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The mechanical performances of the rail fastening system (RFS) exhibit significant randomness. To evaluate its influence on the vehicle-track dynamic interactions, the classical vehicle-track coupled dynamics model (VTCDM) is extended in this paper by thoroughly implementing the refined mechanical behaviors of RFS and advanced stochastic dynamic analysis theory into a three-dimensional vehicle-slab track system. Specifically, a full-scale fastening system finite element model (FEM) is constructed to reveal the nonlinear mechanical behavior of the RFS firstly, and its mathematical expressions are derived. Then, a refined vehicle-track interaction model (RVTIM) involving the clamping force effect of fastening spring clips (FSC) has been proposed and verified by on-site test data. Furthermore, a stochastic dynamic analysis method for the interaction of the vehicle-track system (VTS) is developed according to the theory of the probability density evolution method (PDEM). Subsequently, by applying the proposed model and method, the influences of the random fastening parameters, longitudinal non-uniform distribution characteristics, and vehicle speed on stochastic dynamic performances of the VTS are evaluated in detail. The results show that the vertical stiffness of the rail rubber pad (RRP), the initial installation torque of the FSC, and the lateral stiffness of the RFS are the most sensitive random fastening parameters, and the impact of longitudinal non-uniformity distribution of fastening parameters as well as the vehicle speed are rather remarkable. This study innovatively integrates full-scale nonlinear characterization of RFS, clamping force effect, and PDEM-based stochastic analysis into a unified analytical framework, overcoming the limitations of existing models that overlook RFS refinement or randomness. The findings provide critical insights for targeted optimal design of RFS, maintenance scheduling, and dynamic optimization of the VTS, enhancing both theoretical depth and engineering applicability.
Ma et al. (Fri,) studied this question.