Experimental study on rotor-dynamic behavior dependent on aero-engine bearing inner ring assembly technologies

A test rig was built to stimulate the bearing located in the backstay of the high pressure turbine. In order to identify and assess the effects of the inner ring assembly technology on the vibration of the rotor, an experimental investigation was performed. A range of fit tolerances and the tightening torques of the lock nut were used to test the dynamic behavior of the rotor. The experimental results reveal that the presence of an inner ring in clearance fit and insufficient tightening toque introduces high nonlinearity to the rotor, the support of which responds with rich fractional harmonic components. With the inner ring in interference fit, the rotor vibration is almost independent of the tightening toques. With the inner ring in clearance fit, a considerably large tightening toque is effective in attenuating the fractional harmonic response of the rotor support.