Study On The Damping Performance Of The Structure By The Particle Damping Absorbed With Damping Fluid

The control theory and methods of vibration have always been a hot research direction in the field of mechanics.Particle damping,as a new passive damping technology,has strong non-linearity character.By virtue of its wide damping bandwidth、wide application range、small modification of the original structure、simple structure and low price,particle damping has been widely used in construction engineering、aerospace and mechanical processing field.Particle damping technology is to fill a certain number of particles in the cavity of structure itself on the propagation path of the system structure,or to externally set a box with cavity on the structure.Through the non-elastic collision and friction between particles,the energy has been transferred and dissipation.With the support of the Shanxi Province Key R&D Program(2019GY-067),this thesis took the cantilevered particle damping absorber as the object,and adopted a combination of theoretical analysis,modeling simulation and experimental research,the vibration damping mechanism of the particle damping absorbed with damping fluid was studied based on the energy dissipation and transition.The main work and conclusion of this thesis includes the following aspects:(1)Equivalent theoretical research on particle contact.First,the modal truncation method was used to equivalently convert the cantilevered particle damping absorber to a vibration model with single degrees of freedom,and laid the foundation for the analysis of particle damping through structural simplification.Secondly,the contact theory and multiphase flow theory were used to equivalently convert the particle damping to the damping forces,and divided them into viscous damping force and frictional viscous damping force for theoretical analysis,and characterized the damping effect of particles by the vibration speed of the system,which provided theoretical support for the damping value design of particle damping.(2)Static mechanics study of particle accumulation.In this thesis,the static mechanics of particles in the accumulation state were analyzed,the static model of the particle accumulation at a certain height was obtained;at the same time,the discrete element simulation theory of particle accumulation was analyzed,and the static force distribution of particle accumulation was obtained through static simulation,which provided an important theoretical basis for studying the effective quality of particle damping during vibrationdamping.(3)Experimental study of particle damping absorber.On the basis of theoretical analysis and simulation,particle damping absorbers with different parameters were designed,and the vibration damping performance of particle damping under forced vibration was studied by built a vibration experimental test platform.Through the processing and analysis of the frequency response spectrum of vibration,the mechanism and potential causes of excitation frequency,particle diameter,accumulation height and particle “viscosity” in particle damping were studied.For small cantilever system,the particle damping absorber in this experiment could damp up to 86.3 % of the maximum kinetic energy of the system,and the damping effect was remarkable.