Research On Vibration Absorption Performance Of Elastic Magnetism Reinforced Nonlinear Energy Sink

Nonlinear Energy Sink(NES)has attracted a lot of attention from researchers because of its broadband vibration absorption capability,light weight,rapid and irreversible energy transfer,and other characteristics.However,under large external excitation conditions,the vibration amplitude of NES can be very large,even exceeding several times the amplitude of the damped system itself,which is obviously unacceptable in many engineering fields.Therefore,this paper proposes an elasticmagnetism reinforced NES in order to eliminate the generation of similar phenomena and to improve the vibration absorption performance of the traditional NES.In addition,two variants of NES structures are derived from the creation of the new NES structure:the collision-elasticity reinforced NES and the magnet NES,and their properties will be analyzed one by one in this paper,and the contents of the paper can be summarized as follows.A nonlinear energy sink structure incorporating collision-elasticity and elasticmagnetism elements is proposed,and collision-elasticity and elastic-magnetism nonlinear energy sinks are designed and processed.The dynamical response of the cubic oscillator under shock excitation was studied for both NES without connection to the vibration-damped system.The difference between the effects of the two elements on the elastic potential energy and vibration decay time of the oscillator at different initial displacements is compared,and the effects of two parameters,linear spring stiffness and clearance,on the dynamic response of the oscillator are investigated.Finally,the optimal conditions for the use of elastic-magnetism elements are found to provide experimental data to support the study of elastic-magnetism nonlinear energy sinks.A simplified model of the single-degree-of-freedom collision-elasticity system is developed,and the kinetic equations of the system are derived and solved using the Runge-Kutta methods.The damping coefficient of the system is determined by the free decay vibration method,and the damping coefficient is used to reproduce the response of the oscillator in the experiment under free decay.A new simulation method is proposed,which introduces a velocity decay coefficient based on the Runge-Kutta methods,and uses this coefficient to simulate the transient response generated when the oscillator contacts the collision-elasticity element.The response data of the oscillators in several sets of experiments are reproduced to determine the correctness of the method and to identify the parameters affecting the velocity decay coefficient.Finally,the method is used to extend and complement the previous conclusions.The dynamical response of an elastic-magnetism reinforced oscillator under simple harmonic excitation is studied,and the reinforced oscillator structure with magnet element,collision-elasticity element and elastic-magnetism element is redesigned and processed.The effects of three different elements on the steady-state dynamical response of the cubic oscillator under harmonic excitation are compared and the response law is analyzed when the damped system is not connected,and the results of the response of the oscillator with additional magnet elements and elasticmagnetism elements under experimental conditions are reproduced using the RungeKutta method by introducing the magnetic force equation.An experimental model of the damped system connected with an elasticmagnetism reinforced NES was designed and processed,find the resonant frequency of the damped system,and the effect of the elastic-magnetism reinforced NES on the vibration absorption of the main oscillator was studied around the resonant frequency.In the excitation band centered on the resonance frequency,the frequency response of the main oscillator connected with different NESs and the steady-state response waveforms at the resonance frequency were compared,and the effects of different compression spring stiffnesses on the vibration absorption characteristics of the collision-elasticity and elastic-magnetism reinforced NESs were analyzed,and finally the vibration absorption performance of the elastic-magnetism reinforced NESs was summarized.