轴向插装枞树形叶根成组叶片切向B0型振动特性的研究

采用三维8节点非协调有限法和应变遥测法，对轴向插装枞树形叶根成组叶片的振动特性进行计算分析和实验研究。计算和实验发现，由N个叶片组成的叶片组出现了叶根参与振动和叶根不参与振动的两种形式，共2倍的N-1个切向Bo型振动模态，而且叶根参与振动的切向B0型振动频率远低于叶根不参与振动的情况。不同于目前文献对叶片组切向B0型振动的描述。这种现象在叶片设计和事故分析中是值得注意的。

STUDY ON SECOND TYPE TANGENTIAL VIBRATION OF AXIAL ENTRY GROUP BLADES WITH FIR TREE DOVETAILS

Vibratory characteristics of axial entry group blades with fir tree dovetails are studied using 3-dimensional finite element method and the strain telemetry method. The calculated and measured results show that the group blades with N-blades have double of N-1 second type tangential vibratory models, N-1 models of the second type tangential vibration mainly occurs in the vane and dovetail parts, and another N-1 models mainly occurs in the vane parts. Natural frequencies of the second type tangential vibration occurring mainly in the vane and the dovetail parts are much lower than natural frequencies of vibration occurring mainly in the vane parts. This is a new conclusion for group blades and the concept is different with the concept described in literatures that the group blades with N-blades have N-1 second type tangential vibratory models. The phenomenon should be considered in blade design stage and blade troubleshooting.