چكيده به لاتين
The dynamic performance of rail vehicle which consists of two parts of comfort and safety, is evaluated by indicators including riding quality, car stability and curve passing ability. Riding comfort is one of the most important indicators of a rail vehicle which have a complex concept and is defined as the ability of the railway vehicle to keep riding within the range of human comfort or in a range to ensure no damage will be caused. Riding comfort is affected by parameters like vibration, noise, and temperature. Thus, evaluation of the riding comfort is not a simple process. Based on the studies which have been done in this field, rail vehicle movement on curves, because of centrifugal force, will have negative effects on track and the rail vehicle including reduction in passenger comfort, increased vibration, increased lateral load, etc. When there is a tight curve on a track, to provide the riding comfort and to reduce the rail and wheel wear, the track gauge is increased. Because of increasing the railway travel speed and development of science and technology in this field, railway track geometrical parameters and related tolerances are more sensitive. By reviewing the related literature, it becomes clear that curves are effective parameters affecting the accelerations generated on the track and vehicle and thus affecting the riding comfort. So, considering the technical and research gap in the field of the effect of railway compound curves on riding comfort, this subject is studied in this thesis. In this project, the effect of the compound curves parameters (such as curve radius, length of tangent between curves, and the speed) on riding comfort is investigated by numerical simulation using UM software. The results of the simulation have been validated by conducting field study on Tehran subway Line 1. For this purpose, rolling sock acceleration data have been recorded by instrumentation of tangent and curved track between Mirdamad and Shariati Stations. After model validation, series of sensitivity analysis related to the effect of curves succession on riding comfort carried out. In this analysis, the effect of the succession of the curves on riding comfort has been done both for same and opposite direction curves with different radiuses.
Generally, it can be concluded from this study that first: The riding comfort on compound curves is specifically affected by the tangent track between curves, and second: The riding comfort on same direction compound curves is less than that on opposite direction compound curves (reverse curves). By comparing the results of this study to the standard criteria on horizontal curves succession, it can be concluded that to provide riding comfort, some limitations in criteria and considerations should be revised. For instance, based on the results of this study and the standard criteria in present, riding comfort on tight, average, and high radius compound curves (two successive curves having the same radius) respectively for the speeds lower than 40, 80, and 100 Km/h is considered tolerable while for speeds higher than mentioned above, the riding comfort will be considered as uncomfortable. On the other hand, on “tight-average”, “average-high radius”, and “tight-high radius” compound curves (which two successive curves having different radiuses), the riding comfort respectively for speeds lower than 60Km/h, 60Km/h, and 80Km/h, will be classified as tolerable, while for speeds higher than speeds mentioned above riding comfort will be classified as uncomfortable which in these situations in order to achieve the desired riding comfort, it is suggested to increase the length of tangent between successive curves or to apply speed limitations on related compound curves.
Keyword: Compound curve, passenger comfort, field study, light railway track, sperling index comfort.
