共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
The radial nonstationary vibrations of a piezoceramic cylinder polarized across the thickness and subjected to mechanical
dynamic loading are studied. To solve the initial–boundary-value problem, mesh approximations and difference schemes are used.
The electromechanical state of the cylinder under an instantaneously applied constant force is analyzed in detail 相似文献
3.
4.
The transient operation conditions of a thin-walled piezoradiator containing a viscous compressible fluid and immersed into
an acoustic medium are considered. The problem is solved using the integral Laplace time transformation. Originals of the
general solution of the linearized Navier-Stokes equations are constructed for the interior of the domain. These originals
are used to find the unknowns from a system of integral Volterra equations. Numerical examples are presented.
S. P. Timoshenko Institute of Mechanics, National Academy of Sciences of Ukraine, Kiev. Translated from Prikladnaya Mekhanika,
Vol. 35, No. 12, pp. 63–71, December, 1999. 相似文献
5.
Sandeep Kumar Parashar Anirvan DasGupta Utz von Wagner Peter Hagedorn 《International Journal of Non》2005,40(4):429-443
A wide range of non-linear effects are observed in piezoceramic materials. For small stresses and weak electric fields, piezoceramics are usually described by linearized constitutive equations around an operating point. However, typical non-linear vibration behavior is observed at weak electric fields near resonance frequency excitations of the piezoceramics. This non-linear behavior is observed in terms of a softening behavior and the decrease of normalized amplitude response with increase in excitation voltage. In this paper the authors have attempted to model this behavior using higher order cubic conservative and non-conservative terms in the constitutive equations. Two-dimensional kinematic relations are assumed, which satisfy the considered reduced set of constitutive relations. Hamilton's principle for the piezoelectric material is applied to obtain the non-linear equation of motion of the piezoceramic rectangular parallelepiped specimen, and the Ritz method is used to discretize it. The resulting equation of motion is solved using a perturbation technique. Linear and non-linear parameters for the model are identified. The results from the theoretical model and the experiments are compared. The non-linear effects described in this paper may have strong influence on the design of the devices, e.g. ultrasonic motors, which utilize the piezoceramics near the resonance frequency excitation. 相似文献
6.
A class of similarity solutions is obtained for radial motions of spherical and cylindrical bodies made of a certain type of compressible hyperelastic materials. The equations satisfied by the infinitesimal generators of the symmetry group of the unified governing first order field equations for spheres and cylinders are found. It is shown that these equations admit a special class of solutions which generate a five-parameter group of transformations. The form of the strain energy function corresponding to the resulting symmetry group is evaluated. The similarity variable is determined and ordinary differential equations satisfied by similarity solutions are obtained. Numerical solutions are given for a Ko material which falls into the class of admissible materials. 相似文献
7.
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
8.
Utz von Wagner 《International Journal of Non》2004,39(4):673-688
Characteristic non-linear effects can be observed, when piezoceramics are excited using weak electric fields. In experiments with longitudinal vibrations of piezoceramic rods, the behavior of a softening Duffing-oscillator including jump phenomena and multiple stable amplitude responses at the same excitation frequency and voltage is observed. Another phenomenon is the decrease of normalized amplitude responses with increasing excitation voltages. For such small stresses and weak electric fields as applied in the experiments, piezoceramics are usually described by linear constitutive equations around an operating point in the butterfly hysteresis curve. The non-linear effects under consideration were, e.g. observed and described by Beige and Schmidt [1,2], who investigated longitudinal plate vibrations using the piezoelectric 31-effect. They modeled these non-linearities using higher order quadratic and cubic elastic and electric terms. Typical non-linear effects, e.g. dependence of the resonance frequency on the amplitude, superharmonics in spectra and a non-linear relation between excitation voltage and vibration amplitude were also observed e.g. by von Wagner et al. [3] in piezo-beam systems. In the present paper, the work is extended to longitudinal vibrations of non-slender piezoceramic rods using the piezoelectric 33-effect. The non-linearities are modeled using an extended electric enthalpy density including non-linear quadratic and cubic elastic terms, coupling terms and electric terms. The equations of motion for the system under consideration are derived via the Ritz method using Hamilton's principle. An extended kinetic energy taking into consideration the transverse velocity is used to model the non-slender rods. The equations of motion are solved using perturbation techniques. In a second step, additional dissipative linear and non-linear terms are used in the model. The non-linear effects described in this paper may have strong influence on the relation between excitation voltage and response amplitude whenever piezoceramic actuators and structures are excited at resonance. 相似文献
9.
10.
11.
L. O. Grigor’eva 《International Applied Mechanics》2010,46(2):159-164
The methods of characteristics and difference schemes are used to study the nonstationary thickness vibrations of a piezoelectric
layer polarized across the thickness and subjected to electrical and mechanical loads. The propagation of waves under loading
of various types is studied. The dynamic electroelastic state of the layer is analyzed. It is established that the characteristics
of the electroelastic state are in a linear relationship 相似文献
12.
N. A. Shul’ga A. I. Bezverkhii O. I. Mekievskii 《International Applied Mechanics》2011,46(9):1031-1038
The harmonic electroelastic vibrations of a thin ring plate are considered. The effect of boundary conditions on the natural
frequencies is studied. The asymptotic properties of the frequency spectrum are determined. The dependence of the resonant
and antiresonant frequencies and the dynamic electromechanical-coupling coefficient on the relative size of plate is analyzed 相似文献
13.
14.
15.
16.
17.
18.
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
19.
On the free vibrations of a piezoceramic hollow sphere 总被引:1,自引:0,他引:1
The aim of the paper is to analyze the free vibrations of a piezoceramic hollow sphere with radial polarization. Using the cnoidal method and a genetic algorithm solves the equations of a radially inhomogeneous spherically isotropic piezoelastic medium. The Reddy and the cosine laws represent the functionally graded property of material. It is seen that for a piezoceramic hollow sphere, the piezoelectric effect consists in increasing the values for the natural frequencies in the specified classes of vibrations. 相似文献
20.
Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 24, No. 8, pp. 36–41, August, 1988. 相似文献