The Effect of Inhomogeneity of Elastic Properties on the Stress State in Composite Cylindrical Panels

The effect of inhomogeneity of elastic properties in the circumferential direction on the distribution of stress and displacement fields in orthotropic cylindrical panels is studied. The mechanical properties of the panels and the load acting on them are constant in the axial direction, which makes it possible to neglect the influence of the curvilinear ends. From the initial relations of a three-dimensional problem of the elasticity theory of inhomogeneous anisotropic bodies, a resolving system of partial differential equations is obtained, whose solution is presented in the form of truncated Fourier series, so that the conditions of free support of the rectilinear ends are satisfied. This allows us to separate the variables and to get a system of ordinary high-order differential equations, which is integrated by a stable numerical method. The problem on the stress-strain state of an orthotropic composite panel with a varying relative volume content of reinforcing elements in the circumferential direction is solved. The effect of the change in the reinforcement density on the stresses and displacements of the panel is studied.     

Influence of geometrical and mechanical parameters on the stress-strain state of closed nonthin conical shells

An approach developed to solve boundary-value problems is used to analyze the effect of geometry and orthotropy parameters on the displacement and stress fields in nonthin orthotropic conical shells Translated from Prikladnaya Mekhanika, Vol. 44, No. 10, pp. 52–62, October 2008.     

Refined analysis of the stress state of orthotropic elliptic cylindrical shells with variable geometrical parameters

An approach developed earlier to solve boundary-value problems is used to analyze the behavior of the stress-strain state of orthotropic elliptic cylindrical shells with variation in the geometric parameters of their cross section at constant volume (weight) Translated from Prikladnaya Mekhanika, Vol. 44, No. 9, pp. 53–62, September 2008.     

Soft dipole mode in 8He

The low-lying spectrum of ⁸He was studied in the ³H(⁶He, p)⁸He transfer reaction for small center of mass angles. The 0⁺ ground state (g.s.) of ⁸He and excited states, 2⁺ at 3.6–3.9 MeV and (1⁺) at 5.3–5.5 MeV, were populated with cross sections of 200, 100–250, and 90–125 μb/sr. Some evidence for the excited state at about 7.5 MeV can be found in the data. The possible nature of the near-threshold anomaly above 2.14 MeV in ⁸He is related to the population of a 1⁻ continuum (soft dipole excitation) with a peak energy value at about 3 MeV. This assumption can probably resolve the problem of a large uncertainty existing in the experimental data on the ⁸He 2⁺ state energy. The article is published in the original.     

Influence of Anisotropy on the Response Characteristics of Finite Cylinders Under Free Vibrations

A numerical–analytical approach is proposed to solve a problem on the free vibrations of cylindrical bodies. The approach is based on three-dimensional elastic theory and the semianalytic finite-element method. The free vibrations of isotropic and anisotropic solid cylinders of finite length are examined. It is studied how boundary conditions and mechanical and geometrical parameters affect the distribution of dynamic properties. The efficiency of the approach proposed is tested by comparing results produced by different approaches     

Stress analysis of longitudinally corrugated hollow orthotropic elliptic cylinders

The stress state of longitudinally corrugated hollow orthotropic elliptic cylinders is analyzed using discrete Fourier series and discrete orthogonalization     

Free vibrations of shallow nonthin shells with variable thickness and rectangular planform

The free vibrations of shallow orthotropic shells with variable thickness and rectangular planform are studied. The shear strains are taken into account. The spline approximation of unknown functions is used. The natural frequencies are calculated for different boundary conditions. The dependence of the natural frequencies on the curvature of the midsurface is examined. The natural frequencies of shells with constant and variable thickness are compared     

Influence of geometrical parameters on the stress state of longitudinally corrugated elliptic cylindrical shells

An approach developed to solve static problems for longitudinally corrugated elliptic cylindrical shells is used to analyze the influence of their geometric parameters and thickness on the stress–strain state. The circumferential distribution of stresses and displacements is analyzed for different values of the aspect ratio and number of corrugations Translated from Prikladnaya Mekhanika, Vol. 45, No. 2, pp. 91–98, February 2009.     

Spline-approximation solution of stress–strain problems for beveled cylindrical shells

The problem of bending of beveled circular cylindrical shells is solved by parametrizing the shell and reducing the two-dimensional boundary-value problem to a one-dimensional one by the spline-collocation method. This problem is solved by the stable discrete-orthogonalization method. The effect of the variability of the geometrical parameters on the displacement fields of circular cylinders is analyzed