Vol.10, No 1, 2012 pp. 63 - 70
UDC 629.4.01; 629.4.02; 629.4.027.32; 629.4.027.352
STUDY OF THE RUBBER METAL SPRINGS FATIGUE OF PRIMARY SPRING SUSPENSION OF ELECTRIC LOCOMOTIVES
Dobrinka Atmadzhova, Nencho Nenov
Kableshkov University of Transport, Sofia, Bulgaria
E-mail: atmadzhova@abv.bg
Rubber-metal springs (RMS) that are widely used in both primary and secondary spring suspension of rail vehicles are reliable elastic-damping elements. They are compact since they combine elastic and damping properties and do not require operational maintenance. But their significant disadvantage is the process of characteristics' changes taking place on RMS known as rubber "aging". It has been found that the average lifecycle of RMS of locomotives series 46-000 in the operational practice of the Bulgarian State Railways since 1986 does not exceed 60% of the one guaranteed by manufacturers. Most probably the explanation for this is related both to poor features of the rail network in the country and the operation of locomotives without balancing the static load on their wheels. The study presented includes a simulation analysis carried out by the finite element method in order to predict the distribution of stress and evaluate the behavior of fatigue. Based on the nonlinear quasi-static modeling and analysis, residual stresses have been registered and superimposed and a methodology considering material fatigue has been developed to help predict RMS resource exhaustion. The results obtained in the study can be used to optimize the basic RMS design parameters and features.
Key words: Electric Locomotive, Rubber-metal Springs, Failure Analysis, Life-cycle Prediction
ISTRAŽIVANJE ZAMORA KOD GUMENO-METALNIH OPRUGA PRIMARNOG OGIBLJENJA ELEKTRIČNIH LOKOMOTIVA
Gumeno-metalne opruge ili, skraćeno, GMO, uveliko se koriste i kod primarnog i kod sekundarnog ogibljenja železničkih vozila kao pouzdani elastično-prigušni elementi. Oni su kompaktni budući da kombinuju elastične i prigušne osobine a ne zahtevaju operativno održavanje. Ali je njihov značajan nedostatak proces promena karakteristika poznat kao "starenje" gume. Utvrđeno je da prosečni radni vek GMO-a kod lokomotiva serije 46-000 u operativnoj praksi Bugarske državne železnice od 1986. ne prelazi 60% garancije koju daje proizvođač. Objašnjenje ove činjenice se odnosi i na slabe odlike železničke mreže u zemlji kao i na rad lokomotiva bez uravnoteženja statičkog opterećenja na točkovima. Ovo istraživanje obuhvata simulacionu analizu metodom konačnih elemenata radi predviđanja raspodele napona i procene ponašanja zamora. Na osnovu nelinearnog kvazi-statičkog modeliranja i analize, utvrđeni su rezidualni naponi a razvijena je i metodologija razmatranja zamora materijala kako bi se pomoglo pri predviđanju istrošenja GMO resursa. Rezultati dobijeni u ovom istraživanju mogu se koristiti za optimizaciju osnovnih GMO konstrukcionih parametara i njegovih svojstava.
Ključne reči: električna lokomotiva, gumeno-metalne opruge, analiza otkaza, predviđanje radnog veka