FUNDAMENTAL PERFORMANCE OF A HYDRAULICALLY ACTUATED FRICTION DAMPER FOR SEISMIC ISOLATION SYSTEM BASED ON THE SKYHOOK THEORY

Abstract

A seismic-isolation damper system consisted of a water tank and a high-porosity porous media has been proposed, and its fundamental performance is investigated by numerical computations and model experiments. A time-domain numerical model, coupled with CFD to consider the interaction between the porous media with the fluid motions, was newly developed. Shaking-table experiments with a water tank were conducted to confirm the damper's performance and to verify the validity of the numerical model. Results of the forced vibration tests showed the immobility of fluid inside the stationary porous media that highlighted an established passive damping control strategy which is based on the skyhook damper theory. The frequency-sweep studies confirmed the characteristics of the damper such as the non-increase of acceleration responses of building in the high frequency region as a basic characteristic of the skyhook damper. Numerical parametric studies with the variation of the fiber diameters of the porous media and the dimensions of water tank were also carried out to clarify the region of the immobility of fluid inside the porous media.