共查询到20条相似文献,搜索用时 843 毫秒
1.
I.Intr0ducti0nDishedshallowshellsareakindofthinshellswhichconsistofashallowconicalshellwithacircuiarplateatthecenterregi0n.Thesnap-bucklingphenomenonofdishedshallowshellsisusedasacontrolinformationofthepress-temperatureselfcontroIsysteminprecisioninstrume… 相似文献
2.
The thermoelastic bending of locally heated orthotropic shells is studied using the classical theory of thermoelasticity of
thin shallow orthotropic shells and the method of fundamental solutions. Linear distribution of temperature over thickness
and the Newton’s law of cooling are assumed. Numerical analysis is carried out for orthotropic shells of arbitrary Gaussian
curvature made of a strongly anisotropic material. The behavior of thermal forces and moments near the zone of local heating
is studied for two areas of thermal effect: along a coordinate axis and along a circle of unit radius. Generalized conclusions
are drawn
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 3, pp. 80–85, March 2007. 相似文献
3.
L. V. Kurpa E. I. Lyubitskaya I. O. Morachkovskaya 《International Applied Mechanics》2010,46(6):660-668
The paper proposes a method to solve geometrically nonlinear bending problems for thin orthotropic shallow shells and plates
interacting with a Winkler–Pasternak foundation under transverse loading. This method is based on Ritz’s variational method
and the R-function method. The developed algorithm and software are used to solve a number of test problems and to study complex-shaped
shells. The effect of the shape of shells, the boundary conditions, the stiffness of the foundation, and the load distribution
on the behavior of isotropic and orthotropic shells undergoing geometrically nonlinear bending is studied 相似文献
4.
Abstract This paper gives a brief review of recent theoretical and experimental work on compressed and edge-restrained shallow shells. Yield point and post-yield point behavior of these shells is discussed and the available theoretical results are viewed in light of some experimental evidence. It is shown that the solutions for edge-restrained shallow shells are contained in the solutions for the compressed shallow shells. 相似文献
5.
The paper proposes a numerical-analytic approach to studying the free vibrations of orthotropic shallow shells with double
curvature and rectangular planform. The approach is based on the spline-approximation of unknown functions. Calculations are
carried out for different types of boundary conditions. The influence of the mid-surface curvature and variable thickness
on the behavior of dynamic characteristics is studied
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 6, pp. 102–115, June 2007. 相似文献
6.
We investigate the behavior of the deformations of a thin shell, whose thickness δ tends to zero, through a decomposition technique of these deformations. The terms of the decomposition of a deformation v are estimated in terms of the L
2-norm of the distance from ∇
v to SO(3). This permits in particular to derive accurate nonlinear Korn’s inequalities for shells (or plates). Then we use this
decomposition technique and estimates to give the asymptotic behavior of the Green-St Venant’s strain tensor when the “strain energy” is of order less than δ
3/2. 相似文献
7.
A method is proposed for studying the free vibrations of flexible shallow shells with a complex planform. The method is based
on variational and R-function methods. The R-function method allows constructing a system of basis functions in an analytic
form. This makes it possible to reduce the Donnell-Mushtari-Vlasov equations to Duffing equations. The amplitude-frequency
characteristics of shallow shells with a complex planform are given for different curvatures and boundary conditions. The
results obtained are compared with published results for simply supported square shells to demonstrate the reliability and
efficiency of the method
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 4, pp. 99–109, April 2007. 相似文献
8.
I. Yu. Babich N. B. Zhukova N. P. Semenyuk V. M. Trach 《International Applied Mechanics》2011,46(9):1001-1009
A method to solve stability problems for corrugated shells with dished ends subject to hydrostatic pressure is outlined. Critical
loads are determined by solving a boundary-value problem with unknown amplitude of nonaxisymmetric perturbation. It is shown
that the shells are highly sensitive to the axial component of hydrostatic pressure 相似文献
9.
Yong-Gang Wang Xiao-Meng Li Dan Li Xin-Zhi Wang 《Archive of Applied Mechanics (Ingenieur Archiv)》2011,81(12):1925-1933
An integrated mathematic model and an efficient algorithm on the dynamical behavior of homogeneous viscoelastic corrugated
circular plates with shallow sinusoidal corrugations are suggested. Based on the nonlinear bending theory of thin shallow
shells, a set of integro-partial differential equations governing the motion of the plates is established from extended Hamilton’s
principle. The material behavior is given in terms of the Boltzmann superposition principle. The variational method is applied
following an assumed spatial mode to simplify the governing equations to a nonlinear integro-differential variation of the
Duffing equation in the temporal domain, which is further reduced to an autonomic system with four coupled first-order ordinary
differential equation by introducing an auxiliary variable. These measurements make the numerical simulation performs easily.
The classical tools of nonlinear dynamics, such as Poincaré map, phase portrait, Lyapunov exponent, and bifurcation diagrams,
are illustrated. The influences of geometric and physical parameters of the plate on its dynamic characteristics are examined.
The present mathematic model can easily be used to the similar problems related to other dynamical system for viscoelastic
thin plates and shallow shells. 相似文献
10.
Natural vibrations of shallow cylindrical shells with rectangular plan and varying thickness are studied using a spline-approximation
method developed previously. Computation is carried out for different types of boundary conditions. The effect of the curvature
of the midsurface on the natural frequencies is examined. The natural frequencies of shells with constant and varying thickness
are compared
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 4, pp. 89–98, April 2007. 相似文献
11.
The paper studies the dynamics of nonlinear elastic cylindrical shells using the theory of shallow shells. The aerodynamic
pressure on the shell in a supersonic flow is found using piston theory. The effect of the flow and initial deflections on
the vibrations of the shell is analyzed in the flutter range. The normal modes of both perfect shells in a flow and shells
with initial imperfections are studied. In the latter case, the trajectories of normal modes in the configuration space are
nearly rectilinear, only one mode determined by the initial imperfections being stable
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 9, pp. 63–73, September 2007. 相似文献
12.
E. I. Bespalova 《International Applied Mechanics》2008,44(11):1283-1293
A generalized Kantorovich–Vlasov method is used to solve stationary problems for shallow shells with rectangular planform
and arbitrary boundary conditions. The efficiency of the approach is illustrated by examples
Translated from Prikladnaya Mekhanika, Vol. 44, No. 11, pp. 99–111, November 2008. 相似文献
13.
The dynamic behavior of reinforced shells of revolution in an elastic medium is modeled. Pasternak’s model is used. A problem
of vibration of discretely reinforced shells of revolution is formulated and a numerical algorithm is developed to solve it.
Results from an analysis of the dynamic behavior of a reinforced spherical shell on an elastic foundation are presented as
an example
Translated from Prikladnaya Mekhanika, Vol. 45, No. 2, pp. 99–106, February 2009. 相似文献
14.
A solution is obtained to describe the stability and initial postbuckling behavior of cylindrical shells made of composites
with one plane of symmetry. The solution is based on the Donnell-Mushtari-Vlasov nonlinear theory of anisotropic shells and
Koiter’s theory of buckling and postbuckling behavior. Calculated results are presented for boron plastic shells with reinforcement
of different types under external pressure. It is shown that the conventional model of a composite as an orthotropic material
is erroneous for many types of reinforcement
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 3, pp. 86–103, March 2007. 相似文献
15.
The Matching Property of Infinitesimal Isometries on Elliptic Surfaces and Elasticity of Thin Shells
Marta Lewicka Maria Giovanna Mora Mohammad Reza Pakzad 《Archive for Rational Mechanics and Analysis》2011,200(3):1023-1050
Using the notion of Γ-convergence, we discuss the limiting behavior of the three-dimensional nonlinear elastic energy for thin elliptic shells,
as their thickness h converges to zero, under the assumption that the elastic energy of deformations scales like h
β
with 2 < β < 4. We establish that, for the given scaling regime, the limiting theory reduces to linear pure bending. Two major ingredients
of the proofs are the density of smooth infinitesimal isometries in the space of W
2,2 first order infinitesimal isometries, and a result on matching smooth infinitesimal isometries with exact isometric immersions
on smooth elliptic surfaces. 相似文献
16.
The stress-strain state of a shallow orthotropic shell with rectangular planform and thickness varying in two coordinate directions
is studied. A refined problem formulation is used. Different boundary conditions are considered. A numerical analytic approach
based on the spline approximation and discrete orthogonalization is developed. The stress-strain state of shallow orthotropic
shells whose thickness is varied keeping its mass constant is studied
Translated from Prikladnaya Mekhanika, Vol. 44, No. 8, pp. 91–102, August 2008. 相似文献
17.
L. I. Shkutin 《Journal of Applied Mechanics and Technical Physics》2008,49(2):330-335
A mathematical formulation is given of nonlinear axisymmetric buckling problems for plates and shells in the two-phase zones
of austenite-to-martensite transformation. Numerical solutions of the direct-and inverse-transformation problems are used
to construct hysteresis loops for thermomechanically cycled, pressure-loaded circular plates and shallow spherical domes of
titanium nickelide (NiTi) alloy. It is shown that dynamic instability of the dome deformation process can occur during transformation under loads notably
lower than the upper critical values for the isothermal states of the material outside the transformation zone. A theoretical
analysis gives external loads below which the dome remains stable in the thermally cycled material with phase transformations.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 2, pp. 204–210, March–April, 2008. 相似文献
18.
An approach to the solution of problems of the statics of shallow orthotropic shells is proposed. It is based on reducing
a two-dimensional boundary value problem to a one-dimensional one using the spline-collocation method and solution of the
problem by the stable numerical method of discrete orthogonalization. Solutions are presented for problems on the stress state
of orthotropic shells of double curvature for several values of the elastic constants of the material.
Translated from Prikladnaya Mekhanika, Vol. 36, No. 7, pp. 60–66, July, 2000. 相似文献
19.
In the design of electric machines, devices, and plasma generator bearing constructions, it is sometimes necessary to study
the influence of magnetic fields on the vibration frequency spectra of thin-walled elements. The main equations of magnetoelastic
vibrations of plates and shells are given in [1], where the influence of the magnetic field on the fundamental frequencies
and vibration shapes is also studied. When studying the higher frequencies and vibration modes of plates and shells, it is
very efficient to use Bolotin’s asymptotic method [2–4]. A survey of studies of its applications to problems of elastic system
vibrations and stability can be found in [5, 6]. Bolotin’s asymptotic method was used to obtain estimates for the density
of natural frequencies of shallow shell vibrations [3] and to study the influence of the membrane stressed state on the distribution
of frequencies of cylindrical and spherical shells vibrations [7, 8]. In a similar way, the influence of the longitudinal
magnetic field on the distribution of plate and shell vibration frequencies was studied [9, 10]. It was shown that there is
a decrease in the vibration frequencies of cylindrical shells under the action of a longitudinal magnetic field, and the accumulation
point of the natural frequencies moves towards the region of lower frequencies [10]. In the present paper, we study the influence
of a transverse magnetic field on the distribution of natural frequencies of shallow cylindrical and spherical shells, obtain
asymptotic estimates for the density of natural frequencies of shell vibrations, and compare the obtained results with the
empirical numerical results. 相似文献
20.
In this paper, the nonlinear equations of motion for shallow spherical shells with axisymmetric deformation including transverse shear are derived. The nonlinear static and dynamic response and dynamic buckling of shallow spherical shells with circular hole on elastically restrained edge are investigated. By using the orthogonal point collocation method for space and Newmark-β scheme for time, the displacement functions are separated and the nonlinear differential equations are replaced by linear algebraic equations to seek solutions. The numerical results are presented for different cases and compared with available data. 相似文献