Crack Propagation Simulation and Residual Life Analysis of Coupler Yoke

The operation of 20,000-ton heavy haul freight cars on Datong-Qinhuangdao Railway has played a very important role on the economic development of China, and at the same time it caused serious damage to the couplers and coupler yokes of the freight cars, threatening the traffic safety. In this paper, taking cracks on the coupler yoke into account, the stress intensity factors (SIF) for different crack sizes are calculated using the approach of 1/4 node displacement and sub-model techniques. The commercial finite element code ABAQUS is used for modeling and 3-D prismatic quarter point 20-node isoparametric degenerate singular elements are adopted for the region near the crack tip. Models on fatigue crack growth and residual life prediction are applied with help of Paris equation. Finally, AAR load spectrum is provided and the relationship between crack propagation size and wagon operation mileage is obtained. The work provides fundamental data for setting up the inspection plan and assessing the replacement period of the coupler yoke.