Abstract

Railway carriage model moving on tangent tracks is constructed by deriving the associated equations of motion where single-point and two-point wheel-rail contact is considered. The railway carriage is modeled by 31 degrees of freedom which govern vertical displacement, lateral displacement, roll angle and yaw angle of wheelset whereas vertical displacement, lateral displacement, roll angle, pitch angle and yaw angle of carbody and each of two bogies. Linear stiffness and damping parameters of primary and secondary suspensions are provided to the railway carriage model. Combination of linear Kalker's theory and nonlinear heuristic model is adopted to calculate the creep forces in which introduced at wheel and rail contact area. Computer aided-simulation is constructed to solve the governing differential equations of motion using Runge-Kutta fourth order method. Principles of limit cycle and phase plane approach is applied to study the stability and evaluate critical hunting velocity of the system. The numerical simulation model is used to represent dynamic responses of the components of railway carriage subjected to specific parameters of wheel conicity and suspension characteristics. Longitudinal primary stiffness suspension is controlled using semi-active suspension with lateral displacement indicator. The controlled semi-active longitudinal primary suspension is examined to increase the critical hunting velocity and improve hunting stability of railway carriage.

Key words: Railway carriage, conventional bogies, tangent tracks, semi-active suspension, longitudinal suspension, critical hunting velocity.