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Mathematical Problems in Engineering
Volume 2017 (2017), Article ID 7313956, 19 pages
https://doi.org/10.1155/2017/7313956
Research Article

The Influence of Shaft’s Bending on the Coupling Vibration of a Flexible Blade-Rotor System

School of Mechanical Engineering and Automation, Northeastern University, Shenyang, Liaoning 110819, China

Correspondence should be addressed to Chao-feng Li

Received 28 May 2016; Revised 14 December 2016; Accepted 16 February 2017; Published 19 March 2017

Academic Editor: Dane Quinn

Copyright © 2017 Chao-feng Li et al. 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.

Abstract

The influence of shaft bending on the coupling vibration of rotor-blades system is nonignorable. Therefore, this paper analyzed the influence of shaft bending on the coupling vibration of rotor-blades system. The vibration mode function of shaft under elastic supporting condition was also derived to ensure accuracy of the model as well. The influence of the number of blades, the position of disk, and the support stiffness of shaft on critical speed of system was analyzed. The numerical results show that there were two categories of coupling mode shapes which belong to a set where the blade’s first two modes predominate in the system: shaft-blade (SB) mode and interblade (BB) mode due to the coupling between blade and shaft. The BB mode was of repeated frequencies of () multiplicity for number blades, and the SB mode was of repeated frequencies of () multiplicity for number blades. What is more, with the increase of the number of blades, natural frequency of rotor was decreasing linearly, that of BB mode was constant, and that of SB mode was increasing linearly. Natural frequency of BB mode was not affected while that of rotor and SB mode was affected (changed symmetrically with the center of shaft) by the position of disk. In the end, vibration characteristics of coupling mode shapes were analyzed.