Study On The Mechanical Characteristics And Its Damage Analysis Of Teh Axle-bearing Interference Fit Surface Of The High-speed Train

In recent years, high-speed train has won the favor of all countries for its advantage of rapidity, comfort and safety and so on. However, with the breakthrough in the direction of high speed, heavy load and light weight, the fretting damage of the key interference fit surface(such as the wheel-axle、 the axle-bearing) is becoming more and more serious, which will threaten the safe operation of high-speed train. Therefore, it is necessary to study the mechanical characteristics and its damage of the axle-bearing interference fit surface of the high-speed train. the evolution mechanism and influencing factors of the fretting damage was analyzed. the direction of the research on the fretting damage of the axle-bearing of the train was indicated.In this paper, several typical fretting damage types and its surface damage phenomenon of the key interference fit surface of the train were summarized. And its influence factors and protective measures were analyzed. the research method on the fretting damage of interference fit surface were also discussed. Based on the study of the fretting damage of interference fit surface and the basic contact theory of elastic theory, the calculation method of the contact stress of the interference fit surface under the condition of elastic deformation and elastic plastic deformation was derived. The contact pressure of the interference fit surface of the axle-bearing was calculated by the axle and bearing parameters of the CRH2 type high-speed train.With the finite element analysis theory and analysis technique on elastic contact problems, a simplified finite element model of the axle-bearing was established. The surface stress variation diagram under different loading sleeve was obtained by using the finite element software of ABAQUS. The distribution law of contact stress along the different paths of the model was analyzed. And the theoretical calculation results were verified with the finite element analysis results. The results show that the theoretical calculation and the finite element simulation results are consistent. With the increase of the load, the contact pressure of the interference fit surface is also increased.The solid model of axle-bearing interference fit coupling was established by using Pro/E for the parameters of the axle and bearing of CRH2 EMU. the influence of interference,friction coefficient, load and train speed on the mechanical characteristics of the axle-bearing surface was analyzed by using the finite element software ABAQUS.It is concluded that the influence of the interference and the load on the contact stress is great, and the influence of the friction coefficient and the speed of the train is relatively small.Finally, on the basis of studying on the model of the previous chapters, the stress and strain of the contact surface of the axle-bearing surface were obtained. For the model of the damage parameter model proposed by Smith, the SWT value of the damage parameter of the axle and bearing along the real path were calculated by using the Matlab software. The results show that the maximum value of SWT at both ends of the axle contact interface surface is occurred, and the peak value of SWT is obtained at the roller corresponding to the contact surface of the bearing outer ring. Therefore, it is judge that the fretting fatigue damage is easily to start from both ends of the contact surface of the axle and the roller corresponding,which generate fatigue cracks and lead to fatigue failure.