Failure analysis and optimization design of a cooling fan in auxiliary converter

Failure analysis and optimization design is carried out to solve the on-site problem of the fan in auxiliary converter based on the FEA (finite element simulation) and surrogate-model. Firstly, the mechanism of fan failure is analyzed by field vibration test and modal simulation, and the local resonance caused by insufficient stiffness of the installation structure is determined as the cause of the failure. Then, according to the excited modal shape, the retrofit scheme of mounting-net diagonal reinforcement is designed, and the performance of the retrofit scheme is evaluated by using acceleration spectrum response simulation. Furthermore, a surrogate model is established to fit the mapping relationship between the characteristic parameters and the vibration response characteristics of the retrofit scheme, and an objective function is defined to obtain the optimal solution of characteristic parameters of strengthening scheme by taking avoiding resonance, reducing vibration intensity and reducing reconstruction cost into consideration. Finally, the validation test is carried out. The results show that the strengthening scheme can effectively solve the local resonance problem of the fan and improve the service life of the fan.