Marijonas Bogdevičius

Bio: Marijonas Bogdevičius is an academic researcher from Vilnius Gediminas Technical University. The author has contributed to research in topics: Traffic flow & Vibration. The author has an hindex of 12, co-authored 99 publications receiving 529 citations. Previous affiliations of Marijonas Bogdevičius include Klaipėda University.

An analytical mathematical method for calculation of the dynamic wheel-rail impact force caused by wheel flat

Abstract: The simplified method to determine a vertical impact force of wheel with flat and rail interaction is presented in this article. The presented simplified method can be used to identify maximum contact force and its distribution in the contact length between the damaged wheel and the rail. The vertical impact force depends on geometrical parameters of the rail and wheel with flat, speed of vehicle and the angle of deviation of rail. This article demonstrates the influence of wheel with flat geometrical parameters, speed of vehicle to maximum contact force and its distribution in the contact zone. The obtained values of the simplified method for determination of a vertical contact force are compared with the results obtained from field measurements.

Determination of the dynamic characteristics of freight wagons with various bogie

Abstract: In most cases, dynamic characteristics determine the wagon maintenance cycle, traffic safety, reliability and durability performance. The main dynamic indicators include the vertical Kvd and horizontal Khd dynamic coefficients as well as the stability coefficient Ks, which determines the wheel flange resistance to derailment. The article compares dynamic indications for three different types of bogies. There were no tangible differences observed for all the three different types of bogies running at a speed of 40 to 120 km/h on a direct tangent rail section. Nevertheless, there is a realistic potential to improve the dynamic indicators of a freight wagon by rationalising suspension unit parameters.

Mathematical modelling of network traffic flow

Abstract: The article describes mathematical models of traffic flows to initiate different traffic flow processes. Separate elements of traffic flow models are made in a way to be connected together to get a single complex model. A model of straight road with different boundary conditions is presented as a separate part of the network traffic flow model. First testing is conducted in case the final point of the whole modelled traffic line is closed and no output from that point is possible. The second test is performed when a constant value of traffic flow speed and traffic flow rate is entered. Mathematical simulation is carried out and the obtained results are listed.

Investigation Into the Stability of Driving An Automobile On the Road Pavement With Ruts

Abstract: The article reviews the stability of an automobile on the road pavement with ruts. The problems of road safety depend on many factors. One of those is the quality of the road surface. Big heavy lorries deform the road surface causing ruts especially in the first line of the road. The article analyzes the influence of the geometry of ruts on the stability of the automobile. A mathematical model of a 3D automobile and the interaction between wheels and the road surface and the geometry of the road surface are presented. The mathematical criterion of the stability of the moving automobile on the road surface with ruts is laid down. The results of mathematical simulation and the criterion of the stability of the moving automobile (60 km/h) on the road surface depending on the depth of ruts are introduced.

Dynamic Modeling and Vibration Response Simulation for High Speed Rolling Ball Bearings With Localized Surface Defects in Raceways

Abstract: A dynamic model is developed to investigate vibrations of high speed rolling ball bearings with localized surface defects on raceways. In this model, each bearing component (i.e., inner raceway, outer raceway and rolling ball) has six degrees of freedom (DOFs) to completely describe its dynamic characteristics in three-dimensional space. Gyroscopic moment, centrifugal force, lubrication traction/slip between bearing component are included owing to high speed effects. Moreover, local defects are modeled accurately and completely with consideration of additional deflection due to material absence, changes of Hertzian contact coefficient and changes of contact force directions due to raceway curvature variations. The obtained equations of motion are solved numerically using the fourth order Runge–Kutta–Fehlberg scheme with step-changing criterion. Vibration responses of a defective bearing with localized surface defects are simulated and analyzed in both time domain and frequency domain, and the effectiveness of fault feature extraction techniques is also discussed. An experiment is carried out on an aerospace bearing test rig. By comparing the simulation results with experiments, it is confirmed that the proposed model is capable of predicting vibration responses of defective high speed rolling ball bearings effectively.

A section approach to a traffic flow model on networks

Abstract: The development of real time traffic flow models for urban road networks is of paramount importance for the purposes of optimizing and control of traffic flow. Motivated by the modeling of road networks in last decade, this paper proposes a different and simplified approach, known as section approach to model road networks in the framework of macroscopic traffic flow models. For evaluation of the traffic states on a single road, an anisotropic continuum GK-model developed by [Gupta and Katiyar, J. Phys. A38, 4069 (2005)] is used as a single-section model. This model is applied to a two-section single lane road with points of entry and exits. In place of modeling the effect of off- and on-ramps in the continuity equation, a set of special boundary condition is taken into account to treat the points of entry and exit. A four-section road network comprised of two one-lane roads is also modeled using this methodology. The performances of the section approaches are investigated and obtained results are demonstrated over simulated data for different boundary conditions.

Modelling the interaction of transport system elements

Abstract: Economy and nonproductive sectors of each country could not function without a transport system (TS) Having analysed research works on the interaction of separate TS elements, it was identified that there is no common model for all types of interaction TS consists of material (physical) objects: traffic participants and freight to be carried, a transportation process and operations’ control TS classification scheme devised according to systematically selected criteria, showing that several criteria are often applied at the same time in official documents, is presented Original TS physical elements’ interaction model with 6 interaction levels is presented as well The model is suitable for all modes of transport Six levels of interaction are distinguished: autointeraction of transport elements, the first level; TS elements’ interaction, the second level; TS elements’ interaction with external environment, the third level; interaction of transport modes, the fourth level; TS interaction with t