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• Durability of Fibre Reinforced Polymer (FRP) rods in low carbon concrete
• Developing in orbit manufacturing methods for sustainable composites for space applications
• Biobased auxetic foams: an assessment of manufacturing and multifunctional properties
• An assessment framework for the sustainable use of UK timber
• WrapToR hierarchical space frames made from natural material composites
• Predicting the performance of sustainable composite materials in a range of manufacturing techniques
• How to relate compressive strengths of multi-directional laminates to fundamental unidirectional material strength?
• Dual mode shielding against space radiation using superconductive enhanced composites [AEGIS - Advanced Exploration Guard In Space]
• Novel approaches for the synthesis and applications of inorganic functional materials
• Hot/wet properties of high temperature composites

Durability of Fibre Reinforced Polymer (FRP) rods in low carbon concrete

Student: Asaad Biqai
Supervisors: Eleni Toumpanaki, Ian Hamerton, Manjola Caro

Fiber-Reinforced Polymer (FRP) bars have emerged as a promising alternative to conventional steel reinforcement in the construction industry due to their superior durability performance. FRP bars exhibit non-corrosive properties, effectively addressing the primary issue of steel corrosion-induced degradation in concrete structures. Steel corrosion can lead to prohibitive repair costs in civil infrastructure and brittle catastrophic failures (e.g., the collapse of Morandi bridge). Despite the corrosion-free nature of FRP rods, their matrix/resin component plasticises when exposed to humid conditions (e.g., at a concrete crack location) and degrades due to chemical attack. This is more critical for matrix dominated properties of concrete structures reinforced with FRP bars such as the bond, shear and transverse compressive strength of FRPs. This project focuses on a comprehensive examination of the long-term performance of Glass Fiber Reinforced Polymer (GFRP) and Basalt Fiber Reinforced Polymer (BFRP) bars under various environmental conditions by simulating aggressive environmental conditions, including elevated temperatures, saline, and alkaline exposures, to evaluate the performance of GFRP and BFRP bars.

The project aims to create a test protocol that correlates FRP durability performance under accelerated ageing conditions and short-term exposures with actual on-site conditions. Key variables of interest are resin dominated properties in of FRPs and effect of stress conditions. This test protocol will shed light on the reliability of commonly applied accelerated ageing tests adopted in lab conditions. The test protocol is adopted for both resin samples and FRP bars to obtain an in-depth understanding of how the individual constituents, fiber, matrix perform but also the FRP system performs accounting also for fiber-matrix interfaces. The potential incorporation of FRP bars under applied stresses adds a crucial dimension by examining their degradation properties when subjected to load-bearing conditions while exposed to aggressive environments, closely mimicking real-world applications.

FRP bars will be examined after being exposed to normal and accelerated conditions to be tested to measure their interlaminar and transverse shear strength. Non-exposed and pre-exposed FRP bars will be cast in concrete beams and blocks to measure the effect of exposure degradation on the bond and flexural performance of FRP bars in concrete structures. Resin samples will be cast, exposed, and tested separately to see the effect of direct exposure to pure resin samples after being tested in tension and shear. The type of exposure that will be used to understand the acceleration effect of the used protocol will be by comparing the degradation effect of directly exposed FRP samples in an alkaline mixture that replicates the pH and chemistry of concrete but at elevated temperatures to increase the diffusion to the composite material.

The outcomes of this project offer wide-ranging benefits to the construction industry and sustainability endeavors:

• Enhanced Infrastructure Durability: The development of FRP bars with improved long-term performance can extend the lifespan of concrete structures, resulting in reduced maintenance costs and enhanced sustainability.
• Advancing Net-Zero Construction: The utilization of low carbon concrete reinforced with FRP bars aligns seamlessly with the UK's net-zero emissions targets, making this research directly relevant to sustainability goals.
• Industry-Wide Adoption: The newly established acceleration protocol can be readily adopted across the construction industry to assess the durability of FRP bars, ensuring the reliability and safety of construction projects.

This project delves into the promising realm of Fiber-Reinforced Polymer (FRP) bars as a durable alternative to traditional steel reinforcement in construction while working towards more sustainable and durable approaches.

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Developing in orbit manufacturing methods for sustainable composites for space applications

Student: Ragnar Birgisson
Supervisors: Ian Hamerton, Kate Robson Brown, Ben Woods, Tom Scott, Ali Kandemir

Sustainability is becoming an increasing concern for the space industry as it grows. However, the strict performance requirements of the space application arising from mass and environmental constraints pose a significant challenge. Current spacecraft are made using non-recyclable materials and are either demised or written off at their end-of-life. This solution has been satisfactory for earth-orbiting missions; however, in-situ use/reuse of existing material may become obligatory for long-duration or indefinite missions.

This project aims to develop and investigate an in-orbit manufacturing method as a potential alternative to the current paradigm. A successful method could unlock the ability to create large, efficient structures without the penalties associated with the launch and manufacture of virgin material. While the scope of this PhD is primarily focused on space applications, such a method could also have significant implications for the terrestrial sustainability of composites, which are currently widely used in the aerospace and wind energy sectors.

The proposed concept combines the WrapToR manufacturing method's structural efficiency with discontinuous fibre composite's recyclability and performance enabled by the HiPerDiF alignment process. To date, no group has demonstrated a system simultaneously capable of comparable structural efficiency and recyclability.

To develop this concept, the project aims to tackle the following challenges:

• Identify and develop a discontinuous fibre thermoplastic composite suitable for space application and manufacturing.
• Develop a method capable of consolidating aligned HiPerDiF tapes and thermoplastic into a usable filament feedstock.
• Modify the WrapToR process to be compatible with a thermoplastic input material.

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Biobased auxetic foams: an assessment of manufacturing and multifunctional properties

Student: Jacopo Lavazza
Supervisors: Fabrizio Scarpa, Jemma Rowlandson, Charles de Kergariou, Qicheng Zhang, Wuge Briscoe

Auxetics are a class of mechanical metamaterials exhibiting a negative Poisson's ratio; that is, they expand laterally when extended longitudinally. Foams with auxetic characteristics also possess other desirable features in terms of indentation resistance to shear, energy absorption under cyclic quasi-static and dynamic loading, resistance to low kinetic energy impact, the enhanced dynamic modulus under relative humidity conditions, and tailorable shape memory properties. Over the years, multiple manufacturing processes have been developed to transform conventional foams into auxetics, ranging from thermo-mechanical (involving volumetric compression, annealing, and cooling) to chemical treatments (exploiting acetone and carbon dioxide to soften foam cell walls). No artificial auxetic foam metamaterial has, however, so far been knowingly produced.

Recent developments in bio-based polyurethanes (and related foams) make producing bio-based negative Poisson’s ratio foam materials a distinct possibility. Vegetable oil-based polyols (such as castor oil and soybean oil) have been recently used in different blends to produce biobased open- and closed-cell foams via free-rising both at the laboratory scale and commercially, showing improved compression and thermal properties compared to fossil-based counterparts. An auxetic foam made of bio-based substrates would further increase the appeal of using this class of metamaterials in a wide range of applications because of the enhanced life cycle properties and global warming power reduction compared to their fossil counterparts. Moreover, auxetic biobased foams would also be among the first mechanical metamaterial products designed to be sustainable and eco-friendly from the onset. Potential applications of such materials range from the aerospace industry, where enhanced impact resistance and lightweight would contribute to improved efficiency, to sports equipment in running shoes, helmets, and padding, which would benefit from the unique properties of this class of materials.

In this context, the objectives of this project are:

• Characterise available castor and soy oil-based PU foams from the chemical, thermal, and morphological aspects, combined with mechanical (quasi-static, dynamic, and viscoelastic), acoustic and vibration testing.
• Manufacture biobased auxetic open- and closed-cell metamaterial foams through different conversion routes.
• Assess the viability of the auxetic foams obtained through the different processes by investigating the morphology and the mechanical, acoustic and vibration responses following a Design of Experiment procedure.
• Adapt existing constitutive models available for foams' mechanics, vibration, and acoustics to describe the corresponding properties of these new classes of biobased metamaterials.

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An assessment framework for the sustainable use of UK timber

Student: Matthew Leeder
Supervisors: Neha Chandarana, Eleni Toumpanaki, James Norman, Steve Eichhorn

Timber is an attractive material choice for minimising the environmental impact of engineering projects, as it commonly has a lower embodied energy than its synthetic counterparts and it can remove and store carbon from the atmosphere. Timber is also renewable, however, it takes decades for trees to mature, so it is vital that forests are managed sustainably. To combat deforestation, global forest certification schemes ensure timber is produced from sustainably managed forests. It is therefore good practice for certified timber to be used by engineers. Furthermore, transportation can account for the majority of the embodied carbon of procured timber [1], so timber should also be sourced from local forests, to minimise environmental impacts. In a UK context, this presents a problem; the UK is the second highest net importer of timber in the world, due to its high timber demand and low domestic timber stock, all while the UK government is below its tree planting target [2]. Thus increased use of domestic timber could become unsustainable for UK forests. To complicate matters further, UK forests are changing; forest managers are transitioning away from monoculture plantations to more diverse woodlands that offer greater resilience to disease, pests, and climate change [2]. A sustainable use of UK timber must consider the limitations to domestic timber supply, through using timber both more efficiently and from a diverse range of species. However, this consideration is currently missing in the environmental assessments of timber found in the open literature.

Currently, the most common method to quantify the environmental impact of timber use is a life cycle assessment (LCA). However, commonly used LCA methods often omit key environmental impacts relating to forest land use and land use change [3]. LCA methods are being improved in the literature, which is providing greater insight into the environmental impacts of different forestry methods. However, these advanced LCA methods require compiling and improving before they can be used for a holistic assessment of an engineering project.

This project aims to produce a framework that allows for a holistic assessment of the use of UK timber in engineering projects, taking into account timber availability and supply chains as well as forestry land use and land use change. Life cycle costing and social LCA methodologies will also be included to include all three pillars of sustainability. The framework will be tested and validated using engineering case studies that use UK timber and range in complexity. The sourcing and design decisions made in each case study will be compared against a business-as-usual baseline scenario and a best-case scenario. This will allow for an assessment of the decisions made, to provide guidance, to the industry, on the future sustainable use of UK timber.

References

[1] “Buildings infrastructure priority actions for sustainability: Embodied carbon, timber,” ARUP, 2023.

[2] “Seeing the wood for the trees: The contribution of the forestry and timber sectors to biodiversity and net zero goals,” House of Commons Environmental Audit Committee, 2023.

[3] C. E. Andersen, et al., “Whole Life Carbon Impact of: 45 Timber Buildings,” Department of the Built Environment, Aalborg University, 2023

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WrapToR hierarchical space frames made from natural material composites

Student: Matthew Lillywhite
Supervisors: Ben Woods, Terence Macquart, Eric Kim

Trusses and space frames are some of the most efficient structural configurations developed to date. They achieve very high levels of performance through taking advantage of highly non-linear structural scaling laws by putting small amounts of material into localised members which are spaced far away from each other, allowing them to balance large forces and bending moments with minimal stress. Such structures are typically made from metals, which provide very good performance, but require large amounts of energy and resources to extract, smelt, and form. If such structures could instead be made from natural materials then their environmental impact could be significantly lowered and they could be adopted to a much wider range of applications. However, natural materials tend to have lower mechanical performance than metallic or traditional composite solutions. One potential way of mitigating the lower mechanical properties is to further exploit geometry by creating truss structures made from members which are themselves trusses. These Hierarchical Space Frames have been shown to be very promising in previous initial work with carbon fibre composite materials, and applying them to natural materials is made tenable through adoption of a patented truss beam manufacturing method being developed at Bristol, the Wrapped Tow Reinforced (WrapToR) truss manufacturing approach.

WrapToR trusses are made by using a simple adaptation of filament winding that wraps pre-made longitudinal members in a wetted composite tow to produce a rigid web of shear members when cured. These truss beams can then be made into Hierarchical Space Frames by assembling them with joint structures. This, alongside the innate hierarchical makeup of natural materials, would create a synergistic order of hierarchy from the global structure down to the material level.

WrapToR trusses and spaceframes made from natural materials are currently a promising but unexplored area of research, and practical, cost effective methods for joining WrapToR beams need to be developed. This work aims to develop the WrapToR method to devise a sustainable and low cost process for producing trusses and spaceframes from natural materials. To fulfil this aim the following objectives are set:

• Develop the WrapToR method to maximise structural performance of natural material truss structures, aiming to account for and exploit the unique features of natural materials.
• Experimental testing of natural material WrapToR trusses to characterise unique behaviour that is produced as a result of natural materials being used, that may differ from previously tested WrapToR trusses. Determining key relationships between structural performance, structural failure, material properties and truss geometry. Then using computational modelling and optimisation to design both individual trusses and Hierarchical Space Frames.
• Investigate relevant, existing contemporary and traditional methods for joining trusses and beams in order to develop a practical and cost-effective process for joining individual WrapToR trusses into hierarchical space frames.

These objectives will culminate with the manufacture of a full-scale natural material WrapToR Hierarchical Space Frame demonstrator for a relevant, real world application that can be tested under realistic loading conditions.

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Predicting the performance of sustainable composite materials in a range of manufacturing techniques

Student: William Mahoney
Supervisors: Karthik Ram Ramakrishnan, Neha Chandarana, Ian Hamerton

Recycled carbon fibre (rCF) composites are a valuable solution for industries such as aerospace to move towards a more closed-loop manufacturing model. Reclaiming fibres from manufacturing waste or end-of-life (EoL) components increases the material efficiency of composite materials and decreases their environmental impact of subsequent laminates due to their lower embodied energies from cradle to gate. Recyclates are also cheaper to manufacture than their virgin counterparts. RCF does have its own drawbacks. Depending on the recycling process used, the fibre's modulus, strength and surface energy can be diminished. In addition to this, the majority of economically viable recycling processes chop the fibre into lengths typically between 3-25mm. The result of this is that rCF materials are often downcycled into components that do not require the same load-bearing capabilities as virgin carbon fibre (vCF) components. This is because most recycled materials are in the form of randomly oriented discontinuous fibre mats and therefore do not possess the anisotropic mechanical properties or high fibre volume fractions required for more structural applications. This is not the best use of this valuable material. This is where fibre realignment techniques, such as High-Performance Discontinuous Fibre (HiPerDiF), are closing the discrepancy between vCF and rCF composite fabrics by transforming waste fibres between the lengths of 1 and 12mm into realigned tapes. Laminates made from these tapes have been manufactured using a range of methods such as autoclave, hot press and 3D printing, yet there has not yet been a characterisation of the ability to manufacture these aligned discontinuous materials using liquid composite moulding (LcM) techniques.

This PhD will aim to characterise the ability to manufacture aligned discontinuous fabrics using a selected range of LcM techniques for structural aerospace components. In particular, there is interest in whether the discontinuous aligned fabrics will be displaced by the resin front, known as fibre washout. The degree of alignment of the laminates' fibres, fibre overlap, and fibre volume fraction will be measured and compared to the mechanical properties. The mechanical characterisation methods used will include a range of quasi-static, high-rate and hot/wet tests to understand the full scope of both the simple static response and durability of these laminates. After both proof of concept and bench scale specimens have been created, the materials will then be applied to a demonstrator case study. Mechanical testing of this component will then take place as a way of comparing the current materials and manufacturing methods. A finite element analysis (FEA) modelled will be created to validate the load distribution on the materials compared with the structure. Finally, a life cycle assessment (LCA) can be made to show the impact of using reclaimed materials instead of virgin. This will help to strengthen the case for using recyclates in more challenging structural applications.

This project is supported by GKN Aerospace.

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How to relate compressive strengths of multi-directional laminates to fundamental unidirectional material strength?

Student: Joe Rifai
Supervisors: Michael Wisnom, Giuliano Allegri, Xun Wu, Laura Pickard

Over recent years, fibre-reinforced polymers (FRP) have demonstrated excellent in-plane tensile properties and are used in aerospace, automotive, and energy applications due to their significant weight reduction. However, in-plane compressive properties are 40% lower on average than that of tensile properties. The compressive performance of FRP hasn’t been well understood due to the challenges of identifying the materials’ true compressive strengths. Fundamental compressive tests of composites show inconsistency of results as fibre instability can lead to structural failure. Further research on the compressive performance of composites is required to utilize FRP materials in further applications.

This research project is supported by EPSRC and contributes to the objectives of NextCOMP for the next generation of fibre-reinforced composites to develop novel composite materials that can endure higher compressive load-carrying capability. The development of composite compressive properties can lead to further industrial utilization of composites in compressive applications. A review of naturally occurring composite structures will be used to inspire new techniques to design and manufacture advanced composites with novel architecture.

The aim of this PhD project is to improve the compressive performance of composite materials.

• Experimental procedures must be reviewed and improved to obtain a higher compressive failure strain of FRP materials than those reported.
• Development of finite element analysis (FEA) models to validate experimental results. The model results would be used to predict the compressive performance of FRP materials using different architectures.
• Validate new architectures of composite materials to improve the in-plane compressive performance of composite structures.
• Design, manufacture, test, and analyse complex hierarchical architecture that results in improved compressive properties of composite materials.

The key objectives for this project can be summarised as follows:

• Review the effects of stacking sequence to identify new techniques that can support longitudinally loaded fibres in compression.
• Assess current compressive test methods to identify suitable experimental procedures for compressive failure within composite laminates.
• Investigate methods for fibre stability in compression through the reduction of fibre misalignment.
• Overwound / overbraid architectures to delay kink band initiation.
• Use of pultruded rod architecture to embed into current laminate architecture.
• Monitor uni-directional material stability and its improvement with the use of hybrid composites.

The research would support the purpose of identifying and improving the compressive performance of uni-directional FRP materials. This would increase the use of FRP structures in further engineering applications, in particular the aerospace and civil engineering sector. The traditional materials used are expensive to transport and can cause further risks to employees. FRP structures would re-innovate the current structures to allow for the manufacturing of portable lightweight structures with improved corrosion resistance properties. The development of novel composite architectures from natural composite architectures and current compressive enduring structures will lead to identifying techniques to improve the compressive properties of FRP materials.

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Dual mode shielding against space radiation using superconductive enhanced composites [AEGIS - Advanced Exploration Guard In Space]

Student: Gokhan Sancak
Supervisors: Ian Hamerton, Simon Hall, Tom Scott

Recent advancements in space technology have brought humanity closer to achieving one of its most ambitious goals -manned space exploration. Despite this promising progress, the challenge of mitigating health threats posed by space radiation remains [1]. Thus, beyond the terrestrial magnetic field, ensuring the safety of humans and electronics engaged in extraterrestrial activity has been a compelling research area. This project addresses the critical need for innovative materials to effectively protect human health and essential equipment during extraterrestrial activities, marking a pivotal step toward the actualisation of the plan of manned space exploration.

The extensive range of ionising radiation encountered in space encompasses Solar Particle Events (SPEs) and Galactic Cosmic Rays (GCRs) originating from the sun and outside the solar system. These two radiation sources exhibit distinct energy spectra and radiation compositions, necessitating separate consideration. SPE is characterised by abrupt and extremely intense bursts of low-energy (1-100 MeV) particles, primarily protons and a minor presence of alpha particles (helium ions). On the other hand, GCRs consist of a continuous dose of ionising particles with energy on the order of magnitude of 1 GeV, penetrating deeply throughout the solar system. Approximately 87% of GCRs are protons, followed by 12% of alpha particles and 1% of high atomic number (Z>2) and energy particles (HZE) devoid of all orbiting electrons [2][3].

Various shielding methods have been explored to address the challenges posed by space radiation and can broadly categorised as active and passive shielding. Active shielding utilises an external energy source to create an electromagnetic field around the habitable zone of the spacecraft, deflecting incoming charged particles. Following the discovery of the superconductivity phenomenon in 1911 [4], the application of superconducting magnets, which, through their unique ability to generate strong magnetic fields and exhibit zero electrical resistance, has emerged as a transformative approach in the field of active shielding, with the first proposal in the 1960s [5]. On the other hand, passive shielding relies on static materials as a barrier, able to absorb and/or attenuate both charged and uncharged radiation that is unaffected by the Coulomb forces. Composite materials containing low-Z constituents and enriched with high-hydrogen content have gained recognition through their improved structural and radiation shielding performance (e.g., [6][7]), especially against radiation poses charge neutrality.

Building upon the combined principles of both shielding methods (e.g., [8]), this project draws inspiration from the concept of superconductive-enhanced composite materials. This innovative approach integrates active shielding, leveraging superconducting additives, with passive shielding using matrix constituents within a family of well-characterised polybenzoxazine resins [9][10]. The primary objective of this project is to alleviate the reliance on massive superconducting magnets, considering the overall mass, cost and performance of the superconductive-enhanced composite material in the context of space radiation shielding applications.

The further aims of this project are: (i) to gain an understanding of the requirements of the chosen superconductor based on its scale and morphology as an additive in composite, (ii) to characterise the improved interfacial interaction between superconductor and matrix constituent, (iii) to demonstrate the radiation shielding efficiency of this innovative material, possessing passive and active shielding approach.

References

[1] Durante, M., & Cucinotta, F. A. (2008). Heavy ion carcinogenesis and human space exploration. Nature Reviews Cancer, 8(6), 465-472.

[2] Simpson, J. A. (1983). Elemental and isotopic composition of the galactic cosmic rays. Annual Review of Nuclear and Particle Science, 33(1), 323-382.

[3] George, J. S., Lave, K. A., Wiedenbeck, M. E., Binns, W. R., Cummings, A. C., Davis, A. J., ... & Yanasak, N. E. (2009). Elemental composition and energy spectra of galactic cosmic rays during solar cycle 23. The Astrophysical Journal, 698(2), 1666.

[4] Van Delft, D., & Kes, P. (2010). The discovery of superconductivity. Physics today, 63(9), 38-43.

[5] Levy, R. H., & French, F. W. (1968). Plasma radiation shield-Concept and applications to space vehicles. Journal of Spacecraft and Rockets, 5(5), 570-577.

[6] Evans, B. R., Lian, J., & Ji, W. (2018). Evaluation of shielding performance for newly developed composite materials. Annals of Nuclear Energy, 116, 1-9.

[7] Kaul, R. K., Barghouty, A. F., & Dahche, H. M. (2004). Space radiation transport properties of polyethylene‐based composites. Annals of the New York Academy of Sciences, 1027(1), 138-149.

[8] Al Zaman, M. A., & Monira, N. J. (2023). Shielding effectiveness of different polymers and low-density hydrides in a combined radiation shield for crewed interplanetary space missions. Radiation Physics and Chemistry, 205, 110706.

[9] Kong, K., Gargiuli, J., Worden, G., Lu, L., Brown, K. R., & Hamerton, I. (2023). Non-destructive evaluation of the curing of a polybenzoxazine nanocomposite blend for space applications using fluorescence spectroscopy and predictive mechanical modelling. Polymer Testing, 129, 108291.

[10] He, Y., Suliga, A., Brinkmeyer, A., Schenk, M., & Hamerton, I. (2024). Effect of atomic oxygen exposure on polybenzoxazine/POSS nanocomposites for space applications. Composites Part A: Applied Science and Manufacturing, 177, 107898.

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Novel approaches for the synthesis and applications of inorganic functional materials

Student: Jan Maurycy Uszko
Supervisors: Simon Hall, Avinash Patil, Steve Eichhorn

The project investigates a range of methods for preparing functional inorganic materials. Mainly focusing on developing and studying the detonation method for the synthesis of metal nanoparticles and sol-gel method utilising biobased precursors. Following successful synthesis, material properties and composition will be studied using a plethora of methods inter alia superconducting quantum interference device magnetometry, X-ray and electron diffraction analysis, scanning and tunnelling electron microscopy, and a range of spectroscopical analysis methods.

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Hot/wet properties of high temperature composites

Student: Anna Williams
Supervisors: Giuliano Allegri and Ian Hamerton

The replacement of metals with advanced composite materials within a range of industries has become commonplace. This is due to their excellent specific stiffness and strength, wide range of available constituents and array of manufacturing processes, making them suitable for a multitude of applications, including within the aerospace and energy sectors. As composites are employed in more extreme environments, there has been considerable interest in organic matrices that are able to withstand high temperatures and humidities. Thus, research has been conducted to develop novel thermoset systems with enhanced thermal and moisture durability properties. There has been specific interest in cyanate esters due to their desirable viscosity properties for resin infusion and high glass transition temperatures, making them suitable for a range of applications. Although there is some understanding of the behaviour of the neat resin, there is little knowledge on its performance when integrated within composite laminates.

Delamination, the separation of layers, is the primary failure mechanism within composites. Fracture toughness is a measure of a material’s resistance to delamination. Most tentative applications for these novel materials involve cycling components in the presence of heat and moisture which accelerates degradation mechanisms. Therefore, it is imperative to understand the interlaminar fracture toughness properties of these thermoset systems, with a particular focus on how they react in hot-wet conditions, before they can become routinely used within composites.

This project will focus on the experimental testing of a leading aerospace-grade epoxy-based composite material, IM7-8552, in conjunction with composites containing the novel thermoset resins. This will allow a baseline set of properties to be acquired for performance comparison with the newly developed materials. Although regulations for moisture conditioning of test specimens exist, there is no universally accepted testing standard for acquiring fracture properties of composites at elevated temperatures and humidities. For this reason, a key objective of this project is to develop a more robust, reliable method for testing within extreme environments, along with obtaining the fracture properties themselves. Testing will initially be conducted in static and quasi-static conditions, followed by fatigue testing performed to mimic the conditions experienced by materials in-service under continuous cycling and vibration exposure whilst in high temperature environments. Fractographic analyses will be conducted to create qualitative measures of fractured surfaces, developing easily identifiable visual indicators of how the material failed in each set of testing conditions for future comparison.

Once the behaviour of the novel thermoset systems within composites is more thoroughly understood, supported through rigorous testing within this project, the envisaged application for their use is within the turbofan engines developed by Rolls Royce. However, if these materials prove to have enhanced durability within environments involving repeated cycling at elevated temperatures, this will open them up for use within a broad spectrum of applications. These could include conventional gas turbines, advanced hybrid electric propulsion systems, motors, generators, and hydrogen storage tanks.

The development of a vigorous protocol for static, quasi-static and fatigue testing in elevated temperatures and humidities will be a significant contribution to the fracture mechanics research field. The ability to confidently produce a data set of properties tested within these conditions is essential for the progression of high temperature composites as the boundaries for their use continue to be broadened.

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