Finite Element Simulation of Smart Lightweight Structures for Active Vibration and Interior Acoustic Control

Abstract

The paper presents a numerical approach to active vibration and noise control of smart lightweight structures. The structure is provided with thin piezoelectric wafers as actuators and sensors to control vibrations of the structure. Fully coupled electromechanical field equations were taken into account where model based controllers are applied for design purposes. The objective of vibration control of elastic structures is to reduce interior noise levels. Hence, the mechanical field is also coupled with the acoustic field, and consequently a fully coupled electro-mechanical-acoustical problem needs to be solved. The numerical solution is based on the finite element method, introducing a velocity potential for the acoustic fluid to receive overall symmetric system matrices of the semi-discrete form of the equation of motion. It is shown that the vibro-acoustic coupling can be neglected for controller design purposes, and consequently the modal truncation technique considering only the uncoupled structural modes, can be adapted to vibro-acoustic systems. The behaviour of a smart plate structure coupled with an acoustic cavity is studied as a reference example.