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Shock and Vibration
Volume 20 (2013), Issue 1, Pages 97-108

Transfer Matrix Method to Vibration Analysis of Rotors with Coupler Offsets

Chao-Yang Tsai1 and Shyh-Chin Huang2

1Department of Mechanical Engineering, Army Academy ROC, Taoyuan, Taiwan
2Department of Mechanical Engineering, Ming Chi University of Technology, Taipei, Taiwan

Received 17 May 2012; Revised 4 June 2012

Copyright © 2013 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In this paper a general transfer matrix method (TMM) for rotors containing global and local coupler offset was derived. Rotor response due to imbalances and offsets are then studied via the developed method. The studies showed both global and local offsets played as an external excitation that is a combined effect of all the elements behind the offset. Differences between global offset and local offset were compared and the results showed both types basically retain the same mode patterns but different jumps at the offset. The global offset, yet, imposed more significant dynamic effects since all the offsets accumulate thereafter. The whirling orbits in front and behind the offset were illustrated as well. The results, as expected, showed global offset appeared much larger radii especially after offset. The rotor's whirling orientation reversed, as rotation fell within a certain range and this feature was not changed by offsets. The TMM proposed by this study can be well applied to multiple global and local offsets.