Research on Vibration Suppression of Grounded Stiffness Nonlinear Energy Sink

Nonlinear energy sinks (NESs) have been widely applied as passive control units in the field of vibration control. In this study, a grounded combined-stiffness NES is proposed, which consists of grounded linear stiffness and grounded cubic stiffness. The vibration suppression performance of the model under different excitations is investigated. First, the slow-varying equations of the system are derived using the complexification-averaging method, followed by the derivation of the amplitude-frequency response equation. Next, the influence of system parameters on vibration reduction performance under harmonic and impulsive excitations is analyzed. Finally, a comparative analysis is conducted on the vibration reduction performance of the grounded linear stiffness NES, grounded cubic stiffness NES, and grounded combined-stiffness NES after parameter optimization using the Grey Wolf Optimizer (GWO) under random excitation. The results indicate that introducing grounded cubic stiffness into the grounded linear stiffness NES can significantly enhance the system's vibration reduction performance. However, compared to the grounded cubic stiffness NES, the energy dissipation of the primary system in the grounded combined-stiffness NES is more sensitive to variations in grounded linear stiffness.