Vibration analysis of a new nonlinear energy sink under impulsive load and harmonic excitation

Abstract

Nonlinear energy sink (NES) is a passive energy absorption device, which plays an important role in suppressing structural vibrations. In this study, the vibration reduction effects of different NESs under different impulsive load amplitudes are revealed, and the dynamics and vibration reduction effects of the combined damping NES under harmonic excitation are analyzed. Firstly, by analyzing the vibration reduction effects of different NESs under impulsive excitation, it is concluded that the vibration suppression effect of the linear damping NES is better than that of the nonlinear damping NES when the excitation amplitude is small, and nonlinear damping NES has better vibration reduction effect than linear damping NES when the excitation amplitude is large. Meanwhile, a model of combined damping NES is proposed. By comparing the vibration reduction effects of different NESs, it is shown that the combined damping NES has a good vibration suppression effect under different impulsive load amplitudes. Secondly, by studying the bifurcation phenomenon and strongly modulated response (SMR) of the system with combined damping NES under harmonic excitation, the influence of system parameters and excitation amplitude on the dynamic characteristics is revealed. Lastly, by applying the energy spectrum, time response and Poincare mapping, it is verified that the combined damping NES has better vibration reduction effect under harmonic excitation.