Impact of Damper Stiffness and Damper Support Stiffness on the Performance of a Negative Stiffness Damper in Mitigating Cable Vibrations

Abstract

Due to the superior performance of negative stiffness damper (NSD), its application to the vibration control of bridge stay cables attracts much research attention in recent years. In the current study, an experimental study on the dynamic response of a cable-NSD system is conducted to investigate the effect of negative damper stiffness and damper support stiffness on the efficiency of NSD. In particular, the impact of the latter, which was only reported in a recent analytical study, will be verified in the lab. A numerical simulation is performed to not only validate the experimental results, but also provide a comprehensive evaluation on the influence of various system parameters on NSD performance. An NSD design tool is developed to predict optimum damper size and the corresponding maximum achievable modal damping ratio of a cable-NSD system. Results show that when the stability criterion is satisfied, choosing stronger negative damper stiffness would enhance NSD efficiency. The impact of support stiffness on NSD performance depends on the magnitude of damper stiffness. Attach an NSD to a cable having larger sag and/or higher bending stiffness would yield a lower maximum achievable system modal damping ratio.