Active and Passive Vibration Damping

7Vibration Damping of Structures Using Active Constrained Layer Damping

7.1 Introduction

The performance characteristics of Active Constrained Layer Damping (ACLD) are presented. The ACLD consists of a viscoelastic damping layer that is sandwiched between two layers of piezoelectric sensor and actuator. The composite ACLD when bonded to a vibrating structure acts as a smart treatment whose shear deformation can be controlled and tuned to the structural response in order to enhance the energy dissipation mechanism and improve the vibration damping characteristics.

Particular emphasis is placed on studying the performance of ACLD treatments that are provided with sensing layers of different spatial distributions. The effect of varying the controller gains and the operating temperature on the ACLD performance is determined for beams, plates, and shells. Comparisons with the performance of conventional passive constrained layer damping (PCLD) are also presented.

7.2 Motivation for Using Passive and Active Constrained Layer Damping

In this section, a control theory perspective is presented to motivate the need for ACLD as an effective means for controlling the structural vibrations. In order to illustrate such effectiveness, several structural configurations are considered as displayed in Figure 7.1. The considered configurations include: an undamped structure, a structure treated with an unconstrained damping layer, a structure treated with a constrained damping layer, and a ...