- Can you tell us a bit about your role within the COCOLIH₂T project and what Work Package 8 focuses on?
Within COCOLIH₂T I lead Work Package 8, on Safety & Lifecycle Evaluation. In this work package we had two aims: One, to understand the potential safety risks of a liquid hydrogen tank and how these could be mitigated in the tank design, and two, to understand the durability and lifecycle impacts of the tank. In particular, in COCOLIH₂T we chose for a carbon fibre / thermoplastic tank made with automated fibre placement, and we wanted to understand how this compared in terms of environmental impact to a more traditional carbom fibre / epoxy concept.
- What has been one of the most interesting or unexpected challenges so far, and how did you and/or your team approach it?
There are of course no commercial flights operating on liquid hydrogen yet, so we had to perform a safety assessment on a new design, without having historical data to help us quantify the risks. To get around this, we analysed historical data from other sectors, where there is more experience with using hydrogen. From these we estimated both the frequency and the potential impact of different safety hazards.
- What are some key lessons or takeaways you’ve gained from working on COCOLIH₂T?
A key lesson was that it was still possible to conduct a quantitative preliminary safety assessment, even on a new technology like a liquid hydrogen tank for aviation. We also saw that in manufacturing, a lot of the environmental impact comes from the mould materials, especially if there are low production volumes. Ensuring that hydrogen permeation / leakage is avoided also requires careful lay-up design to keep the transverse stresses in each ply low enough. Doing this on a design is one thing, but then ensuring the analysed lay-up also is manufacturable adds an additional challenge.
- Looking ahead, how do you think this project could shape future research or industry practices?
Hopefully our preliminary safety analysis can guide further design and development of aviation liquid hydrogen tanks.
We also saw that conducting a thorough fatigue and durability analysis on a liquid hydrogen tank will require extensive material characterisation work under cryogenic conditions. Here a lot of research effort is still needed.
- If you could describe the COCOLIH₂T project in three words, what would they be — and why?
Challenging – We faced many challenges, particularly in manufacturing such an unusual shape and dealing with the limited amount of available data.
Persistence – Despite setbacks we always found a way to keep moving forward
Creativity – COCOLIH₂T really moved into new areas in different ways, requiring a lot of exploration and creativity to figure out how to design and manufacture our tank.