Dynamic behaviour of railway's superstructure

ABSTRACT Especially in the last 50 years, railway systems have improved rapidly. This progress has exposed high velocity. Nevertheless, the usage of light and flexible material, having less damping property than wood, has become widespread. The increasing velocity, traffic load and usage of non- wooden material increased the maintenance and repair costs of the railway. Resonance vibration, created by the dynamic behavior of railway, feeds back to the railway as maintenance and repair cost. Briefly, recently constructed systems are under high vibrating forces because of their high velocity and elastic properties. Frequency spectrums of these forces, especially from the side of resonance vibrations, are important to be known. Because, if one or more of the coercing forces frequency coincides with the natural frequency of the system, resonance vibrations, which are destructive because of their vibration, occur. Therefore, to prevent resonance vibration, comprehensive dynamic analysis should be performed during design stages. In this work, first, all kinds of railway superstructures have been described and vibration analyses have been mentioned. Under the dynamic behavior of railway subject; an introduction to the modeling of railway dynamic behavior and its historical development is described. Furthermore, vehicle/railway interaction problems, railway and railway/vehicle interaction models, analyses techniques and their historical progress researches have been performed. Thereafter, under the subject of modeling and analysis of standard railway models, two of the defined suitable models have been chosen and analyzed analytically. As a conclusion, general recommendation has been given to give an idea and a suggestion for future researches. Key Words; Railway dynamics, dynamic modeling of railway, superstructure of railway, Euler -Bernoulli, vibration. XI