Work-package 1.3: Manufacturing of light-weight and multi-functional structural components.

Background

The overwhelming majority of electrical machines research is directed towards the electromagnetically active elements, such as the magnets or coils. However, in terms of the overall power density, the non-active elements, namely the rotor hub/shaft and the stator casing can contribute a significant proportion of the overall mass. This grand challenge will explore a number of alternative materials, processes, and geometries to lightweight the various structural components encountered in a range of electrical machines. We will also be investigating the possibility to integrate additional functionality into the structural components with features such as cooling ducts in casings and end-caps, and self-pumping elements in hollow shafts and hubs. This project also seeks to optimise the method of manufacture and provide superior components in the fewest number of manufacturing steps. Potential manufacturing solutions include the use of composite materials, and the application of novel forming techniques such as flow forming and radial forging.

Figure 1- radial forged then machined transmission shaft

Why it’s important

For current electrical machines, approximately 40-50% of the machine mass is taken up by the non-active components. These non-active components, typically casings and housings, are present for environmental protection and mechanical stability, but play no active role in generating power. For high integrity machines, mass has a huge impact on efficiency, emissions, and performance. The key aim of this work package is to reduce weight and assist the technological advances in the active components to enable the production of more efficient and power dense electrical machines. The introduction of multi-functional components will also go a long way to realising the full potential of fully optimised, high performance electrical machines.

Figure 2- Radial forging process steps. Different components forged from the same starting geometry (L-R part 1,2,3), and radial forged then machined component

Current progress 

• Summary on current state-of-the-art design
• Summary on current manufacturing routes
• Research undertaken into the maturity of non-standard manufacturing routes related to electrical machines, including:
  • Additive manufacturing of structural and active elements
  • Superconducting solutions for electric propulsion for aerospace applications
  • Applications of composite material in machine design
• One PhD student started in October 2019 to look at the light-weighting of non-active components, with an emphasis on the advanced manufacturing techniques employed at the Advanced Forming Research Centre.

Figure 3- Component with internal features formed through the spinning process

Future plans

• Value Analysis, Value Engineering session is being set up to fully evaluate the best strategy of which components to lightweight, what alternative materials and manufacturing processes are viable
• Generate potential future methods of manufacture for non-active components, with a focus on technical optimisation and a reduction of processing steps
• Evaluation on the market projections for the current and future use of electrical machines in key industries including aerospace and wind energy
• Applications of emerging materials in machine design, including metal-matrix composites and polymer composites

Figure 4- Hub with internal splines manufactured through a hybrid forging/spinning process

Staff involved

• Dr Jill Miscandlon, AFRC (WP leader)
• Dr Alasdair McDonald, InstEE
• Prof. Michael Ward, AFRC
• Prof Geraint Jewel, Sheffield
• Dr Pete Osbourn, AMRC

For more information on this project, please contact Dr Jill Miscandlon.