Failure analysis of railroad couplers of AAR type E

The paper is about the failure of Railway couplers of AAR type E. Most of the couplers are being replaced before their expected life due to the high stress concentration near pulling lug region, cage-hole and pivot-hole. Knuckle, a part of coupler is designed and analyzed to determine the key regions of failure. A change in the design has been proposed and analyzed to compare the original and modified version of the knuckle. The results of analysis allowed assessing the failure reasons. A set of dimensions are chosen and the response surface methodology (RSM) technique has been implemented to obtain the optimum values for the design variables within given constraints. Life of the new design shows significant increase in life over the original design.