Study On High Efficiency Target Dynamic Vibration Absorption Of Vibro-impact Bistable Nonlinear Energy Sink

The vibration reduction of structures is often a widespread concern in practical engineering fields.Passive damping structures have also evolved from the linear tuned mass damper(TMD)to the structurally diverse nonlinear energy sink(NES),which is capable of absorbing vibrations in a wider frequency band than the TMD due to the unique intra-modal resonance characteristics of the existing nonlinear structure.Based on the analysis of the existing NESs,a vibro impact bistabel nonlinear energy sink(VI-BNES)is proposed and its dynamics and dynamical absorption effect are studied to verify its efficient targeted dynamic vibration absorption capability.The main innovations and work of this thesis are as follows:(1)A new VI-BNES structure is designed by combining the characteristics of fast-scale energy dissipation of vibro-impact NES(VI NES)with the multi potential wells energy exchange of bistable NES(BNES);(2)The Melnikov method in classical smooth systems is extended to the non-smooth system with impact vibration.By applying this method to analyze a vibro-impact bistable oscillator,the first-order Melnikov function is obtained,and then the chaotic threshold and the its rich dynamics are obtained,which are verified by numerical simulations and experiments;(3)By analyzing the two-degree-of-freedom system coupled by a VI-BNES and a linear oscillator(LO)with the extended Melnikov method,the perormance of the VI-BNES in vibration absorption with different dynamics can be obtained and evaluated.The efficient targeted dynamic vibration absorption effect of the VI-BNES is verified from both simulations and experiments.