Applicability Conditions for Paroxysmal Impulse Vibrations in Intershaft Bearings with Localized Defects

Due to the unique installation position of the intershaft bearing, it can exhibit paroxysmal impulse vibrations and continuous impulse vibrations in the presence of defects in the inner/outer ring. In this study, the applicability of the prediction methods for paroxysmal impulse vibrations in intershaft bearings is studied. The motion equations of a dual-rotor system with defective intershaft bearings are established using the finite element method. The influence of local defects on intershaft bearings is simulated through time-varying displacement excitations. The results demonstrate that there are standardized prediction methods and steps for predicting paroxysmal impulse vibration in intershaft bearings. However, these prediction methods may be ineffective under certain parameter combination conditions. The cause and mechanical mechanism behind such failures under multiple parameter influences are investigated. The dynamic characteristics of both enhanced and weakened paroxysmal impulse vibrations affected by multiple parameters are summarized. Finally, experimental verifications through intershaft vibration experiments confirm the dynamic phenomenon and amplitude modulation behavior of paroxysmal impulse vibration under multiple parameter influences. The findings will contribute to an enhanced comprehension of the nonlinear vibration responses in dual-rotor systems with defective intershaft bearings, offering valuable insights for fault diagnostics.