Research on the influence of random stiffness of the rubber tie plate on the coupled vehicle-turnout system based on the probability density evolution method

Track supporting stiffness plays a crucial role in the running quality of a vehicle crossing through a turnout. This paper mainly focuses on the influence of random stiffness of the rubber tie plate on the vehicle-turnout coupling system. The relevant random field is constructed via the number theoretical method (NTM). The coupled vehicle-turnout model with flexible rails is built via the modal superposition method. The probability density function (PDF) is obtained via the probability density evolution method (PDEM). Cases of normal distributions with various mean values of stiffness are compared to contrast the relevant impact on the dynamic wheel–rail interaction. Research results indicate that an increase of the stiffness of the rubber tie plate can abate the transverse sway of the vehicle and low down the wheel number. The target stiffness should be taken as 35 kN/mm and corresponding normal distribution with a confidence interval of plus and minus 5 kN/mm can be accepted. The discrepancy between the mean value and the relevant PDF contour clarify the importance and necessity for analysis of randomness. Research results of this paper can serve as the theoretical fundament of the track stiffness homogenisation of a turnout in the future.