Dynamic modeling and ride comfort evaluation of railway vehicle under random track irregularities: A case study of a Linke-Hofmann-Busch coach

The ride comfort of passengers is an important parameter for evaluating the performance of railway vehicles. Many standards/ models, such as quarter car, half car, and full car, have been proposed to evaluate the human comfort of railway vehicles. However, a full-scale coupled railway vehicle model is rarely considered for calculating ride comfort. Therefore, this paper proposes a twenty-seven-degree-of-freedom (27-DOF) coupled dynamic model of railway vehicles integrated with wheel-rail contact forces. The developed model is solved using the two-dimensional (2-D) state space method, and the effects of different track irregularities on human comfort are evaluated. The outputs are described in terms of three-dimensional (3-D) Power Spectral Densities (PSDs) under three types of random track irregularities: vertical profile, lateral alignment, and cross-level. Furthermore, Sperling's method is used to evaluate the human comfort index. For the case study, a Linke-Hofmann-Busch coach (LHB) based model has been employed, and the results are validated with the experimental data of ride comfort reported by the Research Design and Standard Organization (RDSO). The simulated results of the proposed model demonstrate a remarkable alignment with the experimental data, exhibiting a small error ranging from 2.36 % to 8.81 % for vertical motion and 5.84 % to 8.30 % for lateral motion, respectively. Such promising results offer valuable insight for the design of future coaches, ensuring enhanced ride comfort even at high speeds.