Publication Date
2019
Document Type
Thesis
Committee Members
Sheng Li, Ph.D. (Advisor); Ahsan Mian, Ph.D. (Committee Member); Joy Elizabeth Gockel, Ph.D. (Committee Member)
Degree Name
Master of Science in Mechanical Engineering (MSME)
Abstract
Pitting is a rolling contact fatigue phenomenon commonly observed in mechanical rolling elements, such as gears and bearings. In case of gear contacts, pitting usually takes place in the dedendum region, where both sliding and contact load are high. In this study, a model is developed to predict surface breaking crack formation fatigue lives, including both nucleation and propagation stages, for spur gear contacts operating under mixed elastohydrodynamic lubrication (EHL) condition. The model utilizes a gear load distribution model for tooth contact Analysis. A mixed EHL formulation is implemented to evaluate the surface normal pressure and tangential shear, incorporating the lubricant non-Newtonian behavior, which is influential on lubrication film thickness and surface tractions under high sliding condition. According to the surface tractions, a boundary element formulation is utilized to determine the stress fields, whose contribution to fatigue damage accumulation is assessed using a multi-axial fatigue criterion, predicting the crack nucleation life. As for the crack propagation life evaluation, the Paris and Erdogan’s formula is adopted. With the developed contact fatigue model, a parametric investigation is performed considering a spur gear pair, operating under different loads and different surface roughness conditions.
Page Count
127
Department or Program
Department of Mechanical and Materials Engineering
Year Degree Awarded
2019
Copyright
Copyright 2019, all rights reserved. My ETD will be available under the "Fair Use" terms of copyright law.
