A comprehensive comparative investigation of frictional force models for dynamics of rotor-bearing systems

A vibration model of a flexible rotor-bearing system considering the defect in a double-row cylindrical roller bearing

“…where K c is the contact stiffness [29][30][31] ; n is the load deformation coefficient and n = 10/9; the deformation coefficients of inner and outer raceways are P j in , which are given as…”

“…The dynamic equations of the inner raceway are given as where m in is the mass of the inner raceway; x in and y in are the displacements of the inner raceway in the X and Y directions; x ¨ in and y ¨ in are the accelerations of the inner raceway in the X and Y directions; x ˙ in and y ˙ in are the speeds of inner raceway in the X and Y directions; C s is the contact damping ratio; k s is the contact stiffness; F 1x in and F 2x in are the contact forces of first and second rows on the inner raceway in the X direction; F 1y in and F 2y in are the contact forces of first and second rows on the inner raceway in the Y direction. Moreover, F i x in and F i y in are given as 28 where K c is the contact stiffness 29–31 ; n is the load deformation coefficient and n = 10/9; the deformation coefficients of inner and outer raceways are P j in , which are given as where, δ j in is the deformation of the inner raceways of j th roller, which is given as 3 where x j in and y j in are the displacements of the inner raceway in the X and Y directions; x j r and y j r are the displacements of j th roller in the X and Y directions; C r is the radial clearance; θ j is the angular position of roller, which is given as where θ c is the angular position of cage; Z is the number of rollers in one row of DCRB; f 1x in and f 2x in are the friction forces of the first and second rows between the inner raceway and roller in the X direction; f 1y in and f 2y in are the friction forces of first and second row between the inner raceway and roller in the Y direction, which are given as 32 where k m is the friction coefficient. F dx1 in and F dx2 in are the damping forces of first and second row between the inner raceway and roller in the X direction; F dy1 in and F dy2 in are the damping forces of first and second rows between the inner raceway and roller in the Y direction, which are given as…”

A fatigue failure investigation and improvement of a high-speed cylindrical roller bearing in a turbofan engine

“…3,4 When fatigue failures happen in the CRBs, a thorough analysis is needed to be presented to determine the failure reasons, which can be useful for optimization designs for CRBs. 5,6…”

“…3,4 When fatigue failures happen in the CRBs, a thorough analysis is needed to be presented to determine the failure reasons, which can be useful for optimization designs for CRBs. 5,6 Many works were developed to analyze the typical failures, such as fretting corrosion, wear, spalls, cracks, and others on the surfaces of bearing components. For instance, Upadhyay et al 7 addressed the fretting failures due to the cyclic stress for a CRB.…”

Dynamic analysis of a flexible rotor supported by ball bearings with damping rings based on FEM and lumped mass theory

“…Finally, the mixed numerical method was employed to study the system's dynamic response under maneuvering. LIU [24] constructed a nonlinear dynamic model of a coupled rotor system considering bearing friction, and analyzed the influence of external load and speed on system vibration. CHOUKSEY et al [25] introduced the rotor's material damping and the journal bearing's oil-film force to the system, and then investigated their effects on the modal characteristics of the flexible rotor-bearing system.…”