Particle Distributions' Effect On Damping Properties Of Particle Damper

Paticle damping technology is a new vibration passive control approach, and causes wide concerns.Damping effect can be provided by collisions and frictions of the particles filled in the structural voids. This technology has several advantages such as: the structure is simple, the cost is low, the effect of vibration absorption is notable, and it is applicable to extreme environment etc.All of them make it to be used widely in the future.At present, a number of researches on the design parameters optimal are not satisfactory, and the particle distributions are not concerned yet. In this paper, by using the planes which are through the axis of the cylinder, the inner space of the cylindrical container can be divided into two, four, eight and twelve cells. Different particle distributions can be conducted both along the peripheral derection and the vertical derection. Experimental investigation of particle distributions'effect on performance of the particle dampers is carried on. The steady state energy method is used for experiment with loss power and loss factor as the performance index, and the damper is vertically excited.The cantilevel test is used to verify the conclusions when the damper is under the harmonic excitation.The thesis includes:1. Under harmonic excitation steady-state energy flow method for single particle damper is deduced from multiple degree of freedom system.A LabVIEW programme is developed for data acquisition.Through the steady-state energy flow method for the experiment, the different particle distributions'effect on the performance of particle damper is obtained under harmonic excitation. For peripheral separation, the index decrease in most of the area on acceleration and frequency with increasing cells. For vertical separation, the damping effect is related with the height of particle bed.2. For the height of particle bed, the study is carried on and the most effective particle height depends on the vibration environment.3. With particles damper applied to cantilever, investigate different particle distributions'effect on damping ratio of cantilever, the experimental results show that, for peripheral separation, the damping ratio of the cantilever beam decreases with the increasing number of seperation, the biggest drop can be 37%; For vertical separation, the damping ratio of the cantilever beam increases with the increasing number of seperation, and the biggest amplitude can amount to 52%.