Fatigue Life Prediction for Gas Turbine Bearing Under 3D Elastoplastic Mixed Lubrication Condition

Abstract

Gas turbine bearings usually work in harsh lubrication environments, with typical characteristics such as high speed, high temperature, and heavy load. Severe working conditions bring micro-contacts in local areas between the bearing rolling elements and the rings. Stress concentration and plastic deformation may further occur between the contact pairs, which will reduce the fatigue life of the bearing. In order to predict bearing fatigue life accurately, in this study, the effects of the real surface roughness and plastic deformation of the bearing are considered, a three-dimensional(3D) elastoplastic mixed lubrication model for gas turbine bearing is established, the 3D dynamic elastoplastic stress calculations under the surface are conducted, and the relative fatigue life of the bearing is predicted. Based on the 3D elastoplastic mixed lubrication model for the bearing, the influences of speed, load, roughness and material hardening on lubrication performance and fatigue life are also studied, which would provide theoretical guidance for the lubrication design and life prediction of the gas turbine bearings.