Enhanced lever-type vibration isolator via electromagnetic shunt damping

Abstract

Considering the damping limitation of traditional lever-type vibration isolators (LVIs) in the low-frequency range, electromagnetic shunt damping (EMSD) utilising a lever to amplify the damping force is introduced in this study to improve the vibration isolation performance of LVIs. Negative resistance (NR) and NR resonant shunts were used to compensate for inherent resistance to improve the effect of LVI with EMSD (LVI-EMSD). A theoretical model of LVI-EMSD was established, and displacement transmissibility was derived. The optimal parameters of the NR resonant shunt were derived according to the fixed-point theorem. The effects of the lever ratio, negative resistance, and resonant frequency of the circuit on the vibration isolation performance of the LVI-EMSD were numerically and experimentally analysed. The lever structure can simultaneously tune the natural frequency and damping to improve the vibration isolation performance of the LVI-EMSD. Both the NR and NR resonant shunts effectively produce a considerable damping effect, and the NR resonant shunt outperforms the NR shunt in the low-frequency region. The NR shunt could produce a mass effect when the negative resistance was carefully designed. This study provides guidelines for the design, modelling, and optimisation of LVI-EMSD.