The Study On Stress And Load Spectrum Of The Wheel Axle Of CR

As an important part of high-speed train,the structural strength of wheel axle system influences the traffic safety significantly.As the operating speed of China's standard EMU "Renaissance" returned to 350km/h,more stringent requirements against fatigue problem of the axle were put forward.This paper focused on the instrumented wheel-set of the CRH-0208 which was produced in CRRC QINGDAO SIFANG CO.,LTD,China,studying and carrying out experimental research against the axle load spectrum and stress spectrum:(1)Development of high-precision measuring wheel-set based on continuous measurement:According to the technical drawings provided by SIFANG,the suitable vertical and lateral load identification points in wheel modeling and simulation were found,and thus the interference was effectively reduced.According to UIC510-5,the Ansys finite element simulation on the instrumented wheel-set were made,and the continuous measurement theory of the bridge and the output of the mathematical laws were analyzed.The result shows that the development condition of high precision continuous force measuring instrumented wheel-set is mature.All aspects of the wheel-set are in line with technical specifications,and the wheel static strength and fatigue strength meet the requirements of safe operation.(2)The obtaining of stress-load transfer coefficient:The calibration scheme of wheel-rail force decoupling loading under various static test conditions was given.And the calibration data was processed based on the concept of quasi-static method.The vertical,lateral and longitudinal stress-load transfer coefficients of wheel-rail forces were also analyzed.The influence of each load acting on each direction was analyzed.(3)The preparation of the load spectrum of the measured axle under line test:The collected data was processed and analyzed according to the typical working conditions and different speed levels,and the data was calculated by multiple means such as integrating the speed signal and the load time history through programming means.And thus the load level of wheel rotation frequency was obtained,and the two-dimensional comprehensive load spectrum which shows the frequency load role at all levels were obtained.The analysis of the wheel-set load spectrum shows that the test condition of DAXI line is good,the value of wheel-set vertical load is influenced by road conditions and axle load,and the maximum frequency load does not change significantly with the increase of speed.However,under the main frequency,The transverse load size and distribution range are affected by the combination of road conditions and speed on the line.The longitudinal load is greatly affected by the traction torque of the gearbox when starting the brake,and the load of the train is stable during steady operation.(4)The stress spectrum was plotted by the rain flow method,and the fatigue strength of the axle at each cross-section of the shaft were obtained:The characteristics of the stress spectrum were analyzed,and the result shows that the main stress values of all the measuring points under heavy truck conditions were greater than the empty truck working conditions.The equivalent stress values of empty and heavy car axles at each cross-section were calculated according to the modified Miner rule.Finally,the equivalent stress values were compared with allowable stress values in the EN standard.The conclusion is that the dynamic force and the trailer force measuring wheel can meet the service mileage of 12 million kilometers of service life.