Active Constrained Layer Damping of Seismic Excitations

This paper aims at demonstrating the feasibility of Active Constrained Layer Dampers (ACLD) as an effective means for damping out seismic-induced vibrations of structures. The ACLD concept is motivated by the destructive effects that seismic excitations have on most of the uncontrolled structures. The effectiveness of the ACLD in enhancing the damping characteristics of conventional visco-elastic dampers is demonstrated experimentally for structures subjected to base excitations. Classical identification methods are used to identify a mathematical model that describes the interaction between the vibrating structures, the ACLD system and the seismic excitation. The model is integrated with a robust Continuous Sliding Mode (CSM) controller to reject the effect of the seismic excitations acting on vibrating structures with uncertain dynamic parameters. In this manner, the ACLD and the CSM algorithm present a simple but yet powerful alternative to classical control methods for rejecting seismic excitations and accommodating wide range of parameter uncertainty. The emphasis, in this paper, is placed on multi-story two-dimensional scaled structures which are provided with diagonal braces of the ACLD. However, the techniques developed can be readily extended to three-dimensional and larger structures.