Study On The Influence Of Wind Sand On Compressive And Erosion Resistance Of Rail Laser Treatment Layer

High speed railway plays an important role in"the Belt and Road Initiative".The Lanzhou-Xinjiang high-speed railway is a significant part of the rail,which is equivalent to the"collateral channels"of the high-speed rail.In the case of extremely poor working conditions,the failure of different forms and different degrees appear in rail of each section of the Lanzhou-Xinjiang high-speed railway,the wind sand erosion has the most regional characteristics for rail damage.The erosion pit formed on the surface of the rail is eroded by wind sand,which not only increases the surface area of rail,increases the speed of rail damage,but also worsens the wear degree of rail.However,the existing research results of high-speed rail can not be directly applied to the line.Models is established in two states,numerical simulation of the service state of rail,and then comparative analysis the rail stress and strain,displacement,stress of the different condition.The variable quantity is the wind speed,the wind angle and the material type.These provide scientific reference for improving the performance of rail of Lan-Xin railway and formulating the mitigation scheme.Relevant experimental research has been done in the early Lan-Xin rail test group^[22,76],and theoptimum process parameters of laser melting and laser cladding are obtained.This paper mainly through ANSYS software simulation of rail laser processing layer material in actual service environment reflects the pressure and erosion resistance performance changes.After treatment,the elastic modulus,Poisson's ratio and density of rail materials change and their values are nowhere to be found.In order to carry out the simulation successfully,the data are obtained by the dynamic elastic modulus tester of solid materials.The main focus of this paper is the numerical simulation part.The variation of sand velocity,stress,strain,displacement,pressure and turbulent kinetic energy with different wind speed and angle is compared and analyzed.The conclusions are as follows:?1?After laser melting and laser cladding,the crystal structure,chemical composition and microstructure of the material change,which makes the elastic modulus of the material different from that of the original rail.The elastic modulus of different materials has been changed compared with the elastic modulus of the original rail.The Poisson's ratio of materials is compared.The Poisson's ratio of material after laser treatment is less than that of raw material Poisson's ratio.The microstructure of the 1 material is mainly long branched crystal and strip martensite,and the microstructure is relatively rough,and the change of unit transverse and longitudinal strain is the most obvious,and the difference is the most from that of the original rail.?2?Through numerical simulation analysis,it is concluded that under the condition of no train running,when the working condition is at the angle of wind angle?=45 and at the speed of wind 40m/s,the rails are most seriously affected by wind erosion.This conclusion is consistent with the experimental conclusion obtained in the literature^[96],which is"for the base metal,the erosion angle has great influence on the erosion rate".?3?Under the condition of high accuracy of numerical simulation,the transient state of the train passing through the rail is further simulated.The results show that rail damage is most serious when wind angle is 45 and wind speed is 40m/s.Through comparative analysis,the effect of changing wind speed on rail is more obvious than that of changing the angle of wind to rail.?4?In the three variables of the contrast angle change,the change of wind speed and the change of material type,the change of material type obtained by laser surface treatment technology,changing material type has the greatest influence on the stress state of the rail.?5?When the wind angle and wind speed change,the most serious erosion of wind sand on rail occurred at the wind angle of 45 and the wind speed of 40m/s.The simulation results are in agreement with the experimental results^[76,96].