ПРИНЦИП ВОЗМОЖНЫХ ПЕРЕМЕЩЕНИЙ В МОМЕНТНОМЕМБРАННОЙ ДИНАМИЧЕСКОЙ ТЕОРИИ УПРУГИХ ТОНКИХ ОБОЛОЧЕК / The Principle of Possible Displacments in the Moment-Membrane Dynamic Theory of Elastic Thin Shells

2021 ◽  
pp. 10-19
Author(s):  
S. Sargsyan

В работе излагается моментно-мембранная динамическая теория упругих тонких оболочек на основе метода гипотез, который соответствует качественной стороне результата интегрирования трехмерной граничной задачи моментной теории упругости в тонкой области оболочки. На основе принципа возможных перемещений трехмерной моментной динамической теории упругости с независимыми полями перемещений и вращений и основных соотношений моментномембранной динамической теории упругих тонких оболочек, устанавливается принцип возможных перемещений для моментномембранной динамической теории упругих тонких оболочек./ In the present paper the moment-membrane dynamic theory of elastic thin shells is presented based on the hypotheses method, which corresponds to the qualitative side of the result of integration of the three-dimensional boundary-value problem of the moment theory of elasticity in a thin region of the shell. On the basis of the principle of possible displacements of the threedimensional moment dynamic theory of elasticity with independent fields of displacements and rotations and the basic relations of the moment-membrane dynamic theory of elastic thin shells, the principle of possible displacements for the moment-membrane dynamic theory of elastic thin shells is established.

2000 ◽  
Vol 11 (6) ◽  
pp. 573-594 ◽  
Author(s):  
A. G. ASLANYAN ◽  
A. B. MOVCHAN ◽  
Ö. SELSIL

This work presents an asymptotic algorithm for the derivation of equations of thin elastic shells. The algorithm is based on the analysis of a boundary value problem for the Navier system in a thin region. The analysis covers both the membrane theory and the moment theory of elastic shells, including the eigenvalue problems.


1998 ◽  
Vol 5 (2) ◽  
pp. 121-138
Author(s):  
O. Jokhadze

Abstract Some structural properties as well as a general three-dimensional boundary value problem for normally hyperbolic systems of partial differential equations of first order are studied. A condition is given which enables one to reduce the system under consideration to a first-order system with the spliced principal part. It is shown that the initial problem is correct in a certain class of functions if some conditions are fulfilled.


1999 ◽  
Vol 6 (6) ◽  
pp. 517-524
Author(s):  
M. Basheleishvili

Abstract The first three-dimensional boundary value problem is considered for the basic equations of statics of the elastic mixture theory in the finite and infinite domains bounded by the closed surfaces. It is proved that this problem splits into two problems whose investigation is reduced to the first boundary value problem for an elliptic equation which structurally coincides with an equation of statics of an isotropic elastic body. Using the potential method and the theory of Fredholm integral equations of second kind, the existence and uniqueness of the solution of the first boundary value problem is proved for the split equation.


Author(s):  
Victor Revenko ◽  
Andrian Revenko

The three-dimensional stress-strain state of an isotropic plate loaded on all its surfaces is considered in the article. The initial problem is divided into two ones: symmetrical bending of the plate and a symmetrical compression of the plate, by specified loads. It is shown that the plane problem of the theory of elasticity is a special case of the second task. To solve the second task, the symmetry of normal stresses is used. Boundary conditions on plane surfaces are satisfied and harmonic conditions are obtained for some functions. Expressions of effort were found after integrating three-dimensional stresses that satisfy three equilibrium equations. For a thin plate, a closed system of equations was obtained to determine the harmonic functions. Displacements and stresses in the plate were expressed in two two-dimensional harmonic functions and a partial solution of the Laplace equation with the right-hand side, which is determined by the end loads. Three-dimensional boundary conditions were reduced to two-dimensional ones. The formula was found for experimental determination of the sum of normal stresses via the displacements of the surface of the plate.


2021 ◽  
Vol 16 ◽  
pp. 250-260
Author(s):  
Evelina Prozorova

Article is proposed, built taking into account the influence of the angular momentum (force) in mathematical models of open mechanics. The speeds of various processes at the time of writing the equations were relatively small compared to modern ones. Theories have generally been developed for closed systems. As a result, in continuum mechanics, the theory developed for potential flows was expanded on flows with significant gradients of physical parameters without taking into account the combined action of force and moment. The paper substantiates the vector definition of pressure and the no symmetry of the stress tensor based on consideration of potential flows and on the basis of kinetic theory. It is proved that for structureless particles the symmetry condition for the stress tensor is one of the possible conditions for closing the system of equations. The influence of the moment is also traced in the formation of fluctuations in a liquid and in a plasma in the study of Brownian motion, Landau damping, and in the formation of nanostructures. The nature of some effects in nanostructures is discussed. The action of the moment leads to three-dimensional effects even for initially flat structures. It is confirmed that the action of the moment of force is the main source of the collective effects observed in nature. Examples of solving problems of the theory of elasticity are given.


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