Electromagnetic shunt damping for shock isolation of nonlinear vibration isolators

Electromagnetic shunt damping (EMSD) can effectively suppress structural vibrations of linear systems. However, the effects of EMSD on shock isolation for either linear or nonlinear vibration systems have not been studied deeply. This paper investigates the shock isolation of nonlinear vibration isolators (NVIs) with negative resistance electromagnetic shunt damping (NR-EMSD). An NVI that is capable of realizing linear and nonlinear characteristics is constructed. The coupled governing equations of the NVI with NR-EMSD are derived. Shock acceleration ratio (SAR), shock displacement ratio (SDR) and relative displacement ratio (RDR) are employed to evaluate the shock isolation performance of linear vibration isolators (LVIs) and NVIs. Both the numerical simulations and experiments are performed. The results demonstrate that with the increase of negative resistance SDR and RDR decrease in a wide frequency band, SAR decreases in the shock amplification region but increases in the shock isolation region. A higher value of inductance leads to the decrease of the period and is harmful to shock isolation. The shock isolation performance of the NVI with NR-EMSD is better than that of the LVI with NR-EMSD, which demonstrates that a properly designed nonlinear stiffness is beneficial to shock isolation. NR-EMSD could increase damping to improve the shock isolation performance for both linear and nonlinear systems. (C) 2020 Elsevier Ltd. All rights reserved.