SEISMIC PROTECTION OF PRECISION EQUIPMENT USING

Without seismic protection, precision equipments in high-technology factories can be fragile and vulnerable to earthquake attacks. In this study, a smart isolation system (SIS), which consists of sliding-type bearings and a variable friction device, is proposed and its performance for the seismic protection of precision equipment is investigated. Due to the static friction of the sliding bearings, motion of the SIS will not be activated nor amplified by a low-amplitude excitation, such as ambient vibration. When the SIS is activated by an earthquake, the slip force of the variable friction device, which provides a resistant and energy dissipating force to the system, can be regulated on-line by a controller. In order to suppress the response of the isolated equipment in a severe earthquake or a near-fault earthquake, SIS is able to effectively reduce the acceleration of equipment, and at the same time prevent a large isolator displacement that may damage the underlying piping system of the equipment. This is usually can not be achieved by a conventional passive isolation system