The reliability of systems relies heavily on accurate fatigue life prediction of related components. Fatigue life prediction is a complicated process requiring the correct methodology to determine accurate and reliable predictions. The Palmgren – Miner damage accumulation hypothesis is widely used in determining the fatigue life of components exposed to variable loading conditions. Modifications have been made to this hypothesis trying to achieve a greater degree of accuracy, of these the Liu – Zenner modification has been the most successful. In this report the systematic process of fatigue life prediction using the Liu – Zenner modification to achieve reliable results is calculated. A representative stress time history measured in service on the component forms the basis for defining a flight cycle which is the chosen unit in which to express the fatigue life. Rainflow cycle counting performed on the stress time history allowed the formulation of a load spectrum to which the component is exposed in one cycle. Combining the load spectrum with the developed SN curve of the component and using the Liu – Zenner modification to the Palmgren – Miner rule a reliable fatigue life in cycles is predicted.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nmmu/vital:9614 |
| Date | January 2010 |
| Creators | Erasmus, Daniel Jacobus |
| Publisher | Nelson Mandela Metropolitan University, Faculty of Engineering |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis, Masters, MTech |
| Format | xxiv, 118 leaves, pdf |
| Rights | Nelson Mandela Metropolitan University |
Page generated in 5.4749 seconds