Abstract: In this paper, the piece-wise linear equations arc presented and analyzed for the Tubbing rotor system. The vibration features arc discussed through both theoretical analysis and experiment, and the results show that there is a good agreement. Meanwhile, the nonlinear behaviour and features of the rubbing rotor arc introduced and summarized, which can be identified by using frequency spectrum, phase analysis and whirling orbit of shaft center mehtods. The analysis results indicate that the signal characteristics of the rubbing rotor arc different from that of sonic other fault rotors.

Key words: rotor, vibration, rubbing