چكيده به لاتين
In a general definition, the transition zone in railway lines refers to the places, where there is a sudden change of stiffness of railway structures. Sudden change of stiffness in the vertical direction causing the increase of dynamic loads, defects on railway structure, elevation of sleeper, ballast escape, permanent deformation of rails, change of the geometry of the railway line, increase Accelerations and stresses on the rail and vehicle, and so on. A set of problems which are mentioned will increases the maintenance costs. Therefore, according to this issue, the present study, specially, focus on the process of increasing the wheel/rail contact force in the transmission zone. This research investigated the effect of speed and length of the transition zone on the contact force. A complete multi-body dynamic model of wagon has been created. At the first, the stiffness of structure has been changed step by step and linear in order to investigated the normal force in transition, after that, the effect of speed has been investigated in transition zone by considering the linear changing and step-by-step changing of stiffness in transition zone.
