Abstract. The paper discusses Bifurcation Diagrams of rotor stator contact problems and the transition from synchronous whirl towards different asynchronous movement patterns. Bifurcation Diagrams based on Poincaré Maps are presented for the model consisting of a Jeffcott rotor and a flexible mounted rigid stator ring. The analysis methods are applied systematically with respect to various motion patterns that have been observed for rotor stator contact in the past. The type of motion is identified using the analysis methods. Also the influence of different parameters on the changes of motion patterns and the transitions that result are described. The unique identification of all motion patterns for rotor stator interaction based on Bifurcation Diagrams is focus of the paper. Further insight on the conditions that lead to the change of motion patterns is given.

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Abstract. The aim of this paper is to provide a compact as well as comprehensive overview of Rotor-Stator Contact in rotor dynamics. A general model is described which accounts for most phenomena of Rotor-Stator Contact observed in literature. This model is compared to different modeling approaches used in the previous literature. A glance on the variety of motion patterns including analytical approaches to the synchronous motion and Backward Whirl motion is given. As an outlook a modal reduction technique is pointed out, which is capable of reducing systems with many degrees of freedom for rotor as well as stator to the described model.

This paper deals with the description of steady-state sub-and superharmonic motion in rotor-stator contact using truncated complex Fourier series. Two different approaches are presented with different stages of simplification. In particular, a kinematic contact condition describing continuous contact is used. The multi-harmonic balance method is applied to solve the differential algebraic system of equations. A further simplification is implemented which uses the triangular inequality to approximate the nonlinear term in the kinematic contact condition. The Fourier coefficients of the nonlinear term are calculated using an integral expression. Reasonable initial values of the Fourier coefficients for the numerical solution are obtained by a hybrid approach. Results show good agreement with calculations by direct numerical integration using a pseudo-linear viscoelastic contact model.

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