Research On Fatigue Performance Of High-speed Railway Track Connector

The high-speed railway is good at speed, security and transport capacity, so it is aninevitable choice for development of low-carbon transport. However, if the railway has abreakdown, the consequence is devastating because of high-speed. High-speed railway is thejointless track. The welded joint of rail is prone to cracking, so it is the weak link of the jointlesstrack. In this paper, stress analysis of the welded joint was made to find out reasons of cracking.And the environment of the welded joint was improved, mainly related to the analysis andoptimization about the welded joint of the supporting environment. The specific works were asfollows:(1)The finite element model of the two welded rail coupling sleeper supporting wasestablished. Then the stress analysis was made about it. The results showed that the weldingresidual stresses and the indentations of weld joints were main reasons of cracks.(2) New measures dealing with cracks of welded joints were made. First, the emergencytreatments were made for cracks. Second, the situ welding repair was made for welded joints.Third, joint plates were fixed to share the stress of the joint. Finite element analysis on the railwith joint plates was made. The results showed that the maximum stress of the rail joint was lessthan the crack growth threshold value of the rail material. It verified the feasibility of therehabilitation program of “resection-welding-fixing plate’’.(3)Analysis of rail joints’ supporting environment was made in two ways. First, the stressanalysis of rail joints was made from the elastic constant of the sleeper. Second, the stressanalysis of welded joints was made from the distribution of the sleeper.(4)Based on the above analysis, some optimization programs about the rail jointenvironment were proposed. First, a sleeper with large support stiffness was designed. Theelastic constant of such sleeper was calculated. Improvement of rail joints’ fatigue by this sleeperwas verified. Second, an optimization program about increasing a sleeper under the rail joint wasproposed. Then the feasibility of this program was verified. Third, analysis and optimizationabout other factors that affected the life of the rail joint were made.