Lead Supervisor: Dr Vengatesan Venugopal

Funding Details:

Fully funded for 3.5 years. Stipend starts at £15,006.

O&G companies need more confidence in the reliability of their mooring chains. This requires better guidance from design rules, and tools for the assessment of damaged chain links. Recent failures have shown that the current recommendations from standards are not sufficient with regards to the complex loading cases and the increase in size of the links.

Because of the complex stress field in the chain, in particular in the region of contact, finite element analysis is a necessary tool for the production of assessment data, which would be used together with measured material properties for fatigue and fracture analyses. In order to give confidence in the results from finite element models, the latter need to be validated by comparing predicted stress values with experimental measurements. Prediction of residual and service stresses and stress measurements are the objectives of the proposed project.

Objectives

• Prediction of residual stress field after manufacturing including different stages:
• Quenching
• Proof loading
• Comparison of predicted residual stress with measurements
• Prediction of fatigue stress range and mean stress in chain link for various loading conditions (tensile, out-of-plane bending, twist) 

Work Programme

A chain manufacturer will be contacted in order to obtain chain links and sections of chains for the experimental tests. The material grade will most likely be R4 as it is the most widely used. The size of the links will be chosen in accordance with the capacity of the testing equipment available at TWI. 

Task 1: Residual stress measurements
Task 2: Finite element modelling of manufacturing process
Task 3: Finite element modelling of service loading
Task 4: Coupling of residual stress and service stress predictions
Task 5: Large scale fatigue testing 

Specific eligibility criteria (approx 100 words)

Essential:

• Degree in Mechanical Engineering
• Experience in a Finite Element Software
• Understanding of inelastic material behaviour

Desirable:

• Experience in experimental measurements
• Knowledge of Fortran programming and Python scripting

Candidates should have a relevant degree at 2.1 minimum, or an equivalent overseas degree. Candidates with suitable work experience and strong capacity in numerical modelling and experimental skills are particularly welcome to apply. Overseas applicants should also submit IELTS results (minimum 6.5) if applicable. 

Further information to be included (eg, institute/ external website /profile page)

The successful candidate will be initially based at the University of Edinburgh for six months and then at the National Structural Integrity Research Centre (NSIRC). NSIRC is a state-of-the-art postgraduate engineering facility established and managed by structural integrity specialist TWI, working closely with academic institutions and a number of leading industrial partners. NSIRC aims to deliver cutting edge research and highly qualified personnel to its key industrial partners.

For more information about NSIRC, visit www.nsirc.co.uk

To apply, please send your CV and transcript of university study, with a cover letter specifying your interest in the research topic to the following: hayley.hodge<στο>nsirc.co.uk, V.Venugopal<στο>ed.ac.uk,philippe.bastid<στο>twi.co.uk. If you meet the criteria, you will be invited for an interview and to submit an application to the University of Edinburgh.