Failure Analysis Of Railway Clip Fastener System

The elastic fastener system plays an important role in the railway track structure,and the energy stored by the elastic deformation plays the role of fixing the rail,bearing the stress of all directions and reducing vibration.In recent years,due to the increase of the traffic density and the speed of the vehicle,the failure of the fastening system becomes more and more serious,which will increase the wheel-rail interaction force and deteriorate the train running environment.To this end,the paper takes the type elastic fastener as the research ?object,using the failure ranking method based on economic losses,the finite element analysis and vehicle-track coupling dynamics theory,to rank the failure mode and analyze the static and dynamic behavior.The results reveal the causes of the failure and predict the fatigue life of the fastener as well as put forward some suggestions.First of all,according to the improved risk priority ranking method based on economic losses,the failure grade of the parts of the fastener system including the rail is ranked and the elastic strip is the highest.A detailed finite element model is established,and the fourth intensity theory(Mises criterion)is selected as the failure evaluation index.The buckling pressure,displacement,equivalent stress(Mises stress),strain properties of fastener bars under different preload pressures are analyzed.The results show that the installation position of fastener system is achieved when the preload is 25 kN.After the installation is in place,continue to analyze the equivalent stress and strain distribution on the surface of the elastic bar to determine the weak position.Secondly,considering the actual situation of train operation,the dynamic effect of weld irregularities and rail corrugation on the fastening system is analyzed by using the vehicletrack coupling dynamic theory.Besides,the vibration characteristics of the bar are analyzed by using modal and frequency response theory.The results show that the shorter wave length,the larger wave depth and the higher vehicle speed will increase the equivalent stress and vibration displacement,and will accelerate the rupture of the spring bar.In addition,the rail corrugation has little effect on the vibration displacement but the vibration acceleration and the equivalent stress.The time-frequency domain analysis of the vibration characteristics reveals the intrinsic relationship between the natural frequency of the spring and the frequency of the wave corrugation,that is,the resonance of the system is also an important reason for the failure.Finally,on the basis of static and dynamic analysis,considering the most unfavorable conditions of preloading and dynamic stress superposition,the fatigue life of the dangerous parts of the spring is analyzed.According to the three optimal indexes,that is,working environment,energy method and fatigue life,the paper gives a scientific optimization proposal.