Bearing Analytical Software Development and Validation

ABSTRACT: The proposed research focuses on a generalized formulation and an integrated implementation of bearing life and heat generation models. Since the internal bearing geometry changes with temperature, mechanical stresses, contributing to fatigue, are intricately coupled with thermal effects. Therefore, a realistic simulation of bearing performance requires innovative numerical techniques to integrate the very small mechanical time scales with the large characteristic times corresponding to thermal transients. In the proposed Phase I effort, the updated life models will be validated against experimental data. Additionally, the elastohydrodynamic traction models, which along with heat generation, are key contributors to the stability of bearing element motion, will be updated for both Newtonian and visco-elastic effects. Finally, preliminary bearing performance simulations in a typical turbine engine operating environment will demonstrate technical feasibility of the modeling approach and showcase expected improvements over the current state-of-the-art models. Phase II will feature a significantly more rigorous development and validation of thermal models for both steady-state and transient effects, the formulation and implementation of experimentally validated churning and drag models, an expansion of the traction and material properties databases, and the development of an interactive user interface to effectively apply the models to practical applications. BENEFIT: 1. Generalized formulation with all model coefficients under user control provides an effective vehicle to continually update the models as the materials and manufacturing technologies advance. In addition, bearings with multiple materials, such as hybrid ceramic bearings can be readily modeled. 2. Integration of mechanical and thermal interactions provides a greatly improved simulation of bearing life and overall dynamic performance. 3. Update to lubrication traction models, along with integrated facility to further update the model coefficients, provides greatly improved simulation of dynamic performance and life under arbitrary operating environment. 4. Parametric evaluation of bearing life, heat generation and overall performance provides significant guidance for practical design and development of new materials and lubricants for future applications. 5. Parametric modeling capabilities also facilitate precise failure diagnosis and subsequent design enhancements for rectification of the observed problems.