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The fatigue life cycle prediction of a light aircraft undercarriage

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.
Date January 2010
CreatorsErasmus, Daniel Jacobus
PublisherNelson Mandela Metropolitan University, Faculty of Engineering
Source SetsSouth African National ETD Portal
Detected LanguageEnglish
TypeThesis, Masters, MTech
Formatxxiv, 118 leaves, pdf
RightsNelson Mandela Metropolitan University

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