An inerter-based electromagnetic damper for civil structures: Modeling, testing, and seismic performance

Abstract

This paper proposes a novel inerter-based damper, termed tuned inertial mass electromagnetic damper (TIMED), to mitigate seismic responses of civil structures. The TIMED consists of three elements, i.e., an inerter, a spring, and an electromagnetic damper, all assembled in parallel. Firstly, a theoretical model is proposed for predicting the damper force and the frequency response of the TIMED, which is then validated by comparison to a set of dynamic tests performed in a TIMED prototype under harmonic excitations. It is shown that, for different parametric conditions, the prediction of the damper performance by the theoretical model well agrees with the experimental results. Besides, both results also indicate that the displacement response and energy dissipation of the TIMED prototype are significantly amplified within its resonance region. Finally, a numerical example is given to demonstrate the control performance of the TIMED in the five-story Kajima-Shizuoka Building against a set of the LA earthquake ground motions. Overall, the TIMED shows a better capacity to reduce the interstory displacement in each floor, compared to the other types of inerter-based dampers and viscous dampers. The proposed TIMED is highly efficient for suppressing the modal responses of targeted vibration modes due to its frequency-dependent amplification mechanism for energy dissipation.