Study On Energy Dissipation Of Particle Damping By Steady Excitation System

Effective methods ofenergy dissipation become the most important problem to be solved for researchers.Technology of particle damping produces damping efect to achieve vibration absorption and energy dissipation by collision and friction between particles and the wall of container.Particle damping has been widely used in engineering because of its advantages such as assembling simply,lower cost,suitable for hostile environment of high temperature,radiation,corrosion and so on.Recently,research for energy dissipation of particle damping with solid-liquid phase change is still inadequate.In the process of energy dissipation of particle damping,research for pivotal typicalparameter remains to be developed This paper is under the steady harmonic vibration to analyze energy dissipation and vibration absorption of particle damper based on program DEM and field experiment.The main works of this paper are:1.Numerical simulation(1)On the basis of contact model of spherical particles,the DEM numerical simulation program based on the FORTRAN language of the energy dissipation analysis of the particle damping phase change is developed.By DEM computing,reseached damping effect of particle media to plate by analysis of the relationship of between force and velocity of the rigid plate,which had been done simple harmonic motion in particle media.Observing frequency doubing phenomena in the simulation,considered the influence of different parameters such as the vibration frequency,amplitude,particle size and so on.The study found that rigid plate vibrated with low-frequency,the force of particles would be sigle frequency and damping effect would be linear.When rigid plate vibrated with high-frequency,the force of particles would appear multplication frequency phenomenon and damping effect would be nonlinear.The study of different amplitudes found that when amplitude of rigid board became larger,damping effect changed from linear to nonlinear.(2)On the basis of the DEM numerical simulation program refered,under the harmonic vibration,energy dissipation and vibration absorption of single degree of freedom composed of box-particle-spring with different parameters of excitation frequency,coefficient of restitution,coefficient of friction,fill factor and number of particles has been researched based on program DEM.With coordination number,freedom number and of phase transformation of solid-liquid's space-time parameter and so on introduced,reseached energy dissipation and vibration attenuation of the system deeply.The results show that coordination number and freedom number of phase transformation of solid-liquid's parameter can be the mark of energy dissipation.When phase transformation of solid-liquid happened,space-time parameter changed obviously at the same time energy dissipation changed suddenly.Feat coefficient of restitution,feat coefficient of friction,feat fill factor all can make energy disspation larger.When particle media type is solid,the number of particles increased does not affect the energy dissipation rate.(3)Features of energy dissipation of damped system with particles of plastic deformation with different excitation frequency have been researched based on program DEM.The relation between energy dissipation and coordination number has been analyzed and each part of energy dissipation has been contrasted.The results show that normal energy dissipation has become the main style of total energy dissipation.Coordination number and freedom number can not be the mark of energy dissipation.Particle energy dissipation of SiO2 is better than Al's.In the same conditions,the amplitude of particle damper with A1 paticles is larger than SiO2's,and the energy dissipation of particle damper with A1 paticles is smaller than SiO2's.2.Field experiment(1)Under the vertical harmonic vibration,particle damper has been researched.The impact force on baseplate with different excitation frequency and particles of different diameter has been respectively researched with methods of amplitude frequency sweep with equal acceleration frequency sweep with equal displacement.It has been observed frequency doubing phenomena and cycle doubing phenomena in the experiment.The results show that cycle doubing phenomena will happen by influence of larger diameter particles and the phenomena will be influenced by acceleration.The larger acceleration,the easier pheromena happened.(2)Try using DEM computing,to test the field experiment,and to compare the two results.Over time the two trends are not the same,but the two middleweight is similar.This shows that the DEM to achieve a more accurate simulation of particle damping characteristics,need to get the friction coefficient test by test,and other key parameters of the coefficient of restitution.