Rolling element bearings are the one of the most widely used machine elements in
the industry. The most important criterion in bearing selection is the endurance life.
The first attempts on the prediction of the endurance life of rolling elements bearings
are done by Lundberg and Palmgren in 1950s (Harris, 1999). Their work adopted as
an ANSI, ABMA and ISO standard which is widely used in industry today. The
basic assumption of Lundberg-Palmgren formulation is that no matter how small the
load applied on rolling element bearing, all material in the stressed volume is subject
to fatigue failure.
In this study, four main life theories / Weibull, Lundberg-Palmgren, Ioannides-Harris,
and Zaretsky on rolling element bearings have been investigated. Three-dimensional
finite element models of a bearing&rsquo / s inner ring and rolling element have been
prepared. The stress fields within the inner ring and the ball with respect to the
applied load are obtained numerically. The fatigue life of the inner ring has been
predicted by two methods that are widely used for fatigue analysis / Total Life
Analysis (S-N method) and Crack Initiation Analysis (& / #56256 / & / #56624 / -N method). Obtained results
are compared with ISO formulation.
As a result of the investigation, S-N and & / #56256 / & / #56624 / -N methods are determined to give more
conservative results than ISO method for higher loads that cause stresses above the
fatigue limit of the material. The used methods for bearing life prediction recognize
the existence of the fatigue limit stress. Hence as the stresses within an operating
bearing do not exceed the limit stress, the bearing can achieve infinite life. It is also
observed that load variation has a direct influence on the bearing life. When the load
significantly changes from the levels which create stress above the fatigue limit to
the levels that result stress is below the fatigue limit, the bearing would have higher
endurance life than predicted by ISO method.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/2/12610421/index.pdf |
| Date | 01 February 2009 |
| Creators | Eroglu, Baris |
| Contributors | Darendeliler, Haluk |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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