| The loads acting on the bogie frame are the basis for its reliability design and evaluation.The load characteristics are closely related to vehicle operating conditions and working conditions.The high-speed EMU running on the Harbin-Dalian line will bear the alpine conditions,the minimum ambient temperature in winter can achieve forty below zero.When the EMU is operating at low temperature,the basic fatigue performance of the welded joint of the material may change,resulting in the change of the reliability index of the bogie frame.On the other hand,the performance of the rubber changes also cause the variety of suspension parameters of the bogie frame,thereby changing the load acting on the frame.Therefore,it is very important to evaluate the structural reliability and study the evolution law of load about the bogie frame of the EMU under the cold conditions.The main research work and conclusions of this paper are as follows:(1)In this paper,the bogie frame of the EMU which running on Harbin-Dalian line are taken as the research object.Based on the UIC615 and EN13749 standards,the finite element analysis is used to determine the large stress positions of the frame.(2)The transfer coefficient between the load of the frame and the stress of the measuring points are learned by the test bench calibration.Based on the long-term tracing test,the stress time course of the stress measurement points of the frame is obtained,and the stress spectrum datas are obtained by the rain flow counting method.(3)The low temperature S-N curve of the T-type welded joint is obtained by investigation,and the fatigue reliability of the high-speed train bogie frame is evaluated by Miner cumulative damage theory.The results show that when the temperature is below 25 degrees Celsius,the low temperature will improve the fatigue life of the frame,and the fatigue reliability of the bogie frame will be evaluated;(4)This paper also introduces the regularization method of solving the disequilibrium matrix by using the stress inversion load problem.The error analysis of the Regularization Truncated singular value method is carried out,and the inversion method is verified by the frame load and stress data of a certain EMU.It can be used to identify the ups and downs,torsion,side roll,anti-snake,motor and gearbox load.(5)Based on the dynamic stress data and the load stress transfer coefficient,the Regularization Truncated singular value method is used in the inverse identification process of the load on alpine EMU,and the load characteristics and the evolution law are studied by using the load characteristics such as equivalent load.In the temperature range of minus 10 degrees to 30 degrees,the load of the bogie frame of the alpine EMU does not change significantly with the temperature. |
