Parameters Influence of New Particle Damper-based Fastener on its Damping Ratio

Objective Fastener stiffness and damping are important factors affecting rail system vibration and wheel-rail noise, especially the fastener damping can directly affects the high frequency attenuation rate of the rail structure（rail noise） and the amplitude of wheel-rail P2 resonance force（low frequency vibration） of track structure. To improve the fastener damping ratio, a new type of fastener based on particle damper is proposed and the influence of fastener parameters on the system damping ratio is studied. Method The fastener is simplified into a single degree of freedom system to establish an overall model of the fastener, and a particle damper model is established by the discrete element method. The variation law of the fastener system damping ratio is explored with the damping ratio lift rate of the fastener vertical system as an indicator, and the particle filling rate and the elastic pad damping ratio as the variables. Result ＆ Conclusion Particle dampers can significantly increase the damping ratio of the fastener system and improve the fastener vibration reduction effect. When the elastic pad damping ratio is 0.070, the maximum increase rate of system damping ratio increase rate is the highest, reaching 43.6%（with a filling rate of 99.9%）; this damping ratio decreases with the increase of the elastic pad damping ratio; the comprehensive vibration reduction effect of the 90.0% and 99.9% filling rates is better than that of 80.0% and below. When the elastic pad damping ratio is above 0.115, the damping ratio improvement rate of the fastener system with a filling rate of 90.0% is better than that of 99.9% filling rate, and vice versa when the damping ratio of the elastic pad is below 0.115. Therefore, for fasteners with a relatively high elastic pad damping ratio, particle dampers with a filling rate of 99.9% are preferred; for fasteners with a relatively low elastic pad damping ratio, particle dampers with a filling rate of 90.0% are prioritized.