Performance Enhancement by Exploiting Geometrical Nonlinearity of Inerters in a Two-Stage Vibration Isolator

Abstract

This research proposes a two-stage vibration isolation system (TS-VIS) exploiting geometrical nonlinearity by inerters for performance enhancement. Lateral inerters are added to upper and lower stages creating geometric nonlinearity. The transmissibility and power flow indices are used for the performance evaluation. It is demonstrated that the inerters in both stages of the TS-VIS can enhance substantially the effectiveness of isolation at low frequencies by bending and shifting the resonance peaks in the force and energy transmission curves to the left while reducing the peak heights in these curves. It shows the use of inerters introduces a local minimum in the transmissibility curve which can be exploited for significant reduction in vibration transmission at a desirable frequency. By tailoring the inertance ratios for both stages of the TS-VIS, further improvements on the performance can be achieved by extending the frequency range of effective isolation. This work shows the benefits of using nonlinear inerters in the TS-VIS to obtain superior low-frequency isolation performance, which is potentially applicable in engineering systems such as floating raft structures.