模態仿形法應用於葉片輪模型凝縮

Model Reduction of Bladed-Disks Using Pseudo Mode Shape Method

楊大中(Ta-Chung Yang) ； 鄭文源(Wen-Yuan Cheng) ； 蒯光陸(Kwang-Lu Koai)

《航空太空及民航學刊.系列B》 40卷1期 (2008/04) Pp. 35-44

https://doi.org/10.6124/JAAA.200804_40(1).05

摘要

大型汽輪發電機組，其轉子動力學之分析非常複雜，多級葉片輪的建模時常發生元素數量太龐大之問題。但在轉子動力學之分析時，高速轉軸之振動行?是關心之重點，故葉片輪模型必須予以適當地凝縮。本文應用改良之模態仿形法，利用葉片輪與轉軸之接點處的頻率響應函數，推出葉片輪結構之凝縮模型的質量、阻尼、勁度矩陣，可同時涵蓋其剛體模態與變形模態情況。本文利用三維實體元素之轉軸與葉片輪模型驗證模態仿形法應用葉片輪凝縮建模之可行性。

關鍵字

模型凝縮 ； 葉片輪 ； 模態仿形法 ； 頻率響應函數 ； 轉子動力學

並列摘要

Rotordynamic analyses of large steam turbine-generators are very challenging tasks. Problems of huge amount of elements occur in modeling the multiple-bladed-disk rotors. However, from the viewpoints of rotordynamics, the major concern is on the vibration of rotating shafts and the models of the bladed disks need to be reduced. A modified pseudo mode shape method was proposed to reduce the models of bladed-disks in this study. The frequency response functions of bladed-disks obtained at the joints with the shafts are used to derive the condensed mass, damping, and stiffness matrices for the bladed-disks. This paper extends the theory of pseudo mode shape method developed previously to include rigid body modes and deformation modes of the bladed-disks. The feasibility and effectiveness of the extended pseudo mode shape method are justified by using a solid-modeled shaft and bladed disk as example.

並列關鍵字

Model reduction ； Bladed disk ； Pseudo mode shape ； Frequency response function ； Rotordynamics