Research On Treatment Measures For Long Wavelength Rail Corrugation In Metro

Metro lines are usually laid with a variety of track structures,which cause rail corrugation of different wavelengths,and long-wavelength rail corrugation is one of them.The uneven passing frequency of long-wavelength rail corrugation is low,and this frequency is likely to overlap with the natural frequency of the vehicle structure,causing the structure to easily resonate when passing through the long-wavelength rail corrugated section.The existing grinding method has obvious effect on the treatment of short-wavelength rail corrugation,but the effect of treatment of long-wavelength rail corrugation is not good.Variable-speed strategy can effectively alleviate the structural service load when the vehicle is running in the longwavelength rail corrugated section.This thesis takes a metro line with serious long-wavelength rail corrugation as the object,through a combination of field test and numerical simulation,researches on the fine grinding strategy for long-wavelength rail corrugation and the strategy of variable speed sports car.Provide basis for perfecting wheel-rail maintenance theory and improving vehicle track service reliability.The main work and conclusions of this thesis are as follows:(1)Conduct field tests and trials on metro lines with severe long-wavelength rail corrugation.The results show that there are rail corrugations in various track structures laid on the line,among which the corrugation of the ordinary short sleeper fastener section is the most serious,and the form of corrugation is long-wavelength steel rail corrugation.Comparing with the corrugated wavelength of the deceleration section of the ordinary short sleeper,it can be seen that the corrugated wavelength of the rail changes with the running speed of the vehicle,but the passing frequency of the corrugated irregularity of the vehicle in the corrugated section is within a specific range.(2)The data of vibration acceleration and spring stress of the vehicle components tested in the test are analyzed.The results show that when the wheel is mainly worn by eccentric wear and there is no polygon,the wheel cannot significantly reduce the vibration level of the axle box.Vehicle speed reduction can effectively alleviate axle box vibration.The wheel-rail vertical vibration transmission is characterized by first increase and then decrease,and the secondary suspension system can effectively attenuate the vibration energy.There are abnormal phenomena of axle box vibration and spring stress in the approach section of the non-normal line.Short-wavelength rail wave grinding can effectively reduce the vibration level of vehicle components,but the effect of long-wavelength rail wave grinding is not obvious.(3)Integrating the dynamic theory and the equivalent theory of grinding,a grinding model of rail longitudinal irregularities is established,and corresponding numerical algorithms are developed to simulate the removal process of rail irregularities during the grinding process.Numerical simulation results show that when grinding short-wavelength rail corrugated,the grinding stone mainly touches the wave crest position of corrugation,so grinding can effectively reduce the corrugation amplitude.However,the long-wavelength rail corrugation has a large wavelength,and the wave crest is also grinded by the grindstone.As a result,the long-wavelength rail corrugation cannot be effectively removed.(4)Through simulation analysis and field test,the effect of fine grinding strategy and variable speed sports car strategy on long-wavelength rail corrugation is analyzed.The results show that the fine grinding method that considers the difference of the peak-to-valley grinding amount can significantly improve the unevenness of the long wavelength rail.The variable speed sports car strategy can effectively reduce axle box vibration and spring stress caused by long-wavelength rail corrugation during vehicle operation.Therefore,the fine grinding strategy and the variable speed sports car strategy are effective methods to control the longwavelength rail corrugation.