Prof Philippa Reed
Applications accepted all year round
About the Project
The main challenge in lifing of welded steel structures (in both transport and off-shore applications) is the lower fatigue strength of the weldment compared to the base steel. Fatigue life is generally dominated by crack propagation from crack-like features at the weld toe. These are hard to find by conventional metallographic techniques, but have been shown to comprise fine shallow intrusions of slag trapped between the weld metal and the parent steel during solidification. The size and distribution of these features have a strong influence on fatigue strength. The proposed project will use a range of techniques to map weld toe features in detail at representative length scales and to examine fatigue initiation and early growth. The extent to which early growth is affected by welding parameters will be studied in order to maximise the fatigue life for a given joint geometry, structural steel composition and welding process. The aim of the project is to compare X-ray CT evaluations and serial sectioning approaches to determine weld toe geometry and the associated stress concentrations. This will allow us to further understand the stress and strains fields around fillet welds produced by shielded metal arc welding (SMAW) in steel plate and how this affects crack initiation and growth under fatigue loading.
Ultimately, this experimentally derived data will underpin numerical modelling of the fatigue responses of the welded structures and eventually be linked to design rules for light-weighting of welded steel structures in a safe and efficient manner. This PhD project will be conducted on two sites, partly at the University of Southampton and partly at TWI (based up in Abingdon, Cambridge) within the National Structural Integrity Research Centre http://www.nsirc.co.uk/, candidates should be prepared to be based at TWI for a significant part of the PhD programme.
If you wish to discuss any details of the project informally, please contact Philippa Reed, Materials research group, Email: [Email Address Removed], Tel: +44 (0) 2380 593763.
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