Stress x Strain diagram of hollow specimens tensile tested in 15 MPa hydrogen and argon with respective SEM images of the fractured cross section.
Source: BAM
The hydrogen economy is regarded as a fundamental contributor to the goal of climate neutrality in Europe, given its significant role in the decarbonization of various sectors, including transport, industry, and power. Ensuring the safety and reliability of infrastructure is crucial for the ramp-up of the hydrogen economy. Therefore, it is necessary to meticulously study the materials and components used for infrastructure under conditions that closely resemble in-service conditions. The currently standardized methods are limited as they do not precisely replicate in-service conditions, and when they do, they are often complex, costly, and not easily accessible.
The hollow specimen technique is a simple and cost-effective method that has the potential to make materials qualification with pressurised gaseous hydrogen widely accessible to academia and industry. The feasibility of this method has been demonstrated in several studies, leading to the initiation of the ISO committee ISO/TC 164/SC 1/WG 9 for its standardisation in ISO 7039. Questions that emerged during this process are currently preventing the extension of ISO 7039 to hydrogen gas as an ambient medium. These questions relate to specimen geometry, specimen manufacturing and gas quality and are being systematically addressed in the TransHyDE-H2HohlZug project presented. The aim of the project is to close the identified gaps towards the standardisation of this method for hydrogen testing.
This work presents the state-of-the-art of the hollow specimen technique followed by the TransHyDE-H2Hohlzug project. Here, the main steps required and the methodology adopted to optimize the hollow specimen technique towards its standardization for tests in high-pressure hydrogen gas are shown.
Tensile testing in high-pressure gaseous hydrogen using the hollow specimen method
Florian Konert, Jonathan Nietzke, Zephanja Krzysch, Thomas Böllinghaus, Oded Sobol, Thorsten Michler, Ken Wackermann, Heiner Oesterlin, Mohamed Tlili, Peter Ruchti, Denise Beitelschmidt, Stephan Elsen-Humberg, Timo Koenigs, Thomas Systermans
MRS Bulletin, 2024