On the design of nonlinear damping with electromagnetic shunt damping

Traditional linear electromagnetic shunt damping (L-EMSD) has been studied deeply, however, the vibration isolation performance becomes worse with the increase of linear damping in the isolation region. To overcome the limitation of L-EMSD, this paper proposes two types of nonlinear electromagnetic shunt damping (N-EMSD) to develop nonlinear damping for the broadband vibration isolation of linear vibration isolators (LVIs). Both the two types of N-EMSD consist of two permanent magnets (PMs) and coils, however, the ways to connect to the external shunt circuits and the configurations between the PMs and coils are different. Nonlinear electromagnetic coupling coefficients are analyzed theoretically. The theoretical transmissibility of the LVI with N-EMSD is derived via the harmonic balance method (HBM). Numerical simulations and experiments are conducted to verify nonlinear damping performance of N-EMSD. The results demonstrate that compared to L-EMSD the proposed N-EMSD have similar vibration suppression performance in the resonance region, but are more effective in the isolation region.