Active viscous damping system for control of MDOF structures

The development and the applications of a supplemental viscous damping device with active capacity are described. The system of the dampers, defined as Active Viscous Damping System (AVDS) is presented herein. Structural control principles defined here as Active Control Theory (ACT) are used to obtain the control forces at each time step during a given excitation. Control of the damping forces is possible due to the mechanical structure of the proposed AVDS. This system can be efficiently used to enhance the damping of a structure without adding in stiffness and strength. The added damping forces can be adjusted within a wide range. Its efficiency is demonstrated by a numerical simulation of a seven story building subjected to seismic loadings. The simulation shows that the behavior of the damped structure with the AVDS is significantly improved compared to that of an uncontrolled system. Moreover, the response is better than which is obtained by adding either passive viscous dampers or electrorheological damping devices.