REMS Blog

Index
  1. 1st REMS Structural Integrity Seminar - Satya Anandavijayan
  2. 4th REMS Annual Conference in Glasgow - Jessica Taylor
  3. Visiting Norwegian Geotechnical Institute (NGI) in Oslo – Toby Balaam
  4. Visiting University of Western Australia, Perth – Iona Richards
  5. Attending a Conference in Taiwan – Russell Mayall
  6. Deng in a Booming Industry – Scott Whyte
  7. Field Experiment Deployment – Waseem Khodabux and Paul Causon
  8. New offshore renewable energy systems by Sandia – Anastasia Ioannou
24/07/19
Following the success of the REMS annual conference this year, a full day seminar was held on structural integrity on the 24th July 2019 at Strathclyde University. The aim of this workshop was to allow students within the REMS structural integrity community working on experimental projects from Cranfield University and Strathclyde University to learn, collaborate, and brainstorm together on ideas and issues within our research area.

The day started off with informative presentations by Professor Feargal Brennan and Dr Ali Mehmanparast on structural health monitoring and residual stresses in weldments. This was followed by individual presentations given by the REMS students on our individual research projects. These presentations included focus on the areas of corrosion monitoring, fracture toughness, additive manufacturing, residual stresses, and microstructure. The session allowed everyone to gain an insight into the other topics of research that were being undergone within the REMS structural integrity stream.

The second half of the day was focused on brainstorming and finding niches for potential inter-departmental collaborations. Hot topics of discussion included the potential issues found within corrosion monitoring, and the effect of thickness on various mechanical and material parameters. This was followed by a brainstorming session on potential cross collaborations within the REMS structural integrity community.


Figure 1 - Dr Ali Mehmanparast leading the brainstorming session on thickness effects

I personally found the workshop incredibly useful, as it allowed a platform for students to share their research within the REMS community. As EngD/PhD students, it is not uncommon to work in isolation, without sharing knowledge that each of us have gained which could help one another in our respective areas of research. I felt I learned a lot and gained a lot of insight throughout the course of the day, and it brought up many topics for further consideration within our subject area.


Figure 2 - The REMS Structural Integrity group from Cranfield and Strathclyde Universities
Satya Anandavijayan
04/07/19
4th REMS Annual Conference

The REMS annual conference is a great place to catch up with colleagues who are spread all over the country (and Europe), and learn a bit more about the vast array of work on offshore renewables which is being carried out at the REMS centre. This year it took place at our new partner university - the University of Strathclyde in Glasgow. Alongside the talks we were able to spend a bit of time exploring the city and surrounding area.

We all met up on Wednesday for the field trip, which was absolutely brilliant and a lot of fun. We visited the AFRC (Advance Forming Research Centre), which is part of the University of Strathclyde and learnt about the kinds of material/mechanical testing which go on there. Afterwards we departed to the Falkirk wheel, which is a massive canal boat lift which takes the place of 11 locks! After the boat trip we were free to explore the Whitlee wind farm and exhibition, which is the largest onshore wind farm in the UK (2nd largest in Europe) and benefitted from a guided tour around the park. This was the highlight of the day for me as we were able to walk freely between the turbines and see many other members of the public doing so - it was really inspiring to experience the scale of the farm and the ways in which our research is applied in the real world.


Figure 1 - Falkirk wheel - it's massive!


Figure 2 - Whitlee wind farm - it's also massive! - this is us all next to a turbine blade!

Thursday was a lot more academically-focused, with presentation sessions from both REMS students and REMS industrial partners on the subject of "Optimisation of Offshore Wind Structures". This was fascinating - covering all areas of the wind turbine support structure from the ground up: geotechnics, structural integrity, risk modelling and financial management. The day brought together speakers from numerous different industries and universities and it is incredibly valuable to see the impact of our research as part of the bigger picture. The day was topped off with a delicious dinner in the level 9 executive suite of the University of Strathclyde's Technology & Innovation Centre, where we were able to network with the industry delegates.


Figure 3 - REMS students and staff at the conference


Figures 4 and 5 - REMS students after the conference - lots of networking going on between students

Friday was just family - whilst the REMS management team met to discuss the Centre's progress, the morning sessions of student presentations were chaired by 4th year REMS students themselves! We each got a chance to present our work and ask each other questions in a relaxed and informal environment. This is a great chance to see what the other students are working on and who we can potentially collaborate with. After a packed few days of conference and before travelling home, a few of us took the chance to spend some time together while we were all in the same city and spent Friday night in the bowling alley before leaving Glasgow.

Photo : it was lovely to see each other again after so long and wind down after a long week

I thoroughly enjoyed the REMS conference - it's a place for us to come together with a common interest but completely different research areas and learn from each other while having a lot of fun. It's different to other conferences I've been to because we already know each other and every person's topic has an impact on the field which we are all working in - offshore renewable energy.
Jessica Taylor
12/06/19
In February 2019, I spent almost a month at the Norwegian Geotechnical Institute (NGI) in Oslo. Firstly, to attend the ‘DENSER’ workshop and then staying for a few weeks to work on a few collaborative projects.
The ‘DENSER’ workshop was a two-day event, held at NGI’s offices, which focussed on cyclic behaviour of dense sands and complementary constitutive models. Invited speakers (and a few PhD students) attended from institutions worldwide. I was struck by the contrast of models presented; these ranged from explicit relationships, empirically estimating development of properties with cycles, to Discrete Element Method (DEM) models capturing behaviour at individual grain scale and many in between. There was much interesting discussion, particularly regarding possible benchmark tests for a more focused approach to modelling dense sands.
The following few weeks were spent in the office with the ‘Numerical Geotechnics’ group. The principal purpose of the visit was to use Hyperplasticity models developed at Oxford to back calculate cyclic element test data on clays acquired by NGI (in the form of contour diagrams). Contour diagrams are well used in industry and provide an inter/extrapolated picture of development of strain with cycles across the full stress space, based upon experience of numerous tests. Calculating these using a mechanistic model could perhaps shed light on the physical processes at play and form a useful test of the formulation of the model.


Figure 1 – The soil testing laboratory at NGI Oslo.

In the final week, we began work on a further collaboration, which aims to take advantage of Hyperplasticity models ability to predict response continuously and quickly for any load input. This aims to complement work undertaken at NGI as part of the WAS-XL (Wave loads and soil support for extra-large monopiles) project. Load histories (based upon time domain integrated analyses of a 10 MW wind turbine) were applied to a sample of over-consolidated North Sea clay in CSS conditions as irregular loading and as idealised packets of increasing magnitude. Predictions of the tests will be made using a model calibrated to constant-amplitude tests and the aim is to publish the work at the ISFOG conference in 2020.



Figure 2 – NGI contour plots in Drammen Clay at N=100. Left – original plot direct from CSS data. Right – back-calculated using Hyperplasticity models.

Oslo was an excellent place to spend a month, particularly in the winter. There is amazing nature at the end of each metro line and cross-country skiing routes outnumber roads! Highlights in Oslo include the Viking ship museum, the old winter Olympic tobogganing run (which can be accessed by metro), and the hike to Kolsåstoppen overlooking the city. Thanks to everyone at NGI for making me feel so welcome and for the many fruitful discussions. Particularly to Ana Page, who went out of her way to help shape the project and make sure I experienced the best parts of the city and surrounding areas.


Figure 3 – Cross country skiing with Ana. Hiking to Kolsåstoppen on the outskirts of Oslo.
Toby Balaam
18/02/19
I arrived in Perth in mid-October 2018, for a 10 week visit to the National Geotechnical Centrifuge Facility (NGCF) at the Centre for Offshore Foundation Systems (COFS), University of Western Australia (UWA). Arriving to Perth in springtime was lovely. It was sunny and warm and perfect for exploring Perth’s many beaches and parks – when I wasn’t in the lab, of course!
During my visit, I carried out centrifuge testing to explore stress level effects for monopiles under both monotonic and cyclic lateral loading. These tests complement laboratory tests I performed at Oxford during the first few years of my PhD, and should provide valuable insight into the monopile’s response to lateral loading, to help inform improved design methods.

Geotechnical centrifuges allow the g-level (acceleration) experienced by geotechnical models to be increased, to simulate large-scale stress-levels with small-scale models. For example, the 40 mm diameter model monopile I used for my experiments simulated a 3.2 m diameter monopile when the centrifuge operated at 80g. During my visit I used the new 10 m diameter beam centrifuge at the NGCF, which is capable of spinning up to 2400 kg at 100g.


Figure 1 – 10 m diameter beam centrifuge at the NGCF

Over the first month I got to grips with operations at the NGCF, designed equipment modifications and discovered how complicated things can become when your apparatus needs to perform at both 1g and 80g. Preparation for the experiments was challenging and required lots of troubleshooting, but with excellent support from the technicians and academics at COFS, preparations were complete by early December.

We began centrifuge testing on December 5th. I was very nervous the first time we span the centrifuge – as I wondered whether we’d tightened all the nuts correctly and if my crimped wire connections would be up to scratch – but for the centrifuge technicians, this was just another typical day. The NGCF is a very busy facility; during my visit five other researchers (including 2 other international visitors) were also carrying out centrifuge testing campaigns.


Figure 2 – Close-up of loading and displacement measurement set-up on the centrifuge

The centrifuge testing went remarkably smoothly, and we completed 20 monopile tests and 12 CPTs (to characterise the soil samples) with a few days spare before I flew home for the Christmas break. I am currently post-processing the results and writing a report on the findings, which we hope to publish soon.

Beside the centrifuge testing, the visit was a great opportunity to experience life at a different university, on the other side of the world. Everyone at COFS was very welcoming, and I learnt a lot through discussions with academics, PhD students and technicians. I am also very grateful to fellow PhD students who helped in the lab, treated me to Aussie BBQs and showed me a little of Western Australia. Many thanks go to Prof. Fraser Bransby and Prof. Christophe Gaudin at UWA for hosting the visit.


Figure 3 – Exploring beaches near Margaret River, Western Australia
Iona Richards
03/11/18
Saturday 3rd November – Arriving in Taiwan
When I booked my ticket for the 9th International Conference on Scour and Erosion (ICSE 2018), I didn’t anticipate exploring the Tonghua night market in Taipei trying to decide which street food to eat, while struggling with sleep deprivation! It’s a Saturday night, and I’ve only been in Taipei for a few hours following a long journey from the UK.

Photo: Taipei 101 greets me when I leave the metro station

Sunday 4th November – Exploring Taipei and conference registration
On Sunday morning I’ve actually managed to catch up on sleep fairly well, with the help of a nap I had on Saturday afternoon. I have some excellent noodle soup for lunch on the recommendation of my Taiwanese colleague on the REMS course at Oxford, then explore the local area around Taipei 101 where there are lots of shops, and I found a big group of musicians in one of the squares demonstrating traditional drumming.
In the afternoon I make my way to the Taipei International Convention Center to register for the conference, where I bump into Richard Whitehouse – my Industrial Supervisor at HR Wallingford and chair of the Scour and Erosion technical committee (ISSMGE TC213). Later in the afternoon I went back to my room to practice my presentation a few times and to work out the narrative of my talk. For this conference I have 12 minutes to talk, but the first practice took me around 15 minutes! I really don’t want to run out of time on the day, so I ended up tweaking my slides and focusing the content of my talk.

Photo: Small-scale renewable energy in Taipei, combining solar with a vertical-axis wind turbine

Monday 5th November – The conference begins
Today is the first day of the conference. The day starts with an opening ceremony and some introductions and welcomes. This is followed by the first keynote presentation and a coffee break. The rest of the day is made up of presentations on a range of scour applications from rivers and dams, through to offshore subjects such as turbidity currents and renewable energy. At this conference the presentations are in three parallel sessions, so there is an exercise in looking through the programme and proceedings to decide which talks to attend. The day is broken up with coffee breaks and lunch, with plenty of time for discussions.
Conferences like this are a fantastic opportunity to meet up with a diverse range of specialists, and I meet people here that I remember from the last ICSE held at Oxford in 2016 but also PhD students, professors, and consultants that are also working on offshore wind projects. Of course in the evening there are more networking opportunities over dinner and then over a few drinks at a bar – it is only at these very specialised conferences that you get the chance to meet with such a range of people to freely share ideas and even to gain new inspiration for your own research.

Tuesday 6th November – Time to give my presentation
Tuesday starts with another two keynote presentations. My talk is in the last session of the day, but with only one other parallel session. The audience was around 100 people. I’ve presented at a similar conference in London back in July, as well as at the REMS conferences over recent years, so I’ve learned to be better prepared and as a result have less nerves before giving a talk than a few years ago. Part way through my talk a “5 minutes left” sign is held up, and by the end of my talk I’ve managed to keep to time and communicate the main messages I wanted to get across. I answer four questions from the audience then more people come to speak to me after the session for further discussions – it is rewarding and encouraging that my talk has generated so much interest.

Wednesday 7th November – The conference formally closes
Wednesday is the last day of presentations, the day follows the same format as the previous two – only today I no longer need to worry about my presentation. The day ends with closing speeches and the conference dinner on the 33rd floor of the Taipei World Trade Center. We are treated to a display of traditional Taiwanese dances, and a delicious range of Taiwanese food.

Photo: Richard Whitehouse and myself with Taipei 101 at night

Thursday 8th November – Visiting a dam and a bridge on the Dajia river
On Thursday, the last day of the conference, an industrial visit is planned. The conference attendees take a coach out of Taipei for 2 hours to the Dajia River on the western side of Taiwan. Our first stop of the day is the Shigang dam, which was badly damaged by a landslide during the 921 earthquake in 1999. The earthquake was magnitude 7.6, and the fault runs right underneath the dam itself. Impressively emergency repairs were rapidly performed before the typhoon season in 2000 but the situation remains challenging due to progressing river erosion and reliance on the reservoir as a water source. In the afternoon we visit the Hualiang steel bridge further downstream – a former railway bridge now just used for pedestrians and cyclists. We are taken down to the river bed, where the bridge foundations are being badly undermined by scour. The scour here is due to a combination of the steep gradient of the river, and the weathered sandstone riverbed which crumbles easily to sand particles and can be broken up by hand into smaller blocks. The day of field visits has illustrated the significant engineering challenges for engineering structures in Taiwan due to combinations of the local geology, climate, as well as potentials for earthquake damage – and demonstrated the interest of the scour and erosion scientific community to organise this conference here. The 10th ICSE will be in Washington DC in 2020 by which time I will (hopefully) be a REMS alumni, but I hope to stay in touch with my old and new friends in this international scientific community. Before I leave I’m having a long weekend in Taipei to see some more sights and take in some culture. Maybe I’ll take a trip up Taipei 101 to see the famous 660-tonne tuned mass damper…

Photo: Hualiang steel bridge foundations undermined by scour
Russell Mayall
24/07/18

I joined the 1st cohort of the Renewable Energy Marine Structures (REMS) Centre for Doctoral Training (CDT) in 2014. At that time there was a feeling of reserved optimism in the developing European offshore wind sector that the CAPEX and OPEX price would incrementally reduce over the subsequent years and as a result the industry would grow at a steady pace. Four years on, in 2018, and now offshore wind is a booming global industry, with tumbling costs resulting in zero-subsidy offshore wind farms becoming a reality.

As part of REMS, I am undertaking a DEng at the University of Oxford, while working at Fugro GB Marine Limited within the GeoConsultancy service line. My aim is to develop practical constitutive models for the numerical modelling of offshore foundations. I selected this as my topic area for research as, based on my time working as a geotechnical consultant on finite element analysis (FEA) projects, it was clear that there was a large gap between industry and academia. I felt the proposed DEng format within a CDT offered the perfect environment for this research to attempt to bridge the gap. Being part of the REMS CDT offers the opportunity to work at the interface between industry and academia in a highly dynamic exciting industry. A DEng is similar to a traditional DPhil (or PhD) in many ways, with the main difference being a practical industry tilt to the research and the opportunity to work on live industry projects. Some components of my DEng have involved development work for live offshore wind projects and others have involved more long term academic focused developments. In my opinion, this mix of academia and industry research offers a unique opportunity for short to medium term innovation within the industry. During the programme I have had many unique opportunities; including, spending 2 months at the University of Western Australia (UWA); undertaking a wide range of renewable energy focused doctorate level technical taught modules; applying my research on a number of commercial offshore wind projects; presenting at conferences and more academic focused research, steered by highly respected Professors from the University of Oxford.

A recent week of work for me in March 2018 within REMS is shown below which I think highlights the diverse opportunities available to me while undertaking my DEng within an engineering consultancy.

Monday:
My week starts at the Fugro office in Wallingford where, first thing in the morning, I attend a weekly design meeting for an offshore wind monopile foundation design project I have been working on. The consultancy project has been ongoing for 6 months and we are reaching the final stages. The project, which forms a section of my DEng portfolio, has been very challenging and has involved development of a number of new models and scripts to run and post-process a large number of 3D FEA. As part of the project we have some stress path tests running in the Fugro laboratory in Wallingford that are to be used for model calibration, so I spend some of my day checking the results completed so far to ensure they are as expected. The rest of my day is primarily spent running verification analyses for a new constitutive model I have implemented. I have been working on the model, termed the MSurf-ACE model, for many months with my supervisors, Prof. Chris Martin and Prof. Harvey Burd from the University of Oxford and Dr. Mike Rattley from Fugro.


Figure 1: Visiting the Fugro laboratory to inspect some ongoing stress path tests

Tuesday:
I am working from my office in the University of Oxford today where I am continuing to run verification analyses for the MSurf-ACE model. I manage to drag myself from the computer to take a break at lunch time and attend the weekly civil engineering seminar in the university.

Wednesday:
I spend Wednesday putting the finishing touches to slides I have prepared for a presentation I am to give in Holland for the Royal Netherlands Society of Engineers (KIVI). The presentation includes work from my research and additional recent innovations from the wider Fugro group.

Thursday:
I arrive in Holland and spend most of the day meeting colleagues at the Fugro office in Nootdorp to discuss innovation ideas across the Fugro group. In the evening I give my KIVI lecture titled: Foundation Optimisation for Ever Larger Turbines: Geotechnical Perspective. The lecture was attended by over 80 engineers and seemed to be well received, with several very interesting questions from the audience. I also had the opportunity to relax at the social event after the presentation and have some very interesting technical discussions with other engineers from the offshore industry.


Figure 2: Presentation at the KIVI lecture

Friday:
I arrive back in the UK early morning and go to the office to start preparing a draft journal paper to describe the new MSurf-ACE model I have been developing. I attend a meeting in the afternoon with my supervisors to discuss the structure of the planned journal paper and some recent results I have produced. After this I head for some much-needed rest!


Figure 3: Presenting results at a supervisory meeting
Scott Whyte
16/01/18

It is wise to start by welcoming the new cohort 2021 to the REMS centre and wish them loads of fun and success in their future researches. The week of the 18th of September was a particularly eventful for the REMS students. It was a week of conferences where both the annual REMS and the EAWE conferences were organised successively at Cranfield University. The sharing of knowledge and passions was demonstrated through various presentations which enabled a unique network to be established between both researchers and industry representatives. That said two REMS students had to leave the conference quite briskly as a result of their deployment for a field experiment. Those two students are Paul Causon and Waseem Khodabux who in the scope of their doctorate are analysing the marine growth effects and pitting corrosion on wind turbine foundation.

The weather displayed a certain kindness on those autumnal days of the 19th and 20th of September 2017. When such a small window of opportunity appears, it does make sense to take a leap. The van was booked waiting for the keys to be collected at the main reception for the adventure for our two protagonists, Waseem and Paul to begin. The destination was Bridlington also known as the lobster capital of Britain and which eventually has also transformed into a major port for offshore wind related projects due to its proximity to various windfarms on the east coast. In that area, quite a few windfarms going through different technological iterations from Round 1 to 3 have been installed. The colossal Dogger Bank also forms part of that cluster of offshore structures populating the seas around that region.

The anchors, plates, frames, ropes, cable ties and spacer were all loaded and it was time to hit the road. It turned out to be quite an impressive experience where Paul was describing the various hurdles that would have to be overcome once the pair were on the deployment boat. During the whole journey to Bridlington a plan was devised. When they reached the hotel they smiled. It had a Disco ball and it seemed the more mature generation were out partying in droves in the hotel. Unfortunately Paul and Waseem could not join the fun as there was work to do; instead they hit the road again to Tesco to gather some essentials for trial the next day.

It was already late by the time they returned to the hotel. They jumped into their respective beds and got up early at around 4am and directed themselves to the quay. The boat was a fishing one, sporting a crane of 500kgs lift capacity at the rear of it. They were welcomed by a small but experienced crew of researchers and the captain, loaded the experiment stuff and had a safety briefing by the captain of the boat.


Paul busy assembling the coupons and fine tuning the tying

The pair set off and as soon as they got familiar with the rocking motion of the waves set out to assemble the experiment. It involved the delicate task of tying the frames to the coupons and the buoys. A lot of rope cutting and cable ties tightening were needed but finally the task was complete. It was time to deploy the experiment. Moment of truth. The crane buzzed into life and the hook was hoisted down. Paul and Waseem retreated to the safety zone. There was the firm grip of the hook to the anchor and the operator manipulated the levers and soon the whole assembly was on the move. The anchor was released in the water first and seconds later, the whole assembly was sinking in the depth of the ocean. This was it, an experience to remember and cherish for a very long time. They cannot wait to go back for the full deployment but before then have to wait for a weather window.


Anchors going in the water Waseem posing

P.S. The trial assembly survived two storms and is still going strong.

Waseem Khodabux, Paul Causon
21/06/17
Offshore wind energy remains an untapped power resource in the United States of America considering the strong offshore wind power potential (of approx.. 4,150 GW according to NREL) along the US coasts, where major population centres are located. Due to slow wind speeds in regions with shallow waters located along the Gulf Coast and mid-Atlantic Coast, proven technology which is currently widely deployed in European shallow waters cannot be directly applied in the US. In contrary, US has significant potential in deep-water locations where floating offshore wind turbine structures are required.

Dr Todd Griffith from Sandia National Laboratories gave a prestige lecture on the 21st of April in Cranfield University providing an overview of the research projects currently taking place at Sandia National Laboratories addressing the unique conditions of the US offshore environment. Sandia is a US Federally Funded Research and Development Centre with the mission to deliver essential science and technology to address National Security challenges.


Figure 1 Snapshots from the Prestige Lecture given by Dr Todd Griffith from Sandia National Laboratories

Dr Griffith presented projects conducted by the Wind Energy Technologies Department of Sandia National Laboratories, covering:
  • Large-scale hurricane resilient wind turbine blade designs
  • Novel floating vertical axis wind turbines for deep-water siting
  • Offshore wind farm code development, and
  • Structural health monitoring & prognostics management systems.

Sandia has developed a series of detailed 100-meter blade reference models that are available to designers and researchers for design studies and cost analysis; while turbine models reaching 50 MW rated capacity using segmented ultralight morphing rotors based on bio-inspired load alignment (e.g. palm tree) have also been designed. The rotor’s load alignment reduces the required mass for blade stiffening, and makes the turbines more resistant to storms, while their segmented design allows the massive blades to be manufactured in segments which reduces the transportation and manufacturing costs.


Figure 2 Load alignment configuration. Source: Dr Todd Griffith’s presentation


Further research studies conducted at Sandia National Laboratories involve: Hi-resolution modeling of floating wind turbines, wherein a state of the art eddy simulation code has been formulated in order to simulate atmospheric turbulence with wind farms in both land-based and offshore environments; structural health and prognostics management with a focus on damage detection and analysis of effects of damage (state of health and remaining life), and floating offshore vertical-axis wind turbines, among others.



Figure 3 Results for Floating 13.2 MW Turbine. Source: Dr Todd Griffith’s presentation


Sandia has developed 6 public domain designs, covering a range of different areas: power performance models, structural models, economic models, anchor and mooring design, PTO design, O&M / Installation, permitting & environment.
Conclusively, this is an exciting time for marine renewables with significant growth prospects within the next decade. However, while there is the necessary technical know-how and proven technology is already deployed in European waters, as we move further from shore and as extreme scale wind turbines start to be deployed, conventional designs will no longer be applicable. Hence, innovative solutions focusing on reducing technology risks and cost of energy (COE) adjusted to location specific conditions need to be invented for different marine hydro-kinetic technologies.

More information on Sandia’s activities may be found here: http://energy.sandia.gov/energy/renewable-energy/wind-power/offshore-wind/

Author - Anastasia Ioannou