Active viscous damping system for control of MDOF structures

The development and applications of a supplemental viscous damping device with active capacity are described. The system of the dampers de ned as active viscous damping system (AVDS) is presented herein. Structural control principles de ned here as active control theory (ACT) are used to obtain the control forces at each time step during an excitation. Control of the damping forces is possible due to a mechanical structure of the proposed AVDS and do not require the input of large power and energy. This system can be e ciently used to enhance the damping of a structure without adding in sti ness and strength. The added damping forces can be adjusted in a wide range. Its e ciency is demonstrated by a numerical simulation of a seven-storey building subjected to earthquakes. The simulation shows that the behaviour of the damped structure with the AVDS is signi cantly improved compared to that of an uncontrolled system. Moreover, the response is better than that of adding either passive viscous dampers or electrorheological damping devices. Copyright ? 2001 John Wiley & Sons, Ltd.