PhD research: David Brearley

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This block, cut from an MRI magnet, consists of an epoxy-infused, insulated copper wire (embedded with filaments of Nb-Ti) spool. The epoxy binds the wires to maintain the structure’s shape, and the copper is used as an electromechanical support for the filaments, which gain superconductive properties when cooled with liquid helium to 4K (-269oC).

The combination of high operational current  (500A, similar to 50 kettles) and a strong magnetic field result in large electromagnetic forces, equivalent to the maximum take-off weight of Boeing 747!

These forces have the potential to cause crack propagation in the epoxy, releasing energy that could significantly increase the local temperature of the wire, meaning it is no longer superconductive. If this happens, the stored current is released, resulting in a rapid chain reaction where the entire magnet undergoes a “quench”.

During the quench, the massive amount of stored electrical energy transforms into heat, causing rapid boil off of the surrounding liquid helium, which is very expensive and, if not vented properly, potentially dangerous to the patient receiving the MRI.

My project aims to get a better understanding of the composite material’s failure initiation, post manufacture, due to operational cryogenic exposure and mechanical loads. My next steps are to examine the combined shear-compression loading effects on the material under cryogenic conditions and use this to inform a model that can predict quench-initiating crack propagation loads.

~ David Brearley, PhD, Aerospace Engineering

Success Through Alignment

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A test idea was developed into a confirmed proof-of-concept with experimental results in 3 months. We co-created a quick testing method for recycled carbon fibre material, reducing test time from hours to minutes.

Lineat Composites: Lourens Blok, Gary Owen

University of Bristol: Axel Wowogno, Robin Hartley, Benoit Welch, James Kratz

Background

Lineat is a BCI spin-out creating a new recycled carbon fibre material by re-aligning chopped waste fibres into highly aligned fibre tapes that mimic the architecture of virgin continuous fibre materials. The process is well suited to deliver carbon fibre materials circularity needed to meet Net Zero. An Accelerated Knowledge Transfer project was awarded by Innovate UK to evaluate what can be achieved through academic/business collaborations.

Challenge

Short aligned fibre materials can reach similar performance as continuous fibre materials, but it is highly dependent on the level of fibre alignment which can be more variable than long fibre materials. As a consequence, variable fibre orientation may arise leading to reduced volume fraction, leading to undesirable properties. A relatively high compaction force may mitigate some of these issues, but can also be an indicator of alignment quality. In this project, Lineat and Bristol worked together to evaluate if a quick and easy compaction test can reduce cumbersome quality control processes from hours to minutes.

Outcome

Lineat made a selection of recycled short carbon fibre tapes to varying degrees of alignment. The materials were prepared into samples and tested at the University of Bristol to identify the best set-up for a potential quality assurance process. The different test methods were assessed for ease of implementation. The methods were able to successfully discern poorly aligned materials straight away, however, medium and well aligned materials initially seemed similar and required development of an alignment indicator (see Figure 1). Mechanical tests and microstructure observations were used to confirm the alignment results.

 

The project performed three main activities with over 100 experimental tests performed over three months:

1) Develop a compaction test method – A compaction test method was developed and tested at different conditions to indicate alignment.

2) Perform compaction and sample testing –  Once the method was set, the compaction response was measured for different material alignment levels.

3) Correlate properties with fibre alignment – Fibre microstructure and mechanical properties were measured to demonstrate statistical relevance as quality indicator.

Impact

An innovative quality control test to quickly and accurately indicate the level of fibre alignment in recycled short carbon fibre tapes made by Lineat. Initial settings for test sample preparation, testing machine configuration, data analysis instructions, and representative plots for comparison were developed for the business.

Lineat has started an internal project to implement the test method into their production environment and use the testing method to improve manufacturing processes. The outcome is expected to have a significant influence on the uptake of recycled carbon fibre materials.

BCI Alumni Q&A: Mike Elkington

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Why did you choose the Bristol Composites Institute for your studies?
It offered a unique ability to spend 6 months getting to know the subject area and building a relationship with a supervisor before committing to a full-length PhD study. I was the second year of the full BCI (then ACCIS) wing being open, and the whole department felt like it had an upward trajectory and expanding resources to get interesting work done.

What research area did you specialise in whilst you were here?
‘Automated layup or prepreg components’. I studied the manual layup process in detail, broke it down into achievable sub-tasks and then replicated them using a 6-axis robot. If you’re interested, a video can be found here.

After leaving the BCI where did you go?
After my PhD I worked as a post doc for 5 years working on numerous robotic layup variations, including Human-Robotic collaborations. I also worked on developing my teaching capabilities, delivering regular lecturers and seminars. I then moved on to the National Composites Centre, along with lots of other BCI Alumni.

What are you currently working on and what do your future plans look like?
I’m currently working on a large European project aiming to reduce defects in Wind Turbine manufacturing. This is done by sensorising the infusion and using machine learning to control to infusion, for more information see www.Turboproject.eu. Alongside this I work on numerous aerospace and defence projects, covering prepreg and Infusion and RTM manufacturing techniques. I’m hoping to pick up more lower TRL level work, and I have recently had interest into further developing my PhD work into a viable industrial process.

How did the BCI prepare you for work outside of academia?
The technical skills and knowledge I developed at the BCI have been very useful, I can drop into most projects and have a good understanding of the technology, ranging from Infusion simulations to Robot programming. Some PhD schemes can be very focused on a single field, but being in the BCI surrounded by other work and frequent dissemination activities gave me a much broader understanding of composites. The BCI has always helped develop the presentation techniques of students and these skills have been very useful in my current role, in meetings, workshops and customer presentations.

BCI Alumni Q&A: Priyanka Priyadarshini

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As part of our Alumni Series, we speak to Priyanka Priyadarshini, Composite Test Engineer at Magma Global, about life after the BCI…

Why did you choose the Bristol Composites Institute for your studies?
Bristol was ranked among the top 100 universities in the world, which is why I was interested in studying there. The city’s diverse cultural acceptance and the atmosphere of Bristol itself impressed me more than any other place. The collaboration between BCI and Rolls-Royce sparked my curiosity, as it offered insight into composite research as advanced subjects. The ongoing improvements, research initiatives, renowned professional guidance, and frequent seminars on composites were all incredibly fascinating and thoughtful. I couldn’t find any other institution that matched BCI in terms of its research opportunities. I knew that this was the right place for me to begin my journey at Bristol.

What research area did you specialise in whilst you were here?
I worked on gaining a deeper understanding of natural fibres and conducted research on how impactful they can be when combined with synthetic materials. I examined few hybrid materials consisting of both flax and carbon fibres to analyse their strength and stiffness. Additionally, I also performed a Life Cycle Assessment to evaluate the amount of carbon dioxide they would generate once they reach the end of their life cycle.

After leaving the BCI where did you go?
Immediately after graduation, I joined a firm in Bristol as a Quality Inspector to address some financial challenges and worked there for few months. Afterward, I shifted my focus and joined Magma Global Private Limited, producer of m-pipe® for oil and gas company, as a Composite Test Engineer.

What are you currently working on and what do your future plans look like?
Our pipes are manufactured using carbon fibre and advanced oilfield polymers to meet the demanding requirements for subsea applications. As a Composite Test Engineer, I test these pipes according to company standards and analyse the data to observe different behaviours and any variances from standard test specifications. Looking ahead, my goal is to become a Chartered Engineer and make meaningful contributions to innovation in understanding carbon-polymer behaviour more deeply.

How did the BCI prepare you for work outside of academia?
Through the BCI programme, I had the opportunity to connect with a variety of companies over a six-month period, gaining valuable insights into their innovative approaches and exploring how I could contribute effectively. During this time, I gained hands-on experience with the equipment provided by BCI, which enabled me to operate machinery and perform different tests independently. This experience proved valuable in enhancing my understanding of operations within the composite industry, while broadening my perspective on potential growth opportunities within my field of interest.

Bristol Scientists conduct composite experiments beyond the Kármán line, or Ad Astra and all that jazz…

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Today, Tuesday 5 November 2024, the John F. Kennedy Space Center in Florida saw the dramatic launch of a Falcon 9 rocket by SpaceX to the International Space Station (ISS) orbiting at an average altitude of 408 kilometres in low Earth orbit (LEO). At a cost of $52M, the SpX-31 commercial resupply mission is carrying a Cargo Dragon CRS-2 space craft, which will dock in the forward Harmony port of the ISS and deliver its payload, containing essential supplies for the astronauts and a number of experiments designed for operation in LEO.

The dramatic launch of a Falcon 9 reusable, two-stage rocket, designed and manufactured by SpaceX. The image shown is the CRS-30 commercial resupply service mission to the ISS, the Falcon 9 carried a host of supplies and integral equipment including science investigations and crew supplies. Image credit: courtesy of SpaceX, original image Ben Cooper.

 

Mission Patch of the SpX-31 commercial resupply mission to the ISS, representing a Cargo Dragon spacecraft, serial number C208, which is making its fifth flight on this mission. Image credit: NASA

 

The successful launch marks a significant milestone for the multidisciplinary research team led by Professor Ian Hamerton of the Bristol Composites Institute (BCI). It represents the culmination of over four years of intensive research to develop new materials for the space environment and the result of significant new collaborations between the BCI, the European Space Agency (ESA), the UK Space Agency (UKSA), the National Composites Centre (NCC), Oxford Space Systems, and Rolls-Royce plc.

In the late summer of 2020, ESA launched an international competition (AO-2020-EMA) to identify participants for a £3.5M Euro Materials Ageing mission to study the behaviour of new materials in space and BCI was one of 15 teams selected after a rigorous multi-stage peer review process. The Euro Material Ageing experimental platform (SESAME – Scientific Exploration Subsurface Access Mechanism for Europa), developed by the French Space Agency (CNES) and manufactured by COMAT, will be deployed by a robotic arm on the Bartolomeo platform designed and operated by Airbus (https://www.airbus.com/en/newsroom/press-releases/2021-01-esa-books-two-payload-missions-on-airbus-bartolomeo-platform), which is located on the front (the RAM face) of the ISS.

 

This mosaic depicts the International Space Station (ISS) pictured from the SpaceX Crew Dragon Endeavour during a fly around of the orbiting lab that took place following its undocking from the Harmony module’s space-facing port on Nov. 8, 2021. The red ringed area indicates the likely location of the SESAME module on the Bartolomeo platform. Original image credit NASA (jsc2021e064215_alt (Dec. 8, 2021), photograph taken by ESA astronaut Thomas Pesquet)

 

 

Preparation of one of the Euro Material Ageing’s experiments for launch. The COMAT designed SESAME module holds specimens selected and tested by ESA, supplied by 15 international research teams with the UoB samples shown in the inset image. Original image credit: Centre National d’Etudes Spatiales/COMAT.

 

Four new polymers, designed by Prof. Hamerton and developed within PhD projects in BCI, were prepared as carbon fibre reinforced composites and submitted to the ESA team at the European Space Research and Technology Centre (ESTEC) based in Noordwijk in the Netherlands for pre-flight tests. During these tests, the laminate samples were exposed to high vacuum and temperature cycling (to determine whether they would lose excessive mass in LEO) and to high intensity ultraviolet radiation (to find out whether they would discolour significantly, thus changing their thermal properties); fortunately, the specimens passed the pre-flight tests with flying colours.

The preparation of the composites on a much larger scale (typical panels measured 500 mm x 500 mm x 3 mm), to enable detailed mechanical tests to be performed in BCI, was funded by the UKSA (in the form of two grants ST/W000377/1 and ST/W004992/1) and undertaken by the team at the NCC. Although BCI has its own in-house autoclave and workshop facilities, when the pressure was on to deliver the precisely engineered composites to ETSEC with a short deadline the NCC was the natural choice of manufacturing partner. The development of the polymer matrices, the results of their exposure to simulated LEO conditions, and the mechanical testing have been published in a series of research publications (see further reading).

The novel composites will be in for a rough ride: the ISS will orbit the Earth some 6,000 times in a year at speeds of 17,000 miles per hour and the space environment is fierce, the temperatures could range from -150ºC to +120ºC, causing small cracks to form, and the samples will be exposed to high vacuum, severe electromagnetic radiation, and the ravaging effects of atomic oxygen which literally erodes the surface of materials that are exposed to it. It’s also crowded as there are already more than 8.8 kilotonnes of human-deposited mass in orbit. More than 30,000 space debris objects are larger than 10 cm, around 900,000 objects larger than 1 cm, 128 million pieces of debris around 1 mm, and 2 trillion pieces of debris around 0.1 mm.  As a result, the specimens might also encounter high-velocity dust, micro-meteoroids, and engineering debris. To counter this, another line of current PhD research in BCI is developing variants of the same polymers that are potentially capable of healing themselves, with the aim of improving their ability to resist microcracking.

During the EMA campaign, real-time mass loss data will be collected to assess how the materials perform, and these will be used to validate analytical models currently being developed within one of the PhD projects to predict the lifetime of composites deployed in LEO. Prof. Kate Robson Brown, who leads the development of these computational models, has recently moved from the University of Bristol to take up a new position Vice-President for Research, Innovation and Impact in the School of Mechanical and Materials Engineering, University College Dublin, extending the collaboration still further.

She says “After nearly five years of research to develop novel composite materials for space applications it is very exciting to see our experiment launch to the International Space Station. I am proud to be part of this mission, and to be working with the mulltidisciplinary and multisector research team to deliver integrated real world and digital testing for innovative materials which will help to drive growth in the new space economy. This mission also demonstrates how space research funding creates career changing opportunities for early career researchers and PhD students in a sector of huge value to both Ireland and the UK.”

After a year or more of exposure in space, the samples will be returned to Earth, allowing scientists at BCI and in the other teams to thoroughly investigate the samples and fully understand the effects of the space environment on the materials, offering some validation of the newly-developed predictive models. However, the samples that have started their arduous journey to the ISS are not the end of the story. Virgil wrote, in his Aeneid, “sic itur ad astra”, thus one journeys to the stars, and the team is focused on the developing materials for the next generation of space travel. The BCI team is conducting research in another ESA programme (AO-2022-IBPER) to investigate the biological and physical effects of radiation on the composites, and team members have recently returned from a research visit to The GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany where the effects of long term galactic cosmic radiation (GCR) exposure can be simulated here on Earth. In another affiliated PhD project, polymer variants are being developed for their shielding characteristics towards GCR, inevitable in the longer space missions that are part of the plans of many space agencies, but potentially deadly to the future astronauts.

Research conducted on Earth under simulated exposure conditions is undoubtedly valuable but the opportunity to test the materials in the real proving ground of space is priceless and will help university scientists on the ground improve fibre-reinforced materials for next-generation space missions. The opportunity to participate in these high-profile ESA missions, with the generous support of the UKSA, has been an exciting dream come true for the academics and early career researchers in the team. By linking PhD programmes to the mission has offered the researchers at the very start of their careers the opportunity to be involved in cutting edge space research programmes.

The space materials team: L-R Gökhan Sancak, George Worden, Fabrizio Scarpa, Stuart Donovan-Holmes, Kate Robson Jones, Ali Kandemir, Ian Hamerton, Kyungil Kong, Mayra Yadira Rivera Lopez (members not pictured: Mark Schenk, Joseph Gargiuli, Yanjun He, James Thomas, Ragnar Birgisson, Lucas Lu, Galina Teshovska, Anton Stoger, Konstantina Kanari, Nick Hewlings, Alex Mathers).

 

The team gratefully acknowledges funding from the following bodies: ESA (AO-2020-EMA and AO-2022-IBPER), UKSA (ST/W000377/1, ST/W004992/1, ST/Z000343/1), the Engineering and Physical Sciences Research Council (EP/L016028/1 and EP/S021728/1), DSTL (DSTL0000020016) and Oxford Space Systems (in the form of a studentship).

 

The Teams

The Bristol Composites Institute (BCI) is one of seven Specialist Research Institutes of the University of Bristol and a world leader in composites research. Established in March 2017 in a dedicated £5.4M extension within the Faculty of Engineering, the BCI builds on the expertise and the 10-year track record of the Advanced Composites Collaboration for Innovation and Science (ACCIS) research group which preceded it. BCI has since grown to become the largest composites research group in the world; it boasts a world leading and cohesive core team of over 30 academics, 32 affiliated academic staff, 50 support staff, and over 150 researchers, and has world class experimental lab facilities enabling cutting edge research in advanced composite materials development, innovative manufacturing and design techniques, and composites testing. The BCI hosts the Rolls-Royce Composites UTC, the Wind Blade Research Hub, two EPSRC-funded Centres for Doctoral Training (CDT) in Composites, and the EPSRC Industrial Doctoral Centre in Composites Manufacture. Strong links exist between BCI and the National Composites Centre (NCC), which was opened in 2011 and is hosted by the University. The NCC is a not-for-profit research and training organisation which is an independent, open-access national centre translating world-renowned innovation into manufacturing excellence.

Space research and engineering is a well established at UCD, led by C-Space -Ireland’s leading centre for interdisciplinary collaborative space-related research, innovation and education. UCD has identified four key established and emerging trends as priorities; Foundational Space Research (addressing fundamental scientific mysteries of the universe, pushing the boundaries of pure knowledge and space exploration); Data-Driven Space Research and Innovation (applying AI, machine learning and data science to optimise space missions, accelerate scientific discovery and develop accessible platforms for EO programmes); Society, Ethics and Policy in Space (engaging with social sciences, business and law to address the societal, governance and legal implications of space exploration and commercialisation); Space Systems Engineering and Technology Development (advancing the design, development and deployments of space technologies including spacecraft, payloads and subsystems supporting space missions and the commercialisation of space).

 

Further Reading

Why Space? The Opportunity for Materials Science and Innovation, version 1.2.1, M. Lappa, I. Hamerton, P.C.E. Roberts, A. Kao, M. Domingos, H. Soorghali, P. Carvil (Eds.), STFC and UK Sat Apps, February 2024. (including Considerations for Material Development and Manufacturing in Space, Hamerton, I., Roberts, P. & Carvil, P. pp. 35-40).

Bristol researchers prepare composites for lift-off to space, Andrea Gaini, 8 July 2021, https://www.iom3.org/resource/on-course-sending-composites-into-space.html

University of Bristol, NCC develop novel composite materials to assess performance in space, G. Nehls, 7/7/2021, https://www.compositesworld.com/news/university-of-bristol-ncc-develop-novel-composite-materials-to-assess-performance-in-space

Effect of atomic oxygen exposure on polybenzoxazine/POSS nanocomposites for space applications, He, Y., Suliga, A., Brinkmeyer, AW., Schenk, M. & Hamerton, I., 2024, In: Composites Part A: Applied Science and Manufacturing. 177, 107898. https://doi.org/10.1016/j.compositesa.2023.107898

Physical and mechanical properties of nano-modified polybenzoxazine nanocomposite laminates: Pre-flight tests before exposure to low Earth orbit, Kong, K., Gargiuli, J. F., Kanari, K., Rivera Lopez, M. Y., Thomas, J., Worden, G., Lu, L., Cooper, S., Donovan-Holmes, S., Mathers, A., Hewlings, N., Suliga, A., Wessing, J., Vincent-Bonnieu, S., Robson Brown, K. & Hamerton, I., 20 Feb 2024, (E-pub ahead of print) In: Composites Part B: Engineering. 111311. https://doi.org/10.1016/j.compositesb.2024.111311

Development of cyanate ester-oligosiloxane copolymers for deployable satellite applications, Rivera Lopez, M. Y., Suliga, A., Scarpa, F. & Hamerton, I., 11 Dec 2023, (E-pub ahead of print) In: Polymer. https://doi.org/10.1016/j.polymer.2023.126573

Development of cycloaliphatic epoxy-POSS nanocomposite matrices with enhanced resistance to atomic oxygen, Rivera Lopez, M. Y., Lambas, J., Stacey, J. P., Gamage, S., Suliga, A., Viquerat, A., Scarpa, F. & Hamerton, I., 25 Mar 2020, In: Molecules. 25, 7. https://doi.org/10.3390/molecules25071483

Publication success for Aerospace Engineering graduate

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written by Prof. Ian Hamerton

I am delighted to report a publication success from one of our recent Aerospace Engineering graduates, Mr Ji Dong, who conducted his final year research project with me (and ably co-supervised by Dr Ali Kandemir) following a summer internship within BCI.

The mechanical performance of discontinuous fibre composites is heavily dependent on the quality of fibre alignment and the ability to gauge this parameter rapidly and reliably (and thus the potential properties of the resulting composite) is key to successful application of the technology, particularly in a production environment.

Ji’s study investigated the application of deep learning-based image segmentation using 2D optical imaging for the microstructural characterisation of composite materials with hybridised fibres, potentially offering a cost-effective and more rapid alternative to computed tomography/3Dimaging. Laminates were produced using the HiPerDiF method, combining discontinuous high modulus carbon and basalt fibres to reinforce a poly(L-lactic acid) (PLA) matrix. Ji found that the Generalised Dice Loss function significantly outperformed others, particularly when discriminating voids, achieving a 19% improvement in Dice Similarity Score on an unseen dataset for full image characterisation. Additionally, volume fraction, relative fibre and void ratios, and fibre alignment computed from the segmentation results closely matched his ground truth data.

Figure: Image of a cross section of hybrid composites containing discontinuous carbo and basalt fibres. The x-axis and y-axis units are expressed in numbers of pixels (a) Image in RGB (b) Greyscale (c) Greyscale image after filtering and CLAHE (d) Ground truth (e) Class segmentation results based on the traditional Multithresh method, where the Class4 and Class5 represent the noise being classified as a category rather than the desired region of interest (f) to (h) are the segmentation results obtained from U-Net model trained under CE, GDL and Comp1 respectively, where it can be seen that the degree of misclassification is significantly less compared to the multithresh method .

A manuscript produced from his research dissertation “Microstructural characterisation of fibre-hybrid polymer composites using U-Net on optical images” has just been accepted for publication in a forthcoming special issue of Composites Part A (Machine Learning and AI in Composite Science and Manufacturing), to be edited by Assist. Prof. Navid Zobeiry and Assoc. Prof. Marco Salviato (both of the University of Washington, Seattle).  The quality of the work is apparent when I note that the manuscript was received at the editorial office on 13th September, rigorously reviewed, revised (with additional work conducted by Ji) and returned by 20th October, and accepted on 30th October.

Ji is currently pursuing an MSc in Engineering Mathematics and is seeking to secure a PhD primary focus on opportunities within bioengineering/biomedical engineering and AI (sadly beyond my research interest areas). He is an exceptional researcher and I’m sure that this will be the first of many such papers in his career.

Opportunities in the EPSRC Centre in Doctoral Training (CDT) in Innovation for Sustainable Composites Engineering

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The University of Bristol is offering four projects for doctoral studies with a focus on the creation of sustainable and efficient solutions for the design of composite structures. The projects will be part of the new CDT launched in 2024 following on from five previous successful centres in Bristol Composites Institute (BCI) https://www.bristol.ac.uk/composites/cdtsustainablecompeng/.

The purpose of the CDT is to train future leaders to doctoral level with the skills and expertise to address the design, manufacture and assurance of composite products. Alongside conducting  your research project you will follow a taught programme that provides an in-depth knowledge of composite materials and their use with a focus on sustainability and the circular economy. You will follow a structured professional development programme, alongside the research, to prepare you for a future career in industry or academia.

We are seeking highly motivated and committed individuals with an eye on the future, who are interested in conducting stimulating and essential industrially relevant research and have a passion for finding sustainable solutions. There are many challenges in understanding the behaviour of composite materials and structures, so the projects seek to develop new manufacturing routes, design concepts, analysis procedures and development of new solutions.

Type of award: Engineering Doctorate/Doctor of Philosophy

Research focus areas: Mechanical Engineering, Civil Engineering, Aerospace Engineering, Design Engineering, Research group Bristol Composites Institute

Scholarship Details An enhanced stipend of £25,789 for 2024/25, a fee waiver and generous research financial support for the successful candidates.

Duration 4 years

Eligibility Home/International

Start Date January 2025

Project 1: Improved design and damage tolerance of lightweight composite sandwich structures – Supervised by Professor Ole Thomsen

The key design drivers for the adoption of sandwich structures include high specific stiffness and strength, damping, thermal insulation and excellent fatigue properties by adopting particular constituents and tailored geometric layouts. The PhD project will:

  • Devise a multi-scale modelling framework for the prediction of the load response and progressive damage and failure behaviour of CFRP sandwich structures.
  • Provide a high-fidelity experimental methodology combining imaging approaches applied to data-rich analysis of the load response and progressive damage and failure behaviour of CFRP sandwich structures.
  • Enable novel design concepts for damage tolerant CFRP sandwich structures.
  • Stimulate your interest in composites and mechanical design to unlock doors for the next-generation of analysis/design procedures and efficient lightweight engineering structures to facilitate Net-Zero sustainability goals.

Project 2: Novel flexible photonic based sensors for health monitoring of composite structures Supervised by Professor Janice Barton

A radical redesign of optical fibre architecture has enabled a new in-situ measurement paradigm that elicits quantitative assessment of through-thickness strains in laminated composite structures during manufacture and service. The novel sensor technology will inform composite design and manufacturing strategies to facilitate Net-Zero sustainability goals by reducing scrappage and extending operational lifetime. You will work closely with industry to:

  • Design procedures that enable the flexible photonic sensor to make multiple measurements quickly with real time reporting on the health of the structure.
  • Develop the new sensors for both manufacturing control and service life predictions of a composite structure.
  • Stimulate your interest in new, developmental sensing methods used as the basis for the creation of future sustainable composite products.

Project 3: Repeated impacts on composite aero-structures (sponsored by Rolls-Royce) Supervisor Professor Stephen Hallett

Aerospace composite components are subject to a multitude of seemingly minor impact threats, for example due to ice shedding or hailstones. Over a part’s lifetime, this can result in millions of such impacts. Whilst no single impact at this energy is sufficient to cause degradation, it is known that repeated loading can lead to fatigue of the material and ultimately failure. There is very limited research into repeated impacts, especially those occurring below the damage initiation threshold, hence you will address an unexplored gap in understanding. Working closely with project sponsor Rolls-Royce within our Composites University Technology Centre you will take a combined experimental and numerical approach to:

  • Investigate repeated loading under low velocity to establish the material’s damage threshold and establish the threshold of initiation and evolution of damage.
  • Provide numerical damage models based on the Bristol Composites Institute’s comprehensive experience to predict the onset and progression of damage, as well as to understand the mechanisms and drives for damage development.
  • Undertake higher strain rate testing, via the use of a drop weight impactor and gas gun to provide understanding of potential rate effects, ensuring the research is relevant for real-world impact loading scenarios.
  • Establish impact fatigue allowables for composite component design, to unlock more sustainable and efficient aircraft designs with reduced engine power requirements.

 

Project 4:

Application of Artificial Intelligence in Life Cycle Assessment of Composites Manufacturing  (sponsored by the National Composites Centre) Supervisor Dr Iryna Tretiak

Life Cycle Assessment (LCA) is a methodology increasingly used in industry for assessing the environmental impact associated with all life cycle stages of a product, process or service. Gathering comprehensive, accurate data for every stage of product life cycle can be challenging, meaning data can be incomplete thus impacting the reliability of LCA results. Moreover, identifying the best impact assessment is subjective and can affect the final result. For composite structures, these effects are further compounded by decisions made early in the design process such as: fibre and matrix selection, geometry and manufacturing processes. Artificial intelligence (AI)/Machine Learning (ML) could potentially overcome these challenges, enhancing the precision, efficiency, and depth of environmental impact assessments.

You will join a large cohort of CDT students sponsored by the National Composites Centre, which has been supporting Engineering Doctorate students for more than 10 years. Supported by this wealth of experience, you will develop AI tools capable of estimating the LCA impact of design decisions early on in the design process. The research will comprise:

  • Surveying existing LCA capabilities for composites to identify gaps in current tools and data.
  • Collect and homogenize primary data for composite manufacture from literature and in collaboration with OEMs. Design and implement a Universal Database Structure for LCA on composite materials.
  • Build an AI framework for design decisions support. Through the use of deep learning technologies, you will make system capable of automatic parametrization of structural geometries and materials, by making use of the widest range of primary LCA data.
  • Design, build and evaluate LCA-AI framework for a demonstrator structure.

 

Candidate Requirements

Applicants must hold/achieve a minimum a 2:1 MEng or merit at Masters level or equivalent in engineering, physics or chemistry. Applicants without a master’s qualification may be considered on an exceptional basis, provided they hold a first-class undergraduate degree. Please note, acceptance will also depend on evidence of readiness to pursue a research degree and performance at interview.

To apply please submit a personal statement, outlining your experience and why you are interested in PhD/EngD project, your CV and transcript of results to https://www.bristol.ac.uk/study/postgraduate/apply/. Please do not submit a project description; this is unnecessary as the project is already defined. Clearly state the project (s) you are interested in order of preference. For projects 1 to 3 select PhD in Advanced Composites and for Project 4 select EngD in Composites Manufacture. In all cases please enter Professor Janice Barton the Director of the CDT as the 2nd supervisor (janice.barton@bristol.ac.uk)

Closing date: 27th October 2024.

 

HyPower Bristol’s development of a 5kN bipropellant liquid rocket engine and supporting liquid feed system

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HyPower Bristol are a team of students from the BristolSEDS society, working on building and launching cutting edge student sounding rockets since 2020. Last year we entered the 2023 EUROC competition, which is held in annually in Ponte de Sor, Portugal. This Europe wide competition is hosted by the Portuguese Space Agency and brings the best rocketry teams from universities across the continent, including Delft, TUM and of course, University of Bristol. Our compact team managed to achieve 3rd place in the ‘Off the shelf’ solid motor category last year and have since built towards even greater engineering challenges for this year’s EUROC 2024 competition.

Following conversations with the Portuguese Space Agency last year, we have embarked on the ambitious development of a 5kN bipropellant liquid rocket engine and supporting liquid feed system. This engine will run on with isopropanol fuel and nitrous oxide oxidiser, exhausting the 19L of propellant tanks in under 6s.

To meet our goals of flying this liquid engine at the EUROC 24 competition, we have had to flight test many new aspects of our design throughout the year such as control electronics and software. To easily make these flight tests, we started the year by manufacturing a half size sized “sub scale” rocket which uses a hybrid metallic/ composite structure.

In this design, the lower carbon section is made up of removeable panels which bolt into an underlying metallic frame, facilitating quick access to the electronics under test. The carbon parts are made with a wet layup of Prime 37 and 600gsm triaxial carbon, and the glass parts used biaxial plane weave E-glass. The parts were laid on to aluminium tools and cured under vacuum. The laminates have not been optimised for mass and are quasi-isotropic, as the requirements of the test vehicle call for high reliability and spare thrust budget is available. A focus of the EUROC 2025 programme will be minimisation of mass through an optimised fully composite structure.

The fin section has been designed to be removeable which allows the testing of different fin configurations and adjusts the rocket’s mass distribution. For this part, individual fins were first laid up using 3d printed aerofoil moulds, before being aligned and bonded to a section of carbon tube. Further uni-directional carbon was then applied between the tips of adjacent fins to reinforce the bonded joints and suppress aeroelastic fin “flutter” which is a common failure mode for similar unstiffened fins. The structure has been flown twice this year and has proven very reliable: this was exemplified by a failed parachute deployment and subsequent drop from 250m which only required the replacement of a single fin. These launches have demonstrated the many systems including robust telemetry and our inflight deployed air brakes which will allow us to control to a specified altitude in Portugal.

The launches have also been key to developing our test procedures and checklists for the future flights. Depending on funding availability, we would like to conduct a final set of launches in September to trial additional functionality with our custom electronics.

Following our work on the test vehicle, we have begun manufacturing the full-size entry for Portugal. The airframe design will be similar to the subscale, with an internal metallic structure to mount valves and electronics, and a stressed carbon panel skin which prevents buckling but still allows quick access to the propulsion system. Our initial design held propellant in commercially available COPVs, however these were difficult to package and would cause the vehicle to be over 5m long. We have therefore developed an aluminium coaxial propellant tank, which minimises the vehicle length by using the entire cross section to store propellant and passes the inertial and aerodynamic flight loads through the tank wall. Despite the less efficient material, this tank option reduces the total mass by more than 5kg by reducing the vehicle length to 3.5m.

The composite manufacture has begun with experiments using low-cost foam tooling, this has been successful for the panel sections. The next step will be manufacture of tube sections, however the internal surface is more critical for these parts, and we will need to see if we can achieve an adequately flat finish for bonding to the metallic and polymer adapters. We recently received the 3d printed Inconel chamber, and the machined propellant tank components are nearly ready for test.

We have also had the opportunity to work with the AENGM0050 Design, Build, and Test unit this year to develop a highly efficient payload mounting structure. This design has been inspired by sea sponge skeletons found in nature and manufactured with prepreg carbon tape. The structure has been built by the students and successfully tested far in excess of the loads that will be experienced in flight. The structure will support our 1kg stack of 3 cube satellites during flight in Portugal.

Some members of the team have also recently built an entry to the UK high powered rocketry competition which took place in Scotland last year. For this we constructed a simple fibreglass airframe based on tape wrapped glass tubes. This rocket hit its target apogee of 2200m and set a new Bristol speed record of 1030km/h and then safely returned on computer deployed parachutes, winning us the UK title.

Our next steps for this design cycle are to pressure test the propellant tank and perform an integrated hot-fire which will prove the engine, propellant loading system, and remote control system. The team would like to say an enormous thank you to the BCI community for supporting us in our rocket journey so far, and we hope you are as excited as us to see what we manage in Portugal!

If you have any thoughts about our design or perhaps can think of a way to support us, please feel free to reach out to lk2093@bristol.ac.uk and hypowerbristol@gmail.com

Follow our journey here: LinkedIn or Instagram and https://euroc.pt/  to learn more about the EUROC competition.

Lillian, Jacob, and the HyPower Bristol Team.

 

BCI Showcases Research at ECCM21

Posted on by jo.rich

In previous years, the European Conference on Composite Materials has been at the forefront of showcasing innovation and key research developments into composites: ECCM21 (July 2024) was no different, with over 25 presenters from Bristol Composites Institute alone! A full list of presentation titles and abstracts can be found here on our blog.

Hosted in the city of Nantes, France, an impressive variety of topics ranging from structural performance and material fundamentals all the way up to large-scale industrial process and simulation were on offer. Comprising of a mix of introductory tutorials, posters and parallel presentation sessions, the conference delivered on providing insight and highlighted trends towards more sustainable use of composites – an ever-growing topic of importance in today’s world.

Of particular note in this conference was the focus on machine learning and data-driven approaches to composites: for example, to advance current simulation and process modelling of liquid composite moulding, to in-line monitoring during deposition using novel sensors and inspection techniques. Data is fast-becoming an increasingly valuable asset used by manufacturers and customers, particularly in the aerospace sector, to make more informed decision-making about how to best navigate the challenges in a post-pandemic global supply chain.

However, the ways in which data is processed is just as important, but can be expectedly variable given the diversity and spread of the composites community. Take the microstructure of a composite laminate, typically, a micrograph of the laminate cross-section is captured and the fibre volume fraction quantified using image-analysis.
The challenge? Methods X, Y & Z used to analyse the same image all return different values. The first step towards a solution? An image-based benchmark to establish guidelines for improving the consistency between researchers and therefore, increasing confidence in their analyses and maturation for industrial applications.

It is clear that composites has a far-reaching impact on many sectors and research themes. To capitalise on these innovations, the continued active dialogue between industrial and academic partners is of critical importance.

written by Umeir Khan, PhD Aerospace Engineering.

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NextCOMP enjoyed a very successful set of 5 special sessions at ECCM21 which took place across two days on the subject of “Understanding and Improving longitudinal Compressive strength”.  With a keynote from Prof Michael Wisnom a highlight, the sessions which took place in a large auditorium at le Cite Congres, Nantes were very well attended and sparked considerable interest, conversations and discussions in and outside the sessions.  Speaker contributions from academia and industry meant the sessions successfully showcased the excellent research into composite compression being undertaken around the world. Once again, this focussed session has facilitated the creation of new connections and collaborations to extend the NextCOMP Programme’s research in the future.

The NextCOMP team from BCI and Imperial College enjoyed a very productive week at the conference, and were pleased to attend numerous fascinating talks on a range of different subjects including the latest composites research.  After-hours highlights in the lovely city of Nantes included many crepes, visits to fascinating historical buildings and some unique street and creative arts spaces – certain members of the NextCOMP team might have even been spotted watching some entertaining Euro football matches (with colleagues and friends from around the world).  We thank the organisers for a fantastic conference, which we all thoroughly enjoyed!

written by Jo Gildersleve, NextCOMP Project Manager.

Festival of Enterprise returns for third year

Posted on by jo.rich

Our Early Career Enterprise Fellows, James Uzzell and James Griffith were fine ambassadors for BCI at the 2024 Festival of Enterprise. Both delivered excellent presentations with aplomb to an expert panel of judges and answered questions on their work.

Judging was extremely tight and both were highly commended; James Griffith being a narrow second in the panel judgement but won the audience vote and prize for the most engaging presentation titled “Developing Composite Solutions for Cryogenic Liquid Hydrogen Fuel Storage on Zero Carbon Emission Aviation (Developing Materials for Net-Zero Flight).”

James Uzzell’s presentation was focused on dynamic induction coils for energy efficient composites manufacturing.

The event, which was held in the Bill Brown Design Suite within the Faculty of Engineering on Thursday 20 June, focused on showcasing the range of research and enterprise activities, the people that have been supported and the impact of the funding and training provided by the University Enterprise Fellowships (UEFs) and Early Career Enterprise Fellowships (ECEFs).

The event featured presentations by the 23/24 Cohort of UEFs, and a series of PechaKucha style presentations by our ECEFs with an expert panel of judges who awarded the prize for best presentation with regards to project outcome & impact, in addition to an audience vote and prize for the most engaging presentation on the day.