Composites Research Group
 

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Michael Johnson

Associate Professor of Composites and Engineering Design, Faculty of Engineering

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Biography

Dr Michael Johnson is an Associate Professor at the University of Nottingham with nearly 20 years experience. Mechanical Engineering is his vocation; machine design is his teaching specialism. Structural composites, particularly how to manufacture them, has formed the core of his research since 1992. This encompasses large, low cost fibre reinforced thermoplastics and heavily loaded composite shafts, for example, bodysides and axles for railway vehicles, respectively. He is a chartered engineer (FIMechE, CEng) with global work experience and an extensive publication record in rail vehicle lightweighting.

Expertise Summary

Dr Johnson's background is in polymer composites paired with engineering design. Trained as a mechanical engineer (CEng, FIMechE), he has worked internationally at Ford (USA), Atkins (UK) and the CRC-ACS (Australia). Specifically, he devises manufacturing processes for structural composites for use across the transport sector. This has included high volume resin transfer moulding with Ford (UK), fire retardant cabins for Incat (Australia), body-in-white structural aluminium bonding (Aston Martin), resin infusion of nacelles (Safran) and low mass railways axles (Horizon 2020/Shift2Rail). His role as Rail Vehicle Design Manager at Aktins gave him the incite to develop an undergraduate Engineering Design course at the University of Nottingham. In addition he established a network within the rail industry which he continues to broaden as a programme board member of the UKRRIN Centre of Excellence in Rolling Stock.

Mike is a part of the Composites Research Group.

Teaching Summary

Dr Johnson's teaching interests are in engineering design. In 2007 he became convenor for the first year design module (MMME1024) taken by the Mechanical, Manufacturing and PDM cohorts. This module… read more

Research Summary

Dr Johnson is a member of the Composites Research Group and is on the Management Board of the EPSRC sponsored, Future Composites Manufacturing Research Hub (CIMComp), a £10.3m investment into UK… read more

Selected Publications

Dr Johnson's teaching interests are in engineering design. In 2007 he became convenor for the first year design module (MMME1024) taken by the Mechanical, Manufacturing and PDM cohorts. This module integrates the strands of engineering design practice, machine element understanding, solid modelling skills and hands on machine tool training. In addition, he tutors second year Mechanical and Manufacturing students through their advanced design module and supervises high level design projects (group and individual) for final year students. Since the inception of the Aerospace Engineering course, Dr Johnson has been a tutor within the years 1 and 2 design modules. He is an AdvanceHE Fellow (FHEA) with teaching roles in the following modules.

Undergraduate Courses:

  • MMME1024-Engineering Design and Design Project (Co-Convenor)
  • MMME2044-Design, Manufacture and Project (Design Tutor)
  • MMME1049-Aerospace Design and Materials (Design Tutor)
  • MMME2033-Aerospace Design and Manufacture (Design Tutor)
  • MMME3083-Individual BEng Project (Project Supervisor)
  • MMME4086-MEng Individual Project (Project Supervisor)
  • MMME4085-Group Design and Make (Project Supervisor)

Postgraduate Courses:

  • H798-Engineering Doctorate (EngD) in Composites Manufacture (Course Director)

Current Research

Dr Johnson is a member of the Composites Research Group and is on the Management Board of the EPSRC sponsored, Future Composites Manufacturing Research Hub (CIMComp), a £10.3m investment into UK composites manufacturing. The "Hub" has the aim of delivering a step-change in the production of polymer matrix composites. As part of the Hub he chairs the Postgraduate Development Committee which oversees the training and progression of PhD and EngD research students, delivers the International Exchange programme, and manages Researcher development through the a bespoke Vitae programme.

Dr Johnson's research is in the design and manufacture of polymer composites primarily for the purpose of rail vehicle lightweighting.

This research segregates into two themes:

1. Carbon Fibre Shafts - TALON (Primary Application: Railway vehicle axles).

While hollow carbon fibre (CF) reinforced composite driveshafts for torque transmission are well understood, the design of annular CF tubes subject to transverse/radial/bending loads largely is unresearched. A mathematical tool based on classical laminate theory (CLT) has been implemented to determine fibre failure (according to Tsai-Wu, Maximum Stress, Maximum Strain and other failure criteria) within the tube under combined loading. This permits CF shaft optimisation with respect to mass or geometric constraints in a matter which is less user and computationally intensive than with Finite Element Modelling. Associated research topics include high cycle fatigue failure, dynamic characteristics, impact damage and joining of shaft elements. While a focus has been on railway vehicle axles, applications are ubiquitous and include aeroengine gearboxes, wind turbine shafts as well as space machinery.

2. Large, Low Cost Fibre Reinforced Thermoplastic Structures - HyVR (Primary Application: Railway vehicle bodysides, roofs, intermediate ends and cabs).

Thermostamping of preconsolidated fibre reinfroced thermoplastic (FRTP) sheet has attracted research interest due to the attractive properties of the thermoplastic matrix including reformability, low FST (fire, smoke and toxicity) properties and corrosion resistance. However, for low to medium volume component manufacture (approximately <30,000 parts per annum) the cost of high stiffness steel tooling and associated manipulation is prohibitive. A manufacturing technique (HyVR) has been developed to form FRTP sheet by combining the diaphragm and incremental sheet forming processes. The technique equally can be used for manufacturing CF prepreg using infrared (IR) heating, bulk vacuum shaping and robotic precision forming. Research areas include the coding of a thermo-mechanical simulation tool to incorporate pixelated IR heating for overcoming geometric part variations as well as supplementing FRTP shaping and slippage across the mould surface. The primary focus has been on rail vehicle carbody applications, however, automotive panelling, aerospace surfaces and marine hatches equally are within scope of the HyVR forming process.

Past Research

Dr Johnson's early career focussed on high volume applications for resin transfer moulding. This included the integration of an in-line microwave resin preheating system to minimise mould quench at the injection gate so that cycle times were reduced. Wider research in liquid moulding included infusion of phenolic resins as well as real-time control of the vacuum infusion process. More recently his liquid moulding knowledge was applied to nacelle manufacture with an emphasis on controlling the mould surface quality. Composite joining using reactive adhesives is an ongoing interest which initiated through work with Aston Martin. Gaining a fundamental understanding of their epoxy adhesive for aluminium BIW bonding of the DB9 permitted removal of the oven "degas" stage from their production process, saving significant cost in both capital equipment and manufacturing cycle time.

Dr Johnson has always maintained an interest in composite lightweight for the rail industry. This included infusion of coal freight wagons in the late 1990's and more recently ballast impact performance of pressurised rail freight vehicles. Constant interaction with rail companies in the East Midlands rail corridor through the 2000's has enabled Dr Johnson to work on diverse topics including pantograph to carbody electrical arcing, railcar ingress/egress solutions, tape laying machines for braking trials, thermal energy harvesting of seating and many others. In the mid 2010's he worked with Bombardier Transportation to identify components on a standard multiple unit having a life-cycle business case for replacement in composites. This seminal work was the foundation for his current work in large, low cost, fibre reinforced thermoplastics. In addition, an interest in wheelset mass reduction spawned by the Shift2Rail project, NextGear, gave basis to his current work in lightweight composite shaft design.

Future Research

Full exploitation of TALON and the HyVR process (see Research Summary) are envisaged for the medium term. Both technologies align with lightweighting within the transport sector for reduced CO2 emissions and improved sustainability. More fully, TALON addresses wheelset lightweighting, minimising track impact damage which affords a significant savings to Great British Railways (GBR) while benefiting passengers through less track outages. Also, HyVR is a fully reversible process which solves end of component life difficulties normally associated with thermoset composites. Specifically, a HyVR 3 dimensionally formed FRTP component has an associated digital twin which lends itself to reversing the HyVR process (DeForm) so that a two dimensional FRTP sheet results with fibre angles reinstated to the original orientations.

Full optimisation of the composite tube design in relation to mass as well as high cycle fatigue and shaft element attachment are ongoing. This will broaden to studies on rotating shaft dynamics (for railway wheelsets) and impact damage (due to track ballast).

Dr Johnson welcomes enquiries from potential PhD candidates from Home, EU and International countries who are interested in the following research areas: Manufacture of polymer composites with an emphasis on thermoplastic sheet forming.

Composites Research Group

Faculty of Engineering
The University of Nottingham
University Park
Nottingham, NG9 5HR


contact: Prof Nick Warrior
email: composites@nottingham.ac.uk