Analytical Studies Of Particle Vibration Damping

Particle vibration damping is a technique of providing damping with granular particles inside the structure hole or cavity which is attached to vibration system. Particles of various shapes, sizes, and materials are partially filled in the hole or cavity, while the particles may experience shaking motions within the structure. When particles vibrate with the structure, the relative motions between particles and between particles and structure wall would happen, this means that particles and the structure will collide each other. As a result of these collisions, the structure will transfer the kinetic energy to particles, and kinetic energy of the vibration system will be dissipated by these collisions in the form of impact and friction losses. The particle damping technology has been used successfully in many fields for vibration reduction. However, it is difficult to define a suitable damping model to predict its effectiveness for different applications.In this thesis, we utilize the 3D discrete element method (DEM) for computer simulation and characterization of particle vibration damping. Discrete element method (DEM) is a computational technique for particle damping modeling. According to contact theory, we can describe the relationships between particles and structure, and determine the kinetic energy dissipation.We show some parameters about the particle vibration damping to help reader understand the thesis well. Then we use the specific damping capacity to define the effect of the particle vibration damper. Then we show that how different factors such as particle packing ratio, particle size and particle material affect the effect of the particle vibration damper.Finally, another parameter loss factor is defined as well as specific damping capacity to express the effect of the particle vibration damper. We try to describe the particle vibration damper by another modeling method, and give the procedure of the prediction, but this method should be verified by further experiments.