For Mechanical Testing at Cryogenic Temperatures, the Fiber Institute Bremen e.V. Relies on ZwickRoell
Case Study
- Customer: Fiber Institute Bremen e.V.
- Location: Bremen, Germany
- Industry: Aerospace, Academies/Institutes
- Topic: Mechanical testing at cryogenic temperatures
October 2023
When developing new fiber materials and high-performance composites, the Fiber Institute Bremen e.V. (FIBRE) supports companies from various branches of industry in mastering the technological challenges of the future. In order to understand the material behavior and change in the mechanical properties of fiber composites under cryogenic temperatures, for example, and thus ensure the reliability and safety of aerospace components, the Fiber Institute at the ECOMAT research site in Bremen uses materials testing machines from ZwickRoell.
The Fiber Institute Bremen e.V. (FIBRE)
The Fiber Institute Bremen e.V. (FIBRE), founded in 1969 and headquartered in Bremen, Germany, has been actively working in the areas of research and development of fiber materials and their applications for many years. Their main task is to develop innovative solutions for industrial use, including for the automotive, construction, medical and textile industries, as well as aerospace, and contribute to the improvement of fiber products in terms of material development, product optimization, quality control and process improvements.
The goal is to strengthen industry competitiveness by providing scientific knowledge, technical expertise and innovative solutions. To this end, the institute focuses on the development of innovative fibers for technical textiles and fiber composites and their manufacturing processes, usually in the form of funded cooperation projects with industry partners. In addition to customized solutions, customers of the Fiber Institute Bremen also benefit from the consulting services of its highly qualified employees.
The Fiber Institute Bremen has modern materials science laboratories with accredited test methods and a wide range of technical facilities for fiber production, plastics processing and CFRP production.
The task
Requirements in material characterization under cryogenic temperatures
At Bremen's research and technology facility ECOMAT, engineers and scientists of the Fiber Institute Bremen e.V. (FIBRE) work in collaboration with the aerospace industry to bundle activities in the field of cryogenics to characterize and further develop CFRP when used at cryogenic temperatures. These are all current challenges in the development of new and innovative technologies for carbon-neutral air travel.
For cryogenic tests performed at cryogenic temperatures as low as -253 °C, the reproducibility of the test results with standard tests otherwise carried out in a temperature range of -55 °C to +120 °C and at ambient temperature must be ensured. Furthermore, these low temperatures present a challenge for the materials used, as well as for the required strain and displacement measuring systems. Different approaches than for standard tests at ambient temperature must therefore be developed for specimen gripping, precise force and displacement measurement and for the alignment of the load string.
The ZwickRoell solution
ZwickRoell materials testing machines with yoke
To meet the special cryogenic testing requirements of the Fiber Institute Bremen e.V. (FIBRE) for tests with hydrogen, a decision was made for standardized and universally applicable materials testing machines from the ZwickRoell product portfolio. These enable the characterization of different materials even at cryogenic temperatures, and ensure excellent reproducibility of the test results—regardless of whether low test loads or high test loads are used, or whether for quality assurance or research purposes.
Different cryogenic testing solutions were selected from the ZwickRoell product portfolio for the Fiber Institute Bremen e.V., which enable both mechanical testing in the cryogenic range using liquid nitrogen (LN2) at 77 K as well as liquid hydrogen (LH2) at 20 K.
The specimen grip with the clamped specimen is immersed in the cryogenic temperature range using a specially developed yoke. The benefit: since the cryostat only has one opening, the highest possible temperature stability is guaranteed. All ZwickRoell cryostats have an optional viewing window that can be used to determine the strain and deformation of the specimen from the outside and without making contact, thanks to the optical technology provided by the videoXtens.
The convenient, user-friendly testXpert testing software is used for control, data acquisition and evaluation purposes and is already being widely used at the Fiber Institute Bremen e.V..
Comprehensive testing options for fiber composites at cryogenic temperatures
“In ZwickRoell we have found the perfect partner and the ideal level of support for our work in the characterization of materials at extreme cryogenic temperatures. The testing systems supplied are testament to an outstanding level of expertise and have been perfectly adapted to both our basic and application-based requirements,” said Dr. Ernö Nemeth, Laboratory Manager at the Fiber Institute Bremen e.V. about their collaboration with ZwickRoell.
The testing systems support a large number of typical tests on fiber-reinforced composites, including tensile, compression, and flexure tests, as well as the determination of interlaminar shear strength (ILSS) and tests for the determination of critical interlaminar energy release rates G1c (under Mode I loading) and G2c (under Mode II loading). Nemeth: “Our close and trusting collaboration throughout the entire duration of the project has significantly expanded our research possibilities and further strengthened our connection with ZwickRoell.”
The result
Based on the extensive product portfolio, ZwickRoell was able to optimally meet the technical requirements of the Fiber Institute Bremen e.V. (FIBRE). They can now carry out tests—including tensile, compression and flexure tests, as well as ILSS, G1C and G2C tests—to characterize material properties at extreme cryogenic temperatures for both research purposes and in cooperation with industrial partners in the aerospace sector, while counting on fully reliable, traceable and reproducible results.
“ZwickRoell is a partner we can count on in the field of material characterization at cryogenic temperatures.
The testing machine manufacturer convinced and supported us with technical expertise and their comprehensive and specialized product portfolio for hydrogen testing throughout the entire duration of the project. The systems they customized for our specific needs are a testament to their expertise and keen sense of our individual requirements as an institute, while ZwickRoell’s professionalism and collaborative approach have helped to significantly advance our research in this challenging field.”
Dr. Ernö Nemeth, Laboratory Manager Fiber Institute Bremen e.V. (FIBRE)
Fiber Institute Bremen e.V. (FIBRE): Mechanical testing at cryogenic temperatures
