Radiation from point source within a hollow elastic cylinder in an acoustic medium

Conclusions An accurate solution has been obtained for the sound emission by a point source in a complex fluid-elastic system. Analytical representation of the wave characteristics is converted to the form of contour integrals, permitting effective numerical estimates of the influence of the geometric and physical parameters of the waveguide structure. A computational algorithm has been proposed, and its effectiveness has been estimated. The existence of two types of surface waves that are not subject to radiative damping has been established. Translated from Prikladnaya Mekhanika, Vol. 33, No. 5, pp. 20–29, May, 1997.     

Interaction of a transient cylindrical acoustic wave with a multimode cylindrical piezoelectric transducer

The interaction between a transient cylindrical acoustic wave and a cylindrical piezoelectric transducer with sectioned electrodes is considered. The solution is obtained using the integral Laplace transform with respect to time (in the form of natural-mode series). In going to the space of originals, the problem is reduced to integral Volterra equations. The results of calculation are presented for various angular dimensions of the electrode sections and various distances from the wave source to the piezoelectric transducer. Translated from Prikladnaya Mekhanika, Vol. 35, No. 10, pp. 37–45, October, 1999.     

Nonsteady-state problem of the emission of acoustic waves by a cylindrical piezoelectric transducer near a planar boundary

We study processes developing when a cylindrical piezoceramic shell with split electrodes located near a planar boundary is excited by nonsteady-state electrical signals. We solve the problem using the Laplace integral transform with respect to time. The boundary conditions are satisfied in the space of the originals. Under these conditions, the unknowns are found from a system of Volterra integral equations. We present the calculation results and their analysis. Translated from Prikladnaya Mekhanika, Vol. 33. No. 12, pp. 60–67, December, 1997.     

Multichannel resonant scattering theory applied to the acoustic scattering by an eccentric elastic cylindrical shell immersed in a fluid

The multichannel resonant scattering theory is developed in the field of the acoustic scattering. Because it takes into account mode conversions, this theory deals with a nondiagonal scattering S matrix. It is used here for the study of the acoustic scattering by an elastic eccentric shell. In this case the mode conversions are due to the fact that the Lamb type waves propagating around the shell are submitted to a reflection-refraction phenomenon when passing through the thinner part of the shell. All informations on the resonances are provided by the study of Argand's diagrams. In particular, the partition of the resonant energy over all the vibration modes of the scatterer is obtained. A numerical validation of the multichannel resonant scattering theory is then given. We focus our attention on the bifurcation of resonances, and the existence of angular diagrams with an odd numbers of lobes; both are due to mode conversions. Experiments have been performed which are in agreement with the theoretical results.     

Shrink fit of an elastic layer having a cylindrical cavity

Summary This paper deals with the problem of determining the stress distribution in an elastic layer with a cylindrical cavity when the mixed boundary conditions are prescribed on the curved surface of the cylinder. The problem is simplified to that of finding the solution of dual integral equations arising from the mixed boundary conditions. These dual integral equations are subsequently reduced to a singular integral equation. The solution of this integral equation is obtained numerically, and the quantities of physical interest are calculated.     

On the load transfer from a rigid cylindrical inclusion into an elastic half space

The present paper examines the problems related to the axial, lateral, and rotational loading of a rigid cylindrical inclusion which is embedded in bonded contact at the boundary of an isotropic elastic half space. The rigid inclusion is modeled as a field of distributed forces which represent the normal and shear tractions that act on the inclusion-elastic-medium interface. The intensities of these distributed tractions are determined by enforcing displacement compatibility conditions at discrete locations of the interface. These compatibility conditions are derived from rigid-body displacement modes appropriate for each loading. The results derived from this numerical scheme are compared with equivalent results derived via analytical techniques which focus on the solution of the governing integral-equation schemes and other approximate-solution schemes. The numerical results presented in the paper illustrate the manner in which the generalized stiffnesses of the embedded inclusion are influenced by its geometry and Poisson's ratio of the half-space region.     

Propagation of harmonic elastic waves from a curvilinear cylindrical cavity

International Applied Mechanics -     

Interaction of a spherical shockwave and an elastic circular cylindrical shell

The paper studies the interaction of a spherical shock wave with an elastic circular cylindrical shell immersed in an infinite acoustic medium. The shell is assumed infinitely long. The wave source is quite close to the shell, causing deformation of just a small portion of the shell, which makes it possible to represent the solution by a double Fourier series. The method allows the exact determination of the hydrodynamic forces acting on the shell and analysis of its stress state. Some characteristic features of the stress state are described for different distances to the wave source. Formulas are proposed for establishing the safety conditions of the shell.Translated from Prikladnaya Mekhanika, Vol. 40, No. 9, pp. 94–104, September 2004.