Research students: REMS 2020

Abdullah Al-Mamun Shaikh

Mamun Shaikh is a Civil and Structural Engineer with a special interest in offshore engineering. He obtained his MEng (Hons) from The University of Manchester in 2014. After graduating he completed his CELTA and taught at ‘English as a Foreign Language’ at Bell Cambridge in addition to teaching Maths on the Bell UFP course. For his thesis, he will be looking at optimising numerical design methods for offshore monopile foundations. He is enrolled at the University of Oxford, with the support of Mott MacDonald.

Thesis title: Numerical Design Methods for Offshore Monopile Foundations

Project description: Current design methods for offshore monopile foundations, have been shown to poorly estimate the stiffness and ultimate capacity of offshore wind structures, leading to over conservative design methods. This project will develop procedures to incorporate state-of-the-art soil models within aero-elastic codes to better explore the interaction between the design of the foundation and the overall dynamics of the wind turbine structure. The project will take a holistic approach, investigating the coupling between nonlinear aerodynamic loading and the foundation response. Further work will aim to optimise the calculation of the soil reaction curves determined from 3D FE analysis and the effect that the choice of soil constitutive model has on the quality of the 3D FEA.

Academic supervisor: Professor Harvey Burd, Ross McAdam
Industrial supervisor: Dr Barnali Ghosh (Mott MacDonald)

Satya Anandavijayan

Satya is a Materials Engineer, with experience in the Subsea industry. She obtained a BEng (Hons) from Queen Mary University of London before obtaining her MSc in Subsea Engineering from the University of Strathclyde in 2013. Since graduating, Satya has worked as a Subsea Engineer in Aberdeen, but a keen interest in the offshore renewables industry led Satya to return to academia, becoming an EPSRC funded member of the third cohort of the REMS CDT program. Satya's EngD thesis will focus on material pre-straining effects on fatigue and fracture behaviour of offshore wind monopile structures.

Thesis title: Material Pre-Straining Effects on Fatigue and Fracture Behaviour of Offshore Wind Monopile Structures

Project description: An important issue to be considered in the structural integrity assessment of offshore wind monopile structures is the influence of material pre-straining, introduced into the structures during fabrication processes such as welding, bending, rolling etc, on the fracture toughness and fatigue crack initiation and growth behaviour of the material. The main aim of this project is to investigate the effects of material
pre-conditioning on mechanical response, fatigue and fracture behaviour of an offshore structural steel, both in air and seawater.

Project Poster

Academic supervisor: Dr. Ali Mehmanparast, Feargal Brennan

Toby Balaam

Toby is a Civil Engineer with a particular interest in renewable energy. He obtained an MEng in Civil and Structural Engineering from the University of Sheffield. Since graduating, Toby was a teacher in South America and more recently has been working for the Geotechnical Consulting Group in London. An ESPRC funded student, he is part of the DPhil program at Oxford in the third cohort of the REMs CDT. Toby’s interests lie in the long-term effects of turbine loads on current foundations and reducing the cost of current foundation design to ensure continued growth in the industry.

Thesis title: Calibration of Cyclic Loading Models for Monopile Foundations

Project description: Monopiles are the most popular foundation for offshore wind turbines and are subject to cyclic lateral loading from wind and waves. This is not yet properly understood or accounted for. Recent work at Oxford has led to the development of a new approach to modelling cyclic loading within the hyperplasticity framework. This methodology can capture the pile response on a cycle by cycle basis, and be accelerated to many cycles. The model is currently calibrated with experimental data at macro-scale (full pile rotation), though, for design, it would be more convenient if the model parameters were found for site-specific conditions using laboratory element tests. Toby’s project will critically analyse the suitability of element tests for the purpose of predicting long-term cyclic loading of monopiles.

Project Poster

Academic supervisor: Prof Byron Byrne, Prof Guy Houlsby

Debora Cevasco

Debora Cevasco is a Naval Architect and Marine Engineer, who developed a special interest in the modelling of the dynamics of offshore wind turbines structures. Debora obtained her Bachelor degree at Genoa University. Always at Genoa University, she completed the MSc double-degree programme in collaboration with Cranfield University, where she attended the Advance Mechanical Engineering course, receiving a degree with distinction. During the MSc studies she had grown a great interest in the mooring systems modelling and, more widely, in models of dynamics for offshore wind turbines. Debora is now a member of the third cohort of the REMS CDT programme enrolled at Cranfield

Thesis title: Development of Multi-disciplinary Prognostic and Diagnostic Model of Dynamics for the O&M of an Offshore Bottom-fixed Wind Farm

Project description: The need to cut the costs of offshore wind farm assets by improving the O&M scheme, led to the creation of different worldwide project with the common aim of performing research in the areas of structural health monitoring and prognostics management. However, what is generally lacking in the current projects is a global view and the possibility to optimise the O&M strategy by integrating interdisciplinary solutions. Only recently the UK’s EPSRC launched a project aiming to fill this gap, and involving the common effort of both universities and industries: the HOME-Offshore project. This collaboration wants to investigate an innovative prognostics approach to predicting critical subsystem faults and ageing, coupling it with innovation in sensor technology, robotics and autonomous systems. As a part of the HOME-Offshore project, this research is aimed to develop a multi-disciplinary model of dynamics for an offshore bottom-fixed turbine, first, and finally for the whole farm, being able to catch and trigger the electro-magnetic disturbances due to stochastic variation of the wind and wave conditions to mechanical faults mapped through all the systems. The first step will be to surpass the “silos” approach and approximations in the study of structural and power chain models, for the analysis of turbines from a holistic point of view.

Project Poster

Academic supervisor: Dr Maurizio Collu, Athanasios Kolios

Mareike Leimeister

Mareike Leimeister is an Offshore Wind Engineer with special interest in floating offshore renewable energy systems. Mareike studied Renewable Energies at Stuttgart University in Germany and obtained the Bachelor of Science with distinction. Afterwards, she graduated from the Erasmus Mundus European Wind Energy Master and received a double degree with honours from Delft University of Technology (Offshore Engineering and Dredging) and Norwegian University of Science and Technology (Technology-Wind Energy). Mareike wrote her Master’s thesis in cooperation with the Fraunhofer Institute for Wind Energy and Energy System Technology (IWES) in Germany and continued working as research assistant for three more months. Now she is a research student in the third cohort of the REMS CDT Engineering Doctorate Programme, with the support of Fraunhofer IWES.

Thesis title: Reliability-based Optimisation of Floating Wind Turbine Support Structures

Project description: With a number of wind turbines already deployed and several more planned, and taking into account developments in the industry involving novel concepts and deployment environments (i.e. floating support structures in deep waters), performance based design methodologies can provide robust structures while at the same time achieving required levels of safety. This project proposes to review reliability-based concepts already used for offshore wind structures and also those employed for years by other industries (Oil & Gas, Civil Infrastructure etc.), taking into consideration the specific nature of wind energy applications: number of units in a farm – one of a kind vs mass production, safety considerations – unmanned structures with limited susceptibility to environmental damage, wind energy as a “marginal business”. The aim of this project is to derive guidelines for reliability-based design of floating wind turbine support structures, taking into account target safety levels and failure mechanisms from existing standards and applying them in such novel concepts.

Project Poster

Academic supervisors: Dr Athanasios Kolios, Dr Maurizio Collu
Industrial supervisor: Philipp Thomas (Fraunhofer IWES)

Lun Ma

Lun Ma is a Mechanical Engineer, specialising in Fluid dynamics with rich experiences in CFD and Beam Element Method modelling. He obtained his 1sr Class Bachelor degree of Mechanical Engineering in City University London, and in 2015 completed his MSc in Advanced Mechanical Engineering in Cranfield University. He had grown a great interest in renewable energy during his MSc study, his research in novel designs of tidal turbine was the main trigger. Lun is currently a member of the third cohort of the REMS CDT program, and his research interests line in optimising wind turbine array efficiency with aerodynamic modelling methods.

Thesis title: Wind Turbine Array Efficiency Optimisation With CFD Modelling

Project description:
The main purpose of this research project is to carry out a comprehensive fluid dynamic analysis of turbine array using two-scale momentum theory, in terms of turbine type and arrangement. The objectives of the project are analysing different types of turbine design, to understand the aerodynamic and hydrodynamic characteristics of various turbine arrays; study the effects of different types of turbine on the same turbine array design; optimising turbine array design such as turbine spacing and array configuration, under possible environmental condition.

Project Poster

Academic supervisors: Dr Taka Nishimo, Dr Athanasisos Kolios

Mark Richmond

Mark Richmond is a structural engineer with a special interest in structural health monitoring and asset management. Mark obtained a BEng in aerospace engineering at Swansea university and then worked as a design engineer before returning to Swansea university to complete an MSc in Mechanical engineering. Mark is now part of the third cohort of the REMS CDT programme enrolled at Cranfield and is EPSRC funded.

Thesis Title: Extrapolation of Offshore Wind Turbine SHM Data From Instrumented to Non-instrumented Units

Project description: Operation and maintenance of offshore wind turbines contributes a large amount to the total levelised cost of energy. Use of structural health monitoring sensors can improve maintenance strategies but can themselves cost a significant amount and so are only placed on a small percentage of all the turbines within a wind farm. This project aims to develop a framework for extrapolating structural health data from sensored wind turbine units to non-sensored units based on a combination of high-fidelity CFD, FEA and spatial variation models. There are two main reasons why this is important: first, performance of the wind farm can be optimised by evaluating which layout nets the greatest return; second, the cost of operating the wind farm can be reduced by placing the turbines in such a way that loads are reduced and maintenance activities can be performed more economically.

Project Poster

Academic supervisor: Dr Athanasios Kolios, Dr Lin Wang

Jessica Taylor

Jessica is a structural engineer with a special interest in fracture mechanics. She attained a BSc in Physics at Warwick University before joining Cranfield in 2015 for an MSc in Offshore and Ocean Technology with Offshore Renewable Energy. For her thesis, she will be investigating crack arrest as a method of fracture prevention in thick steel sheets, with applications in shipping and wind industries. For this project, she is working with TWI and Lloyd's Register and with their support, hopes to have a large positive impact on these industries.

Thesis Title: Assessment of Crack Arrest Behaviour in Modern Structural Steels.

Project description: Investigating crack arrest of high strength, large thickness steels for modern container ships with a view to understanding the crack arrest mechanism. This should lead to improved certification and improved engineering design. Most structural integrity procedures aim to reduce the chance of fracture initiation. An alternative approach uses the concept of crack arrest. In this approach, it is assumed that a crack will initiate in a region of local stress intensity or embrittlement, however the material is designed with a toughness high enough to arrest the crack outside these regions. As such, the crack is prevented from through-thickness growth. This is additionally important in welded structures where local welding imperfections and embrittlement can cause failure if the crack is not arrested in the bulk material.
Whilst the empirical relationships between small and large scale tests were valid for previous material specifications, a deeper understanding of the mechanism governing crack arrest is needed in order for it to be a futureproof approach to preventing fracture. New test procedures may need to be developed in order for appropriate certification of materials and vessels to be possible. Additionally, current test procedures need to be optimized for this purpose to ensure compliance with one another and more confidence in results.

Project Poster

Academic supervisor: Dr Ali Mehmanparast

Enrico Di Martino

Enrico is an Offshore Engineer, working as a Project Manager in the Oil and Gas business unit of D’Appolonia (a consultancy and engineering company of the RINA Group). Enrico obtained his Bachelor degree in Mechanical Engineering at Genoa University in 2015, and he completed his MSc in Offshore and Ocean Technology with Risk Management with distinction at Cranfield University in 2016. His expertise is the risk and integrity management of oil and gas related assets. Enrico is now a member of the third cohort of the REMS CDT Engineering doctorate programme, with the support of D’Appolonia S.P.A.

Thesis Title: Valuation and Financial Modelling Methodology to Support Decision Related to Energy Investment Under Uncertainty

Project Poster

Academic supervisor: Dr Athanasios Kolios, Dr Lin Wang

Wai Jun Lai

Wai Jun is a graduate Mechanical Engineer from the University of Bradford having obtained a First Class Honours in MEng (Hons) Mechanical Engineering with a Diploma in Industrial Studies. Having undertaken an undergraduate placement with E.On at Ratcliffe coal-fired power station, he has gained a deeper understanding of the electricity market and electricity generation which has led him to develop an interest in the marine renewable energy sector. He is now enrolled at Cranfield University as a research student focusing on the application of hybrid laser-arc welding for the fabrication of renewable energy marine structures funded by the EPSRC.

Thesis Title: Integrity Issues in High Productive Hybrid Welding Processes of Renewable Energy Marine Structures

Project Description: The project involves the application of hybrid laser-arc welding for structural steels used within the offshore wind energy sector as a means of manufacture compared to existing welding technologies. Typically offshore wind turbine structures i.e. the tower; are primarily fabricated through using submerged arc-welding (SAW) to apply a longitudinal weld to rolled steel plates to form a circular section (can) and then girth welding a number these together to form the structure. With the push for increased capacity and power output of offshore wind; the aim is to investigate the use of the hybrid laser-arc technology to create sound, deep welds to improve the productivity of offshore wind turbine structures.

Project Poster

Academic supervisors: Dr Supriyo Ganguly, Dr Wojciech Suder

Philip Taiye Dirisu

Philip Taiye is a UK registered Chartered Engineer with vast experience in Welding and Materials selection issues for the offshore and onshore Oil and Gas sector. Philip worked extensively in major offshore and onshore pipeline projects by Exxon Mobil, WorleyParsons, Shell, NNPC and other international pipeline manufacturers. Philip possesses expertise in material selection, weld design, procedure qualifications and applications of welding procedures and processes complying with international codes and standards. Philip obtained his Bachelor degree in Mechanical Engineering in 2003 and completed his MSc in Welding Engineering at Cranfield University in 2015. Philip is now enrolled in the 2020 cohort of the REMS CDT Programme at Cranfield University. Philip’s project is sponsored in parts by Vesta Wind System and by Total Exploration and Production Nigeria Limited.

Thesis Title: Development of Multi Grade Functional Steel Structure by Wire plus Arc Additive Manufacture (WAAM) for Marine Application.

Project Description: Traditionally offshore structures are made of plain carbon steels as specified by different structural steel standards e.g. BS EN 10025. The design flexibility for such structures is limited by the manufacturing process and traditionally a singular grade is used in the entire structure which may lead to inefficient design. Wire plus arc additive manufacture (WAAM) is a disruptive technology and capable of significant design improvement by using different strength of steel structure depending on the stress analysis of a structure. The project aims to understand the underpinning interaction between different grades of steel to create a functionally graded structure. Interpreting the variation in mechanical properties in a graded structure will be vital to understand and predict the performance of such advanced structures. Study of different heat sources and metal deposition principles will be performed to generate a robust understanding and process optimisation for such complex structure.
This research would form part of the 6 M£ LASIMM (Large Additive Subtractive Integrated Modular Machine Project) consortium funded by the EC. BAE Systems, Foster & Partners, Vesta Wind System, A/S Global Robots, Loxin 2002 are the main industrial contributor. Vesta Wind System are the main client for this specific part of the project.

Project Poster

Academic supervisor: Dr Supriyo Ganguly, Filomeno Martina