Abstract
This paper presents a vehicle operation safety evaluation model; to this end, a nonlinear vehicle‐track coupled dynamic system stochastic analysis model under random irregularity excitations based on probability density evolution method was developed. The nonlinear coupled vehicle‐track dynamic system is used to accurately describe the wheel‐rail contact state. The stochastic function‐spectral representation is used to simulate the random track irregularity in the time domain for the first time; consequently, the frequency components in the irregularity are preserved and random variables are reduced. In the process of evaluating the safety of train operation, the probability evolution, reliability of evaluation indices for different limit values, and evaluation indices for different probability limits are calculated for more accurate evaluation. The dynamic model and safety evaluation method was verified using the Zhai‐model and Monte Carlo method. The results show that, when the probability guarantee is increased, the running safety index of the vehicle increases more rapidly with running speed and the left/right wheel‐rail derailment coefficient increases rapidly at running speeds above 400 km/h. The computational model provides a novel direction for vehicle operation safety evaluation.
Highlights
Vehicle-track coupled dynamic system is a nonlinear and stochastic system in nature as random track irregularity is one of its main random excitations
Due to the complexity involved in the safety assessment of train operation, the problems generally need to be addressed through simulation methods
Wu et al [1] developed a vehicle-railbridge interaction model for analyzing the 3D dynamic interaction between the moving trains and railway bridge; in this established model, the wheelset has 3 degrees of freedom, the vertical, lateral, and rolling, and no jumps occur between the wheelsets and rails
Summary
Vehicle-track coupled dynamic system is a nonlinear and stochastic system in nature as random track irregularity is one of its main random excitations. Lu et al [11], Zhang et al [12], and Zeng et al [13] established random vibration analysis model for linear vehicle-track-bridge coupling system by pseudoexcitation method (PEM). E introduction of stochastic vibration analysis method makes it possible to use the probability theory to evaluate the safety of vehicle-track coupled power system or vehiclebridge coupled dynamic system. Using the principle of virtual work, utilizing a linearized wheel-rail contact equation to avoid iterative solution at each time step of the integration, and applying rail irregularity as random excitations to the system, the probabilistic evaluation approach for nonlinear vehicle-bridge dynamic performances has been analysed by Jin et al [22]. A stochastic analysis model of nonlinear vehicle-track coupled dynamic system under random irregularity excitations was established based on probability density evolution method. A safety evaluation model of train operation is presented and validated by comparison with previous study. e developed computational model provides a new research direction for train safety evaluation
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