Significance of Considering Nonlinear Effects in Predicting the Dynamic Behavior of Rotating Machinery

Abstract

Limitations of the currently practiced linearized analysis of industrial rotating machinery are dis cussed. An appreciation of these limitations is particularly significant for the development of new generation, high performance machinery in which new materials, rotor supports, coupling components, and sophisticated control systems will be used. In the absence of adequate familiarity and experience with the new systems, vari ous complex phenomena associated with their nonlinearities, which may lead to malfunction or catastrophic failure, could be missed altogether. A uniform approach to accurate modeling and analysis of rotor-support systems will therefore be essential. The present paper provides an exposition of recently published studies in nonlinear rotordynamics and their relevance to the design, analysis, and monitoring of rotating machinery. This includes a brief discussion of available analytical/computational methods and the various techniques proposed, which seek reducing the order of rotor systems with large number of degrees of freedom. In ad dition, new results on the nonlinear behavior of fluid-film bearings are presented herein to further emphasize the importance of nonlinear effects.