Riding-comfort Analysis For High-speed Trains On Track Irregularities

High speed rail has been widely used and rapidly developed in transportation of the world because of its high speed, large energy efficiency, safety and reliability. In the wake of the growing running speed of high-speed trains, the excitation frequency of track irregularity increases and the interaction between vehicle and track significantly enhances; on the other hand, through the optimization of body structure and using new materials, body structure lightweight has become an important trend in the development of high-speed trains technology. Random vibration of elastic body on track irregularities is particularly important for the running stability and riding-comfort of trains. For the actual train system, the interaction of vehicle-track coupling system is complex, the track irregularity excitation is uncertain, the traditional methods of random vibration analysis are inefficient and other complex factors affect, which makes it a great challenge to research precisely on riding-comfort for high-speed trains for the moment.In the above context, in this present paper, according to the rigid-flex hybrid model for major finite vehicle-track coupling system, the pseudo-excitation and sympectic method was established for riding-comfort estimation of the flexible high-speed vehicle body. Firstly, the track was regarded as infinite long period chain structure then the orbital dynamics equation of motion with low degree of freedom was established by symplectic algorithm, which solved the influence on dynamic response of system from boundary effects of finite long track structure; secondly, through tight contact theory, the rigid-flex hybrid vehicle dynamics equation and symplectic orbital dynamics equation were coupled. Lastly, though pseudo excitation theory further, the track irregularities were transformed into a series of pseudo harmonic track irregularities, which transformed the random vibration problem into steady state response solution. Then symplectic algorithm of harmonic wave propagation in the periodic chain structures was used. The two methods finally built the efficient analysis method for riding-comfort estimation of the flexible vehicle body. In the numerical example, on the basis of the methods above, riding-comfort estimation for high-speed trains in view of Sperling Method, GB5599-85, TB/T2630-93, ISO2631-1and UIC513was conducted. Then the influence from modal interception order, speed, track irregularity, etc. factors on riding-comfort was discussed. These efforts provided effective reference information on riding-comfort analysis of high-speed trains considering vehicle-track coupling effects and parameter optimization of train dynamic systems.