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

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.

Eligibility

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.

Funding

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.

Before you apply

We strongly recommend that you contact the supervisor(s) for this project before you apply. 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.

How to apply

Apply online through our website: https://uom.link/pgr-apply-2425

When applying, you’ll need to specify the full name of this project, the name of your supervisor, if you already having funding or if you wish to be considered for available funding through the university, details of your previous study, and names and contact details of two referees.

Your application will not be processed without all of the required documents submitted at the time of application, and we cannot accept responsibility for late or missed deadlines. Incomplete applications will not be considered.

After you have applied you will be asked to upload the following supporting documents:

• Final Transcript and certificates of all awarded university level qualifications
• Interim Transcript of any university level qualifications in progress
• CV
• Supporting statement: A one or two page statement outlining your motivation to pursue postgraduate research and why you want to undertake postgraduate research at Manchester, any relevant research or work experience, the key findings of your previous research experience, and techniques and skills you’ve developed. (This is mandatory for all applicants and the application will be put on hold without it).
• Contact details for two referees (please make sure that the contact email you provide is an official university/work email address as we may need to verify the reference)
• English Language certificate (if applicable)

If you have any questions about making an application, please contact our admissions team by emailing [email protected].

Equality, diversity and inclusion is fundamental to the success of The University of Manchester, and is at the heart of all of our activities. We know that diversity strengthens our research community, leading to enhanced research creativity, productivity and quality, and societal and economic impact.

We actively encourage applicants from diverse career paths and backgrounds and from all sections of the community, regardless of age, disability, ethnicity, gender, gender expression, sexual orientation and transgender status.

We also support applications from those returning from a career break or other roles. We consider offering flexible study arrangements (including part-time: 50%, 60% or 80%, depending on the project/funder).