Aseismic Design of Structure-Equipment Systems Using Variable FrequencyPendulum Isolator

摘要

Several sliding isolation systems such as friction pendulum system (FPS) have emerged as very usefulvibration control systems incorporating isolation, energy dissipation and restoring mechanism in one unit. However,these systems often have practical limitations and are not very effective when the input excitation level issignificantly different from the designed level. To overcome these limitations while preserving the advantages, anew system called the variable frequency pendulum isolator (VFPI) has been developed by the authors. The naturalperiod of VFPI varies with horizontal sliding displacement leading to a more robust isolation system. In this paper,it has been shown that isolating a structure using VFPI is very effective for vibration control of structure-equipmentand other similar primary-secondary systems. An example five-storey shear structure with equipment mounted at itstop has been analysed to demonstrate the effectiveness of VFPI. It is found that VFPI provides better performancecompared to other friction isolation systems, and excellent response reduction is observed for a wide range ofequipment properties.