Analysis of weld fatigue cracking causes and structural improvement of the cooling unit columns of EMU
For the weld fatigue cracking of the aluminum column of the EMU cooling unit in service,the fatigue damage was firstly calculated based on the three intervals method for the simulated long-life random vibration condition specified in the IEC 61373 in this paper,and the results showed that the maximum fatigue damage of the aluminum column was 0.27,which met the use requirements.Then,with reference to the measured aerodynamic load data of the line,the fatigue life of the aluminum column under the condition of 500 Pa aerodynamic pressure on bottom plate was calculated to be 4.14×105 cycles,which was more consistent with the actual service life and crack location,indicating that the cause of fatigue cracking of the column should be attributed to the dynamic aerodynamic load in the service.Finally,a fatigue evaluation of the improved steel column was carried out.The results showed that the fatigue life of the column was significantly improved under both fatigue conditions,and it could be inferred that the fatigue strength of the steel column met the service requirements by referring to the actual service life of the aluminum column.
万方数据
维普
