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1.
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
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 7, pp. 98–106, July 2007. 相似文献
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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
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 5, pp. 89–96, May 2007. 相似文献
4.
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
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Translated from Prikladnaya Mekhanika, Vol. 41, No. 7, pp. 58–67, July 2005. 相似文献
5.
The influence of the curving and twisting of an elongated blade on its vibrations during complex rotation is studied. It is shown that these geometrical factors may cause additional resonant vibrations__________Translated from Prikladnaya Mekhanika, Vol. 41, No. 4, pp. 126–132, April 2005. 相似文献
6.
The transverse vibrations of a circular disk of uniform thickness rotatingabout its axis with constant angular velocity are analyzed. The resultsspecialized to the linear case of disks clamped at the center and free atthe periphery are in good agreement with those reported in the literature.The natural frequencies of spinning hard and floppy disks are obtained for various nodal diameters and nodal circles. Primary resonance is shown to occur at the critical rotational speed at which, in the linear analysis, the spinning disk is unable to support arbitraryspatially fixed transverse loads. Using the method of multiple scales, wedetermine a set of four nonlinear ordinary-differential equations governingthe modulation of the amplitudes and phases of two interacting modes. Thesymmetry of the system and the loading conditions are reflected in thesymmetry of the modulation equations. They are reduced to an equivalentset of two first-order equations whose equilibrium solutions aredetermined analytically. The stability characteristics of thesesolutions is studied; the qualitative behavior of the response isindependent of the mode being considered. 相似文献
7.
V. M. Shul'ga 《International Applied Mechanics》2005,41(7):766-769
An approach is proposed to calculate the natural frequencies and modes of vibrations of cylindrically anisotropic piezoelectric
cylinders. The frequency equation is derived, and the frequency spectrum is analyzed
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Translated from Prikladnaya Mekhanika, Vol. 41, No. 7, pp. 68–72, July 2005. 相似文献
8.
L. O. Grigor’eva 《International Applied Mechanics》2007,43(3):303-308
The paper proposes a method to solve the problem of vibrations of a radially polarized piezoelectric cylinder subject to nonstationary
electric excitation. The dynamic electromechanical state of the cylinder is analyzed. The time-dependences of electric and
mechanical characteristics are plotted. The distribution of these characteristics over the cross section of a short cylinder
is examined. The region of end disturbances in a long cylinder is identified
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 3, pp. 73–79, March 2007. 相似文献
9.
Steady precession vibrations of a single-support thin-walled rotor whose rotation axis is forced to make an additional rotation are simulated numerically. It is established that compared with double-support rotors, single-support rotors are more dynamically compliant and undergo two precession resonances over the range of rotation speeds being considered. Mode shapes of precession vibrations are drawn 相似文献
10.
The results from studies into the vibrations and dynamic stability of thin elastic shells with initial geometric imperfections are analyzed. The corresponding dynamic problems are solved in both linear and nonlinear formulations. The influence of initial axisymmetric and nonaxisymmetric deflections on natural, forced, parametrically excited, and self-excited vibrations (flutter) is studied. The dynamic buckling of imperfect shells under short-term impulsive loading is examined. Some aspects of experimental investigation into the vibrations of shells with small geometric imperfections (deviations from the design shape) are considered 相似文献
11.
Radial vibrations and dissipative heating of a polarized piezoceramic ring plate are studied. The plate is excited by a harmonic electric field applied to nonuniformly electroded surfaces of the plate. The viscoelastic behavior of piezoceramics is described in terms of complex quantities. An analytical solution is found in the case of quasistatic harmonic loading. The dynamic nonlinear problem of coupled thermoviscoelasticity is solved with regard for the temperature dependence of the properties of piezoceramics by step-by-step integration in time, using the numerical methods of discrete orthogonalization and finite differences. A numerical analysis is conducted for TsTStBS-2 piezoceramics to study the influence of partial electroding on the stress–strain distribution, natural frequency, and amplitude–frequency and temperature–frequency characteristics 相似文献
12.
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
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Translated from Prikladnaya Mekhanika, Vol. 41, No. 9, pp. 94–100, September 2005. 相似文献
13.
本文用边界元法对销钉接触角及销钉孔半径对三种电流输入方式下紧凑拉伸试样的电位函数影响进行了分析。结果证明,人们在电位法测试中常用的电流输入方式容易引起误差,并非最佳方案.最佳方案是另一种同样方便的电流输入方式. 相似文献
14.
V. F. Sivak 《International Applied Mechanics》2004,40(12):1419-1421
The resonance synchronization of the vibrations of a system of shells is studied. It is established that the vibrations of isolated components excite the vibrations of the whole system, consisting of three cylindrical shells on a common elastic base.__________Translated from Prikladnaya Mekhanika, Vol. 40, No. 12, pp. 134–137, December 2004. 相似文献
15.
In this paper the weakly nonlinear, transversal vibrations of aconveyor belt will be considered. The belt is assumed to move witha low and time-varying speed. Using Kirchhoff's approach a singleequation of motion will be derived from a coupled system ofpartial differential equations describing the longitudinal andtransversal vibrations of the belt. A two time-scalesperturbation method is then applied to approximate the solutionsof the problem. It will turn out that the frequencies of the belt speed fluctuations play an important role in the dynamic behaviourof the belt. It is well-known in linear systems that instabilitiescan occur if the frequency of the belt speed fluctuations is thesum of two natural frequencies. However, in the weakly nonlinearcase as considered in this paper this is no longer true. It turns out that the weak nonlinearity stabilizes the system. 相似文献
16.
V. F. Sivak 《International Applied Mechanics》2007,43(9):1024-1027
A technique and results of experimental determination of vibrational stresses in a system of two truncated conical shells
joined by three thin plates are presented. An analysis of the data obtained shows that the stress peaks near the added point
mass at resonance
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 9, pp. 93–97, September 2007. 相似文献
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The nonlinear response of rectangular and square metallic plates subjectto transverse harmonic excitations is studied. The nonlinearitiesoriginate from the use of Von Kármán strains. The method of multiplescales is used to solve the system of differential equationsapproximately. Frequency response curves are presented for both squareand rectangular plates for primary resonance of either mode in thepresence of a one-to-one internal resonance. Stability of steady statesolutions is investigated. Bifurcation points and their types arediscussed. 相似文献
20.
电极电势对氮化硅/黄铜滑动摩擦副摩擦磨损性能的影响研究 总被引:4,自引:3,他引:4
在自制摩擦磨损试验机上考察了黄铜表面电极电势的变化对氮化硅 /黄铜滑动摩擦副摩擦磨损特性的影响 .结果表明 ,在不同的电势区间内 ,摩擦系数表现出不同的变化趋势 ,特别是在 - 1.4~ - 1.0 V电势区间内摩擦系数表现出可控性 .利用扫描电子显微镜观察发现 ,在摩擦系数可控区摩擦系数有所增大但磨损并未加剧 .根据黄铜在润滑液中的循环伏安曲线可以初步推断 ,在不同的电势区间内 ,电化学反应的不同是引起摩擦系数变化的主要原因 相似文献