VIBROACOUSTIC DYNAMICS OF HETEROGENEOUS MEDIA AND NPP STRUCTURES
Vibroacoustic dynamics of heterogeneous media and systems includes a wide range of research areas. These include the dynamics of multiphase dispersed media, saturated with liquid natural or artificial porous media and composite materials. One of the most important areas is vibroacoustic dynamics of machines and devices and nuclear power plants, in particular. Such parts of a NPP, as the core, consisting of a large number of fuel assemblies, fuel assemblies consisting of bundles of fuel elements, heat exchangers and steam generators with tube bundles, in some dynamic problems should be treated as pseudohomogeneous medium with some effective dynamic properties, reflecting the processes of interaction of the rode-shaped elements with the coolant. The results of theoretical and experimental studies describing the dynamics of dispersed media and heterogeneous systems from the unified position are given in this paper. Thus, in particular, the dependencies for effective dynamic density and viscosity of liquid translational dispersion media reflecting a relaxation nature sound dispersion in suspensions emulsions and two-phase bubble media were obtained. Resonant dependencies for solid dispersion media (composites) as well as for bundles of elastic rods or tubes in a liquid coolant resulting in significant and vibroacoustic effects of practical importance were also obtained. To illustrate the feasibility and effectiveness of using the concept of effective dynamic properties of heterogeneous media dynamic problems of free oscillations of a shell with a liquid and a bunch of elastic rods as well as gravitational oscillations of a fluid with a free surface in a tank with a bundle of rods are considered.