A STUDY OF THE RESPONSE OF A DISCONTINUOUSLY NONLINEAR ROTOR SYSTEM

In this paper the numerical and experimental response of a two degree of freedom, discontinuously nonlinear rotor system, which is subject to excitation by out-of-balance is considered. The nonlinearity in the form of a discontinuous stiffness is effected by a radial clearance between the elastically supported rotor and an elastically supported outer ring. The rotor is placed eccentrically within this ring so that it is just touching one side of the inner bearing housing. The equations of motion for the system are presented and the numerical techniques used to solve them are described. A description of a corresponding experimental rig is presented, along with details of the procedures used to investigate its response. By employing various chaos and spectral analysis techniques comparison is made between the results obtained from the two methods of investigation. Reasonable correlation is found. Subsequently, the results from further numerical simulations are presented which investigate the effect on the systems response when various system parameters are altered systematically. These show that the response of the system is extremely sensitive to changes in these parameters and that chaos can exist over large regions of the parameter space.