Determining the dynamic indicators of the pneumatic spring for high-speed rolling stock in the zone of a rail joint along a railroad track

The object of this study is the pneumatic spring of the high-speed railroad rolling stock that moves over the rail joint of a railroad track with a vertical ledge. The task solved was establishing the dynamic behavior of the rubber cord shell of the pneumatic spring of the high-speed railroad rolling stock, taking into account the design features of the railroad track, namely the rail joint. The methodology for experimental testing of the pneumatic spring of the high-speed railroad rolling stock using the proposed dynamic test installation is given. Experimental tests of the pneumatic spring were carried out within the rail joint of the railroad track, which has a vertical ledge of 7.0 mm. It was established that the maximum value of the accelerations of the rubber cord shell of the pneumatic spring occurs in the vertical plane. The maximum vertical accelerations of the rubber cord shell of the pneumatic spring were 2.4 m/s2, horizontal transverse accelerations – 0.85 m/s2, and horizontal longitudinal accelerations – 0.9 m/s2. It was determined that the deformations of the pneumatic spring in the vertical plane are higher than the deformations in the horizontal plane. The value of the maximum vertical deformations of the pneumatic spring was 4.1 mm, while the maximum value of horizontal deformations was 1.2 mm. The natural frequencies and logarithmic decrements of oscillations damping were determined based on the obtained records of the free oscillations of the rubber cord shell of the pneumatic spring. It was established that the value of the first natural frequency of oscillations of the pneumatic spring is 3.21 Hz. The logarithmic decrement of oscillation damping of the rubber cord shell of the pneumatic spring was determined based on the constructed graph of oscillation damping with an approximating exponent. It is 0.2147. The obtained values of the dynamic indicators of the new pneumatic spring could be used in the future to control changes in the physical and mechanical properties of the rubber cord shell of the pneumatic spring under the operational conditions of the railroad track. In practice, engineers and scientists will be able to take into account the obtained dynamic parameters of the spring when designing and improving the pneumatic spring for high-speed train movement