Center for Railway Engineering

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    Comparison of Floating Ladder Track and RHEDA2000Ballast-less Track for Dynamic Responses
    (Addis Ababa University, 2016-11) Aklilu, Bekele; Mequannent, Mulugeta (Mr.)
    The purpose of this thesis is concerned with the comparison of FLT and RHEDA2000 ballast-less Track-form with respect to their dynamic performances. The comparison is done based on the analysis of the simulation results and it would be achieved via FEM software (ABAQUS). The analysis have been done in time domain at various Speed of the moving Load and the mode of vibration as well as natural frequencies of both track-forms were extracted from frequency domain analysis. The analysis is done by varying the speed of the rotating wheel from 120 to 420 Km/hr and keeping track stiffness‟s constant. As the speed of the moving load increases from 120 to 420 Km/hr, the vertical displacement of the rail in FLT is increasing to nearly 8mm, in contrast the vertical displacement of Rheda2000 is slightly increasing to 3mm throughout their time domain. With similar manner, the comparisons of these Tracks‟ with respect to peak value of stresses variation on the Rail have been done and in FLT this value vary from 130Mpa to 250Mpa in its time domain. Then again, the maximum stresses on Rheda2000 ballast-less Track varies from 136Mpa to 160Mpa in its‟ time domain. Besides, it is possible to understand that the vertical acceleration level of Rail in FLT is comparatively less than the vertical acceleration of Rail in Rheda2000 ballast-less Track. The maximum acceleration level of Rail in FLT is 70m/s2 and maximum acceleration level of Rail in Rheda2000 is about 200m/s2. Moreover, from the analysis, it was found that FLT has better capacity of vibration reduction than Rheda2000 ballast-less Track at higher frequency but at frequency lower than 400Hz, there is no much difference in both track forms. The other dynamic responses of both track-forms are nearly comparable and in both tracks form as the speed of the moving load increases the dynamic response increases. However, at similar speed of moving load, the dynamic performance of Rheda2000 ballast-less track is better than the dynamic performance of FLT. From the discussion, it could be deduce that FLT is good for vibration reduction and Rheda2000 have better dynamic performances.