Torsional stability of a glass-reinforced plastic cylindrical shell with an elastic core

The problem of the stability of a glass-reinforced plastic cylindrical shell with an elastic core subjected to twisting moments applied to the edges of the shell is considered. As in various other studies [4–6], the glass-reinforced plastic is treated as an elastically orthotropic material. The core is treated as an isotropic elastic cylinder, whose outer surface is bonded to the shell. Expressions for the critical stresses are obtained for an infinitely long shell and a shell of finite length.Moscow. Translated from Mekhanika Polimerov, No. 6, pp. 1082–1086, November–December, 1970.     

Stability of composite shells with an elastic core

The stability in axial compression of orthotropic cylindrical shells with an elastic core is investigated with allowance for the following factors: transverse shear strains in the shell material, precritical state of stress of the core, and the moments due to the surface forces exerted on the shell by the core. The numerical results obtained are compared with the results of approximate methods in which the above-mentioned factors are disregarded.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 3, pp. 544–547, May–June, 1976.     

Local stability of an orthotropic cylindrical shell partially filled by an elastic core and subjected to external pressure

The local stability of an infinitely long orthotropic cylindrical shell partially filled by an elastic thick-walled cylindrical core and subjected to external pressure is investigated.Scientific-Research Institute of Chemical Technology, Moscow Region. Translated from Mekhanika Polimerov, No. 3, pp. 538–542, May–June, 1971.     

Concerning the critical load for an orthotropic cylindrical shell with a viscoelastic core

The problem of determining the critical load for a cylindrical shell with a viscoelastic core is considered. An expression for the critical load under quasistationary loading is obtained on the basis of a generalization of the Winkler hypothesis.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 6, pp. 1049–1053, November–December, 1973.     

State of stress of flexible plastic shells with an opening

The state of stress of flat flexible shells with an opening is investigated with allowance for the viscoelastic properties of the material. The equilibrium equations and boundary conditions are written in finite-difference form. A nonlinear system of algebraic equations is solved by successive approximations. A method of accelerating the convergence of slowly converging iteration processes is proposed. The effect of the viscoelastic properties of the shell material on its state of stress is investigated with reference to the example of a polymethyl methacrylate shell. The variations of the ring moment and ring forces at the free edge of the shell are plotted for various moments of time, load values, and flatness parameters. It is shown that as soon as the viscosity factor begins to take effect, the state of stress and strain of the shell changes sharply; the concentration of forces and moments increases in the flexible viscoelastic (as compared with the elastic) shell.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 1071–1075, November–December, 1973.     

Stability of shear-compliant cylindrical shells connected with an elastic foundation in a geometrically nonlinear formulation

The effect of transverse shear strains on the stability "in the large" of a cylindrical transversal-isotropic shell with an elastic filler under the effect of axial compression is investigated. The length of the cylindrical shell is assumed to be greater than the diameter. The approximate solution is obtained by the Bubnov-Galerkin method. Such a problem for an isotropic shell was considered earlier in [2, 4] on the basis of the equations of the classical Kirchhoff-Love theory.L'vov Physicomechanical Institute, Academy of Sciences of the Ukrainian SSR. Ternopol Branch, L'vov Polytechnic Institute. Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 1, pp. 113–117, January–February, 1972.     

Optimization of a cylindrical composite shell with a viscoelastic core in axial compression

The problem of the optimal design of a composite shell in creep is formulated. The progressive buckling of a cross-wound reinforced cylindrical shell supported on a viscoelastic core is considered as a particular case. The reinforcement structure and shell thickness corresponding to minimum weight for a given load and service life are found.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 3, pp. 442–446, May–June, 1975.     

Stability of a transversely isotropic spherical shell coupled with an elastic foundation

The stability "in the small" of a flat spherical shell with elastic reinforcement is investigated. It is assumed that the shell is made of material (glass-reinforced plastic) with low shear resistance [7, 8], which determines the choice of calculation procedure: generalized applied shell theories of the Timoshenko and Ambartsumyan types [1, 3]. The results obtained are compared with the corresponding results of the Kirchhoff-Love theory.L'vov Polytechnic Institute. Translated from Mekhanika Polimerov, No. 1, pp. 129–131, January–February, 1970.     

Behavior of glass-reinforced plastic cylindrical shells subjected to an external pressure pulse

The transient process of deformation of a cylindrical glass-reinforced plastic shell loaded with an axisymmetric external pressure pulse has been experimentally investigated. It is shown that as the amplitude of the load is monotonically increased (duration fixed), the axisymmetric motion of the shell is characterized first by linear and then nonlinear flexural oscillations.Moscow. Translated from Mekhanika Polimerov, No. 2, pp. 327–330, March–April, 1972.     

Axially symmetrical deformation of an orthotropic layered cylindrical shell

An orthotropic layered cylindrical sheet subject to axially symmetrical loading is considered. A solution free from the hypothesis of the straight normal is presented; the material of the shell is regarded as incompressible in the radial direction. An attempt is made to allow for the real character of the rigid fixing at the edge of the shell. The stressed state in the neighborhood of the edge is analyzed.S. Ordzhonikidze Moscow Aviation Institute. Translated from Mekhanika Polimerov, No. 5, pp. 816–823, September–October, 1972.     

Stability of a laminated spherical shell

The stability "in the small" of a spherical shell consisting of alternating stiff and soft layers is investigated. The spectra of the bifurcation values of the load are found for a closed shell subject to hydrostatic pressure and their dependence on the buckling mode is studied. The effect of the relative stiffness of the layers on the buckling of the shell is investigated.Moscow Power Engineering Institute. Translated from Mekhanika Polimerov, No. 3, pp. 459–464, May–June, 1976.     

Stability of an orthotropic cylindrical shell reinforced by ring ribs with allowance for transverse shear

A detailed discussion is given on the stability of a freely supported orthotropic cylindrical shell reinforced by similar ring ribs (frames) placed at equal distances under the action of a uniform external pressure. The shear is taken into account both in the shell itself and in the frames. The solution obtained is illustrated by examples.Translated from Mekhanika Polimerov, No. 3, pp. 490–495, May–June, 1974.     

Research in the flexural buckling modes of a cylindrical sandwich shell under the action of a temperature field inhomogeneous across its thickness

A solution to the problem on the stability according to the flexural buckling mode is given for a cylindrical sandwich shell with a transversely soft core of arbitrary thickness. The shell is under the action of a temperature field inhomogeneous across the thickness, and its end faces are fastened in such a way (in the axial direction, the face sections of the external layer are fixed, but of the internal one are free) that an inhomogeneous subcritical stress-strain state arises in the shell across the thickness of its layers. It is shown that, under such conditions, the buckling mode of the shell is mixed flexural. To reveal and investigate this mode, equations of subcritical equilibrium and stability of a corresponding degree of accuracy are needed.Translated from Mekhanika Kompozitnykh Materialov, Vol. 40, No. 6, pp. 715–730, November–December, 2004.     

Attenuation of normal waves in a cavity with a liquid in the presence of an elastic shell

The attenuation of normal waves is investigated in a cylindrical cavity of an unbounded viscoelastic medium, in which there is a thin elastic shell filled with a viscous compressible liquid. It is assumed that the absorption of waves in a liquid or solid is small. The effect of the shell thickness on the value of the absorption coefficient of the normal waves is studied.Translated from Matematicheskie Metody i Fiziko-Mekhanicheskie Polya, No. 25, pp. 49–52, 1987.     

Numerical analysis of axisymmetric oscillations of an orthotropic cylindrical shell

The frequency spectrum of shells is analyzed by numerical methods using three-dimensional and applied theories. The axisymmetric oscillations of an orthotropic cylindrical shell with Navier conditions on the edges are investigated. The effect of boundary conditions on the frequency spectrum is also studied numerically.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 55, pp. 106–109, 1985.     

Ductility of nonmetallic hybrid fiber composite reinforcement for concrete

Reinforcing units, FRP, of unidirectional fiber composites for concrete have elastic behavior up to tensile failure. For safety reasons an elongation of 3% at maximum load is usually required for the reinforcement. Ductile behavior with the necessary elongation and stress hardening could be obtained with braided fiber strands around a core of foam plastic, thin glass fiber cylindrical shell, or unidirectional carbon fibers. Braids around a porous core reveal the ductility when epoxy resin breaks up and collapse of core enables the braids to rotate. The same seems to happen at that cross section, where carbon fiber core breaks in tension. The best result is obtained using a cylindrical glass fiber reinforced core shell surrounded with aramid fiber braid.Presented at the Ninth International Conference on the Mechanics of Composite Materials, Riga, October, 1995.Division of Building Materials, Chalmers University of Technology, S412 96 Göteborg, Sweden. Institute of Polymer Mechanics, Latvian Academy of Sciences, Riga, LV-1006 Latvia. Published in Mekhanika Kompozitnykh Materialov, Vol. 32, No. 2, pp. 167–179, March–April, 1996.     

Study of oscillations in a viscoelastic cylindrical shell in an elastic medium

An equation was obtained and solved for oscillations in a viscoelastic cylindrical shell located in the ground. A numerical example is examined.Moscow Electronic Engineering Institute. Translated from Mekhanika Polimerov, No. 1, pp. 178–181, January–February, 1974.     

Refined stability theory for sandwich shells with transversally stiff core. 1. Nonlinear equilibrium equations

A refined version of geometrically nonlinear relationships is proposed for the static thermoelastic response of sandwich shells with face sheets made of composite or homogeneous materials and a transversally stiff core. This theory has primary importance for studying mixed forms of buckling of the bearing sheets, which are mainly realized in the zones of a momentary stress-deformed state of the shell on the whole. An iteration procedure was developed for construction of the model. In the first step, assuming that the core is transversally soft, expressions are derived for the components of the displacement vector after integration of the three-dimensional equilibrium equations. In the second step, the tangential stresses are determined assuming a transversally stiff core to obtain the in-plane stresses and highly accurate transverse normal stresses. The proposed model admits a formal changeover to the model of a shell with a transversely soft core.Center for the Study of Dynamics and Stability. A. N. Tupolev Kazan State Technical University, Kazan, Tatarstan, Russia. Translated from Mekhanika Kompozitnykh Materialov, Vol. 32, No. 4, pp. 513–524, July–August, 1996.     

Stability with the axial compression of an axisymmetrically heated orthotropic cylindrical shell fastened to an elastic cylinder which is pliable with respect to shear

The article gives a solution to the problem of stability with the axial compression of an axisymmetrically heated orthotropic cylindrical shell fastened to an elastic thin-walled cylinder through an intermediate layer. It is assumed that the parameters of the elasticity of the orthotropic shell depend on the temperature, and vary over the thickness of the wall. The intermediate layer is assumed to be isotropic and absolutely rigid in a radial direction, but pliable with respect to axial shear. The thin-walled cylinder is considered to be elastic, isotropic, and unheated.Scientific-Research Institute for Chemical Engineering, Moscow Region. Translated from Mekhanika Polimerov, No. 3, pp. 546–550, May–June, 1970.     

Torsion of laminated cylindrical shells with adhesive interlayers

Based on refined equations of the Timoshenko-type shell theory, the contact stresses in torsion of a two-layer cylindrical shell with an adhesive interlayer are numerically studied. The effect of the geometric and physical-mechanical parameters of the load-carrying layers and adhesive interlayer of the shell on the distribution of the interlaminar tangential stress is analyzed. The results are presented graphically.Presented at the 10th International Conference on the Mechanics of Composite Materials (Riga, April 20–23, 1998).Pidstryhach Institute of Applied Problems of Mechanics and Mathematics, National Academy of Sciences of Ukraine, Lviv, Ukraine. Translated from Mekhanika Kompozitnykh Materialov, Vol. 34, No. 4, pp. 501–506, July–August, 1998.