Research Students: REMS 2022

Anna Ermakova

Biography: Anna holds a Bachelor’s Degree in Mechanical Engineering from a leading university in Russia and a 1st class Master’s Degree in Aerospace Engineering from Coventry University. Upon completion of her MSc, she ventured east for four years and worked at a British owned manufacturing company based in Zhuhai, China. During her employment, Anna was able to acquire a wealth of knowledge and experience across various manufacturing processes, which she is now successfully applying as she undertakes her EngD project. Anna is enrolled at Cranfield University and sponsored by EPSRC.

Thesis title: Structural integrity assessment of functionally graded components created using additive manufacturing technology for marine applications

Project description: An efficient source of clean energy, which is increasingly becoming the preferred solution to realising Britain’s and Europe’s energy demand, is offshore wind. The current challenge in offshore wind industry is to reduce the Offshore Wind Levelised Cost of Energy (LCoE) and make it competitive with alternative sources of energy. Monopile foundation, which is traditionally made of large welded plates, is the dominant type of support structure in offshore wind farms. The proposed project will explore the possibility of creating a managed residual stress field and microstructure in future monopiles using multi-metallic-layer wire plus arc additive manufacture (WAAM) technology, which has a great potential to reduce the LCoE and lead to significant fatigue life enhancement in monopile structures. Different strength, e.g. ER70S, ER100S, of ferritic and austenitic steel grades will be used to create critical optimised functionally graded structure with enhanced tolerance towards damage propagation in harsh corrosive environments.

Project Poster

Academic supervisor: Prof Ali Mehmanparast

Sarah Martin

Biography: Sarah is a Chartered Professional Engineer of Australia (CPEng) and Registered Professional Engineer of Queensland (RPEQ) specialising in geotechnical engineering. She graduated with a Bachelor of Civil Engineering in 2012 from the University of New South Wales at the Australian Defence Force Academy. Sarah obtained 1st Class Honours and was awarded the University Medal for best overall performance, AH Corbett Prize for best final year performance and Kaliope Vassilopolous Women in Engineering Prize for best final year performance by a female student. Sarah then worked as a geotechnical engineer with Golder Associates for almost 6 years and contributed to major infrastructure projects throughout Australia and New Zealand. Her industry experience included soil testing, construction supervision, geotechnical field investigations, project management, geotechnical analysis and design. Sarah is enrolled in the DPhil program at the University of Oxford and is funded by Ørsted

Thesis title: Medium Scale Field Testing of Monopile Foundations Under Cyclic Lateral Loading

Project description: This DPhil project forms part of a larger research framework which aims to improve design methods for monopile foundations subject to cyclic lateral loading. Monopiles are the most widely used foundation type in the offshore wind industry and such structures experience significant cyclic lateral loading from wind and waves. Medium scale field testing is required to obtain data on pile behaviour for the validation of theoretical design methods. Similar testing was conducted as part of the PISA project focusing on monotonic lateral loading, while this testing campaign will extend the research to cyclic lateral loading and rate effects. This project is funded by Ørsted.

Project Poster

Academic Supervisor: Prof Byron Byrne

Mark Qiu

Biography: Mark is a geotechnical engineer with a particular interest in geotechnics and renewable energy. Prior to joining the REMS CDT program, Mark obtained a 1st class BSc Eng degree in Civil Engineering from the University of Cape Town and was awarded the DC Robertson Memorial prize for the top final year project. Following this Mark extended his stay at the University of Cape Town to achieve a MSc Eng (with distinction) in Geotechnical Engineering. After which he pursued a career as a graduate geotechnical engineer at Meinhardt Consulting, based in Shenzhen China. His research interests include advanced laboratory testing and offshore foundation design. Mark is funded by the EPSRC and Ørsted. He is enrolled on the DPhil program at Oxford.

Thesis title: Simple Shear Testing of Sand under Cyclic and Multidirectional Loading

Project description: The behaviour of offshore wind turbine foundations is typically assessed using numerical modelling techniques, such as Finite Element Analysis (FEA). A fundamental element of FEA is the selection and calibration of suitable constitutive models that describe the mechanical behaviour of soils. For clays and sands under monotonic loading, these models are well-defined. However, for soils under real-life complex cyclic loads, including multidirectional and multi-amplitude loading, rate effects and ratcheting, the constitutive relationships are less well developed. This DPhil project will develop an extensive database of high-quality experimental tests using the simple shear and triaxial apparatus to assist the development of the constitutive models for cyclic loading. The work will make use of a novel variable direction simple shear testing system, specially developed for the University of Oxford.

Project Poster

Academic supervisor: Prof Byron Byrne

Alessandro Annoni

Biography: Alessandro is a Mechanical Engineer with special interest in structural integrity. He received his Bachelor’s degree in Industrial production engineering from Politecnico di Milano (Italy) and completed his Master’s degree in Advanced Mechanical Engineering at Cranfield University. He is currently a research student in the final intake of the REMS CDT.

Thesis title: Integrity Assessment of MP-TP Connections in Offshore Wind Turbines

Project description: An important issue to be considered in the structural integrity of offshore wind turbines is the design and life assessment of the connection between the monopile foundation and the transition piece (MP-TP connections). These connections are subject to variable loads and stresses imposed by the forces and moments generated by the effects of winds, waves and currents. Therefore, careful considerations must be made to design these connections against fatigue cracking and failure. Flanged bolted connections are widely used in the currently deployed offshore wind turbines. However, the suitability of these connections for future generation of offshore wind turbines, which will be much larger in size and capacity, needs to be evaluated and compared with alternative solutions do not involve bolts such as wedge connections. The objective of this research is to investigate the fatigue performance of the current and future MP-TP connection types by accounting for different factors that affect fatigue performance such as marine environment, welding and variable amplitude loading. Through theoretical, numerical and experimental study will be analysed the effect of the different factors on fatigue life of both bolted and non-bolted MP-TP connections. In particular, the research will aim to verify the design on non-bolted connections and determine any threats to structural integrity and limitations on safe working life.

Academic supervisor: Prof Ali Mehmanparast
Industry supervisor: John Wintle (TWI)

Sarah Kelly

Biography: Sarah is a Renewable Energy Engineer with a background in Mechanical Engineering. She completed her MEng in Mechanical Engineering at the University of Sheffield before going to work for Mott MacDonald Ltd in their Water and Environment team. Having been inspired by the challenges currently facing our planet, she returned to education to receive a MSc in Renewable Energy Systems Technology from Loughborough University. Her current research at the University of Strathclyde builds on her passion for sustainability and renewable energy technologies.

Thesis title: Novel Tidal Power Device

Project description: The UK is a global leader in developing offshore renewable energy technologies with significant marine energy resources (50% of Europe’s tidal energy and 35% of its wave energy potential). The research project focuses on developing the proof of concept of an innovative tidal power device. From the functional design framework and computational modelling to the power take off and prototype design. This is a high-level project that encompasses many key aspects of engineering design and renewable energy.

Academic supervisor: Prof Athanasios Kolios, Prof Feargal Brennan

Mohammad Rezvanipour

Biography: Mohammad is a Mechanical Engineer with a particular interest in Material. Before joining the REMS CDT program, Mohammad completed his BSc degree in Mechanical Engineering from Shiraz IA University. He then started to work in Zagros Petrochemical Company (ZPC) in 2010 until 2012 and continued his work as a senior engineer and designer in SINA Control Design and Manufacturing company until 2015. He received his MSc degree in 2018 in Mechanical Engineering in Material from University of Strathclyde, Glasgow

Thesis title: A reliability constrained optimisation framework for offshore wind turbine support structures

Project description: Targets for renewable energy have yielded significant investments in offshore wind because of their benefits compared to onshore wind turbine and other renewable energy technologies. Different types of support structures for OWTs are available for deep water deployments and a number of criteria should be investigated for optimum decision making. Optimisation in this section is an efficient way to decrease the cost of OWT. In this project, the main aim is to develop an advanced framework for the optimisation of typical support structures of OWT based on combination of structural models and appropriate methods for optimisation such as Genetic Algorithms.

Project Poster

Academic supervisors: Prof Athanasios Kolios, Prof Feargal Brennan

Bohan Chen

Biography: Bohan Chen spent her first three years of undergraduate in Shandong University majoring in City Underground Space Engineering and participated in a collaborative program in the stream of Civil Engineering at Durham University in her fourth year. After spending two years in Durham, Bohan obtained a BEng degree from Shandong University (Outstanding) and an MEng degree from Durham University (First Honour) in 2018. Her final year project of MEng was Numerical Investigation of Water Coning with Enriched Boundary Element Method. Now she is enrolled on DPhil programme at Oxford University and will focus on developing an optimised design method for offshore wind turbine foundations. Bohan’s research is funded by China Scholarship Council and Oxford University.

Thesis title: Progressive Distortion of Offshore Wind Turbine Monopile Foundations During Installation

Project description: The research will focus on the monopile foundation, but with a view to further developing a more optimised structure through advanced design methods. The research will rely on numerical, theoretical, and experimental methods.

Project Poster

Academic supervisors: Prof Byron Byrne, Prof Chris Martin

Luc Simonin

Biography: Luc is a civil and geotechnical engineer. He studied in two top French engineering schools: graduating from Ecole Nationale Supérieure de Techniques Avancées, he studied civil engineering for his MSc at Ecole Nationale des Ponts et Chaussées. During his MSc, Luc specialised in geo-technical engineering and in finite element modelling of underground civil works (master thesis). He also accomplished an ERASMUS semester at TU Delft (The Netherlands) where his interest for offshore wind grew. His research activities will encompass theoretical mechanics, numerical implementation and finite element modelling. Luc is funded by Ørsted and is enrolled at Oxford University for his DPhil.

Thesis title: Theoretical Developments for Soil Behaviour Under Cyclic Loading

Project description: Monopile foundations for offshore wind turbines are subjected to cyclic lateral loading from waves and wind. To characterise the behaviour of an offshore wind turbine, modelling of the soil is essential, especially its stiffness, strength and damping properties, as well as their evolution with cycles. To properly represent the behaviour of saturated sand under cyclic loading, a constitutive model in effective stress is being developed in the hyperplastic framework. The objective is to accurately reproduce the evolution of stress-strain cycles and pore-pressure, and to validate this model against laboratory and field test data.

Project Poster

Academic supervisor: Prof Byron Byrne

Ayo Fajuyigbe

Biography: Ayo holds a Master of Engineering (Meng) and a Master of Arts (MA, Cantab) from the University of Cambridge. He also holds a Master of Science (MSc) with distinction in Advanced Engineering Design from Brunel University. Ayo is hugely experienced in the finite element analysis of complex structures. He has extensive experience in the design, analysis and structural monitoring of offshore oil and gas systems as well as onshore telecommunications lattice structures. He hopes to apply the breadth of his experience to make a valuable contribution to the REMS development program. Ayo is a Chartered Engineer through the Institution of Mechanical Engineers.

Thesis Title: A Surrogate Model Framework for Structural Lifetime Extension Assessment of Monopile Wind Turbines

Project Description: The development of renewable energy sources is one of the critical engineering challenges of the modern era. Amongst the plethora of renewable technologies available, wind turbine technology has an edge due to its technological maturity and relative cost competitiveness. The profitability of a wind turbine unit is dependent on its ability to operate with minimal outages during its design life.
Structurally, the biggest obstacle to this aim is fatigue loading of the turbine. Fatigue is the phenomenon of slow deterioration of steel due to continuous varying loads over time. Fatigue design is in the form of a desktop simulation accounting for; environmental loads over the lifetime of the structure, steel properties at the most severely loaded sections (typically: welds) and fatigue resistance of the details of these welds: empirical S–N curves.
The analysis often contains conservatisms due to several factors ranging from simplification of loading history to reduce computation time, uncertainties in the environmental conditions and uncertainties in the structural properties. Hence, one key challenge in the operational management of commercial wind turbines is to accurately determine the remaining useful life (RUL) of the wind turbine. As wind turbines are typically designed for a target life of 20 years, many of the current installed units are nearing or over the design life. An accurate methodology for the determination of RUL is therefore needed to assess the true capabilities of these existing structures and to guarantee the operation of future installations.

Project Poster

Academic Supervisors: Prof Feargal Brennan, Prof Athanasios Kolios

Innes Murdo Black

Biography: Innes Murdo Black is a Wind Energy Engineer with a particular interest in Data science. He studied an MEng in Mechanical engineering from the University of Aberdeen, followed by an MSc in Aerospace Engineering at the University of Glasgow. Before joining the REMS CDT he has had a particular interest in Machine Learning algorithms applied to the renewable energy sector. His individual master project focused on predicting weather patterns to optimise power generation of a domestic wind turbine using a time series artificial neural network.

Thesis title: Machine learning techniques applied to future wind turbines

Project description: The offshore wind industry is rapidly developing, demonstrating a need for improving its infrastructure on structural health monitoring by providing prescriptive action preventing critical failure. Preventative maintenances’ purpose is to increase the value of the offshore wind turbine while improving the operational uptime and preventing failure using intervention. The goal of this field is to develop a diagnostic module to determine the direct cause of failure for prognosis. Machine learning has opened the door to possibilities of preventing failures ahead of time using SCADA data for effective maintenance. The aim of this project is to determine effective Machine learning methods for failure detection and critically analyse the most effective methods for specific failure modes. This is performed by firstly reviewing current methods of structural health monitoring applying machine learning to understand the industry trends. Secondly, developing a diagnostic module, this will require the development of an advanced program to determine failure modes using a machine learning method.

Project Poster

Academic supervisor: Prof Athanasios Kolios

Cameron Simpson

Biography: Cameron Simpson is an Electrical & Electronic Engineer with a particular interest in the power converter system of the drivetrain. He studied a BEng (Hons) in Electrical, Electronic, and Energy Engineering at GCU, followed by an MSc in Wind Energy Systems at the University of Strathclyde. During his MSc project he did work involving the modelling and control of a HVDC transmission system required for the transportation of electrical power from the Offshore Wind Farm to the local consumers. He now wishes to further expand his knowledge into the world of Mechanical Engineering in order to have a more broad understanding of the Wind Energy Industry. Using his knowledge of Electrical Engineering & his newly acquired knowledge in Mechanical Engineering, he wishes to further explore the influence of the mechanical dynamics of a FOWT on the Power Converter Systems reliability.

Thesis Title: The development of a coupled model of dynamics of a FOWT for the analysis of the failure modes

Project Description: Offshore Wind Farms have a significantly higher LCOE compared to alternative power generation technologies. Around 25% of the LCOE is associated with the O&M costs where accessibility to the offshore wind farm strongly relies on favourable weather conditions (wind, wave, etc.). The objective is therefore to reduce the O&M cost in order to make Offshore Wind competitive with other power generation technologies. This reduction of O&M cost can be achieved by improving the reliability of the critical component and/or by better understanding the failure of the critical component of the Offshore Wind Turbines (allowing for the maintenance strategy to be optimised). The power converter is considered the most critical subassembly of the OWT, as it suffers as from a high failure rate and lacks an effective condition monitoring system. As there is no condition monitoring system in place, the health of the power converter is predicted using a physics of failure model and SCADA data. Within the power converter system it is found that the weak points of the converter are the semiconductor devices and the DC- link capacitor. This problem is only growing in magnitude as Wind Turbines continue to transition from PRC to FRC in order to meet the stricter grid requirements necessary for large Offshore Wind farms. The main cause of failure within the power converter is attributed to the thermal dynamics of the power converter which is response for failure mechanisms such as bond wire life-off and solder joint fatigue. This PhD therefore seeks to assess the influence of the stochastic nature of wind and waves, as well as of the FOWT complex, nonlinear dynamics, including aerodynamics, hydrodynamics, control system, and structural dynamics, on the thermal performance of the Power Electronics focusing on medium-to-long thermal dynamics.

Project Poster

Academic Supervisor: Prof Maurizio Collu

Kingsley Sunday

Biography: Kingsley is a Chartered Engineer through the Institution of Civil Engineers and a Chartered Manager through the Chartered Management Institute. He holds a master’s degree with Distinction in Subsea Structural Engineering from the University of Aberdeen and a Civil Engineering degree from the University of Port Harcourt. Kingsley has extensive experience in structural dynamics, with particular expertise in the analysis and design of subsea riser systems, telecommunications lattice and monopole mast structures, structural monitoring and integrity.

Thesis Title: Optimising and closing the design loop of offshore wind farm and assets useful life using measured (monitoring) data

Project Description: Recent development of offshore wind turbines relative to offshore oil and gas structures, and the increasing demand for clean and sustainable energy have prompted the need for further research to deal with structural related challenges. Structural reliability and safety, design uncertainties, manufacturing defects, installation induced stresses, and ageing, amongst others can lead to high life-cycle costs and even catastrophic structural failure. These challenges are exacerbated by harsh environmental conditions, such as in the North Sea, in addition to the dynamic behaviour of wind turbines. The understanding, design, maintenance, and operation of offshore wind turbine structures are mostly achieved using transferred knowledge from offshore oil and gas structures. There is a need for better understanding of the special dynamic behaviour and challenge related to wind turbine structure and foundation systems in the offshore environment. This project will provide an analytical reliability model to identify, analyse and evaluate the impacts of different types of uncertainties on condition assessment and monitoring of wind turbine foundations based on their sensor system, damage sensitive parameters, damage identification techniques, and system reliability index.

Project Poster

Academic supervisors: Prof Feargal Brennan, Prof Athanasios Kolios

Adebayo Ojo

Biography: Adebayo Ojo is a structural analysis engineer, with particular interest in subsea structures. He has MScs in Systems Engineering and Subsea Engineering from the Universities of Lancaster and Strathclyde respectively. He has over 2 years of experience as a subsea structural analyst in the oil and gas industry, which is complemented by project planning and management experience (circa 3 years) in the solar energy renewables sector.

Thesis Title: Analysis and Design Methodology for Development of Novel Floating Support Platform for Wind Turbines

Project Description: Floating offshore wind turbines (FOWT) can untap substantial wind resources in deeper waters, where larger areas and higher, more consistent winds are available. Nonetheless, the Levelized Cost of Energy (LCoE) of the energy generated by these is still high, and it is imperative to develop new floaters to meet the above requirements. So far, the floating support structure configurations adopted have been heavily based on concepts developed for the oil & gas industry – in a completely different context than offshore renewables. The objective of this research is to develop a novel design framework which will allow the exploration and analysis of unconventional floating support structure geometries, optimized specifically for FOWT requirements. The developed concept will meet the minimal requirements of effective hydrodynamic stability in deep waters and also provides a low levelized cost of energy (LCOE) from the FOWT system.

Academic supervisors: Prof Maurizio Collu