风机桥架的振动特性取决于其结构形式。文章利用有限元分析软件ANSYS对2种不同结构形式的空冷风机桥架进行比较。通过模态分析对比2种风机桥架的刚度和振动频带，并采用谐响应方法对比2种风机桥架在正常运行不平衡力、叶片断裂时不平衡力以及电动机正常运行不平衡力等激振载荷作用下的频率响应特性。分析结果表明，通过优化风机桥架的结构形式可以改善其振动特性。

Vibration characteristics of fan bridge are determined by the structure. Based on ANSYS software, the stiffness and vibration bands of two types of ACC fan bridge structures are analyzed by modal analysis. Furthermore, the frequency response curves under three different vibration loads are calculated separately by harmonic response method, which of the two fan bridges are contrasted. It is demonstrated that the vibration characteristics of fan bridge are improved by structural optimization.