LAUSR

Based on theoretical and experimental investigations, this paper proposes a nonlinear energy sink (NES) with piecewise linear springs to enhance vibration suppression effects. A cubic nonlinear oscillator is coupled with a piecewise linear spring to form an enhanced NES (E-NES). Without adding a new resonance region and changing the resonance frequency of the primary system, the enhanced NES can achieve better vibration suppression effects. Based on the free vibration and the forced vibration, the effect of piecewise linear stiffness and gap displacement on the vibration suppression is profoundly investigated. Moreover, the parameters of the piecewise spring are optimized through the differential evolution algorithm to obtain the best damping effect of the E-NES. Furthermore, the experiments are conducted to verify the theoretical results. The results show that the E-NES has a better suppression effect on the vibration of the primary structure than that of the cubic NES in most cases. However, it also happens that the vibration suppression effect of the E-NES is weaker than that of the conventional NES. The design parameters can be optimized efficiently by the differential evolution algorithm. Experiments show that vibration elimination efficiency of the E-NES can exceed 90%. Therefore, it is believed that research on using piecewise springs to enhance the vibration suppression efficiency will attract attention.