Advanced Manufacturing of Through-Thickness Reinforced Composites

Summary

This PhD project aims to address one of the biggest weaknesses for fibre reinforced composites, i.e. their relatively weaker out-of-plane properties compared to in-plane properties, by developing an advanced through-thickness reinforcement (TTR) manufacturing process. The novel manufacturing process allows embedding through-thickness reinforcement in composites with minimal damage to TTR and composites themselves. This PhD project will be undertaken in an active composite group affiliated with the world-class Institute of Design, Robotics and Manufacturing (iDRaM) at the School of Mechanical Engineering, University of Leeds. This PhD project presents a distinctive opportunity for the successful candidate to specialise in composites and manufacturing. Apart from researchers in the Institute, School and University, the PhD student will also have plenty of opportunities to intensively interacting with our industry partners in the areas of aerospace, energy, healthcare and automotive to facilitate the real-world applicability of their research findings. The PhD student is expected to publish high-quality papers on high-profile international journals, and disseminate research outcomes at national and international conferences, workshops and seminars.

Project background:

Fiber-reinforced composites are increasingly used across various engineering sectors as they are strong and lightweight, e.g. aerospace, automotive, renewable energy and sport. Numerous modern engineering products prominently feature composites, including A350 and Boeing 787 aircrafts, the new generation of Rolls-Royce and General Electric aero engine fan blades, and the long-span wind turbine blades manufactured by Siemens and Vestas. Additionally, composites are increasingly utilised in electric vehicles to increase power density.

Fiber-reinforced composite structures are typically fabricated by layering reinforcement materials, such as carbon or glass fibres, in the thickness direction. Matrix materials, like resin, are then applied to impregnate the reinforcement, either before or after layup. Heat and pressure are applied to consolidate the entire assembly of fibres and matrix to removing voids and volatiles and achieving the desired fibre volume fractions and dimensional tolerances. However, one drawback is the lack of reinforcement in the thickness direction. Thus, composites have relatively weaker out-of-plane properties compared to in-plane properties, and they are susceptible to debonding between plies. To overcome this limitation, various through-thickness reinforcement techniques have been developed, including tufting, Z-pinning and stitching, to introduce reinforcement phase through the thickness of composites. This PhD project aim to advance the TTR technique by developing an advanced manufacturing process that allows embedding through-thickness reinforcement in composites with minimal damage to TTR and composites themselves.

References

Partridge, I. K. and Hallett, S. R. (2016) ‘Use of microfasteners to produce damage tolerant composite structures’, Philosophical Transactions of the Royal Society A, 374(2071).

Mouritz, A. P. (2020) ‘Review of z-pinned laminates and sandwich composites’, Composites Part A: Applied Science and Manufacturing, 139(September), p. 106128.

Zhang, B., Hallett, S. R. and Allegri, G. (2022) ‘Sensing delamination in composites reinforced by ferromagnetic Z-pins via electromagnetic induction’, Composites Science and Technology, 217(October 2021), p. 109113.

Zhang, B. et al. (2015) ‘Micro-mechanical finite element analysis of Z-pins under mixed-mode loading’, Composites Part A: Applied Science and Manufacturing, 78, pp. 424–435.

Zhang, B., Allegri, G. and Hallett, S. R. (2016) ‘An experimental investigation into multi-functional Z-pinned composite laminates’, Materials & Design, 108, pp. 679–688.

Verma, K. K. et al. (2019) ‘The key role of thread and needle selection towards “through-thickness reinforcement” in tufted carbon fiber-epoxy laminates’, Composites Part B: Engineering, 174, p. 106970.

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline. The criteria for entry for some research degrees may be higher, for example, several faculties, also require a Masters degree. Applicants are advised to check with the relevant School prior to making an application. Applicants who are uncertain about the requirements for a particular research degree are advised to contact the School or Graduate School prior to making an application.

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.