时速400km条件下钢轨焊接接头平直度及廓形偏差限值OA

The wheel-rail dynamic interaction is intensified on 400 km·h-1 high-speed railways,while the control limits for rail weld straightness and rail profile deviation remain unspecified.Accordingly,a method for determining such limits is proposed,combining parametric modeling of field-measured conditions,rigid-flexible coupled vehicle-track dynamics simulation and field adaptability verification:first,a rigid-flexible coupled dynamics model of a new-type EMU and the track is established,parametric models of rail weld irregularity and rail profile deviation are constructed from measured data,and the model is validated against field-measured dynamic responses;second,the influence of rail weld straightness on the wheel-rail dynamic response is investigated and a limit for weld straightness is proposed;then,the influence of rail profile deviation on the lateral vibration of the vehicle is investigated in both the time and frequency domains and a limit for profile deviation is proposed;finally,the adaptability of the proposed limits is analyzed with reference to field test results.The results show that when the weld straightness amplitude is less than 0.2 mm,the wheel-rail vertical force,wheel unloading rate and contact stress increase relatively gently with rising speed,whereas beyond 0.2 mm the growth rates of these indices accelerate markedly and both the wheel-rail impact and the local contact stress increase significantly;the influence of profile deviation on the lateral dynamic performance of the vehicle depends on the wheel-rail matching condition,in that a negative deviation with a magnitude exceeding 0.2 mm mainly amplifies the low-frequency lateral vibration of the carbody when matched with new wheels,whereas a positive deviation exceeding 0.2 mm mainly intensifies the lateral vibration of the bogie frame when matched with worn wheels;it is therefore recommended that,for 400 km·h-1 high-speed railways,the rail weld straightness be controlled within 0 to 0.2 mm·m-1 and the rail profile deviation within-0.2 to+0.2 mm;field tests show that after grinding more than 90%of the welds and rail profiles satisfy the proposed limits,and that the wheel-rail force,wheel unloading rate and vehicle vibration acceleration measured during the high-speed running tests of the new-type EMU all retain a substantial safety margin,which verifies the field feasibility and high-speed adaptability of the proposed limits and provides a basis for rail maintenance on 400 km·h-1 high-speed railways.