Development of a novel tuned negative stiffness inerter damper for seismic induced structural vibration control

Abstract

Recently, inerter-based devices have been widely explored for possible applications to both civil and mechanical engineering structures for effective vibration control. The control force-displacement relationship of an inerter is related to the vibration frequency, which may lead to excessive force under high-frequency excitation. A negative stiffness element, on the other hand, is effective for the shear force and acceleration response mitigations. The combined use of inerter and negative stiffness element therefore has the potential to further improve the control performance compared to a single device in terms of controlling both the displacement and acceleration responses. In this paper, a novel tuned negative stiffness inerter damper (TNSID) integrating negative stiffness and inerter elements is proposed for seismic induced structural vibration control. A physical realization of the proposed device is developed, and its working mechanism is analysed. The closed-form expressions for its optimal parameters are attained based on the fixed-point theory by minimizing its maximum displacement amplification factor. The proposed TNSID is then implemented to control the vibrations of a single-degree-of-freedom structure and a five-storey building subjected to different excitations to evaluate its feasibility and effectiveness. For comparison, the systems without control, with a tuned viscous mass damper, a tuned inerter damper and a negative stiffness amplifying damper are also investigated. The results reveal that the combination of the negative stiffness and inerter elements endows TNSID with the capacity to attain dual mitigation effects on both the displacement and acceleration responses and widen the effective frequency bandwidth, therefore achieve the most evident control effectiveness compared to the other devices investigated in this study.