Experimental study on stiffness characteristics of Vossloh W300 fastener system under assembly state

Using the high-frequency fatigue dynamic stiffness test platform and combining with the actual operation conditions of high-speed railway, the stiffness characteristics of Vossloh W300 fastener system under assembly state were studied, and following results were obtained. 1) Under different preloading loads, the static and dynamic stiffness have the same growth trend, and the static stiffness under 20 kN (40 kN) preloading load is 17.7% (59.5%) higher than that without preloading load, the static stiffness corresponding to 40 kN obviously exceeds the design limit of the overall static stiffness of the fastener system. The dynamic stiffness under 20 KN (40 kN) preloading load is 4 dB (10 dB) greater than that under 0 kN. 2) Both the static and dynamic stiffness of the fastener system show low temperature sensitivity. When the temperature is lower than 20 ℃, the static stiffness increases with the decrease of temperature, especially the static stiffness increases sharply from −30 ℃ to −60 ℃, and the static stiffness at −50 ℃ (−60 ℃) is 1.4 (4.4) times that of 20 ℃. The dynamic stiffness at −30 ℃ is 8~10 dB greater than that at 30 ℃, and the elastic unit loses elasticity, which directly affects the vibration reduction effect of the fastener system. 3) The fastener system stiffness has obvious frequency variation characteristics within 5~1000 Hz. When the preload is certain, the dynamic stiffness increases with the increase of frequency, and the dynamic stiffness value at 1000 Hz is 15 dB higher than that at 5 Hz in the national standard.