Studies on dissipative characteristics and equivalent model of particle damper in railway application

Abstract

Particle damping technology brings the advantages of good durability, high reliability, insensitivity to temperature change and easy to be used in harsh environment. Hence, it has considerable potential for suppressing structural vibrations. In this study, a series of experiments under vertical harmonic excitations with different frequencies and acceleration amplitude were systematically conducted. The mechanical behavior and dissipative characteristics of the damper in railway application were analyzed by observing the particle motion state and calculating two energy dissipation evaluation indexes. The results show that the damping effect is strongly related to frequency and acceleration amplitude of the harmonic excitation. Subsequently, a discrete element model of the particle damper was established to simulate the test conditions, and the consistency between the simulation and test results verified the rationality of the simulation. The energy dissipation mechanism and characteristics of the particle damper were further explored based on the time-history responses of the contact force and energy dissipation. In order to simplify the analysis of nonlinear multi-particle damper, a simplified theoretical model consisting of mass, stiffness and damping elements was proposed based on the analysis of dynamic motion and dissipation mechanism. Based on the principle of energy equivalence and mechanical behavior equivalence between the theoretical model and simulation results, the equivalent equations were derived and the key parameters of the equivalent model were determined. These equivalent parameters are amplitude-frequency dependent. This model can be used to predict the damping properties of the damper at any input frequency or excitation amplitude, and to estimate the vibration attenuation performance of the damper for specific railway applications.