A non-dimensional parametric study of enhanced Active Constrained Layer damping treatments

The purpose of this research is to extend the previous work of Liao and Wang [1, 2] (Journal of Smart Materials and Structures 5, 638-648; Journal of Vibration and Acoustics 120, 894-900) on the Enhanced Active Constrained Layer (EACL) damping treatments and provide more comprehensive results that can be better generalized. For given strain distributions in the host structure and utilizing a self-sensing control law, closed form solutions to the longitudinal motion of the active cover sheet of the EACL are derived. Active, passive, and hybrid (total) loss factors are defined to discuss the damping properties of the treatments. With a non-dimensionalized formulation, this research identifies and examines the major factors that affect the EACL damping characteristics. These factors are: the bending stiffness ratio between the host structure and the constraining layer, the offset distance of the constraining layer from the host structure, the strain distribution in the host structure, the active control gain, the characteristic length of the EACL, the Viscoelastic Material (VEM) loss factor, and the stiffness distribution of the edge elements. The effects of these factors on open-loop and closed-loop damping characteristics of the treatment are discussed. This investigation provides insights and design guidelines to generic one-dimensional EACL surface damping treatments. (C) 1999 Academic Press.