Three-dimensional dynamic modeling and vibration analysis of roller bearings under compound fault excitation

Abstract

Dynamic modeling is widely used in bearing fault diagnosis. Bearings with compound fault produce more complex vibration characteristics, making fault characteristic extraction more difficult. Current studies on dynamic characteristics with bearing compound fault are insufficient, and characteristic analysis for bearing physical variables is not fully investigated. Therefore, a novel three-dimensional dynamic model with bearing compound faults is established. Quaternionic attitude algorithm is introduced to characterize the rotational attitude of bearing inner raceway and the balls in three dimensions. Meanwhile, in order to accurately portray the bearing physical variables, the proposed model considers multiple rigid body degrees of freedom, dynamic circular motion, mixed elastic lubrication of the bearings, and dynamic changes in the position and speed of the contact points between the balls and the raceway. The proposed model is validated by experiments. The effect of compound fault on the bearing physical variables (quantities) characteristics is investigated. The changing trend of bearing physical variables under different fault length and drive motor rotational speeds is explored. The conclusions of this work would be helpful to explain and analyze the dynamic characteristics of roller bearings with compound faults.