Effect of inerter locations on the vibration control performance of nonlinear energy sink inerter

Although the grounded inerter is an effective concept to enhance the control capability of a nonlinear energy sink inerter (NESI), it is usually difficult to be implemented on a large-scale civil engineering structure. Practically, two terminals (or ends) of the inerter can be connected to different locations of the structure (e.g., two stories for a tall building or two segments for a long-span bridge). However, the effect of inerter locations (more specifically, the difference between modal values at two terminals) on the control performance of an NESI remains unclear. In this paper, the impulsive-load-induced vibration control of a simply supported beam and the vortex-induced vibration (VIV) control of a continuous beam bridge are used as case studies to investigate the effect of inerter locations on the control performance of an NESI. The governing equation of a general flexible structure attached with an NESI is deduced based on a reduced-order modal expansion of the primary structure response. The proper NESI stiffness and damping properties are determined through a systematic parametric analysis considering both control effectiveness and robustness. It is found that the NESI performance depends signifi-cantly on the inerter locations. The NESI outperforms the conventional NES as long as the difference between modal values at two terminals is larger than a threshold value that is typically quite small. Both the control effectiveness and robustness of an NESI improve with increasing the difference between modal values at two terminals. The NESI is robust to uncertainties involved in the stiffness and damping properties of the primary structure and the NESI itself. Furthermore, for a multiple-degree-of-freedom structure, an NESI designed for vibration control of the first mode is also effective for controlling the vibrations of several higher-order modes.

Automated summary

This study investigates the effect of inerter locations on the control performance of an NESI, finding that the performance of NESI significantly depends on the inerter locations. The NESI outperforms the conventional NES as long as the difference between modal values at two terminals is larger than a threshold value, and it shows robustness to uncertainties.