共查询到20条相似文献,搜索用时 546 毫秒
1.
The paper addresses the geometrically nonlinear problem of dynamic stability of a viscoelastic plate with concentrated masses.
The Bubnov-Galerkin method based on polynomial approximation is used to reduce the problem to a system of nonlinear Volterra-type
integro-differential equations with singular relaxation kernels. This system is solved by numerical method based on quadrature
formulas. The critical loads are found and their dependence on the arrangement and number of concentrated masses is studied
for a wide range of mechanical and geometrical parameters of the plate. The choice of a relaxation kernel for dynamic problems
for viscoelastic thin-walled plate-like structures is justified. Results produced by different theories are compared
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Translated from Prikladnaya Mekhanika, Vol. 44, No. 2, pp. 109–118, February 2008. 相似文献
2.
B. Kh. Eshmatov Kh. Eshmatov D. A. Khodzhaev 《Journal of Applied Mechanics and Technical Physics》2013,54(4):578-587
The problem of flutter of viscoelastic rectangular plates and cylindrical panels with concentrated masses is studied in a geometrically nonlinear formulation. In the equation of motion of the plate and panel, the effect of concentrated masses is accounted for using the δ-Dirac function. The problem is reduced to a system of nonlinear ordinary integrodifferential equations by using the Bubnov-Galerkin method. The resulting system with a weakly singular Koltunov-Rzhanitsyn kernel is solved by employing a numerical method based on quadrature formulas. The behavior of viscoelastic rectangular plates and cylindrical panels is studied and the critical flow velocities are determined for real composite materials over wide ranges of physicomechanical and geometrical parameters. 相似文献
3.
B. Kh. Eshmatov 《Journal of Applied Mechanics and Technical Physics》2006,47(2):289-297
The dynamic stability problem of viscoelastic orthotropic and isotropic plates is considered in a geometrically nonlinear
formulation using the generalized Timoshenko theory. The problem is solved by the Bubnov-Galerkin procedure combined with
a numerical method based on quadrature formulas. The effect of viscoelastic and inhomogeneous properties of the material on
the dynamic stability of a plate is discussed.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 2, pp. 165–175, March–April, 2006. 相似文献
4.
B. Kh. Eshmatov 《Nonlinear dynamics》2007,50(1-2):353-361
The vibration problem of a viscoelastic cylindrical shell is studied in a geometrically nonlinear formulation using the refined
Timoshenko theory. The problem is solved by the Bubnov–Galerkin procedure combined with a numerical method based on quadrature
formulas. The choice of relaxation kernels is substantiated for solving dynamic problems of viscoelastic systems. The numerical
convergence of the Bubnov–Galerkin procedure is examined. The effect of viscoelastic properties of the material on the response
of the cylindrical shell is discussed. The results obtained by various theories are compared. 相似文献
5.
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
6.
The paper addresses the forced flexural vibrations and dissipative heating of a circular viscoelastic plate with piezoactive
actuators under axisymmetric loading. A refined formulation of this coupled problem is considered. The viscoelastic behavior
of materials is described using the concept of complex moduli dependent on the temperature of dissipative heating. The electromechanical
behavior of the plate is modeled based on the Timoshenko hypotheses for the mechanical variables and analogous hypotheses
for the electric-field variables in the piezoactive layers of the actuator. The temperature is assumed constant throughout
the thickness. The nonlinear problem is solved by a time stepping method using, at each step, the discrete-orthogonalization
and finite-difference methods to solve the elastic and heat-conduction equations, respectively. A numerical study is made
of the effect of the shear strain, the temperature dependence of the material properties, fixation conditions, and geometrical
parameters of the plate on the vibrational characteristics and the electric potential applied to the actuator electrodes to
balance the mechanical load
Translated from Prikladnaya Mekhanika, Vol. 44, No. 9, pp. 104–114, September 2008. 相似文献
7.
I. F. Kirichok 《International Applied Mechanics》2006,42(3):336-341
The forced flexural vibrations and dissipative heating of a bimorph ring plate are studied. The plate is made of viscoelastic
piezoceramics and is polarized across the thickness. The outer surfaces of the plate are nonuniformly electroded, and harmonic
electric excitation is applied to the electrodes. The viscoelastic behavior of the material is described using the concept
of temperature-dependent complex moduli. The coupled nonlinear problem of thermoviscoelasticity is solved by time iteration
using, at each iteration, the discrete-orthogonalization method to integrate the mechanics equations and the explicit finite-difference
method to solve the heat-conduction equation with a nonlinear heat source. Numerical calculations demonstrate that by changing
the size of the ring electrode we can influence the natural frequency, stress and displacement distributions, dissipative-heating
temperature, and amplitude-and temperature-frequency characteristics. With certain boundary conditions, there is an optimal
electrode configuration that produces deflections of maximum amplitudes when an electric excitation is applied
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Translated from Prikladnaya Mekhanika, Vol. 42, No. 3, pp. 102–109, March 2006. 相似文献
8.
I. F. Kirichok 《International Applied Mechanics》2009,45(2):215-222
The bending vibration and dissipative heating of a viscoelastic isotropic ring plate with piezoceramic actuators under electromechanical
loading and shear deformation are studied by solving a coupled problem. The temperature dependence of the complex characteristics
of the passive and piezoactive materials is taken into account. The nonlinear problem of thermoviscoelasticity is solved by
time stepping with discrete orthogonalization used at each iteration to integrate the equations of elasticity and using an
explicit finite-difference scheme to solve the heat-conduction equation with a nonlinear heat source. The effect of shear
deformation, fixation conditions for the plate, the geometry of the piezoactuators, and the dissipative-heating temperature
on the active damping of the forced vibration of a circular plate subject to uniform transverse monoharmonic compression is
studied
Translated from Prikladnaya Mekhanika, Vol. 45, No. 2, pp. 124–132, February 2009. 相似文献
9.
Nonlinear vibrations and stability of elastic and viscoelastic systems under random stationary loads
V. D. Potapov 《Mechanics of Solids》2011,46(3):444-454
The paper deals with numerical analysis of nonlinear vibrations of viscoelastic systems under a stochastic action in the form
of a Gaussian stationary process with rational spectral density. The analysis is based on numerical simulation of the original
stationary process, numerical solution of the differential equations describing the motion of the system, and computation
of the maximum Lyapunov exponent if the stability of this motion is studied. An example of a plate subjected to a random stationary
load applied in its plane is used to consider specific issues concerning the application of the proposed method and the peculiarities
of the behavior of geometrically nonlinear elastic and viscoelastic stochastic systems. Special attention is paid to the interaction
of a deterministic periodic action and a stochastic action from the viewpoint of stability of the system motion. It is shown
that in some cases imposing a “colored” noise may stabilize an unstable system subjected to a periodic load. 相似文献
10.
I. V. Denisova D. A. Indeitsev A. V. Klimenko 《Journal of Applied Mechanics and Technical Physics》2006,47(4):515-522
The stability of an infinite viscoelastic plate on an elastic foundation in a viscous incompressible flow is studied. The
Navier-Stokes system is linearized for an exponential velocity profile. The problem is reduced by a Fourier-Laplace transform
to a system of ordinary differential equations, whose solution is found in the form of convergent series. The roots of the
dispersion relation that characterize the stability of the system are found numerically. The effect of the viscosities of
the fluid and the plate on the stability of the waves propagating upstream and downstream is studied. The results are compared
with available data on the stability of a viscoelastic plate in an ideal fluid flow.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 4, pp. 66–74, July–August, 2006. 相似文献
11.
The forced monoharmonic bending vibrations and dissipative heating of a piezoelectric circular sandwich plate under monoharmonic
mechanical and electrical loading are studied. The core layer is passive and viscoelastic. The face layers (actuators) are
piezoelectric and oppositely polarized over the thickness. The plate is subjected to harmonic pressure and electrical potential.
The viscoelastic behavior of the materials is described by complex moduli dependent on the temperature of heating. The coupled
nonlinear problem is solved numerically. A numerical analysis demonstrates that the natural frequency, amplitude of vibrations,
mechanical stresses, and temperature of dissipative heating can be controlled by changing the area and thickness of the actuator.
It is shown that the temperature dependence of the complex moduli do not affect the electric potential applied to the actuator
to compensate for the mechanical stress
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Translated from Prikladnaya Mekhanika, Vol. 44, No. 1, pp. 79–89, January 2008. 相似文献
12.
Nonlinear vibration analysis of viscoelastic plates based on a refined Timoshenko theory 总被引:2,自引:0,他引:2
B. Kh. Éshmatov 《International Applied Mechanics》2006,42(5):596-605
Nonlinear vibrations of viscoelastic orthotropic and isotropic shells are mathematically modeled using a geometrically nonlinear
Timoshenko theory. Nonlinear problems are solved by using the Bubnov-Galerkin method and a numerical method based on quadrature
formulas. Results obtained from different theories are compared and analyzed. For each problem, the Bubnov-Galerkin method
is tested for convergence. The influence of the viscoelasticity and inhomogeneity of materials on the vibrations of plates
is demonstrated
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Translated from Prikladnaya Mekhanika, Vol. 42, No. 5, pp. 120–131, May 2006. 相似文献
13.
The paper examines the effect of dissipative heating on the performance of a sensor in a viscoelastic rectangular plate undergoing
resonant vibrations. The thermoviscoelastic behavior of materials is described using the concept of complex characteristics.
The coupling of the electromechanical and thermal fields is taken into account. The nonlinear problem is solved by the Bubnov–Galerkin
method. The effect of the mechanical boundary conditions and dissipative-heating temperature on the performance of the sensors
is analyzed 相似文献
14.
Wei Cao Changyu Shen Chunjie Zhang Lixia Wang 《Archive of Applied Mechanics (Ingenieur Archiv)》2008,78(5):363-377
A numerical approach is introduced to solve the viscoelastic flow problem of filling and post-filling in injection molding.
The governing equations are in terms of compressible, non-isothermal fluid, and the constitutive equation is based on the
Phan–Thien–Tanner model. By introducing some hypotheses according to the characteristics of injection molding, a quasi-Poisson
type equation about pressure is derived with part integration. Besides, an analytical form of flow-induced stress is also
generalized by using the undermined coefficient method. The conventional Galerkin approach is employed to solve the derived
pressure equation, and the ‘upwind’ difference scheme is used to discrete the energy equation. Coupling is achieved between
velocity and stress by super relax iteration method. The flow in the test mold is investigated by comparing the numerical
results and photoelastic photos for polystyrene, showing flow-induced stresses are closely related to melt temperatures. The
filling of a two-cavity box is also studied to investigate the viscoelastic effects on real injection molding. 相似文献
15.
Yajuan Guo Guang Meng Hongguang Li 《Archive of Applied Mechanics (Ingenieur Archiv)》2009,79(2):147-155
The parameter determination of viscoelastic material is a multi-variable, multi-aim nonlinear optimization problem, which
made the optimization process very complicated. In this paper a hybrid optimal algorithm was proposed to determine the viscoelastic
parameters in the constitutive relation according to the experimentally obtained mechanical properties. This algorithm merges
the Broydon–Fletcher–Goldfarb–Shanno search into a genetic algorithm framework as a basic operator in order to enhance the
local search capability. The proposed hybrid algorithm not only can reduce the iterative times greatly but can abolish the
limitation of initial parameter values. Nonlinear material characteristic curve-fitting was carried out using the proposed
algorithm and other existing approaches. And the comparison results show this algorithm is accurate and effective. The numerical
simulation and experimental study of viscoelastic cantilever beam also indicates that the finite element formulation and the
calculative viscoelastic model parameters are reliable. The proposed optimization method can be extended to further complex
parameter estimation researches. 相似文献
16.
Flexural vibrations and vibrational heating of a ring plate with thin piezoceramic pads under single-frequency electromechanical loading 总被引:1,自引:1,他引:0
I. F. Kirichok 《International Applied Mechanics》2008,44(2):200-207
The paper deals with the coupled problem of flexural vibrations and dissipative heating of a viscoelastic ring plate with
piezoceramic actuators under monoharmonic electromechanical loading. The temperature dependence of the complex characteristics
of passive and piezoactive materials is taken into account. The coupled nonlinear problem of thermoviscoelasticity is solved
by an iterative method. At each iteration, orthogonal discretization is used to integrate the equations of elasticity and
an explicit finite-difference scheme is used to solve the heat-conduction equation with a nonlinear heat source. The effect
of the dissipative heating temperature, boundary conditions, and the thickness and area of the actuator on the active damping
of the forced vibrations of the plate under uniform transverse harmonic pressure is examined
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Translated from Prikladnaya Mekhanika, Vol. 44, No. 2, pp. 99–108, February 2008. 相似文献
17.
The stress-strain state of an anisotropic plate containing an elliptic hole and thin, absolutely rigid, curvilinear inclusions
is studied. General integral representations of the solution of the problem are constructed that satisfy automatically the
boundary conditions on the elliptic-hole contour and at infinity. The unknown density functions appearing in the potential
representations of the solution are determined from the boundary conditions at the rigid inclusion contours. The problem is
reduced to a system of singular integral equations which is solved by a numerical method. The effects of the material anisotropy,
the degree of ellipticity of the elliptic hole, and the geometry of the rigid inclusions on the stress concentration in the
plate are studied. The numerical results obtained are compared with existing analytical solutions.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 4, pp. 173–180, July–August, 2007. 相似文献
18.
Nonlinear vibration analysis of isotropic cantilever plate with viscoelastic laminate 总被引:1,自引:0,他引:1
The nonlinear vibration of an isotropic cantilever plate with viscoelastic laminate is investigated in this article. Based
on the Von Karman’s nonlinear geometry and using the methods of multiple scales and finite difference, the dimensionless nonlinear
equations of motion are analyzed and solved. The solvability condition of nonlinear equations is obtained by eliminating secular
terms and, finally, nonlinear natural frequencies and mode-shapes are obtained. Knowing that the linear vibration of this
type of plate does not have exact solution, Ritz method is employed to obtain semi-analytical nonlinear mode-shapes of transverse
vibration of this plate. Airy stress function and Galerkin method are employed to reduce nonlinear PDEs into an ODE of duffing
type. Stability of plate and chaotic behavior are investigated by Runge–Kutta method. Poincare section diagrams are in good
agreement with results of Lyapunov criteria. 相似文献
19.
20.
A. D. Zamanov 《International Applied Mechanics》1999,35(10):1035-1039
The natural vibration of a thin rectangular plate made of a composite material with periodically bent structures is studied.
The problem is examined by the finite-element method using the variation principle. The effect of the bending parameters on
the natural frequency of the plate is analyzed using the numerical results obtained.
Institute of Mathematics and Mechanics, Academy of Sciences of Azerbaijan, Baku, Azerbaijan. Translated from Prikladnaya Mekhanika,
Vol. 35, No. 10, pp. 68–73, October, 1999. 相似文献