Transient response of a moving spherical shell in an acoustic medium

A ring-stiffened spherical shell is submerged in an acoustic medium. The shell is thin and elastic. The acoustic medium is inviscid, irrotational and compressible. The center of mass of the shell is subjected to a translational acceleration which is an arbitrary function of time. The absolute displacements of the shell are expressed in terms of the relative displacements and the displacement of the base of the shell, base being defined as the rigid ring placed at the equator. The motion of the acoustic medium is governed by the wave equation. The transient response of the shell is investigated numerically. The results are compared with the results of the in-vacuo response. The effects of the plane wave approximation and the base velocity on the transient response of the shell are studied. The numerical results show that the plane wave approximation accurately predicts the response of the shell in the acoustic medium for short times after excitation. The displacements of the shell in fluid are larger than those in vacuo. But when the base of the shell is restrained from translating, the displacements in fluid are smaller than those in vacuo. Therefore, base translation has a very significant effect on the transient response of the shells submerged in an acoustic medium.     

Stress-strain analysis of a composite truncated conical shell

The stress-strain state of a nonshallow truncated conical shell made of a composite material and subjected to axial forces at the ends is studied. A variational difference method is used. Calculations are carried out for an orthotropic shell with low shear stiffness __________ Translated from Prikladnaya Mekhanika, Vol. 43, No. 7, pp. 66–72, July 2007.     

Thin-walled conical shell drawing from a plane blank

We present a model of the nonstationary process of drawing a thin-walled conical shell from a plane blank, which is based on the membrane theory of plastic form change of a rigidplastic body with the contact friction, the thickness variation in the sense of von Mises, the material strengthening, and the die and the matrix radii of rounding taken into account. The computational model determines the thickness and strengthening distributions along the shell generator, the graph of technological force, and the process critical parameters at which the blank fracture may occur.     

Stress-strain state of a ribbed conical shell at resonance

Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 27, No. 4, pp. 25–28, April, 1991.     

Magnetoelastic nonlinear deformation of a conical shell of variable stiffness

A complete system of equations of nonlinear magnetoelasticity of shells is presented. A resolving system of equations of a conical shell of variable thickness is constructed for the axisymmetric case. A numerical example of a flexible shell illustrates the possibility of using the proposed technique to solve this class of problems. T. G. Shevchenko National University, Kiev, Ukraine. Translated from Prikladnaya Mekhanika, Vol. 35, No. 11, pp. 34–39, November, 1999.     

Torsional buckling of generally laminated conical shell

Meccanica - Buckling of generally laminated conical shells under uniform torsion with simply-supported boundary conditions is investigated. The Donnel type strain displacement relations are used to...     

Vibration damping characteristics of a thin cylindrical shell stiffened with viscoelastic rings

Summary The vibrations of a circular cylindrical shell reinforced with viscoelastic rings are theoretically treated. The frequency equation is derived using the transfer matrix together with the stiffness matrix. The numerical example surveys the damping effect of viscoelastic rings upon the dynamic behavior of the system.

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Übersicht Die Schwingungen einer durch viskoelastische Kreisringe versteiften dünnwandigen Kreiszylinderschale werden theoretisch behandelt. Die Frequenzgleichung wird durch eine Kombination der Übertragungsmatrix mit der Steifigkeitsmatrix abgeleitet. An numerischen Beispielen wird ein Überblick über die dämpfende Wirkung der viskoelastischen Kreisringe auf das dynamische Verhalten des Systems gewonnen.

     

Asymptotic method for analysis of a conical shell under local loading

Differential equations of the general theory describing the stress-strain state of conical shells are very complicated, and when computing the exact solution of the problem by analytic methods one encounters severe or even so far insurmountable difficulties. Therefore, in the present paper we develop an approach based on the method of asymptotic synthesis of the stressed state, which has already proved efficient when solving similar problems for cylindrical shells [1, 2]. We essentially use the fourth-order differential equations obtained by Kan [3], which describe the ground state and the boundary effect. Earlier, such equations have already been used to solve problems concerning force and thermal actions on weakly conical shells [4–6]. By applying the asymptotic synthesis method to these equations, we manage to obtain sufficiently accurate closed-form solutions.     

Stability of a multilayered composite conical shell under uniform external pressure

The stability of equilibrium of a layered composite circular conical truncated shell loaded with uniform external pressure is investigated. A parametric analysis of the critical pressure intensities is carried out with allowance for the transverse shear, the moment character of the subcritical state of equilibrium, and the subcritical strains. Kemerovo State University, Kemerovo 650043. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 40, No. 4, pp. 198–207, July–August, 1999.     

Effect of rotation on frequency characteristics of a truncated circular conical shell

In the current dynamic model of rotating truncated conical shells, the expressions of centrifugal and coriolis accelerations and initial hoop tension were incomplete and some terms were missing. This might cause the frequency characteristics of rotating conical shells to be overestimated (or underestimated). Therefore, the effects of rotation upon frequency characteristics of rotating truncated conical shell are studied in the paper. Accurate expressions of centrifugal and coriolis accelerations and initial hoop tension are derived, and then a modified dynamic model for the rotating truncated conical shell is presented. The generalized differential quadrature method is utilized to obtain the natural frequencies. The influences of various boundary conditions and rotating speed on the free vibration of the conical shell are discussed in detail. Through comparison analysis, the errors in current model are also pointed out.