Theoretical Research Of Particle Damper With Elastic Coating

Particle damper is applied to the main structure for vibration reduction has become one of the research hot spot in the today.Particle damper means that putting a certain amount of metal or nonmetal particles into the cavity of the vibration structure or within the cavity of the additional vibration structure.The vibration reduction mechanism of particle damper is inelastic collision and friction between particles and particles or between particles and damper's wall,in order to achieve the purpose of the momentum transfer and energy dissipation.Particle damping has many irreplaceable advantages,in addition to effectively reduce the vibration amplitude and vibration frequency band width,also can be applied to extremely bad environment.In this paper,a particle damper with elastic coating is proposed based on the research of the viscoelastic material properties.Although viscoelastic damping materials has been used to reduce vibration and noise nearly for eighty years,but its application on the particle damping technology is relatively rare,and because the vibration reduction mechanism of viscoelastic damping materials is extremely complex,led to the current using theoretical model to predict the vibration effect is still not perfect.Therefore,this paper studies the vibration reduction mechanism of this new damper from two aspects of theory and simulation based on the characteristics of this new type of damper.The main contents of this dissertation are expressed as follows:(1)The material characteristics of viscoelastic damping materials and energy dissipation mechanism are studied,and a particle damper with elastic coating on the basis of predecessors' research is proposed.(2)The friction energy dissipation model of inter-layer between particles with viscoelastic coating is established,and the viscoelastic coating thickness for the influence of particle damper damping effect and the optimum thickness value are emphatically analyzed.(3)The classical theory of Hertz and the theory of viscoelastic material energy dissipation are used to establish piecewise energy dissipation models of frontal collision between particles with viscoelastic coatings and between damper's wall and particle with viscoelastic coating particles.The nonlinear finite element analysis software LS-DYNA is used to simulate under the condition of frontal collision,and the correctness of the established energy dissipation model of frontal collision is verified.The viscoelastic coating thickness for the influence of energy dissipation of frontal collision under different working conditions is analyzed,and finally find out the optimum thickness value under these working conditions.(4)The LS-DYNA software is used to simulate under the condition of oblique collision between elastic coating particles,and find out three parameters which has the greater influence on the friction energy dissipation based on friction energy dissipation theory,and matlab software is applied to fit the friction energy dissipation curve when these parameters are as independent variables,finally the formulas of friction energy dissipation under different working conditions are obtained.