The project aimed to develop the use of wire arc additive manufacturing (WAAM), a production process used to 3D-print metal parts that uses an electric arc to melt a metal wire, depositing layers of melted metal on top of each other, until a desired 3D shape is created.
WAAM is used in multiple industrial sectors, including energy, defence, construction and automotive, to produce large and complex structural components, whilst reducing the need for assembly and joining technologies, as well as waste material.
The process has been used for repair and remanufacturing purposes in the aerospace industry already, which has the advantage of greater supply chain flexibility, enabling on-demand production in small quantities, and saving time and costs.
AMRC tested the utilisation of WAAM to construct a demonstrator storage tank for liquid hydrogen using an aluminium alloy for use in the aerospace sector.
Hydrogen is a highly sustainable energy carrier and is considered by many as pivotal for achieving climate neutrality in the EU by 2050, particularly for industry and heavy transport. However, challenges around how to store hydrogen limit its full potential, according to the research team.
In a statement, Dr Evren Yasa, head of additive manufacturing (AM) for the AMRC and lead researcher, said: “The main challenges of storing hydrogen for use as a fuel source in aerospace, are the additional storage requirements, along with the complicated geometry needed for integral tanks as well as operation at cryogenic temperatures when it is stored in liquid form.
“These challenges make AM technologies one of the promising manufacturing routes for hydrogen storage tank demands, which is also supported by the Cryogenic Hydrogen Fuel System and Storage Roadmap Report published by the UK’s Aerospace Technology Institute in 2022.”
Currently, sheet metal forming, machining and welding are used for metallic fuel tank production; WAAM provides design freedom to make novel shapes, which researchers said can open the opportunity to store hydrogen in more compact areas.
Dr Yasa’s team wanted to explore the feasibility of using WAAM for metallic storage tanks by identifying the process parameters, as well as the deposition strategies, for good mechanical properties. Furthermore, the aim was to investigate and counteract the residual stresses occurring due to the high heat input generated during the WAAM process.
The seven-month project was funded through the High Value Manufacturing (HVM) Catapult, of which the AMRC is a member alongside six other national research centres.
The research team hope to gain funding for a second phase, to explore the effect of AM on the cryogenic mechanical properties, as well as hydrogen permeability to ensure that it is a feasible route for liquid hydrogen applications.
“The goal is to showcase the economic viability and competitiveness of this solution,” said Dr Yasa.