Fatigue Assessment of Aluminium Welded Joints

Abstract

The research was designed to investigate the accuracy and reliability of the nominal stress approach in estimating fatigue strength of aluminium welded joints using the available design codes which are the IIW and EC9. The thesis gives a useful literature review for fatigue behaviour of the structural components to understand the main concepts and principles of this topic, for example, it explains the fatigue definition, Wöhler curve, statistical determination of fatigue curves, etc… Furthermore, it introduces the stress-based approaches which are the nominal stress, hot-spot stress and effective notch stress approach. According to the main aim of this research, the results of the nominal stress approach (Section 4.1) can confirm that the recommended design curves of the IIW and EC9 for estimating the fatigue strength of aluminium welded joints using the nominal stress approach give a great level of accuracy and reliability. Regarding to one of the objectives for this research which is to investigate the effect of non-zero mean stresses on the fatigue strength of aluminium welded joints, the results of this investigation (Section 4.2) can demonstrate the recommended values of the enhancement factors are conservative for both EC9 and the IIW.