ANALYSES OF DYNAMIC RESPONSE OF VEHICLE AND TRACK COUPLING SYSTEM WITH RANDOM IRREGULARITY OF TRACK VERTICAL PROFILE

A dynamic computational model for the vehicle and track coupling system is developed by means of finite element method in this paper. In numerical implementation, the vehicle and track coupling system is divided into two parts; lower structure and upper structure. The vehicle as the upper structure in the coupling system is a whole locomotive or rolling stock with two layers of spring and damping system in which vertical and rolling motion for vehicle and bogie are involved. The lower structure in the coupling system is a railway track where rails are considered as beams with finite length rested on a double layer continuous elastic foundation. The two parts are solved independently with an iterative scheme. Coupling the vehicle system and railway track is realized through interaction forces between the wheels and the rail, where the irregularity of the track vertical profile considered as stationary ergodic Gaussian random processes and simulated by trigonometry series is included. The amplitudes of vibrations, their velocities and the accelerations generated in the vehicle and rail and the interaction forces between the vehicle and the rail due to the random irregularity of the track vertical profile and different line grades and train speeds have been analyzed numerically by this model. Analyses of system responses are performed in time and frequency domains.