Dynamic Analysis of Variable Stiffness Nonlinear Energy Sink Enhanced by Adjustable Mass

An active varying stiffness nonlinear energy sink (NES-AVS) characterized by targeted energy transfer and stiffness adjustment can achieve broadband and efficient vibration control. However, under low damping and large external excitation, the damping performance of the vibration absorber requires improvement. A novel NES-AVS vibration absorber enhanced by rotating mass (NES-AVS-RM) is proposed for improving the vibration reduction effects. The rotating mass system, regarded as a time-varying mass, can be adjusted by applying an external force. The dynamic model of the NES-AVS-RM vibration absorber is established, and the variable mass characteristics are studied. Compared with the NES-AVS, the introduction of the rotating mass system can shorten the time to reach the steady state and improve the robustness. The NES-AVS-RM vibration absorber demonstrates the capability of harvesting energy across multiple frequency bands and speeds up the dissipation of vibration energy of the primary structure by the wavelet transform analysis. This study aims to provide an innovative design proposal for the NES.