Ukrainian Journal of Mechanical Engineering and Materials Science
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Item Evaluation of dynamic characteristics of DPKr-2 diesel train on straight sections of railway track(Lviv Politechnic Publishing House, 2017-10-19) Kuzyshyn, Andriy; Batig, Andriy; Lviv Research Institute of Forensic ScienceThe increase in motion speed of the trains moving along certain routs changes the operational conditions and interaction of the rolling stock and the track, and requires the solution of important issues related to the specifications of their maintenance, since there occur additional dynamic loads. In this case, the particular attention is paid to the interaction of the rolling stock and the railway track; to the problems of scientific substantiation of the criteria for assessing the dynamic characteristics of carriages; to the motion smoothness, traffic safety and travelling comfort; as well as to improvement of the maintenance specifications of the track and the rolling stock in the process of their operation and on the basis of scientific analysis and determination of top (safe) speeds of the trains motion. Using the three-dimensional mathematical model of the DPKr-2 Diesel train waggon, its basic dynamic characteristics were determined and analysed: coefficients of vertical and horizontal dynamics, maximum acceleration of the body both in vertical and in horizontal plane. The influence of the amplitude of vertical and horizontal obliques of the railway track on the dynamic characteristics of the Diesel train was investigated. The determination of the basic dynamic characteristics was carried out on the basis of the developed three-dimensional mathematical model of the waggon, which consists of 38 differential equations of the Diesel train motion. The simulation (solving) of the mathematical model was carried out using Maple software. The geometrical periodic equivalent obliques of the left and right rails were adopted as perturbations both in vertical and in horizontal plane. The determination of the basic dynamic characteristics of the DPKr-2 Diesel trane waggon will allow evaluating its vibro-protective properties. The determination of the coefficients of vertical and horizontal dynamics both in central and in axle leaf-spring suspension, of the maximum accelerations of the waggon body in vertical and in horizontal plane will allow carrying out the analysis of vibro-protective properties of the mechanical part of the Diesel train wagon. The obtained results may be used to define the safe interval of the Diesel train motion speeds on the track sections in the presence of vertical and horizontal obliques.Item Investigation of influence of the train motion speed on the process of the rolling stock derailment in the presence of railway track oblique(Lviv Politechnic Publishing House, 2017-01-01) Batig, Andriy; Lviv Research Institute of Forensic Science, Lviv, UkraineThe article is aimed to construct the plots of speed range change, at which the necessary and sufficient condition of wheel rolling onto the rail head is satisfied, on the basis of generally accepted methodologies of the wheelset off-loading calculation. First of all, for the specific example, it is necessary to define the value of the train motion speed, at which it takes place the largest wheel off-loading on the curved section of the track with the existing oblique, to determine the minimal height of the oblique, at which the change of the train speed will not lead to the satisfaction of the necessary condition of wheel rolling onto the rail head. One should also construct a generalized scheme of checking the conditions of the rolling stock derailment if there is a railway track oblique of the certain value. In order to determine the influence of the train motion speed on the satisfaction of conditions of the car wheel rolling onto the rail head, it is necessary to solve the system of differential equations that describes the motion of the over-spring part of the rolling stock on the oblique track section under the influence of the forces applied to it. As a result of research carried out, there was obtained the value of train motion speed, at which the largest off-loading of the car wheel on the curved track section with oblique takes place. There was defined the minimal oblique value, at which the change of the train motion speed will not lead to the satisfaction of the necessary condition of the wheel rolling onto the rail head. There were constructed the plots of changing the speed range, at which the necessary and sufficient condition of car wheel rolling onto the rail head is satisfied. In the article, there was constructed the generalized scheme of checking the conditions of the rolling stock derailment if there is a railway track oblique. There were determined the speed ranges, at which the rolling stock derailment may occur if there is a railway track oblique of the certain value. There was defined the value of the train motion speed, at which the largest off-loading of the car wheel on the track curved section with the skew takes place. The obtained dependencies may be used for defining the safe range of the train motion speeds on the track sections with oblique of the certain value. They may be also used while carrying out the forensic railway-transport examinations.