Mechanics |
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2006, No. 9
Y.N. Radayev
ON SLIP KINEMATIC OF THE PERFECTLY PLASTIC FLOW ALONG A MAXIMUM SHEAR STRAIN RATE SURFACE
In the paper slip kinematic on a surface of maximum shear strain rate in perfectly plastic continuous media is studied. Sliding on the surface is shown can be realized only along asymptotic directions and only within hyperbolic zones of the surface (wherein the Gaussian curvature of the surface is negative). Integrable equations along asymptotic lines of the maximum shear strain rate surface for the jumps of tangent velocities are obtained. Kinematic equations corresponding to elliptic zones on a maximum shear strain rate surface (i.e. if the Gaussian curvature of the surface is positive) are derived and analyzed.
V.A. Kovalev
AN ASYMPTOTIC APPROACH TO PROBLEMS OF ACOUSTIC WAVES IN ELASTIC SHELLS
An asymptotic approach to solution of stationary problems of scattering of acoustic waves by thin shells is proposed. The approximate solution is obtained by matching various asymptotic models. In the vicinity of zero frequency a refined Kirchhoff–Love theory is applied. In the vicinity of thickness resonance frequencies the long-wave high-frequency approximations are employed. Otherwise the flat layer model is used. A comparison with the exact solution for circular cylindrical and spherical shells confirms high efficiency of the proposed approach for various values of shell parameters.
O.V. Lomovskoj, V.S. Feoktistov, O.V. Feoktistova
A highly effective resource-savings technological process of precision assembly of the pipelines, equipped by devices and a power drive based of shape memory effect and providing layer management of residual pressure in welded seams of pipelines is presented.