Nonlinear Dynamics of Rotor Bearing System in Deformable Housing Subjected to Stator Rubs and Contour Error of Shaft Due to Manufacturing

Nonlinear dynamic response can occur in turbo-machinery that contains self-excited force due to any deflection of the shaft away from the center of the housing or intermittent contact friction due to clearance between rotor and stator, and hysteresis from rubbing between assemblies of shrink or contour error of shaft due to machining. The equation of motion of non-linearity effects could be appeared in the stiffness term (e.g. softening spring and harden spring) or in damping term (e.g. self-excited motion, or aerodynamic flow induced vibration). In this study, we emphasis the nonlinear restoring force effects of the rotor dynamics between rotor and stator and in the deformable housing of the mathematical model. Chaotic motion could be found by changing parameters of the nonlinear stiffness and damping terms in different operation speed regimes. Multiple-period solutions, simple-period, quasi-period and chaotic responses of the rotor bearing system are shown and discussed. Among all the types of period solutions, the multiple-solutions and chaos have large influence on the rotor bearing system. X-Y circular contour error of the shaft due to machining of manufacture involved in dynamic equations was also used to find the non-linear response in rotor bearing system.