DYNAMIC RESPONSE OF AN UNBALANCED ROTOR SUPPORTED ON BALL BEARINGS

The non-linear dynamic analysis of a horizontal rigid rotor having unbalance and supported on ball bearings has been done. The non-linearity is both due to Hertzian contact and the radial internal clearance. The system is excited by the varying compliance frequency and the rotational frequency. For finding out the fixed point and stability of the system the concept of higher order Poincare map and interpolation technique has been applied. The results show the appearance of instability and chaos in the dynamic response as the speed of the rotor-bearing system is changed. Period doubling and mechanism of intermittency have been observed as the routes to chaos. The experimental investigations for a horizontal rotor-bearing system have shown the effect of varying compliance and increase in non-linearity due to radial internal clearance of the ball bearing. The orbit plots, cascade plots and frequency plots bring out the effect of radial internal clearance on the rotor response.