Optimal Design of Bistable Nonlinear Energy Sink Based on Global Vibration Control

Abstract

Although a linear vibration absorber (LVA) or nonlinear energy sink (NES) can effectively mitigate the vibration of the main system in harmonic excitation, the amplitude of the absorber can be very large. Using the single-objective differential evolutionary (DE) algorithm, this paper pioneers the global control of the main system and a bistable NES to achieve decent vibration mitigation effects and decrease the global response of the system. Using the multi-objective DE algorithms and comparing the optimization results of the LVA, this paper proposes multi-objective and multi-parameter design criteria of a bistable NES. The mass ratio, the displacement amplitude, and the mechanical energy are optimization goals. The results show that the maximum amplitude of the main system and the absorber can be controlled at the same level, and the global control strategy does not change the resonance frequency of the main system. Compared with the LVA, the bistable NES has similar vibration mitigation effects with the variation of the mass ratio in the multi-objective optimization. However, the bistable NES can achieve better control over a larger spring stiffness range. Therefore, through single- and multi-objective optimization design, this paper proves the superiority of the bistable NES in the vibration mitigation. Meanwhile, this paper provides an optimization design method for global vibration control.