Rimantas Subačius

Mathematical model of dynamic interaction between wheel-set and rail track

Abstract The main goal of this title is to show how the effects on maximum bending tensions at different locations in the track caused by simultaneous changes of the various parameters can be estimated in a rational manner The dynamic of vertical interaction between a moving rigid wheel and a flexible railway track is investigated. A round and smooth wheel tread and an initially straight and non-corrugated rail surface are assumed in the present optimisation study. Asymmetric linear three-dimensional beam structure model of a finite length of the track is suggested including rail, pads. sleepers and ballast with spatially non-proportional damping. Transient bending tensions in sleepers and rail are calculated. The influence of eight selected track parameters on the dynamic behaviour of the track is investigated. A two-level fractional factmial design method is used in the search for a combination of numerical levels of these parameters making the maximum bending tensions the minimum. Finally, the main con...

Analysis of locomotive wheel sets wearing

Abstract Wearing dynamics of traction rolling-stock wheel tyres of diesel locomotives was investigated. Based on research results it is possible to predict wheel-tyre safety margin, to improve maintenance and state periodicity of repair, as well as to use traction rolling-stock repair funds most efficiently.

The Improvement Conception of Drivers Training and Examination System in Lithuania

The current paper presents the structure of the drivers training and examination system existing in Lithuania and describes the interrelations between the institutions involved in the said process. In course of analysis of models of drivers training and examination systems of various countries, their advantages and imperfections are highlighted. The experience of Germany, Holland, Sweden and Great Britain in the sphere of training and examination of motor vehicles drivers is described. In the end of the paper, conclusions and recommendations for improving the quality of drivers training and examination system as well as traffic safety in Lithuania are provided.

Investigation of quality change in locomotive lubricant

This paper describes experimental investigation of lubricant properties used in locomotive engines. The workbench for experimental investigation is described, and experiment technique is presented. Results and their interpretation show direction for further investigation. Conclusions of results are made.

Employment of Two New Methods for the Research of Interaction of Wheel with a Flat and Rail

Dynamic force that strains on the rail and the wheel occurs. In case of wheel flats, during wheel and rail interaction, exposure time of dynamic forces acting in contact is very short and depends on the railway vehicle speed and the length of flat.Results obtained from a method that uses mathematical model of a system “Railway Vehicle Wheel-Track” and the simplified method to determine a vertical impact force of wheel with flat and rail interaction are presented in this article.The results of the mathematical and physical results of this system are analysed and presented.

Experimental Definition of Compressive Stiffness of Cotton Flock

Definition of Young’s modulus for majority of materials is the routine operation. In case of materials with low stiffness this task requires special procedure and sophisticated machinery. Cotton flock is the case, where compressive stiffness of cotton flock is so small for direct measurement, so one of possible solution is proposed indirect method of its definition. Recently cotton processing industry uses dynamic methods of cotton cleaning, therefore it is required to know compressive stiffness of cotton flock in order to optimize vibration parameters of device and adjust them to current status of cleaning material. Real compression stiffness of cotton depends on many factors, so in this paper is made an attempt to create simple method of compressive stiffness definition, which can be applied in simple workshop. Paper contains initial assumptions, mathematical derivations of final formula, methodology of experimental research and results.

Investigation of properties of lubricants in locomotive diesels

Abstract This paper describes experimental investigation of lubricant properties used in locomotive engines. The workbench for experimental investigation is described, which presented theoretical background and technique of the experiment. The results are analyzed and presented graphically. Their interpretation shows the direction for further investigation. Final conclusions of the results are made.

Detection of Defects in Steel Ropes Using Dynamical Methods

Early defect detection and monitoring of rope systems constitute important safety requirements for equipment that employs ropes as single driving component, e.g. lifts, rope trains, etc. Quality characteristics of ropes are regulated by procedures of safety standards and are prescribed in safety standards of transportation machines, which are particularly stringent in the case of human elevating equipment. Many types of rope quality control are applied in practice but standard control procedure of such nonhomogeneous structures as ropes with electromagnetic methods are still not fully reliable, particularly in the case of broken wires in rope strands. The paper presents a method for detection of the aforementioned rope defects using dynamic properties of a rope that is treated as a dynamic system. The proposed method enables to measure dynamic characteristics of a rope system and, based on obtained results, evaluate rope quality, determine the presence of broken strands and define cross-section of the defects. Analysis of dynamic properties is used in order to establish existence of a defect. Aim of such analysis is to determine some characteristic natural frequencies corresponding to broken strand and change of the lowest natural frequencies that represent the rope as a constrained system. The paper also addresses the issues of equipment and methodology required for defect detection in ropes together with the necessary conditions. Final conclusions are formulated with regard to possibility of implementing the proposed method in real working conditions.