Mitigation of hanger pin failure in Pakistan railway carriage system by the application of COMSOL Multiphysics

Abstract

The frequency of failures in hanger pins of Pakistan Railway carriages has risen to an alarming level. Such as hanger pins have become the reason for the highest number of cases regarding failures of Carriage and Wagons in Pakistan. The pins have been failing after only 3 months while the intended life of these pins was supposed to be 6 months at least. Previously we have been using rectangular cross-section cotter pins in the hanger brackets. Studies have shown that instead a circular cross-section cotter pin can make a major contribution to the lower the value of these fatigue stresses. In this study, we compute and perform the stress and fatigue analysis on the hanger pin assembly using Findley criterion. Findley criterion was used as it most closely resembled in the properties needed to carry out our desired simulation. COMSOL model is used to compute the stresses as well as do the fatigue analysis on the said model. Fatigue usage factor has been used in the COMSOL. The first part contains the analysis on the already in-effect hanger pins of rectangular cross-sectional area. While the second half contains analysis done by changing the cross-section to modified circular shaped hanger cotter pins. The new proposed material proved to have decreased the stresses induced in the components thus increasing its life.

Keywords

• fatigue and stress analysis
• findley criterion
• comsol multiphysics