Although a component satisfies all operating static requirements, failures can still occur due to vibration induced fatigue. Vibration induced fatigue is a frequent phenomenon, in cases where the natural frequencies of the structures are excited by the loading. Hence, the methods which consider all dynamic characteristic of the structure should be used to obtain accurate fatigue life predictions. These methods in frequency domain are called vibration fatigue methods which give accurate, reliable and fast results.
In this thesis, a numerical code is developed in order to predict fatigue life of structures and it is used for a bracket that is installed on an air platform. However, for verification of the numerical code, a cantilever beam is used as a case study at the beginning. First, finite element model of the cantilever beam is constructed and experimental analyses are performed to verify the finite element model.
Then fatigue life is calculated using the numerical code and it is verified comparing the results obtained by both commercial software and performed fatigue tests. For predicting fatigue life of the bracket, flight test is performed in order to obtain acceleration loading. Finite element modeling of bracket and verification of it by experimental analyses are performed and finally, accelerated fatigue life of the bracket is obtained by the developed numerical code, commercial software and fatigue test. It is concluded that the results obtained from the fatigue analyses and fatigue test are considerably close enough to justify that the analysis is significantly accurate.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12614129/index.pdf |
| Date | 01 March 2012 |
| Creators | Eldogan, Yusuf |
| Contributors | Cigeroglu, Ender |
| 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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