| Rail grinding is recognized at home and abroad as an effective rail maintenance method,which can effectively eliminate or delay all kinds of rail diseases,restore or generate the rail target profile,improve the geometric relationship of wheel-rail interface,thus prolongs the service life of rail and ensures the safety and stability of line running.Rail grinding using abrasive belt is a new rail grinding technology.Compared with traditional rail grinding technology,rail grinding using abrasive belt has the characteristics of high efficiency grinding,elastic grinding and cold grinding,and significantly reduces the peak temperature in the grinding process.However,when the crack damaged rail is grinded by abrasive belt,the surface of the rail still appears blue burn phenomenon,which indicates that a higher instantaneous temperature occurs at this time,which will inevitably affect the rail grinding quality and the service life of the abrasive belt and rubber contact wheel.Therefore,this paper will study the grinding temperature field of the rail grinding using closed abrasive belt from the morphology characteristic parameters of the crack itself,the direction of grinding operation,the speed of grinding operation,the force of grinding and the times of grinding processes.The main contents are as follows:Based on the principle of rail grinding using closed abrasive belt and the actual rail grinding equipment,the heat transfer model of cracks damaged rail grinding using abrasive belt was established.On this basis,the heat transfer analysis was carried out,and a thermodynamic coupling finite element calculation method for the process of cracks damaged rail grinding using closed abrasive belt was proposed.Through three crack morphology characteristic parameters including cracks’ Angle(10～30 °),cracks’ spacing(2～4 mm)and cracks’ depth(0.4～2 mm),the model of cracks’ damaged rail grinding using closed abrasive belt simplified necessarily to establish the threedimensional model,import the finite element simulation model is established in ABAQUS software,get the distribution of grinding temperature field,for the follow-up studies the influence of different factors on the grinding temperature field.Change the cracks’ Angle,and adopting the direction of forward and reverse two grinding direction,the simulation analysis of grinding temperature field on R80 arc and R13 arc was taken,found that the peak temperature of grinding under forward grinding direction is generally lower than that under reverse grinding direction,this is caused by the difference in the severity of heat accumulation due to the differcence in grinding operation direction.On the basis of this conclusion,the effect of cracks’ spacing and cracks’ depth on grinding temperature field was studied by using forward grinding direction.The influence of the cracks’ morphology characteristic parameters on the grinding temperature field on R80 arc and R13 arc is consistent.For the same cracks’ morphology,the grinding temperature of R13 arc is higher than that of R80 arc due to the larger curvature of R13 arc.For R80 arc and R13 arc of rail,the effect of grinding process on grinding temperature field of rail grinding using abrasive belt with crack disease was considered from the perspectives of grinding force(80～120 N),grinding speed(1～5 km/h)and grinding times,respectively.On R80 and R13 arc,the peak temperature of grinding using abrasive belt increases with the increase of grinding force,and decreases with the increase of grinding speed.At the same grinding force and grinding speed,the peak temperature of grinding using abrasive belt on R80 arc is lower than that on R13 arc.When the rail is grinded by the second time,the surface curvature of the contact position is reduced to zero and the cracks’ depth is slightly reduced,thus the grinding temperature of the second time is significantly lower than that of the first time.During the subsequent grinding,the grinding temperature continues to decrease as the cracks’ depth continues to decrease. |
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