Dynamic modelling of combination imperfects of a cylindrical roller bearing

Local fault failures could greatly affect the vibrations of cylindrical roller bearings (CRBs). However, most previous works defined the fault surface as the smooth ones, whose actual roughness features were ignored. To overcome this problem, this study presents a time-varying stiffness excitation model for a CRB including a local fault with the roughness surface based on Greenwood and Williamson's method. A dynamic model with the time-varying stiffness excitation model is developed to analyze the effects of the roughness and local fault on the contact features and vibrations of CRB. The changes of time-domain contact features and vibrations for defective CRB with and without the roughness surface are analyzed. Note that the roughness surface can greatly affect the contact stiffness, contact deformation, and vibrations for CRB under a small force. But its effect will decrease with the increment of radial load, which will close the value of smooth CRB. This paper can show some guidance for CRBs including the local faults with the roughness surface.