Analysis Of The Acoustic Reflection From The Underwater Elastic/Piezoelectric Bi-laminated Plate

Using matlab, the acoustic reflected pressure from a submerged elastic/piezoelectric bi-laminated plate is calculated. The active acoustic control method is used to cancel the reflected pressure of the fluid. Applying an appropriate voltage across the piezoelectric layer, the reflected pressure of a certain point in the fluid is cancelled, and the reduction effect on the reflection is localized in a small region around the points where the cancellation occurs. Using the finite difference method and boundary integral method, we transform the reflected pressure of the fluid into force boundary condition of the fluid-solid interactive surface. Applying the finite difference method, the displacements of the plate are computed. And as followed, Green function is applied to calculate the total reflected pressure of the fluid. An appropriate voltage across the piezoelectric layer can cancel the reflected pressure of a certain point in the fluid. In a cone of the fluid, the reflection reduction exists at the region around this point. And the control voltage depends on the frequency ,the angle(for plane wave),and the position of the point source( for the point source wave) of the incident acoustic wave. It also relies on the position of the point where cancellation occurs. When the point of the point source incident acoustic wave is far enough away from the plate, it can be considered as the plane wave. The reflected pressure of the fluid is similar between the plane acoustic wave and the point source acoustic wave. And comparation of the reflected pressure in fluid between this two kinds of acoustic waves is demonstrated in this article.