Experimental investigation of an active nonlinear energy sink for vibration suppression

Nonlinear Energy Sinks (NES) have gained significant attention in vibration control due to their lightweight design and broader frequency bandwidth compared to linear Dynamic Vibration Absorbers (DVAs). However, their performance is sensitive to the excitation amplitude of the primary system, limiting their practical use. To address this, this study proposes an Active NES (A-NES) based on a voice coil actuator (VCA). The A-NES replicates the nonlinear restoring force of a passive NES through programmed control of the VCA, while also allowing dynamic adjustments to its parameters to adapt to changing amplitude conditions. Numerical simulations and experiments are conducted to compare the vibration suppression efficiency of the A-NES with the conventional passive NES under various excitation frequencies and amplitudes. The results show that the A-NES achieves similar vibration suppression efficiency curves and amplitude-dependent trends as the passive NES, with a maximum efficiency of 96%, confirming their functional equivalence. Additionally, experiments on parameter adjustment show that modifying the cubic nonlinear stiffness coefficient significantly expands the high-efficiency suppression range and improves robustness against amplitude variations. Unlike conventional mechanical adjustment methods, the proposed A-NES eliminates the need for complex mechanisms and allows real-time parameter tuning based on the vibration state of the primary system, enhancing its practical applicability.