Series NESs for Suppressing Strongly Forced Vibration

Improving the ability of nonlinear energy sink (NES) to suppress large vibrations under strong excitation has been widely concerned. Moreover, distributing NES to suppress multimodal resonances is also an issue that deserves more attention. This paper investigates the distribution strategy of the series NES in suppressing the vibration of a two-degree-of-freedom (2-DOF) system. Dynamic models are developed for two strategies: centralized and distributed series NES. The vibration reduction efficiency of these strategies is compared, and the approximate results obtained from the analytical analysis were verified using numerical methods. The research results indicate that distributing the series NES among different vibration sources can lead to improved vibration reduction performance. Moreover, the distributed vibration reduction strategy exhibits greater adaptability to different modes of primary system. Furthermore, while keeping the total additional weight of the NES unchanged, the effects of the series NES and 1DOF NES on vibration control were compared. The results demonstrate that, under large amplitude excitation, the series NES has a better vibration reduction effect than the 1DOF NES when using distributed NES to control the vibration of a 2-DOF system. Additionally, by studying the energy transfer between NES oscillators in series, the series NES with high stiffness asymmetry exhibits superior vibration reduction. The findings of this study contribute to the advancement of research on the NES control of strong excitation vibration and multi-mode structure vibration.