Research on fatigue reliability of draught fan of auxiliary converter for high-speed EMU

The draught fan of the auxiliary inverter is the core cooling device of the auxiliary power supply system of high-speed trains, and its fatigue reliability determines the performance of the auxiliary inverter. A systematic evaluation method for fatigue reliability combining finite element analysis, bench testing, and line testing is proposed to address the problem of structural failure of draught fan of auxiliary converters for high-speed trains. Firstly, the finite element method was used to calculate the modal frequency and vibration fatigue strength of the draught fan structure. Secondly, the vibration fatigue bench test of draught fan was conducted using the measured equivalent acceleration of the line as input. Finally, a study on the fatigue strength assessment of draught fan was conducted based on dynamic stress testing. The simulation and experimental results show that the maximum damage to the draught fan structure is 9.4×10-2 when the simulated triaxial acceleration is continuously excited for 5 hours. When the stress cycle reaches 10 million times in the bench test, the maximum damage to the draught fan structure is 3.89×10-3. The maximum equivalent stress amplitude of the measuring point in the track test is 59.4 MPa. The above results indicate that both the static strength and fatigue strength of the draught fan structure meet the design requirements. This paper can provide useful reference for the structural health monitoring and evaluation of rail vehicles.