Contact Fatigue Analysis On Journal Box Spring Of EMU

box spring is the support and cushioning device whose reliability is an important factor to ensure the safety of railway traffic. Accidents of spring break caused by contact fatigue between bracing ring and effective coil of the axle box ring are very common, and the influence factors of contact fatigue are very complicated. However, relevant research is very few at home and aboard. In practice, load on the spring is an important factor to influence contact fatigue. So research on the transitive relations between contact stress and load of the spring and analysis on spring contact fatigue life become the important basics of the spring contact break study.This paper analyzes the actual load condition of the axle box spring of the Multiple Units by road tracing test. Besides it computes the transitive relations between contact stress and load and analyzes the influence to contact fatigue from lateral and vertical load with ABAQUS, and then gets the spring fatigue life. It raises the experiment solution on reasonable spring contact fatigue and proves its rationality.The researches show that:(1) The middle test point of the spring has a better load identification than those of the up and bottom ones;(2) In the process of imposing the spring with vertical load, the parts with greater contact stress begin to stay away from the end of the spring with the load increasing, presenting non-linear change tendencies;(3) The simulation of contact shear stress is not enough to have an impact on contact fatigue, there may be other factors affect the contact shear stress or contact fatigue limit;(4) The lateral displacement of the spring has a greater effect on contact fatigue than that of the vertical load, according to the road test. So it is necessary to impose the vertical and lateral load at the same time in the spring fatigue test.