A magnetic nonlinear energy sink with quasi-zero stiffness characteristics

Due to their reliable strong nonlinear characteristics, magnetic forces have been used to design nonlinear energy sinks (NES). However, the linear magnetic force affects the performance of NES. In this paper, a quasi-zero stiffness magnetic nonlinear energy sink (QZS-MNES) is proposed. Negative stiffness is introduced to counteract the linear part of the magnetic force. Based on the magnetic force expression of the permanent magnet, the dynamic equations of the linear oscillator (LO) coupled with the QZS-MNES are established. The dynamic characteristics are analyzed by numerical and approximate analytical solutions. Transient response and steady state response are used to discuss the effect of linear magnetic force on the vibration suppression efficiency. Moreover, the vibration suppression of QZS-MNES is compared with the magnetic nonlinear energy sink (MNES) with linear stiffness and the triple-magnet magnetic suspension dynamic vibration absorber (TMSDVA), respectively. The results show that compared with MNES, the elimination of linear magnetic force can improve the parameter adaptability of NES. Compared with TMSDVA, QZS-MNES not only has a better parameter adaptability, but also has a stronger vibration suppression ability. The parameter adaptability of QZS-MNES is verified by particle swarm optimization (PSO) algorithm. In conclusion, the QZS-MNES proposed in this paper is an effective and highly adaptable vibration control strategy. Furthermore, the necessity of eliminating linear stiffness in NES is illustrated.