Simulation and experimental investigation on dissipative properties of particle dampers

To understand the mechanical properties of Particle Dampers (PD) in depth, this work studies the characteristics of energy dissipation of PDs by computer simulation and vibration experiment. The average loss power is defined to describe the capacity of the energy dissipation of a PD. 3-D Discrete Element Method is employed to evaluate the loss power in the simulation and the steady state power technique is used to measure the loss power in the vibration experiment where the PD is under harmonic excitation and the excitation level and frequency are under control. The restitution coefficient is a major factor in energy dissipation, and modelled with a velocity-dependent function to improve the accuracy of the simulation. Then the dependence of the loss power on excitation level and frequency is verified and the contours of 3-D surface of loss power are obtained. Through the results, it appears that the parameter A omega is the dominant factor of the capacity of energy dissipation for PD, not the dimensionless acceleration Gamma = A omega(2)/g which usually used in the granular study. The comparison between the simulation and experiment results shows that a velocity-dependent restitution coefficient can better model the energy dissipation due to particle motions.