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http://dx.doi.org/10.5050/KSNVN.2005.15.10.1137

Vibration Analysis of Flexible Rotor Having a Breathing Crack  

Jun, Oh-Sung (전주대학교 기계자동차공학과)
Publication Information
Transactions of the Korean Society for Noise and Vibration Engineering / v.15, no.10, 2005 , pp. 1137-1147 More about this Journal
Abstract
The dynamic response due to the unbalance and crack and the quasi-static response due to gravity are analytically derived based on the complex transfer matrix. The additional slope is expressed as function of the bending moment at crack position based on the fracture mechanics concept, and inversely the bending moment is expressed as function of the additional slope at the crack Position. At each angle step during the shaft revolution, the additional slope and bending moment are calculated by an iterativemethod. The transient behavior is considered by introducing Fourier series expansion concept for the additional slope. Simulation is carried out for a simple rotor similar to those available in the literature and comparison of the basic crack behavior is shown. Using the additional slope, the cracked rotor behavior is explained with the crack depth increased: the magnitude of the additional slope increases and the closed crack duration during a revolution decreases as the crack depth increases. The direction of unbalance is also shown as a factor to affect the crack breathing. Whirl orbits are shown near the sub-critical speed ranges of the rotor.
Keywords
Cracked rotor; Transverse Crack; Unbalance; Additional Slope; Stress Intensity Factor;
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