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The 2020s so far have been a significant decade for hydrogen fuel technologies, with countries around the world passing national hydrogen roadmaps or strategies and companies conducting demonstration and pilot trials of hydrogen-fired industrial processes.
But as the initial fervor surrounding hydrogen dies down, the practical challenges of adopting this technology on a large scale are coming to the forefront of discussions. For example, how we can sustainably source hydrogen for widespread adoption and how use of hydrogen fuel will affect refractory design.
Safe storage of hydrogen fuel is another practical challenge that researchers are working on. Hydrogen can be stored physically as either a gas or a liquid, or chemically within molecular compounds such as metal hydrides or metal–organic frameworks. Each option has its tradeoffs, and likely all will be used for different applications in the future hydrogen economy.
For aerospace purposes, liquid hydrogen is considered a leading choice due to its superior energy-to-weight ratio, which allows for long-range flights without the need to refuel. But storing hydrogen as a liquid requires complex, energy-intensive cooling infrastructure that is prone to experiencing logistical issues under demanding operational conditions.
Various studies have individually evaluated the thermal performance, structural integrity, fatigue life, and impact resistance of liquid hydrogen storage tanks. However, “These interrelated challenges necessitate a holistic analytical framework that can evaluate [all these aspects] in an integrated manner,” researchers write in a recent paper.
The researchers are led by several professors from Seoul National University of Science and Technology. In their study, they developed an analytical framework that accounts for all the interrelated aspects—thermal, structural, fatigue, and impact—specifically tailored for the unique operational conditions of unmanned aerial vehicles.
The researchers used an aluminum-shielded stainless steel liquid hydrogen storage tank as the standard for framework development. First, they measured temperature-dependent properties of the tank using a 100 kN tensile-fatigue testing system. They then used these values to develop finite element models for each of the interrelated aspects, with the model for impact analysis based on a new computer simulation method that they developed.
Experimental tests confirmed the effectiveness of their models, including the innovative impact simulation. That model successfully predicted the progressive failure behavior of the vessel’s multimaterial structures under impact loading, identifying connecting pipes and supporters as vulnerable areas requiring design optimization.
“These findings establish new standards for comprehensive safety assessment of liquid hydrogen storage tanks in UAV [unmanned aerial vehicle] applications, while highlighting the critical need to balance thermal isolation requirements with structural integrity demands during flight operations,” the researchers write.
They conclude by advocating for the development of more sophisticated analytical models that incorporate fluid–structure interaction effects, as such models “could further improve prediction accuracy for dynamic loading scenarios.”
The paper, published in International Journal of Hydrogen Energy, is “Analytical framework for liquid hydrogen storage tanks in UAVs: Thermal performance validation and structural integrity assessment” (DOI: 10.1016/j.ijhydene.2025.06.042).
