A comparison of active, passive and hybrid damping in structural design

Abstract

The QUAD4 element found in ASTROS is modified to include piezoelectric layers and a viscoelastic layer. These features are developed and combined to allow for active damping using piezoelectrics, passive damping using constrained layer damping (CLD) and hybrid damping in the form of active constrained layer damping (ACLD). These features are implemented in the QUAD4 element as additional layers in the composite layup definition. The development of these features are presented and the integrity of the implementation is validated by comparing with results found in the literature. A patch placement process is developed which allows the damping treatment to move on the structure and to distort its shape so as to improve the damping characteristics of the design. The structure and damping treatment are simultaneously designed for minimum weight with constraints on the frequency and damping ratio. Both beam and plate structures are used to illustrate this concept. A proportional-derivative controller is used for the active control of the beam and the linear quadratic regulator (LQR) is used to design the active controller for the plates.