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http://hdl.handle.net/11701/2376
Tue, 23 Oct 2018 10:28:20 GMT2018-10-23T10:28:20ZIn memory V.P. Khavin
http://hdl.handle.net/11701/3849
Название: In memory V.P. Khavin
Краткий осмотр (реферат): In memory V.P. KhavinTue, 01 Mar 2016 00:00:00 GMThttp://hdl.handle.net/11701/38492016-03-01T00:00:00ZTerminal movement of the thin elliptical plate on the horizontal plane with orthotropic friction
http://hdl.handle.net/11701/3848
Название: Terminal movement of the thin elliptical plate on the horizontal plane with orthotropic friction
Авторы: Dmitriev, Nikita N.; Silantyeva, Olga A.
Краткий осмотр (реферат): In a number of engineering problems friction forces can vary significantly depending on the direction of
sliding. This research deals with orthotropic friction. The presented model describes final motion of the
thin elliptical plate on the horizontal plane. The system of differential equations, which describe dynamical
behavior of the plate, is solved numerically for different initial conditions. Final movement of the plate
depends from interrellations between the moment of inertia, friction coefficients and plate orientation. The
comparison of the motion of elliptical and circle plates is presented. It is shown that sliding and spinning
end simultaneously for both types of plates. The results may be used for more accurate simulations of
railway contact. Refs 14. Figs 3. Tables 2.Tue, 01 Mar 2016 00:00:00 GMThttp://hdl.handle.net/11701/38482016-03-01T00:00:00ZFree localized vibrations of a long double-walled carbon nanotube embedded in nonhomogeneous elastic medium
http://hdl.handle.net/11701/3847
Название: Free localized vibrations of a long double-walled carbon nanotube embedded in nonhomogeneous elastic medium
Авторы: Mikhasev, Gennadiy I.; Botogova, Marina G.
Краткий осмотр (реферат): On the basis of the modified Flu¨ugge equations for thin cylindrical shells and non-local theory of elasticity,
free axisymmetric vibrations of a long double-walled carbon nanotube embedded in nonhomogeneous
elastic medium is studied. The surrounding medium is modelled by the Winkler foundation. To take into
account the interaction between the nanotube walls, the van-der-Waals forces are introduced into the
governing equations. By using the asymptotic method of Tovstik, eigenmodes are constructed in the form
of functions decaying far from the line on the outermost wall where the coefficient of soil reaction has
a local minimum. Eigenmodes and natural frequencies corresponding to the like-directed and differently
directed motions of walls have been found. It has been revealed that the introduction of a parameter of
nonlocality into the model «generates» the eigenmodes which are nonrelevant for macro-sized shells. In
particular, the increase of the tensile axil force results in: 1) more high rate of localization of vibrations
and growing amplitudes of tangential oscillations of atoms; 2) increasing natural frequencies in the case
when the tube is in the sufficiently stiffen medium. Refs 13. Figs 3. Tables 1.Tue, 01 Mar 2016 00:00:00 GMThttp://hdl.handle.net/11701/38472016-03-01T00:00:00ZOn stiffness matrix construction for naturally twisted rod
http://hdl.handle.net/11701/3846
Название: On stiffness matrix construction for naturally twisted rod
Авторы: Kurbatova, Natalia V.; Romanova, Natalia M.; Ustinov, Yuriy A.
Краткий осмотр (реферат): Here we considered the Saint Venant problem for a naturally twisted rod with a rectangular cross-section.
Research was conducted on the basis of homogeneous solutions in conjunction with the finite element
method. The general solution is constructed as a linear combination of elementary solutions corresponding
to three four-roots eigenvalues of spectral problem on the cross section. Elementary solutions determining
the stress-strain state of Saint Venant type contain unknown eigenvectors and associated vectors. To
determine of unknown solutions the authors formulated boundary value problems and their variational
formulations previously. They are correspond to problems of stretching-torsion, pure bending and bending
of the lateral force. Variational problems were solved using FEM. The stress-strain state of the rod was
studied numerically and non-zero elements of the stiffness matrix were found in the case of square and
rectangular cross-sections of the rod for the different values of twist. Graphically shows the numerical
results for a wide range of change of the twist parameter τ. Calculations showed that the identified
patterns are consistent with the corresponding behavior untwisted rods (for small twist parameter), and
with the growth of the twist, new effects, which confirm the hypothesis proposed earlier. Refs 17. Figs 3.Tue, 01 Mar 2016 00:00:00 GMThttp://hdl.handle.net/11701/38462016-03-01T00:00:00ZElliptic boundary layer in shells of revolution under normal shock surface loading
http://hdl.handle.net/11701/3845
Название: Elliptic boundary layer in shells of revolution under normal shock surface loading
Авторы: Kirillova, Irina V.; Kossovich, Leonid Yu.
Краткий осмотр (реферат): Asymptotic equations for the elliptic boundary layer in shells of revolution at shock normal surface loading
are derived in the present paper. Considered boundary layer type has place only at surface and edge
shock loading and is localized in the small vicinity of the front of the Rayleigh surface waves. There are used asymptotic methods together with A. I. Lourier’s symbolic integration. There are obtained elliptic
equations discribing the boundary layer behaviour with respect to the normal coordinate and hyperbolic
equations defined the boundary layer on the shell faces. Refs 18. Figs 1.Tue, 01 Mar 2016 00:00:00 GMThttp://hdl.handle.net/11701/38452016-03-01T00:00:00ZRelationship between the Udwadia—Kalaba equations and the generalized Lagrange and Maggi’s equations
http://hdl.handle.net/11701/3844
Название: Relationship between the Udwadia—Kalaba equations and the generalized Lagrange and Maggi’s equations
Авторы: Zegzhda, Sergey A.; Naumova, Natalya V.; Soltakhanov, Shervani Kh.; Yushkov, Mikhail P.
Краткий осмотр (реферат): In their paper “A new perspective on constrained motion” F. E. Udwadia and R. E. Kalaba offered a new
form of matrix equations of motion for nonholonomic systems subject to linear nonholonomic second-order
constraints. The obtained equations contain all the generalized coordinates of the mechanical system in
question, and at the same time they do not contain the constraint reaction forces. This is an undoubted
advantage of the equations presented, so the authors assume that “the equations of motion obtained in
this paper appear to be the simplest and most comprehensive so far discovered”. To write these equations
the authors apply a rather specific transformation proposed by Moore already in 1920 and developed by
Penrose in 1955. In Russian literature it is said that in this case a pseudoinverse matrix is used.
The present paper reveals that the equations obtained by those authors can be naturally derived from
the generalized Lagrange and Maggi’s equations or when using a contravariant form of the equations of
motion of a mechanical system subject to linear nonholonomic second-order constraints. It is noted that a
similar technique for eliminating the reaction forces from differential equations is usually used in practical
studying of motion of mechanical systems that are subject to holonomic and classical nonholonomic
first-order constraints. As a result, we obtain the equations of motion containing only the generalized
coordinates of a mechanical system, what corresponds to the equations of Udwadia—Kalaba form. Refs 7.Tue, 01 Mar 2016 00:00:00 GMThttp://hdl.handle.net/11701/38442016-03-01T00:00:00ZSome basic problems of the theory of elasticity for plane with the cuts
http://hdl.handle.net/11701/3843
Название: Some basic problems of the theory of elasticity for plane with the cuts
Авторы: Dahl, Yuriy M.
Краткий осмотр (реферат): It was found the new solutions for the elastic plane with arbitrary quantity of cuts on real axis. Two basic
cases were investigated. The first is: the both borders of cuts are load with concentrated forces, but on
the infinity there are no stresses. The second is: the both borders of cuts are free, however in the infinity
the plane has stretched out for external stresses.Tue, 01 Mar 2016 00:00:00 GMThttp://hdl.handle.net/11701/38432016-03-01T00:00:00ZComparative analysis of initial state in inhomogeneous rods
http://hdl.handle.net/11701/3842
Название: Comparative analysis of initial state in inhomogeneous rods
Авторы: Vatulyan, Aleksandr O.; Nedin, Rostislav D.
Краткий осмотр (реферат): The development and improvement of models of inhomogeneous bodies in the presence of residual stress
and deformation fields plays an important role in the mechanics of deformable solid body. From the
viewpoint of practical applications, one of the most prospective inhomogeneity type is the class of
functionally graded composites (FGC), which material properties vary depending on coordinates. The
gradient of properties in such materials is due to the inhomogeneous chemical composition, or the
microstructure, or the atomic order. Research on beam-like FGC is the very first global step of exploration
of FGC properties. A key question in the problem of monitoring of technical conditions of an object is often a question
of proper selection of material’s damage characteristics detectiontechnique, and conducting a set of
corresponding experimental investigations. A failure under loading belowthe allowable one is often due
to unaccounted preliminary state (PS). It is important to provide the analysis of different types of
inhomogeneity of material properties and PS factors (including residual stress and deformations) on
dynamic characteristics.
In the present paper the effect of various types of PS on acoustical characteristics spectrum
(eigenfrequencies, frequency-response functions) is analyzed in FGC-beams. In the framework of the
Timoshenko model, such PS factors are considered as residual stress, residual deflection, and residual
angle of rotation of the principal axe of the beam due to bending. The computational experiments are
conducted and analyzed. Refs 19. Figs 4.Tue, 01 Mar 2016 00:00:00 GMThttp://hdl.handle.net/11701/38422016-03-01T00:00:00ZOn natural frequencies of transversally isotropic circular plates
http://hdl.handle.net/11701/3841
Название: On natural frequencies of transversally isotropic circular plates
Авторы: Bauer, Svetlana M.; Voronkova, Eva B.
Краткий осмотр (реферат): Impact of material properties of transversely isotropic circular plates on its natural frequencies is discussed
in the present paper. Two refined theories of plates are used to analyze the free vibration behavior of
homogeneous plates. Both theories take into account normal and rotary inertias. Fundamental frequencies
for plates with radial inhomogeneity are obtained with the help of finite element package Comsol
Multiphysics 5.0. It is shown that the inhomogeneity of the plate have a profound impact on the first
(lowest) frequency of the plate while the plate orthotropic influences more on the second and higher
vibration modes. Refs 2. Figs 1. Tables 1.Tue, 01 Mar 2016 00:00:00 GMThttp://hdl.handle.net/11701/38412016-03-01T00:00:00ZOn the frequency spectrum of free vibrations of membranes and plates in contact with fluid
http://hdl.handle.net/11701/3840
Название: On the frequency spectrum of free vibrations of membranes and plates in contact with fluid
Авторы: Ivanov, Denis N.; Naumova, Natalia V.; Sabaneev, Valentin S.; Tovstik, Petr E.; Tovstik, Tatiana P.
Краткий осмотр (реферат): A container of rectangular parallelepiped form filled by ideal incompressible fluid is studied. The container
is closed by an elastic cover which is modeled by a membrane or by a plate of constant thickness. The rest
container sides are undeformable. The frequency spectrum of small free vibrations of the cover is built.
The motion of fluid is assumed potential and the attached mass of fluid is taken into account. The main
peculiarity of problem is that the fluid volume under cover is not changed. As a result the mode of cover
deflection satisfies to a restriction equation which follows from the condition that the fluid volume under
cover is constant. Refs 11. Figs 5.Tue, 01 Mar 2016 00:00:00 GMThttp://hdl.handle.net/11701/38402016-03-01T00:00:00Z