Abstract
This paper includes modal analysis of an asymmetric rotor system. The analysis has been carried out in the rotating co-ordinate system so that the equations of motion do not include time dependent terms in it. After analysis, the eigenvalues are transformed back into stationary co-ordinate system. The real and imaginary parts of the eigenvalues thus obtained are plotted. Such analysis is very important as rotor systems with asymmetric nature gets unstable between some speed ranges. Stability graphs are plotted and analyzed to find out the regions of instability for the rotor system using a simple rotor model.
Highlights
Introduction and Literature ReviewModal analysis of rotor systems is important
The real and imaginary parts of eigenvalues obtained for the rotor system are plotted in both stationary co-ordinate system and rotating co-ordinate system
As the equation of motion has been solved in rotating co-ordinate system, first the roots obtained for the rotor system in rotating co-ordinate system are plotted
Summary
Modal analysis of rotor systems is important. Modal analysis is used to find out the natural frequencies, modal damping and model shapes of structures ((Kessler 2009). Modal analysis studies for rotor systems is carried out to analyze whirl speed maps (Campbell diagram), stability plots etc and rotor modes The stability of rotor systems is generally found out by plotting stability plots In these plots, modal damping factors or the real part of eigenvalues are plotted against spin speed of the rotor-shaft. Universal Journal of Control and Automation 3(1): 10-14, 2015 gives information about the possible regions of resonances and stability Another way of addressing the issue of stability is by plotting the eigenvalues of the rotor system as a function of rotor spin speed on the complex plane (Argand plane).Lee & Seo (2010) compared various forms of whirl speed maps and stability plots in use and proposed a unified diagram, which is called as ‘Lee diagram’.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
