Prediction Of Rail Wear Based On Accumulated Shear Plastic Strain

With the development of railway transportation industry towards to high speed and heavy load,the problems faced by wheel/rail system are becoming more and more prominent.Rail wear problem not only leads to the increase of vehicle maintenance cost,but also aggravates the geometric matching relationship,the indirect contact force and dynamic characteristics,more importantly,which will be a great threat to traffic safety and even lead to a train derailment and other safety accidents.Therefore,rail wear has been an important research field.Doing related research works has important engineering background and great social significance.In this paper,the main works of rail wear are as follows:(1)The three-dimensional finite element model of wheel-rail contact is established,and the three-dimensional model is verified and analyzed by Hertz theory.The contact load of wheel and rail under low speed running state and different wheel weight conditions is obtained,and the shear plastic behavior of rail is calculated and analyzed.Simplified the three-dimensional wheel-rail contact problem to the two-dimensional problem.Finally,the two-dimensional wheel-rail load is applied to the surface of rail through parametric loading.(2)The Lemaitre-Chaboche model is introduced to calculate and analyze the plastic shear behavior of the rail.The results show that the plastic deformation of the rail surface will occur when the rail under different loading conditions.In the process of loading,from the surface,the rail begins forms an obvious plastic shear strain layer along the depth direction,and the accumulation rate of shear plastic strain on the rail surface is relatively fast at the beginning of loading.With the loading repeatedly,the accumulation rate of shear plastic strain tends to a stable value_cv and continues to accumulate at this rate.(3)The rail wear predicted results of high speed are close to the measured results,and the results of low speed wear are smaller than those of high speed.Under the action of different wheel weight loads,the predicted rail wear depth of wheel weight 10 t and 15 t is0.5 mm,2.5 mm bigger than that of wheel weight 12.5 t when running 1×10~5 km.When running 2.5×10~5 km,the predicted rail wear depth of wheel weight 10 t is 0.2 mm smaller than the measured wear depth of 12.5 t wheel weight,and the rail wear depth predicted by 15t load is 5 mm larger than that measured 12.5 t.The predicted rail wear depth of wheel weight 5 t is much smaller than that of 12.5 t,10 t and 15 t,respectively,and the prediction results show that the heavier the wheel weight is,the greater the wear is.