Ultrasonic scanning of an acoustic medium through a two-layer plate at the critical frequency

The plane problem of ultrasonic scanning of an acoustic medium through a two-layer plate at high frequencies is investigated. In passing, the problem of the localization of oscillations in the neighbourhood of the finite region where the load is applied in such a way as to eliminate the propagation of sonic energy along the plate is solved. The possibility of radiation patterns of acoustic pressure being formed in the acoustic medium is investigated by the stationary-phase method. The theory constructed is illustrated by a series of calculations for a steel-rubber-water system.