Experimental study on thin three-layer rings with a pliable filler

The bearing capacity of thin three-layer rings containing a pliable filler and exposed to internal and external stresses has been studied experimentally. The deformation and strength properties of the filler have been examined. The initial stresses in the rings examined have been determined by application of three methods; their effect on the bearing capacity has been estimated.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 6, pp. 1032–1037, November–December, 1974.     

Study of the effect of asymmetric arrangement of the layers on the stability of three-layer cylindrical shells in axial compression

The stability of a three-layer cylindrical shell under axial compression is examined in a three-dimensional linearized formulation. The load-bearing layers are assumed to be orthotropic, while the binder is modeled by an isotropic body. The effect of asymmetric arrangement of the layers and the mechanical characteristics of the material on the critical strains is determined.Translated from Teoreticheskaya i Prikladnaya Mekhanika, No. 19, pp. 103–106, 1988.     

Investigation of stressed-strained state of three-layer cylindrical shells under the action of localized loads

The problem of the determination of the stressed-strained state of three-layer cylindrical shells with a light filler under the action of localized loads is solved by means of semimomentless hypotheses. By using single trigonometric series, the solution is reduced to integration of ordinary differential equation of the fourth order, similar to the Vlasov's equation. Decisive relationships were obtained for the components of the stressed-strained state of an asymmetric three-layer packet. A solution is given for a series of problems of the action of differently applied radial forces on a long cylindrical shell.Moscow. Translated from Mekhanika Polimerov, No. 2, pp. 300–305, March–April, 1975.     

Optimized synthesis of cylindrical shells of reinforced plastics with elastic filler for stable performance

A cylindrical shell of reinforced plastic with an elastic filler is optimized. Limited local stability and certain geometrical constraints are taken into account. The method of projectable gradients, according to J. B. Rosen, is used for optimizing the design. Optimum reinforcement structures are obtained for a shell, depending on the stiffness of the elastic filler.     

Stress concentration in a three-layer plate with two cylindrical cavities

The stressed state of a thick three-layer plate with two circular holes is studied. Resolving functions are expressed in terms of Kolosov-Muskhelishvili integral potentials and modified Bessel functions. The problem is reduced to solving an infinite set of linear algebraic equations.Translated from Teoreticheskaya i Prikladnaya Mekhanika, No. 18, pp. 25–28, 1987.     

An experimental study of the vibrations of cylindrical shells with holes

We give the results of an experimental study of the frequencies and shapes of the natural vibrations of thin-walled cylindrical shells of revolution weakened by cuts; these results were obtained by the method of holographic interferometry. We establish the effect of the profile and the number of holes, reinforcement by elastic ribs, and attached solid bodies on the fundamental dynamic characteristics of the shell system. We describe the method by which the experiment was conducted. Four figures, 2 tables. Bibliography: 3 titles. Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 27, 1997, pp. 121–125.     

Use of three-dimensional model of filler in stability problems for triple-layer shells with delaminations

Mechanics of Composite Materials -     

Spectra of the eigenfrequencies and regions of dynamical instability of cylindrical shells with elastic filler in the case of nonaxisymmetrical vibrations

Conclusions 1. The number of natural vibration frequencies in any frequency interval for an empty cylindrical shell increases in direct proportion to the second power of the interval size, and for a shell with filler — in direct proportion to the third power of it.2. The widest (and also located at the smallest frequencies) dynamical instability region of a cylindrical shell with elastic filler corresponds to nonaxisymmetrical modes of wave formation.3. The limiting transition in the equations of this paper in the case of the frequency of the driving force tending to zero results in an expression for the critical static force for a shell with an incompressible filler. Numerical calculations in this case show, in particular, an increase of the critical force upon an increase in the modulus of elasticity of the filler, which has been noted in a number of the papers of other authors.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. P. Stuchki Latvian State University, Riga. Translated from Mekhanika Polimerov, No. 2, pp. 263–269, March–April, 1977.     

Parametric vibrations of cylindrical shells with a viscoelastic core

The method of calculating the axisymmetric and nonaxisymmetric parametric vibrations of a cylindrical shell bonded to an elastic core [2] is extended to the case of hollow and solid viscoelastic cores by substituting for the material moduli in the equations of motion of the core integral operators with kernels in the form of an exponential and a sum of exponentials. Expressions are given for the reaction of the viscoelastic core, together with the equation of the boundaries of the spectrum of principal regions of dynamic instability. The effect of relaxation time and the long-term modulus of elasticity of the core on the shape and location of the regions of dynamic instability is analyzed.     

Vibrations of thin cylindrical shells with a periodic structure

Free vibrations of thin linear–elastic Kirchhoff–Love cylindrical shells, having a periodic structure along one direction tangent to the shell midsurface, is considered. In order to take into account the effect of the periodicity cell size in this problem, a new averaged non–asymptotic model of such shells, proposed by Tomczyk (2006), is applied. The new additional higher–order free vibration frequencies dependent on the microstructure size will be derived and discussed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)