Fatigue analysis of railway coupling joint

A new type of railway coupling joint, developed by a leading international railway manufacturer, has shown limited fatigue lives in service, in a preliminary service assessment of fatigue life. To get more data about this problem a detailed study was carried out of the fatigue design of the component including stress analysis and fatigue life evaluation.The main objective of this paper consisted in getting accurate information concerning the level of operational reliability of the fatigue behaviour of this new type of coupling used in carriages for passenger transportation in suburban lines.The strains in service were obtained with strain gauge rosettes in a typical line. Values of the cumulative fatigue damage were obtained in this service conditions. Linear damage accumulation laws were used.A numerical stress analysis using FE methods were performed. Detailed stress distributions were obtained in the component. Hot spot areas of stress were obtained and also the values of critical fatigue damage in these critical points of stress distributions. The extrapolation method to the hot spot points, was used to obtain the critical values of fatigue damage.The results of fatigue damage gave an infinite value of fatigue life for the coupling.