| Wheel rail load is not only the basis of indoor simulated axle fatigue test,but also an important evaluation index of vehicle line operation safety.At present,the common methods of wheel rail force acquisition include force measuring wheel set method and force measuring rail method.However,due to their respective advantages and disadvantages,these two methods can not be widely popularized in urban rail vehicles.Therefore,it is very necessary to develop a wheel rail force measurement method with low cost,simple operation and high precision.Taking a trailer bogie of Guangzhou Metro as the research object,this paper makes the bogie frame into a force measuring sensor that can identify the wheel rail load through a specific method,then carries out the line test,compiles the measured load spectrum,and analyzes the wheel rail time domain load and the compiled load spectrum.The main conclusions are as follows:(1)The rigid flexible coupling dynamic model is established by SIMPACK software.The dynamic simulation results show that after the axle box acceleration is transmitted to the frame through the primary spring and primary damping,the acceleration below 20 Hz has good transmissibility,there is a strong linear relationship between acceleration power spectral density and acceleration amplitude frequency,and the component transmission effect above 20 Hz becomes worse;The axle load is transmitted through a series spring,and the load acting on the frame is similar to the acceleration transmission characteristics;(2)Through the finite element analysis of the bogie frame,it is found that the inner and outer sides of the upper and lower cover plates of the frame side beam are more sensitive to the vertical load response of the axle,but not to the transverse load response of the axle.At the same time,because they are far away from the cross beam with complex load,the linearity of the vertical response is ensured;Conduct patch,bridge assembly and calibration tests on the frame to determine the vertical load identification of the axle of the bogie frame;(3)The test results show that the axle load identified by the frame force method is consistent with the axle load waveform identified by the indirect measurement method.The maximum error proportion of the load after low-pass filtering is 6.1%,and the maximum error of the root mean square value of the load after high pass filtering is 17%;(4)The results show that the waveforms of the axle vertical load spectrum obtained by the two methods are consistent.The maximum error ratio of the corresponding load at the highest frequency is 1.8%,and the maximum error of the frequency is 7%,which can better reflect the axle vertical load spectrum;(5)The results show that the normal distribution function has a good fitting effect on the transverse load spectrum data.Under the straight-line working condition,the standard deviation of the normal distribution probability density curve increases with the increase of speed σ It is also increasing,and the axle transverse load fluctuation is more discrete.Under the curve condition,with the increase of train running speed,the axle transverse load fluctuation is more concentrated.139 figures,23 tables,and 78 references... |
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