Theoretical and experimental analyses of structures with supplemental clutching inertia devices

Abstract

AbstractClutching inertia device (CID) is a novel device that incorporates the function of an inerter and the clutching effect that can be provided by a ratchet. In this paper, the performance of an SDOF system with supplemental clutching inertia is investigated through theoretical analyses and experimental tests. First, the dynamic equation for a structure with a CID is built in the form of multi‐body motion. Second, an inertia device (ID), a CID, and an inertia‐enhanced CID (ECID) by reducers are designed for dynamic testing in a small‐scale steel structure. Third, the influence of clutching effect, flywheel inertia and accessory damping of the CID on the structural response is analyzed through a comparative study of numerical simulation and shaking table tests under harmonic and seismic excitation. The results confirm previous predictions that the clutching effect helps to reduce the resonant response of the structure and that the increase in flywheel inertia can further mitigate the resonant response when considering certain accessory damping in the CID. The increase in accessory damping, either viscous damping or friction damping, will obviously reduce the resonant response and resonant frequency of the controlled structure, and the structure with the ECID shows better performance than that of CID when considering the same accessory damping. It is confirmed that the tested CIDs improved the structural seismic performance by slightly prolonging the fundamental structural period and prominently controlling the response in resonant frequency and high frequency owing to the effect of supplemental clutching inertia and accessory damping.