHOR]

In this work, a cylindrical lead-free rotary-linear ultrasonic motor was attached to piezoelectric plates of MnO2-doped (Ba0.97Ca0.03)(Ti0.96Sn0.005Hf0.035)O3 ceramics using the first bending vibration to pull a thread output shaft of the interior of a stator. The effect of the proposed ceramics’ d33 and Qm values are the key factors for ultrasonic motors. Therefore, MnO2-doped (Ba0.97Ca0.03)(Ti0.96Sn0.005Hf0.035)O3 lead-free piezoelectric ceramics with high values of d33 = 230 pC/N, Qm = 340.8 and a good temperature stability of their dielectric and piezoelectric properties are suitable for application to linear piezoelectric motors. The structure of the linear piezoelectric motor was simulated and fabricated by Finite Element Analysis. The characteristics of linear piezoelectric motors were also studied. The output characteristics of the lead-free piezoelectric motor were a left-pull velocity = 3.21 mm/s, a right-pull velocity = 3.39 mm/s, an up-pull velocity = 2.56 mm/s and a force >2 N at 39.09 kHz for an input voltage of approximately 200 Vp-p (peak to peak). These results are comparable to those for a lead-based piezoelectric motor that uses PZT-4 ceramics. The proposed lead-free piezoelectric motors were successfully fabricated and used to pull a 0.5 mL commercial insulin syringe.

This paper describes the theoretical modal analysis of continuous systems that are subjected to displacement excitation. Because vibration modes of continuous systems whose boundaries actively move are unknown, we proposed an equivalent replacement method of displacement excitation with an excitation force and fixed boundary. We can easily derive the vibration modes of the continuous system because the excitation boundaries are fixed by this replacement method. Using the proposed replacement method and modal analysis, we can derive a certain vibration mode independently. In other words, the number of degrees of freedom can be decreased using the proposed method even when continuous systems are subjected to displacement excitation. The equivalent replacement methods for ‘one-dimensional and multi-dimensional continuous systems whose equation of motion is a wave equation’, and ‘one-dimensional and two-dimensional continuous systems whose equation of motion is a fourth-order partial differential equation’ were proposed in this research. As a representative, an acoustic tube and a cuboidal room were used as the analytical models for the one-dimensional and multi-dimensional continuous systems whose equation of motion is a wave equation. In contrast, an Euler-Bernoulli beam and a Kirchhoff-Love plate were used as the analytical models for the one-dimensional and two-dimensional continuous systems whose equation of motion is a fourth-order partial differential equation. The correctness of the proposed methods was mathematically proved. In addition, the effectiveness of the proposed method was verified through numerical simulations.

To study the impact of suspended equipment on the ride comfort in a railway vehicle, a rigid flexible general model of such a vehicle is required. The numerical simulations is based on two different models, derived from the general model of the vehicle, namely a reference model of a vehicle with no equipment, and another model with six suspended elements of equipment mounted in various positions along the carbody. The objective of this paper arises from the observation that the literature does not contain any study that highlights the change in the ride comfort resulting exclusively due to the influence of equipment. The influence of the suspended equipment on the ride comfort is determined by comparing the ride comfort indices calculated in the carbody reference points, at the centre and above the two bogies, for a model with six elements of equipment and a model of the vehicle with no equipment.

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effects of Al3+-Fe3+ substitution on 10 synthesized garnet samples along the grossular-andradite binary were investigated using Raman spectroscopy. Twenty and nineteen peaks were observed in non-polarized Raman spectra for grossular and andradite end-members, respectively. The frequencies of most peaks were changed almost linearly with the composition. Two-mode behavior was not observed in this study. Differing from previous reports on other garnet solid solutions, the medium frequency modes, which are assigned to internal bending vibrations, have the largest average rate of change with the composition, which may be related to structural connectivity and coupled vibrations. Due to the reduction of symmetry, extra peaks appear in the Raman spectra of garnets with intermediate compositions. Peak broadening in intermediate compositions was also observed, which is related to disordering and distortion. One-parameter Margules equation was used to describe the full width at half maximum of peaks, and a relationship with enthalpy of mixing was proposed. [ABSTRACT FROM AUTHOR]

This study examines the effect of shear and rotatory inertia on the accuracy of the vibration method with additional mass (VAM). Bending vibration tests were performed for rectangular bars with a width of 30 mm, thicknesses ranging from 5 to 60 mm, and a length of 300 mm, small round bars with diameters in the range of 6–36 mm, and lengths of 150–300 mm, and cross beams for timber guardrails with and without a concentrated mass under a free–free condition. The estimation accuracy of the VAM and the effect of shear and rotatory inertia increased and decreased, respectively, as the length/thickness ratio of the rectangular bar and length/diameter ratio of the round bar increased. The estimation accuracy of the VAM decreased with an increase in the effect of shear and rotatory inertia, and it could be corrected. The range of the effect of shear and rotatory inertia for the sufficient estimation accuracy of the VAM was obtained. [ABSTRACT FROM AUTHOR]

• We reconstruct the mass distribution in nanobeams from bending eigenfrequency data. • The modified strain gradient theory has been used to describe the nanobeam. • The unknown mass distribution is determined by an iterative procedure. • A finite number of lower resonant frequencies belonging to one or two spectra is used. One-dimensional vibrating nanostructures show remarkable performance in detecting small adherent masses added to a referential configuration. The mass sensing principle is based on measuring the resonant frequency shifts caused by the unknown attached masses. In spite of its important application in several fields, few studies have been devoted to this inverse eigenvalue problem. In this paper we have developed a distributed mass reconstruction method for initially uniform nanobeams based on measurements of the first lower resonant frequencies of the free bending vibration. Two main inverse problems are addressed. In the first problem, the mass variation is determined by using the first lower eigenfrequencies of a supported nanobeam, under the a priori assumption that the mass variation has support contained in half of the axis interval. In the second problem, we show that the a priori assumption can be removed, provided that the spectral input data include an additional set of first lower eigenfrequencies belonging to a second spectrum associated to different end conditions. The nanobeam is modelled using the modified strain gradient elasticity accounting for size effects. The reconstruction is based on an iterative procedure which takes advantage of a closed-form solution when the mass change is small, and shows to be convergent under this assumption and for smooth mass variation. The accuracy of the reconstruction deteriorates in presence of discontinuous mass variation. For these cases, a constrained least-squares optimization filtering shows to be very effective to reduce the spurious oscillations around the target coefficient. Numerical simulations show that the identification method performs well even for not necessarily small mass changes and it is stable in presence of errors on the data. An experimental validation of the method has provided encouraging results, despite the fact that only the first four eigenfrequencies under cantilever end conditions were used. [ABSTRACT FROM AUTHOR]

• The precise parameters transfer matrix method exhibits excellent accuracy and applicability. • The effect of moment of inertia on the band calculation accuracy is smaller than that of shear deformation. • Both Young's modulus difference and density difference jointly affect the bandgap characteristics. • The appropriate axial wall pressure is beneficial for the low-frequency broadband design. The phononic crystal theory provides a novel approach for effectively controlling the bending vibrations in fluid-filled pipelines. This paper innovatively proposes the precise parameters transfer matrix method to investigate the band calculation accuracy and bandgap characteristics of fluid-filled periodic pipelines with various beam types. Firstly, the differential equations for bending vibration of fluid-filled pipelines are established based on deformation and force analysis. The parameters of the system state are precisely represented by the structural form of multiplying the constitutive matrix with the derivative matrix. Combined with Bloch's theorem, the novel precise parameters transfer matrix method for calculating the band structure is proposed. Secondly, the validity of this method is verified through a comparison with finite element simulation results. A detailed analysis is provided regarding the mechanism of bandgap formation and the effect of fluid filling on the band structure. Then, the influence of shear deformation, moment of inertia, and their coupling on the band calculation accuracy for fluid-filled periodic pipelines is studied based on various beam theories. Finally, it delves into the bandgap characteristics of fluid-filled periodic pipelines under different material parameters, structural parameters, and excitation conditions. This research offers valuable insights for the structural design and vibration damping application in fluid-filled periodic pipelines, providing theoretical support for accurately determining their bandgaps. [Display omitted] [ABSTRACT FROM AUTHOR]

The topic of reducing structural vibrations in the case of flexible carbodies of railway vehicles has been intensively studied, but it is still an active research topic thanks to the importance of the perspective of improving the ride comfort. However, no study has been identified in the specialty literature to feature the contribution of the vibration structural modes upon the vibration behaviour of the railway vehicle carbody. The structural vibration modes of the flexible carbodies are particularly complex; however, the first vertical bending mode holds great significance in terms of the ride comfort. This paper analyses the influence of the first vertical bending mode on the vibration behaviour in three reference points of the railway vehicle carbody in correlation with the carbody flexibility, the vehicle velocity and the suspension damping. This study relies on comparisons between the results of the numerical simulations obtained for a ‘flexible carbody’ type model of the vehicle and the ones obtained for a ‘rigid carbody’ type model. The first part of this study analyses the characteristics of the vertical vibrations behaviour of the flexible carbody based on the dynamic response of the vehicle and expressed as the acceleration power spectral density. In the second part, the influence of the vertical bending on the vertical vibrations level of the carbody is analysed using the root mean square of the vertical acceleration.

Thick wall structures are usually applied at a highly reduced frequency. It is crucial to study the refined dynamic modeling of a thick plate, as it is directly related to the dynamic mechanical characteristics of an engineering structure or device, elastic wave scattering and dynamic stress concentration, and motion stability and dynamic control of a distributed parameter system. In this paper, based on the partial differential operator theory, an exact elasto-dynamics theory without assumptions for bending vibrations is presented by using the formal solution proposed by Boussinesq–Galerkin, and its dynamic equations are obtained under appropriate gauge conditions. The exact plate theory is then compared with other theories of plates. Since the derivation of the dynamic equation is conducted without any prior assumption, the proposed dynamic equation of plates is more exact and can be applied to a wider frequency range and greater thickness.

An ultrasonic motor as a kind of smart material drive actuator has potential in robots, aerocraft, medical operations, etc. The size of the ultrasonic motor and complex circuit limits the further application of ultrasonic motors. In this paper, a single-phase driven ultrasonic motor using Bending-Bending vibrations is proposed, which has advantages in structure miniaturization and circuit simplification. Hybrid bending vibration modes were used, which were excited by only single-phase voltage. The working principle based on an oblique line trajectory is illustrated. The working bending vibration modes and resonance frequencies of the bending vibration modes were calculated by the finite element method to verify the feasibility of the proposed ultrasonic motor. Additionally, the output performance was evaluated by experiment. This paper provides a single-phase driven ultrasonic motor using Bending-Bending vibrations, which has advantages in structure miniaturization and circuit simplification.

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Screening of fine wet particles or near-aperture particles by traditional screen devices is often not quite effective for sieve plugging. Different from traditional rigid regular mesh sieves, a cantilevered vibrating sieve (CVS) with open screen holes, composed of cantilevered sieve rods, was proposed in this paper. The CVS proved to have a higher screen-penetrating probability relative to traditional sieves. By establishing a bending vibration model for the CVS, it can be found that additional vibrations may emerge during the screen body motion, and a smaller difference between the natural circular frequency and the vibration frequency will achieve a larger vibration of cantilevered sieve rod. On this basis, this investigation also analyzed anti-plugging mechanism of the CVS and systematically discussed the influence laws of the geometric parameters and vibration parameters of the sieve on screening efficiency by the discrete element method. [ABSTRACT FROM AUTHOR]

Featured Application: The 2-2 piezoelectric composite bilaminated vibrator with lower resonance frequency and larger vibration displacement used for making low frequency acoustic transducer. A piezoelectric composite vibrator with a bilaminated structure is designed and fabricated, in this work by applying bending vibration to increase vibration displacement and reduce resonance frequency. The finite element software ANSYS (ANSYS, Inc. USA) is used to simulate the 2-2 and 1-3 piezoelectric composite bilaminated vibrators under free boundary condition and optimize their design. Simulation results show that the vibration displacement of the 2-2 vibrator is higher than that of the 1-3 vibrator, and the resonance frequency of the former is lower than the latter. Five pieces each of the 2-2 and piezoelectric ceramic vibrators are prepared. In addition, simulation and experimental results indicate that the vibration displacement of the 2-2 vibrator increases by 2.3 times, whereas its resonance frequency decreases by nearly 100 Hz, in comparison with those of the piezoelectric ceramic bilaminated vibrator. [ABSTRACT FROM AUTHOR]

This paper presents a short review of numerical methods used for lateral vibration analysis in the case of straight Euler and Timoshenko beams. A particular integral method is described with more details. This approximate integral method is based on the use of flexibility influence functions (Green's functions). It leads to a matrix formulation and to an eigenvalue problem for vibration analysis. The presented approach is able to estimate separately the shear effects and the rotary inertia effects and also the combined effects. Simple numerical examples are also presented for comparisons with analytical and finite elements results. The results show good agreement. [ABSTRACT FROM AUTHOR]

A two-degrees-of-freedom (two-DOF) ultrasonic motor, which could output linear motions with two-DOF by using only one longitudinal–bending hybrid sandwich transducer, is proposed and tested in this paper. The motion in the horizontal (X) direction is achieved by the hybrid of the second longitudinal and fifth bending vibrations of the motor, while the motion in the vertical (Y) direction is gained by the composition of two orthogonal fifth bending vibrations. The proposed ultrasonic motor is designed and the principles for the two-DOF driving were analyzed. Then, the simulation analyses of the motor are accomplished to verify the described principles. Finally, a prototype is fabricated and its mechanical output characteristics are tested. The results indicate that the maximum no-load velocities of the motor in horizontal and vertical directions are 572 and 543 mm/s under the preload of 100 N and the voltage of 300 Vp-p, respectively. The maximum output forces in horizontal and vertical directions are 24 and 22 N when the preload is 200 N. The simulation and experiment results verify the feasibility of the proposed two-DOF ultrasonic motor. [ABSTRACT FROM AUTHOR]

Machining of hard and brittle materials is usually troublesome due to their high stiffness. In order to improve the processing speed of hard and brittle materials, ultrasonic assisted processing was developed. This paper reports a novel ultrasonic drill method, where longitudinal-bending hybrid ultrasonic vibration is used instead of single longitudinal or bending vibration. The cutting tool in this process is a core drill attached to an ultrasonic transducer, which generates longitudinal and bending vibrations. Thus an elliptical movement with ultrasonic frequency that is vertical to the working surface is formed at the cutting edge. The longitudinal vibration can help the cutting edge impact the workpiece and thus crush it. With the rotation of the cutting tool, the cutting edge scratches a groove on the working surface. While the bending vibration speeds up the movement of the cutting edge toward the workpiece in the working surface so as to amplify the fracture region. Moreover, a radial clearance assisting chip removal is made by the bending vibration. Merits of this machining method, including improved processing speed and avoidance of jamming are verified by experiment.

This paper proposed a new crossbeam ultrasonic motor, which was made of a cross-shaped metal frame and eight pieces of lead zirconate titanate ceramic plates with a size of 10 mm × 3 mm × 1 mm. Two cross-cone-shaped horns were machined at two ends of the crossbeam, and the tips of the horns served as the driving feet. Ellipse trajectories of the two driving feet were generated by superimposing two orthogonal first bending vibrations with the same resonance frequency but a temporal shift of 90°. A Symmetric structure of the proposed ultrasonic motor solved the problem of mode frequencies degeneracy. A new method to excite these two bending vibrations was proposed. Finite-element method simulation was developed to obtain the vibration characteristics of the crossbeam motor. The new excitation method was compared with the traditional one, and it was found that the vibration amplitudes of the driving feet under the new excitation method were about three times that of the traditional one. At last, experiments were accomplished on a fabricated prototype. The two tested first bending resonance frequencies agreed well with each other at ~ 40.5 kHz. Mechanical output performance of the prototype was tested; the maximum speed was ~ 64 r/min, and the maximum output torque was ~ 10.4 mN · m. This paper provides a new idea for an ultrasonic motor with a miniature structure and also a new excitation method for bending vibration.

Ladder type disc acoustic radiator is widely used in high power ultrasonic field. The frequency equation of stepped thickness disk in free boundary condition are derived based on Mindlin theory from the acoustic point of application and The frequency equation was numerically solved,At the same time,the effects of geometric parameters on the frequency is analyzed. The results show that when the other parameters are constant,the frequency increases with the increase of the disk and the base ring thickness,and decreases with the diameter increases,increases with the increasing diameter. The test results of the calculated frequencies and finite element simulation and experiment is consistent with the basic. Design of bending vibration radiator the conclusion of the thick disc provides the theory reference and the frequency of debugging basis.