Engine vibration control based on bistable parallel nonlinear energy sink

A bistable parallel nonlinear energy sink (BPNES) is proposed in this paper to improve the vibration reduction performance and stability through inter-well chaotic response and mass configuration, so as to achieve vibration control of the engine under broadband and wide energy excitation. In order to provide the design theory of BPNES, the relationship between structure parameters and thresholds of the inter-well chaotic response and strongly modulated response (SMR) are obtained by Melnikov theory and multiscale analysis, and the numerical results indicate that the analytical solution is reliable. The concepts of energy dissipation and energy spectrum were defined to analyze the vibration reduction performance of BPNES under transient and steady-state excitation, respectively. The analysis results indicate that compared to Cubic stiffness NES(CNES), BPNES has better vibration reduction performance under wide energy excitation, especially when the excitation intensity is low. The results under steady-state excitation also indicate that BPNES is less likely to generate high branching under different excitation intensities, indicating better stability. The results of this study indicate that the proposed BPNES is very suitable for vibration control with a wide vibration frequency band and a wide range of vibration intensity changes, such as engines, machine tools, etc.