Studying the load of composite brake pads under high-temperature impact from the rolling surface of wheels

The object of the research is the processes of thermal stress, perception and redistribution of loads by the brake composite pad during braking of the car in operation. In the current conditions, wedge-dual wear of composite brake pads is observed in the braking systems of freight cars, the feature of which is the deterioration of the braking efficiency of freight trains. With this type of wear, both an increase in the load on the brake pad and an "underuse" of the amount of pressure on it can occur. A comprehensive thermal calculation was carried out for composite brake pads with uniform and wedge-dual wear. The results of the calculation showed that the amount of pressure on an abnormally worn pad is 23.3 % less than that acting on a pad with nominal values. It has been proven that the change in the pressure force on the composite pad with different values of the wear parameters during braking leads to a change in the braking force that occurs between the wheel and the rail during braking. The calculation of the strength of the composite brake pad with wedge-dual wear was carried out. The obtained results will make it possible to develop measures to modernize the elements of the brake lever transmission of freight cars. The field of practical use of the obtained results is car-building enterprises. The conditions for the practical use of the results are the brake lever transmissions of carriages of cars with a gauge of 1520 mm. The conducted studies prove the negative impact of wedge-dual wear not only on braking efficiency, but also on the strength of brake pads. This makes it necessary to create measures aimed at its elimination, which will contribute to increasing the level of train traffic safety and significantly reducing the operational costs of maintaining freight car

DETERMINATION OF THE RATIONAL GEOMETRICAL PARAMETERS OF PLATE TYPE ELEMENTS OF MAGNETIC MATRIX OF THE POLYGRADIENT SEPARATOR

Introduction. Polygradient magnetic separation has wide application in industry and in biomedicine. Working process in polygradient separators takes place in a matrix, magnetic elements of which create magnetic forces sufficient to remove small ferro- and paramagnetic inclusions. Problem. The influence of mutual arrangement of elements on character of distribution of magnetic field is not taken into account during calculation of characteristics of magnetic field in magnetic matrixes. It makes comparative analysis of matrixes of different configurations quite difficult. Fulfillment of comparative analysis of strength characteristics of magnetic fields of multicomponent matrixes of polygradient separators of various configurations requires further researches. Goal. To determine the dependence of the strength characteristics of the polygradient electromagnetic separator on the geometrical parameters of the plate type elements of the multicomponent matrix. Methodology. The finite element method for calculation of power characteristics of separator magnetic field, method of comparative analysis and simple search method for determination of rational geometric parameters of the matrix have been used during the solution of the paper problem. Results. Estimation of entire spectrum of force field in plane of working zones of investigated structures in two-dimensional location for determination of rational variants of polygradient matrixes has been done. The main stages of computational experiment are given. Method of comparative analysis of power characteristics of investigated variants of matrix structures with corresponding characteristics of basic version of separator for determination of rational geometrical variants of polygradient matrixes has been applied. By results of calculations the rational geometric parameters of polygradient matrix has been chosen. The characteristics of power magnetic fields in working gaps of matrixes of polygradient separator have been studied. It made possible to determine the rational structural variants of matrix on basis of parameter of effective area of working zone. Practical value. The results of research can be used in practice of design of electromagnetic separators with polygradient matrixes

Die Wärmeninteraktionseffekte zwischen dem Fahrgestellrad und dem Bremsklotz

Článok pojednáva o niektorých javoch teplotnej interakcie medzi brzdeným železničným kolesom a brzdovým klátikom pri brzdení na spáde. Pozornost' je tu venovaná vzniku a šíreniu sa teplotných polí do kolesa a brzdového klátika, sú tu poukázané možnosti a sposoby riešenia priebehu nestacionárneho teplotného pol'a. Vzhl'adom na náročnost' analytického riešenia, pozornost' je zameraná na experimentálne merania. V krátkosti je tu popísaný brzdový stav KKVMZ VSDS na ktorom boli merania vykonané. Predmetom skúšok bol brzdový klátik typu 013 - P10, v ktorom boli umiestnené termočlánky v troch vrstvách, Týmto klátikom bolo brzdené monoblokové železničné koleso UIC s priemerom 920mm róznymi brzdovými výkonmi. Namerané priebehy teplot boli zapísané, vyhodnotené. Hodnoty teplot pri určitých podmienkach boli použité aj ako okrajové podmienky pre výpočet rozloženia teplot a napätl v klátiku.This paper deals with some phenomena of thermic interaction between braked monoblock of railway wheel and cast iron brake block during down-hill braking. Our attention is paid to a generation and expansion of thermic fields into the railway wheel and into the brake block, referring as well to the possibilities and manners of solution of the nonstationary thermal field development. With regard to the analylical solution difficulty, the attention is paid to the experimental measurements. The brake test stand KKVMZ VŠDS, using that the measurements were done, is roughly described. The brake block of type 013-P10 was used as the subject for testing, with the thermocouples arranged in three layers. This brake block was used for braking the railway wheel of type UIC with diameter 920 mm applying different braking power. The measured distributions were put down and evaluated. The given values of temperatures were used as the boundary conditions for thermal and stress analysis of the brake blocks.lm Artikel werden einige Wärmeinterraktionseffekte zwischen dem Fahrgestellrad und dem Bremsklotz beim Bremsvorgang auf dem Gefälle behandelt. Die Aufmerksamkeit wird hier dem Entstehen und der Verbreitung von Wärmefeldern in das Laufrad und den Bremsklotz gewidmet. Weiter wird hier auch auf die Möglichkeiten und Arten der Lösung des nichtstazionerten Verlaufs vom Wärmefeld hingewiesen. lm Hinblick auf den Aufwand der analytischen l.ösunq ist hier die Aufmerksamkeit den experimentalen Messungen gewidmet. Kurz wird hier auch der Bremsstand am Lehrstuhl KKVMZ der VŠDS beschrieben, an dem die experimentalen Messungen gemacht durchgeführt wurden. Das Objekt der Proben stellte der Bremsklotz des Typs 013-P10 vor, in dem die Thermoelemente in drei Schichten angeordnet waren. Mit diesem Bremsklotz wurde das Monoblock - Fahrgestellrad UIC mit Durchschnitt von 920 mm mit verschiedenen Bremsleistungen gebremst. Die gemessenen Bremstemperaturen wurden notiert und ausgewertet. Die Temperaturwerte bei bestimmten Bedingungen wurden auch als Grenzbedingungen zum Ausrechnung der Temperatur-und Spannungsausbreitung im Bremsklot zverwendet

The assessment of the integration methods for the rail vehicle ride dynamics solution

The article is devoted to the analysis of the dynamic characteristics of the mechanical system composed of rigid bodies mutually connected with flexible bindings that represent springs and dampers. The analysed system represents the rail vehicle, which is distinguished by the contact link between the wheel and rail, or wheelsets and the track. Currently, analyses of similar type are carried out basically by using commercially distributed software packages, where you enter inputs (which the input forms allow) and the user may achieve results respecting the handling procedures. In accordance with the different approaches to solutions of partial solutions of the issue, the results of the simulations can differ. In the article the theoretical analysis is conducted the parameters of calculation are set out and the results are compared with the results obtained from the calculation by SIMPACK

Analýza mechanických sústav s využitím Component Works

Príspevok pojednáva o možnosti analýzy mechanických sústav pomocou programového balíka Component Works z hľadiska dynamiky a merania. Programový balík predstavuje ucelený celok využiteľný vo vývojových systémoch schopných implementovať komponenty typu ActiveX

Vývoj programového systému pre skúšky spaľovacích motorov

Automatic measure and control system je aplikačný program určený na pribežné monitorovanie stavu meraných miest, automatizované meranie, zaznamenávanie nameraných údajov, vyhodnotenie zaznamenaných údajov, spracovanie a tlač protokolu o meraní na železničných rušňových spaľovacích motoroch K 12 V 230 DR po generálnej oprave na skúšobni naftových motorov v Železničných opravovniach a strojárňach Zvolen a.s. Meranými veličinami sú prúdy, napätia, teploty, tlaky, otáčky, celkom 40 meraných veličín. Systém pracuje vo Windows 3.11 využíva zariadenia National instruments PC zásuvnú kartu AT-MIO-16X, zásuvná karta (čítače/časovače) PC-TIO-10, obvody na spracovanie signálu SCXI. Celý systém je variabilný z hľadiska druhu, kvality ako aj počtu meraných miest. Tvorcom aj realizátorom systému je KKVMZ ŽU v Žiline

Wheelset/Rail Geometric Characteristics Assessment with Regard to Wheelset Rolling

The geometric relation between a wheelset and a rail is assessed with the help of geometric characteristics. Geometric characteristics are: equivalent conicity function, delta r function placement of contact points of a wheelset and a rail, tangent gamma function and effective conicity.It turned out that these characteristics are at present the most important not only for the judgment of ride characteristics of a vehicle on the rail but also for the wearing of wheel treads and rail heads, e. i., for the assessment of the track and vehicles in order to find out the current state and for the assessment of changes of the wheels and rails profile shapes in order to improve the current state too. The process of geometric characteristic assessment of a wheelset and rail with regard to wheelset rolling is analysed in the article

Railway Wheel and Rail Roughness Analysis

The paper deals with the railway wheel unroundness (out-of-round) analysis and with the rail head roughness analysis. Roughness of the running surfaces is the predominant source of noise of rail bound transport systems today. Reliable measurements of the roughness of rails and wheels are crucial for noise reduction purposes. In the past, the main purpose of measurements was the understanding of corrugation growth and rolling noise generation. Meanwhile, quantitative descriptions have gained considerable importance

Programový systém LaGer

Programový systém LaGer je nástroj na interaktivní vytváření programů (aplikačních formulářů) pro předběžné monitorování stavu měřených míst, automatizované měření, zaznamenávání naměřených údajů, vyhodnocování údajů, řízení experimentů, export dat ve formátech vhodných pro další zpracovávání (CSV, TXT), grafické zobrazení s exportem do WMF, zpracování protokolu o měření a tisk. Programový systém LaGer, je postavený na filozofii komponovaného otevřeného systému. S výhodou je možné implementovat sadu ActiveX komponentů Component Works (National Instruments) pro sběr dat, numerickou analýzu, výpočty a zobrazení dat. Program obsahuje designer, který umožňuje editaci aplikačního formuláře za běhu programu

Wheel/Rail Contact Stress Evaluation by Means of The modified Strip Method

The Strip Method is often used for rail/wheel contact area and contact normal stress evaluation. The paper deals with the computational time saving procedure when the computation accuracy is guaranteed. We included the local coordinate system with a presupposed semi-circular course of the normal stress for the purpose of the integral that is necessary for deformation in the middle of individual strips evaluation. The integral is solvable analytically. The input parameters for individual parts of splines and individual strips expression are possible to insert after analytical solution