EPSRC DTP – Numerical Investigation and Uncertainty Quantification of Composite Flexible Risers

Pipelines, traditionally constructed from steel, form the backbone of the oil and gas industry, facilitating crucial transportation in both onshore and offshore operations. Recent advancements in manufacturability and the distinctive properties of composites, notably carbon fibre composites, have propelled them into the spotlight as a compelling alternative. Offshore pipes are primarily classified into two types; risers and generic tubulars. While all offshore components face challenges, risers, subjected to the most extreme conditions, have become the focal point for the quest for improved solutions.

Offshore risers are required to withstand a multitude of combinations of functional, environmental and accidental loads. These challenges include excessive twist and compressive forces encountered during installation, operation, and recovery, along with potential interference or clashing between the riser and the vessel hull, adjacent risers, and mooring lines. Additionally, there is exposure to thermal stresses, thermal cycling, and the risk of fatigue failure induced by the dynamic action of waves and currents. On the other hand, the susceptibility of steel pipes to corrosion necessitates frequent inspections and repairs, leading to regular shutdowns. This challenge is further compounded by the industry’s shift to deeper waters, requiring longer pipes and imposing substantial loads on the platforms due to the use of steel. Hence, flexible risers, composed of multiple unbound layers incorporating materials such as carbon fibre or other composites, stand out as a preferred choice among available riser options. This innovative design is particularly favoured for its ability to withstand heavy loads and effectively address the shortcomings associated with traditional steel risers.

The fatigue performance of composite flexible risers (CFR) is a crucial design consideration. The cumulative impact of cyclical stresses induced by waves, currents, vessel motion, thermal cycles, and pulsating fluid flow within the tubes results in fatigue. This fatigue, coupled with the development of interlaminar and intralaminar stresses, raises concerns such as delamination, matrix cracking, and fibre breakage, collectively compromising the overall structural integrity of the pipe. Despite its significance, the behaviour of CFR under these conditions has been rarely studied. The responses to fatigue in CFR depend on various factors, including manufacturing technology, environmental conditions, composite architecture, and geometry. Consequently, existing uncertainties in these sources contribute to variations in fatigue responses. A comprehensive understanding and quantification of these uncertainties will facilitate optimal designs, considering that current safety factors are high due to an incomplete grasp of this aspect. Therefore, prediction and uncertainty quantification of the fatigue performance of CFR emerge as a promising research avenue.

Entry Requirements:

Students with, or to achieve, a 2.1 degree in Materials Science, Physics, Mathematics or an aligned Engineering subject are encouraged to apply. An MSc in a related filed would also be acceptable. Experience in MATLAB, ABACUS, COMSOL, C++ or any other programming languages and modelling would also be preferable. Also, an MSc and/or publications in a relevant field should also be useful.

Self-funded candidates can also apply.

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). 

How to apply:

You will need to submit an online application through our website here: https://www.manchester.ac.uk/study/postgraduate-research/admissions/how-to-apply/ – ensure you mention ‘EPSRC DTP’ and the title / supervisor of the project in the ‘Research Details’ section of the application.