The use of hydrogen as an energy source is a promising strategy to replace fossil fuels, in addition to batteries and biofuels. The European aerospace industry is already working on the development of propulsion technologies with low or zero emissions and heavily considers hydrogen technology. It is favoured in aeronautics to store H2 in liquid form, LH2, at temperatures of 20K to have the highest possible energy density of the fuel. This means that all materials in contact with LH2 need to be characterized at this temperature.
INTA began to carry out cryogenic tests on composite materials 27 years ago. Initially in the field of characterization of composite materials for tanks for reusable launchers. Later, the structural monitoring of LH2 tanks, the detection of hydrogen leaks and fuel cells have also been investigated. Currently, INTA is involved in the characterization of composite materials in LH2 tank projects and the composite material structures that these tanks carry for sustainable aviation.
The article gives an overview of the activities carried out in the field of cryogenic tests of composite materials and provides data obtained in these tests, comparing the behaviour of different materials and different types of tests. In addition, the new lines of research that are being carried out at INTA in the characterization of composite materials and their behaviour before and after being in contact with hydrogen will be explained.
Abstract
The use of hydrogen as an energy source is a promising strategy to replace fossil fuels, in addition to batteries and biofuels. The European aerospace industry is already working on the development of propulsion technologies [...]
This work describes the collaboration between ITER, CERN and APPLUS LABORATORIES to develop and validate innovative methodologies for the mechanical characterization of advanced epoxy-based composite materials with fiberglass reinforcement under cryogenic conditions (77 K) post-irradiation. These materials were selected for critical applications in the ITER reactor due to their combination of dielectric properties and mechanical behavior, requiring them to maintain structural integrity under extreme conditions of neutron irradiation (up to 10 MGy). The research faced significant challenges related to specimen slippage in test grips, especially critical in irradiated materials that experience embrittlement. To overcome this problem, an innovative system was developed based on a flexible liquid nitrogen repository that allows maintaining the central area of the specimen at 77 K while using conventional hydraulic grips at room temperature to hold the ends. Three different materials (A, B, and C) with various fiber configurations and testing methodologies adapted to each case were analyzed. The developed system proved to be fundamental for obtaining valid results in materials susceptible to slippage, combining the advantages of conventional hydraulic grips with precise temperature control in the test area. The methodologies and solutions developed have significant implications for establishing future standardized testing protocols for materials used in nuclear fusion applications, reducing the need for large specialized facilities and potentially accelerating materials qualification programs for future fusion facilities.
Abstract
This work describes the collaboration between ITER, CERN and APPLUS LABORATORIES to develop and validate innovative methodologies for the mechanical characterization of advanced epoxy-based composite materials with fiberglass [...]
Characterization of composite material at cryogenic temperatures of 20K and the influence of hydrogen on its mechanical properties 