ENHANCED ROTOR MODELING TAILORED FOR RUB DYNAMIC STABILITY ANALYSIS AND SIMULATION*

New methods are presented that allow straightforward application of complex nonlinearities to finite element based rotor dynamic analyses. The key features are 1) the methods can be implemented with existing finite element or dynamic simulation programs, 2) formulation is general for simple application to a wide range of problems, and 3) implementation is simplified because nonlinear aspects are separated from the linear part of the model. The new techniques are illustrated with examples of inertial nonlinearity and torquewhirl which can be important in rubbing turbomachinery. The sample analyses provide new understanding of these nonlinearities which are discussed.