PhD Studentship: The impact of geometrical constraint on weld residual stress profile (Numerical and Experimental)

This 3.5 year PhD project is fully funded for home applicants and EU applicants with settled status; the successful candidate will received a tax free stipend set at the UKRI rate (£19,237 for 2024/25) and tuition fees will be paid.

Welding processes can introduce significant residual stress field within the structure which can be particularly detrimental to the service life of components. Welded structures are often subject to Post Weld Heat Treatment (PWHT) to reduce the level of welding induced residual stresses. Residual stress relaxation during PWHT process in heavy section welds of complex geometric form, however, can be inhibited due to the state of stress triaxiality in such structures.

This PhD project aims to investigate the effects of stress triaxiality on residual stress relaxation during PWHT. Finite Element (FE) weld modelling will be used to optimise the design of suitable laboratory scale specimens with different levels of stress triaxiality that is relevant to plant structures. The state-of-the-art weld modelling techniques will be implemented to predict the level of as-welded residual stresses in benchmark specimens made from ferritic materials that exhibit solid state phase transformation effect. The modelling aspect of the project will further investigate simulating appropriate methodologies to capture the PWHT process and predict the state of residual stresses after PWHT. A limited selection of benchmark test specimens with different levels of stress triaxiality will be manufactured and residual stresses characterised with diverse measurement techniques. The experimental aspect of the project will serve as validation of the numerical tasks. The outputs will be a matrix of experimentally validated predictions of weld residual stresses in a series of weldments with different levels of stress triaxiality in the as-welded and PWHT conditions.

This output from this project will serve as a rich database to support development and improvement of R6 engineering guidance, specifically for weld residual stress estimates used in defect tolerance assessments.

Applicants should have, or expect to achieve, at least a 2.1 honours degree or a master’s (or international equivalent) in a relevant science or engineering related discipline.

To apply, please contact the main supervisor; Dr Anastasia Vasileiou - anastasia.vasileiou@manchester.ac.uk. Please include details of your current level of study, academic background and any relevant experience and include a paragraph about your motivation to study this PhD project.

Advert information