Finite element analysis on performance of rail thermite welding joint

YE Yuan1， PAN Wen-bin1， YANG Tao1， SONG Jia-wang2
（1. School of Mechanics， Zhejiang University of Technology， Hangzhou 310014， China；
2. Research Institute of Superplasticity and Plasticity， Jilin University， Changchun 130012， China）

Abstract： Rail thermite welding joint is the weakest link in continuous welded rail（CWR）. In order to study the performance of welding joint，vehicle/track coupling dynamics theory based on Timoshenko beam model was used with the results of simulation on thermite welding process. The wheel/rail contact parameters under short wave irregularity of welding joint were figured out with this method. Finally，based on Hertz contact theory，the wheel/rail contact elastic-plastic finite element model was constructed and analyzed. The results indicate that under pure rolling working condition，the largest Mises stress and equivalent plastic strain（PEEQ）are both 4.1 mm beneath the rail head surface where cracks may probably form. While under pure sliding condition，they both move to the surface where the welding joint may be squashed or even break. Under pure rolling circumstances，the largest Mises stress，PEEQ and residual displacement are increasing with the increased vehicle speed and also increasing when the distance between welding center and nearer rail sleeper is minishing，but has no significant change if the width of heat affected zone（HAZ） of welding joint changes.
Key words： high-speed railway； continuous welded rail（CWR）; rail thermite welding； joint performance； wheel/rail contact theory； finite element analysis