轴流散热风机共振失效分析与优化设计

为研究某磁悬浮列车辅助变流器的轴流散热风机的失效问题，提出了一种基于现场测试、有限元仿真与代理模型的失效分析与优化设计方法。首先，通过振动路谱测试与模态仿真分析剖析了轴流散热风机的失效机理，确定了由安装结构刚度不足和转速下降引发的局部共振为风机失效的根本原因。然后，基于模态分析结果，设计了轴流散热风机安装网斜向筋局部加强改造方案，并采用加速度谱响应分析对改造后的风机进行了性能评估。接着，利用代理模型拟合了安装网加强结构特征参数与轴流散热风机振动响应特性之间的映射关系，并以避免共振、降低振动烈度和改造成本最低为优化目标，通过智能算法获得了最优改造方案。最后，通过振动性能评估试验和长寿命振动试验验证了最优改造方案的可行性。结果表明，最优改造方案能有效地解决轴流散热风机的局部共振问题，提高了其使用寿命。研究结果可为轴流散热风机的共振失效分析与优化设计提供参考，具有重要的工程实践价值。

Resonance failure analysis and optimal design of axial cooling fan

In order to study the failure of the axial cooling fan of the auxiliary converter in a maglev train,a failure analysis and optimization design method based on the field test,finite element simulation and surrogate model was proposed.Firstly,the failure mechanism of the axial cooling fan was analyzed through the vibration spectrum test and modal simulation analysis,and the local resonance caused by the insufficient rigidity of the installation structure and the decrease of the rotating speed was determined as the root cause of the fan failure.Then,based on the modal analysis results,a retrofit scheme for local strengthening of diagonal reinforcements in the installation network of axial cooling fan was designed,and the performance of the retrofit fan was evaluated by the acceleration spectrum response analysis.Then,the surrogate model was used to fit the mapping relationship between the characteristic parameters of the installation network strengthening structure and the vibration response characteristics of the axial cooling fan.The optimal retrofit scheme was obtained by the intelligent algorithm with the optimization objectives of avoiding resonance,reducing vibration intensity and minimizing retrofit cost.Finally,the feasibility of the optimal retrofit scheme was verified by the vibration performance evaluation test and the long-life vibration test.The results showed that the optimal retrofit scheme could effectively solve the local resonance problem of the axial cooling fan and prolong its service life.The research results can provide a reference for the resonance failure analysis and optimal design of the axial cooling fan,which has important engineering practical value.