The work proposed (Figure 1) is a first step towards an 'Industry Standard Life Estimation Program' for Rolling Bearings. Phase I will focus on a single ball bearing model with innovative STRESS BASED-Variable Stressed Volume fatigue life models and choice of decisive stress and fatigue life estimates per the classical theory and more recent theories of Ioannides/Harris or Weibull/Zaretsky. The model will account for changing cartesian stresses and resulting stressed volume as the equilibrium state of the ball changes within the bearing. Stress contributions from Hertzian contact, press fit, centrifugal force, residual stress and axial clamping are included. The model will include developments in bearing technology from the 1970's through the 1990's incorporating STLE Life Factor (1992) modification of the standard ISO/ABMA load based rating methods. Many of these Life Factors evolved from NASA funded/conducted work.Standard rating methods do not account for applications factors such as internal clearance, distortion, misalignment, etc. These methods are load based as opposed to stress based and employ a constant stressed volume. Introduction of stress based life models into computer programs that can quantify these effects and can track actual stressed volume will lead to more accurate bearing life prediction and sizing.
Potential Commercial Applications:
