Bearing Analytical Software Development and Validation Phase II

ABSTRACT: With the objective of developing validated bearing performance software, this proposed development focuses on several technical areas. First, the generalized life models developed in Phase I shall be extended to include elastic property variation with depth for improved modeling of case hardened materials such as M50 NiL. In addition rolling elements shall be modeled as separate elements to better define the composite bearing life. Secondly, analytical formulations and computer code shall be developed for more complex traction models based shear thinning. The models shall be validated against available experimental data, and compared with the current Newtonian and visco-elastic models. Thirdly, lubricant churning and drag models shall be validated against the large amount of experimental data collected in Phase I. The resulting churning and drag coefficients along with the improved traction models shall provide validated bearing heat generation prediction. Finally, parametric evaluations shall be undertaken to develop time-averaging guidance to efficiently integrate the greatly different thermal and mechanical time scales for reliable prediction of bearing element temperatures, which will link life models with thermal interactions. The overall software development shall include a graphical user interface to efficiently process all inputs and outputs for practical bearing design and performance diagnosis. BENEFIT: 1. Modeling of elastic property variation for case hardened materials, such as M50 NiL, will significantly extend the practical significance of the already proven and validated generalized life models developed in Phase I. 2. Implementation of shear thinning effects and further development of visco-elastic models to predict lubricant traction in high-speed heavily loaded bearings in turbine engines will have significant practical benefit in improved prediction of both heat generation and bearing stability. 3. Extensive validation and correlation of empirical churning and drag coefficients over the large experimental database, developed in Phase I, will provide greatly improved bearing heat generation capabilities for rolling bearings operating in any arbitrary environment ranging from cryogenic conditions of space applications to high loads and high temperatures of gas turbine engine bearings. 4. Prediction of validated temperature fields by carrying out numerically complex and compute intensive heat transfer analysis will for the first time permit materials property variation with temperature to closely integrate the thermal and life models. 5. In addition to greatly improved performance diagnosis and simulation of current rolling bearing applications, the integrated thermal and life model, will provide viable guidance for materials and design development for applications of the future.