共查询到20条相似文献,搜索用时 31 毫秒
1.
V. L. Karlash 《International Applied Mechanics》2007,43(5):547-553
An attempt is made to systematize experimental data for a rectangular piezoceramic plate and to compare them with those on
planar vibrations of a thin piezoceramic half-disk. Experimental data on planar vibrations of a half-disk are discussed for
the first time. Neighboring vibration modes of a rectangular plate with solid electrodes demonstrate strong superposition
and coupling
__________
Translated from Prikladnaya Mekhanika, Vol. 43, No. 5, pp. 89–96, May 2007. 相似文献
2.
Piezoceramic transducers, acting as actuators and sensors, are attractive for generation and reception of Lamb waves in Structural
Health Monitoring (SHM) systems. To get insight into the source-mechanisms of Lamb waves, the vibrations of piezoceramic actuators
are analyzed for the free and bonded state of the piezoceramic by analytical and finite element (FEM) calculations. Mode shapes
and spectra of piezoceramic actuators and Lamb wave fields are experimentally recorded by scanning laser vibrometry. The analytical
solutions for bending modes are shown to be valid for large diameter-to-thickness-relations of a free piezoactuator (D/H > 10)
only. For thicker piezoceramics, a FEM-solution gives better results. Calculated frequencies for radial modes of vibration
are confirmed by 3-D-laser-vibrometry and measurements of electrical impedance. The bonded case of a piezoactuator exhibits
a broad resonance peak resulting from the strong coupling between radial and bending modes. The assumption that optimal excitation
of Lamb modes occurs for a matching of the wavelengths to the diameter of the piezoceramic holds only for thin ceramics. Otherwise
the distinct modes of out-of-plane and in-plane vibrations control the excitation of the Lamb modes more than the wavelength
matching. 相似文献
3.
V. L. Karlash 《International Applied Mechanics》2008,44(4):361-387
Scientific results from studies on the resonant electromechanical vibrations of piezoceramic thin-walled shells of revolution,
their fragments, and segmented cylinders are analyzed, systematized, and generalized. Considerable attention is focused on
experimental studies of resonant vibrations. It is shown that the modes in which deformation occurs inphase throughout the
volume are of the highest intensity in all piezoceramic shell structures
__________
Translated from Prikladnaya Mekhanika, Vol. 44, No. 4, pp. 3–34, April 2008. 相似文献
4.
V. L. Karlash 《International Applied Mechanics》2005,41(7):709-747
The scientific results on the resonant electromechanical vibrations of piezoceramic plates in the form of disks, rings, and
polygons obtained over the last 30 years are analyzed, systematized, and generalized. Emphasis is on experimental methods.
It is shown that all piezoceramic plates have vibration modes at which deformations are in-phase over the entire volume of
the body
__________
Translated from Prikladnaya Mekhanika, Vol. 41, No. 7, pp. 3–46, July 2005. 相似文献
5.
The experimental measurement of resonant frequencies for piezoelectric material is generally performed by impedance analysis.
In this paper we employ an optical interferometry method, called amplitude-fluctuation electronic speckle pattern interferometry
(AF-ESPI), to investigate the vibration characteristics of piezoceramic plates. This method demonstrates its advantages of
combining noise reduction, like the subtraction method, and high fringe sensitivity, like the time-averaged method. As compared
with the film recording and optical reconstruction procedures used for holographic interferometry, the interferometric fringes
of AF-ESPI are produced instantly by a video recording system. Based on the fact that clear fringe patterns measured by the
AF-ESPI method will be shown only at resonant frequencies, both the resonant frequencies and corresponding mode shapes are
obtained experimentally at the same time. Excellent quality for the interferometric fringe patterns of the mode shapes is
demonstrated. We find from experimental results that the out-of-plane vibration modes (type A) with lower resonant frequencies
cannot be measured by impedance analysis and only the in-plane vibration modes (type B) will be shown. However, both the out-of-plane
(bending) and in-plane (extension) vibration modes of piezoceramic plates are obtained by the AF-ESPI method. Finally, numberical
finite element calculations are also performed, and the results are compared with the experimental measurements. Excellent
agreement for the resonant frequencies and mode shapes are obtained from both results. 相似文献
6.
V. L. Karlash 《International Applied Mechanics》2007,43(7):786-793
The evolution of the planar vibrations of a rectangular piezoceramic plate as its aspect ratio is changed starting with 1
is studied. Experimental data are obtained using an integrated technique based on Meson’s circuit, Onoe’s circuit, and a piezotransformer
transducer. As the aspect ratio increases (square plate becomes rectangular), the intensity of electromagnetic vibrations
rapidly increases at the first longitudinal resonance and gradually decreases in the first radial mode. When the aspect ratio
is changed so that the length of one of the plate sides remains constant, the resonant frequencies of all vibration modes
change too
__________
Translated from Prikladnaya Mekhanika, Vol. 43, No. 7, pp. 98–106, July 2007. 相似文献
7.
A Nonlinear Vibration Absorber for Flexible Structures 总被引:6,自引:0,他引:6
An approach for implementing an active nonlinear vibration absorber for flexible structures is presented. The technique exploits the saturation phenomenon exhibited by multidegree-of-freedom systems with quadratic nonlinearities possessing two-to-one autoparametric resonances. The strategy consists of introducing second-order controllers and coupling each of them with the plant through a sensor and an actuator, where both the feedback and control signals are quadratic. Once the structure is forced near its resonances, the oscillatory response is suppressed through the saturation phenomenon. We present theoretical and experimental results of the application of the proposed vibration absorber. The structure consists of a cantilever beam, the feedback signal is generated by a strain gage, and the actuation is achieved through piezoceramic patches. The equations of motion are developed and analyzed through perturbation techniques and numerical simulation. Then, the strategy is tested by assembling the controllers in electronic components and suppressing the vibrations of the first and second modes of two beams. 相似文献
8.
《International Journal of Solids and Structures》2002,39(6):1463-1486
This work presents a two-dimensional (2D) closed-form solution for the free-vibrations analysis of simply-supported piezoelectric sandwich plates. It has the originality to consider all components of the electric field and displacement, thus satisfying exactly the electric equilibrium equation. Besides, the formulation considers full layerwise first-order shear deformation theory and through-thickness quadratic electric potential. Its independent mechanical and electric variables are decomposed using Fourier series expansions, then substituted in the derived mechanical and electric 2D equations of motion. The resulting eigenvalue system is then condensed so that only nine mechanical unknowns are retained. After its validation on single- and three-layer piezoelectric, and hybrid sandwich plates, the present approach was then used to analyze thickness modes of a square sandwich plate with piezoceramic faces and elastic cross-ply composite core. It was found that only the first three thickness modes are global, thus can be modeled by the mixed equivalent single-layer/layerwise approach, often retained in the literature; the remaining higher thickness modes being characteristic of sandwich behavior; i.e., dominated by the deformations of either the core or the faces. These results, together with presented through-thickness variations of the mechanical and electric variables clearly recommend full layerwise modeling. Several numerical results are provided for future reference for validation of 2D approximate analytical or numerical approaches; in particular, of 2D piezoelectric adaptive finite elements. 相似文献
9.
Yu. N. Podil'chuk 《International Applied Mechanics》2000,36(8):1037-1046
The explicit solution is constructed for a static thermoelastic problem for an infinite transversally isotropic piezoceramic body containing a heat-insulated parabolic crack in the isotropy plane. The crack surface is assumed free of forces. The body is under a uniform heat flow, which is perpendicular to the crack surface and is far from the crack itself. The problem is solved for two cases of electric conditions on the crack surface. In the first case, an electric potential is absent on the crack surface and, in the second case, the normal component of the electric-displacement vector is equal to zero. The intensity factors, which depend on the heat flow, crack geometry, and the thermoelectroelastic properties of the piezoceramic body, are determined for the force field and electric displacement near the crack tip 相似文献
10.
I. F. Kirichok 《International Applied Mechanics》2005,41(9):1037-1042
The flexural vibrations and dissipative heating of a circular bimorph piezoceramic plate are studied. The plate is excited
by a harmonic electric field applied to nonuniformly electroded surfaces. The viscoelastic behavior of piezoceramics is described
in terms of temperature-dependent complex moduli. The nonlinear coupled problem of thermoviscoelasticity is solved by step-by-step
integration in time, using the discrete-orthogonalization method to solve the mechanics equations and the finite-differences
method to solve the heat-conduction equations. A numerical analysis is conducted for TsTStBS-2 piezoceramics to study the
influence of the nonuniform electroding on the resonant frequency, amplitude, and modes of flexural vibrations and the amplitude-
and temperature-frequency characteristics of the plate
__________
Translated from Prikladnaya Mekhanika, Vol. 41, No. 9, pp. 94–100, September 2005. 相似文献
11.
This paper investigates the transverse and planar vibration characteristics of two-layered piezoceramic disks for traction-free boundary conditions by theoretical analysis, finite element numerical calculation, and experimental measurements. Amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI), laser Doppler vibrometer (LDV), and impedance analysis were used to perform measurements and verify the theoretical solutions for extensional, tangential, and transverse vibrations. The poling direction of piezoelectric elements determines whether they are denoted as either of series- or parallel-type. This study observed that the resonant frequencies and mode shapes of the series- and parallel-type piezoceramic disks present different dynamic characteristics in resonance. Planar and transverse vibrations are coupled in series-type piezoceramic disks and uncoupled in those of parallel-type. Good agreements of dynamic characteristics determined by theoretical analysis, experimental measurements, and numerical calculation are presented for series- and parallel-type piezoceramic disks. 相似文献
12.
The electroelastic problem for a transversely isotropic prolate ceramic spheroid is solved explicitly. The spheroid surface
is free from external forces. The case is considered where the piezoceramic body is subjected to a given potential difference
between electrodes partially covering the surface at the vertices. The normal component of electric-flux density is equal
to zero on the noneletroded portion of the surface. Plots of normal stresses in the symmetry plane of the piezoceramic body
are given
__________
Translated from Prikladnaya Mekhanika, Vol. 41, No. 7, pp. 58–67, July 2005. 相似文献
13.
The monoharmonic radial vibrations and dissipative heating of an infinite hollow piezoceramic cylinder are studied in dynamic formulation, taking into account the temperature dependence of the complex electromechanical characteristics over a wide range of temperatures, including depolarization temperatures. The influence of the heat exchange conditions, the level of electric load, and geometry on the thermoelectromechanical characteristics is studied in the case of forced vibrations at the first resonance__________Translated from Prikladnaya Mekhanika, Vol. 41, No. 3, pp. 101–107, March 2005. 相似文献
14.
The exact solution is found to the three-dimensional electroelastic problem for a transversely isotropic piezoceramic body with a spheroidal cavity. The solutions of static electroelastic problems are represented in terms of harmonic functions. The case of stretching the piezoceramic medium at a right angle to the spheroid axis of symmetry is analyzed numerically. The dependence of the stress concentration factor on the geometry of the spheroid and the electromechanical characteristics of the material is studied.Translated from Prikladnaya Mekhanika, Vol. 40, No. 11, pp. 92–105, November 2004.This revised version was published online in April 2005 with a corrected cover date. 相似文献
15.
An approach to the solution of three-dimensional static problems for a transversely isotropic (rectilinear anisotropy) body is expounded and the solutions for piezoceramic canonical bodies are systematized. The result of the study is explicit analytical solutions of three-dimensional problems. Bodies are examined whose boundary surface is the coordinate surfaces in coordinate systems that permit the separation of the variables in the three-dimensional Laplace equation. The stress concentration in bodies near necks, cavities, inclusions, and cracks is investigated. The stress intensity factors of the force field and electric induction near elliptic and parabolic cracks are determined. The contact interaction of a piezoceramic half-space with elliptic and parabolic dies is studied. The bodies are under various mechanical, thermal, and electric loads 相似文献
16.
Natural frequencies of submerged piezoceramic hollow spheres 总被引:1,自引:0,他引:1
An exact 3D analysis of free vibration of a piezoceramic hollow sphere submerged in a compressible fluid is presented in this
paper. A separation method is adopted to simplify the basic equations for spherically isotropic piezoelasticity. It is shown
that there are two independent classes of vibration. The first one is independent of the fluid medium as well as the electric
field, while the second is associated with both the fluid parameter and the piezoelectric effect. Exact frequency equations
are derived and numerical results are obtained.
The project supported by the National Natural Science Foundation of China (No. 19872060) 相似文献
17.
《International Journal of Solids and Structures》2007,44(7-8):2209-2224
A non-linear control strategy is applied to a simply supported uniform elastic beam subjected to an axial end force at the principal-parametric resonance frequency of the first skew-symmetric mode. The control input consists of the bending couples applied by two pairs of piezoceramic actuators attached onto both sides of the beam surfaces and symmetrically with respect to the midspan, driven by the same voltage, thus resulting into symmetric control forces. This control architecture has zero control authority, in a linear sense, onto skew-symmetric vibrations. The non-linear transfer of energy from symmetric motions to skew-symmetric modes, due to non-linear inertia and curvature effects, provides the key physical mechanism for channelling suitable control power from the actuators into the linearly uncontrollable mode. The reduced dynamics of the system, constructed with the method of multiple scales directly applied to the governing PDE’s and boundary conditions, suggest effective forms of the control law as a two-frequency input in sub-combination resonance with the parametrically driven mode. The performances of different control laws are investigated. The relative phase and frequency relationships are designed so as to render the control action the most effective. The control schemes generate non-linear controller forces which increase the threshold for the activation of the parametric resonance thus resulting into its annihilation. The theoretical predictions are compared with experimentally obtained results. 相似文献
18.
19.
A numerical–analytic method for the identification of the axisymmetric mechanical shock load on a disk-shaped metal–piezoceramic
bimorph transducer is proposed. A problem is formulated based on the theory of thin two-layer plates. The solution is found
using the Laplace transform. By recovering the original function analytically, the problem is reduced to a system of Volterra
equations, solved numerically using Tikhonov’s regularization algorithm. The finite-element solution of the direct problem
is used as input data (potential difference between the electrodes of the piezoceramic layer). The results are analyzed 相似文献
20.
The sound attenuation in a sonic composite is studied using a new method that combines the features of the piezoceramic theory, cnoidal method and genetic algorithms. A sonic composite consists of an array of acoustic scatterers embedded in an epoxy matrix. Acoustic scatterers are piezoceramic hollow spheres made from functionally graded materials – the Reddy and cosine graded hollow spheres. We show that stable attenuation bands may coexist with different patterns of dynamics, including chaos. In order to extend the method towards a tool for analyzing the sound attenuation in sonic composites, the behavior of a real sonic composite is simulated. The results concerning the full band-gaps have been validated by experimental data. 相似文献