Stochastic Dynamic Analysis of High‐Speed Railway Vehicle–Track Systems Based on the Adaptive Probability Density Evolution Method

The theoretical and analytical approaches of stochastic dynamics constitute the foundation for performing in‐depth inquiries into the random dynamic behavior of high‐speed railway vehicle–track system (RVTS). The proposal of the generalized probability density evolution method (PDEM) has opened up new perspectives for the stochastic dynamic analysis of complex multidimensional nonlinear systems, which is conducive to promoting the formation of a complete theoretical framework of stochastic dynamic analysis and a key technology system for the RVTS. However, as a high‐dimensional, nonlinear, and strongly time‐varying stochastic dynamics system, if a unified probability density calculation interval and a constant spatial‐integration step are used in solving the generalized density evolution equation (GDEE) of the high‐speed railway vehicle–track stochastic system, it will inevitably lead to a waste of computational memory and efficiency. Therefore, based on the theory of PDEM, this paper establishes a stochastic dynamic analysis model for the RVTS. Most importantly, an adaptive optimization of the probability density calculation interval and spatial‐integration step in the solution process is conducted, and an adaptive PDEM is developed, which provides a precise and efficient research approach for the stochastic dynamic behavior evolution analysis of the RVTS, achieving a profound balance between computational accuracy and computational efficiency. Moreover, while ensuring the accuracy, the calculation efficiency has been increased by more than 20%. Subsequently, the parametric sensitivity analysis, probability density evolution analysis, and the impact analysis of vehicle speed on the stochastic dynamic performance of the RVTS are carried out with the adaptive‐PDEM. The results show that the random vehicle loads are the most sensitive parameters in the vehicle system, which are greater than those of the stiffness and damping of the primary and secondary suspension. The vehicle speed is another important factor, and when the vehicle speed increases from 350 to 480 km/h, the vertical accelerations of the wheelsets and rails increase to ~2 times and 3 times, respectively. Additionally, some significant conclusions are obtained.