Active control of harmonic sound transmission into an acoustic enclosure using both structural and acoustic actuators

TLDR

The study investigates active control of harmonic sound transmission into a structural‑acoustic enclosure, aiming to globally reduce the internal sound field and examine the roles of structural and acoustic actuators. The authors model a rectangular enclosure with five rigid walls and a flexible plate, and compare three control configurations—single point‑force actuator, single acoustic piston, and a hybrid of both—to reduce sound transmission. Analytical and experimental results show that a point‑force actuator suppresses plate‑dominated modes, an acoustic piston suppresses cavity‑dominated modes, and a hybrid configuration effectively controls both, making it the preferred approach.

Abstract

This paper describes an analytical and experimental investigation into the active control of harmonic sound transmission in a structural-acoustic coupled system. A rectangular enclosure is considered that has five acoustically rigid walls and a flexible plate on the remaining side through which a harmonic sound wave is transmitted into the enclosure. The control system is designed to globally reduce the sound field inside the enclosure, and the roles of structural and acoustic actuators are of particular interest. Three control configurations, classified by the type of actuators, are compared and discussed. They are: (i) use of a single point-force actuator, (ii) use of a single acoustic piston source, and (iii) simultaneous use of both a point-force actuator and an acoustic piston source. It is shown both analytically and experimentally that the point-force actuator is effective in controlling plate-dominated modes while the acoustic source is effective in controlling cavity-dominated modes. Since the transmitted sound field is governed by both plate- and cavity-dominated modes, the hybrid use of both types of actuators is shown to be a desirable configuration for the active control of sound transmission into a structural-acoustic coupled system.