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University of Virginia Rotating Machinery and Controls Laboratory P.O. Box 400746 122 Engineer’s Way Charlottesville, VA 22904 (434)924-3292 (434)982-2246(fax) |
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Rotating Machinery and Controls Laboratory |
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Rolling Element Bearing Analysis and Code
Faculty: Prof. Paul Allaire Ph.D. Student: Amir Younan,
Many rotating machines are supported in rolling element bearings, but computer models that predict the operating properties as well as stiffness and damping coefficients for rotor dynamic analysis are not widely available. A number of member companies have expressed an interest in having a modeling code for rolling element bearings similar to MAXBRG for fluid film bearings. The plan is to first develop a simplified solution using perturbation methods as outlined in the next paragraph. Then a full-scale finite element computer code will be developed. It will include the Reynolds equation for pressure, the elasticity equation for contact deformations, and the energy equation for thermal solutions. The initial method employed by UVA consists of an isothermal elastohydrodynamic (EHD) numerical analysis for roller element bearing. The analysis will include the variation of the lubricant viscosity with pressure which affects the film thickness in the contact region. A steady state solution and dynamic solution of Reynolds equation is implemented using a linear perturbation approach. The film thickness is obtained from the geometry of the contact between the roller and the races modified by the elastic deformations of their surfaces. The elastic deformations are obtained from the analysis of force and deflection distributions over the loaded rollers which depend on the geometry aspects and the total applied load. Small perturbations produce the stiffness and damping properties using the dynamic pressures. These methods will be used to produce the first computer code for ball and roller bearings.
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