Computational model for calculation of static capacity and lifetime of large slewing bearing's raceway

Abstract

A computational model for determination of static capacity and fatigue lifetime of large slewing bearings is presented. In the proposed model, contact load distribution along the bearing raceways is calculated on the basis of the static equilibrium between contact loads acting on the raceways, and external loads acting on the bearing. On the basis of the maximum contact force and some typical and experimentally determined material parameters, the static capacity of a bearing is calculated and a comparison of different approaches for a calculation of the fatigue lifetime of a bearing is presented. The following calculation methods are compared: ISO standardised calculation approach, a stress-life approach and a strain-life approach. The presented vector based calculation approach for a calculation of the contact load distribution seems to be an appropriate approach for a fast evaluation of the influence of the bearing clearance and the deformation of bearing rings on the contact load distribution. The comparison of fatigue lifetimes calculated with different calculation methods shows that the choice of method for the calculation of an equivalent mean stress significantly effects the calculated lifetimes. Furthermore, the comparison of lifetimes also shows that, by assuming that ISO standardised calculation approach gives relevant results and provided that material parameters are properly defined, the stress-life approach is, to some degree, a proper method for calculation of the rolling bearing fatigue lifetime.