Fuzzy approach for the analysis of rotor bearing systems

Date of Award




Degree Name

Doctor of Philosophy (Ph.D.)


Mechanical Engineering

First Committee Member

Singiresu S. Rao - Committee Chair


A theoretical study has been conducted on the modeling, analysis and simulation of rotor dynamics. The uncertainties in material properties, geometry and external forces etc. have been modeled as fuzzy quantities and fuzzy logic has been used to develop the dynamics analysis models for both linear and non-linear rotor bearing systems. Numerical simulations have been conducted to demonstrate the applicability and utility of the proposed techniques.Using fuzzy set theory and fuzzy computation, the influence of system uncertainties on the natural whirl frequencies and forced responses of the system have been investigated, with both Jeffcott and continuous models. With this method, the influence of manufacturing/assembling errors and environmental/operating conditions on the performance of the system can be taken into account during the design process. Nonlinear behaviors, such as periodic, quasi-periodic and chaotic motion, of an uncertain rotor system have also been studied. An effective method of predicting the chaotic motion of the nonlinear uncertain rotor system has been proposed, which combines the fuzzy logic and Monte Carlo method.Several applications and numerical results are presented along with a discussion and interpretation of the results. The results demonstrate that the fuzzy approach is an effective tool to deal with the uncertainties present in the rotor bearing systems and can provide more realistic solutions.


Engineering, Mechanical

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