A dynamic modelling method of a rotor-roller bearing-housing system with a localized fault including the additional excitation zone

Abstract

Rotor-roller bearing-housing systems (RBHSs) are widely utilized in many industrial machinery, such as aero-engines, high speed trains, wind turbine, etc. A clearly investigation of vibrations for the RBHSs is very valuable for condition monitoring and fault detection applications for the above industrial machines. A new analytical dynamic model for a RBHS is conducted, which can consider the time dependent additional contact zone excitation caused by the fault on the raceways, deformable interface between the outer raceway and housing, lubricating oil film, and deformable rotor and housing. The time dependent addition contact zone is determined by Hertzian contact theory and the relative relationship between the roller and fault. Influences of the rotor speed, roller load and fault length on the additional excitation zone are studied. The ratio of the additional excitation zone to the fault length is also discussed. To consider the complex profiles of the outer raceway, an analytical method combined with a slice method and an integral method is used to obtain the total interface stiffness at the interface. Influences of the housing materials and height on the total interface stiffness are analyzed. A time dependent displacement excitation model with a half-sine function profile is applied to formulate the time dependent displacement excitation due to the fault. The dynamics of the RBHS from the presented model with the additional excitation zone are compared with those from the previous model without the additional excitation zone. An experimental study is presented to validate the proposed model. Influences of the housing materials, housing height, additional excitation zone of the fault, and fault length on the dynamics of the RBHS are studied. The simulation results provide that the presented model can give an accurate simulation method for investigating the dynamics of the RBHS with a localized fault.