Deliverables Measurement facility for the coefficient of moisture expansion The coefficient of moisture expansion of Carbon fibre reinforced polymer composites is a necessary material parameter for the design of space structures that have to perform high dimensional stability, like optical benches, antenna platforms. The values depend on the polymer material, the fibre direction, and the lay-up of the laminates and the fibre content. The environmental conditions the material has experienced, like temperature and humidity lead to the phenomenon of shrinkage and expansion of the material. The capacities of which should be precisely known to space industries but is also interesting for aeronautics application. With this unique facility it is possible to measure a variation of length due to moisture desorption in carbon fibre reinforced polymer composites with a resolution of 0,1 micrometer. Samples with a length between 30 and 200mm can be considered. Additionally the facility can measure in two axes and is adaptable to more complicated structures like pipes. The measurements are performed under vacuum (5E-6), the temperature can be chosen between 0 and 90 degrees centigrade. For highly exact values of the coefficient of moisture expansion moisture diffusion data of water in the polymers are required. This data is obtained by measuring the time dependent desorption of moisture in another facility under the according conditions. Additionally a sophisticated control and data acquisition programme for the commercial sensors were developed. Moisture influence on CFRP properties, methods and measurement results Different methods for the determination of moisture influence on the properties of CFRPs have been established and assessed in this project and results for particular materials are available. The comparison of the results using other methods will be essential for the evaluation of the new methods. Particularly standardization will be necessary for their use beyond R&D applications. At IBMT-NMR the hydration properties of several CFCs were studied, using non-invasive MR-Microimaging as well as NMR- Spectroscopy, relaxation and diffusion measurements, which represents a molecular level of the study of the molecular properties of water molecules within carbon fibre composites. On the other hand, the obtained data reflect the physical-chemical properties of the materials itself (e.g. defects, which CFC has a stronger affinity to water uptake, and more). The focus here are materials used for aircraft-industry, although there is a strong interest for modifying such materials for medical use, like Magnetic Resonance compatible surgery instruments used in clinical MRI scanners [basic for new grant applications with industry- participation]. The investigation of molecular properties of CFCs materials in combination with hydration and dehydration studies is a very promising research field. Until now, to our knowledge, there are not such comprehensive reports published. Still, there are much more opportunities to go into deeper details. This needs longer measurement times and different materials of well designed composition. In a final stage one should go to the materials really used for production. Non-invasive detection of moisture properties in carbon fibre reinforced composites The hydration properties of several carbon fibre composites were studied, using non-invasive MR-Micro Imaging as well as NMR- Spectroscopy, relaxation and diffusion measurements, which represents a molecular level of the study of the molecular properties of water molecules within carbon fibre composites. We have obtained 2 and 3 dimensional images of the water distribution in several uni-directional, bi-directional CFCs, as well as the hydration properties of resins of different types for production. For the first time we were able to get MR-images of dry and hydrated CFCs. Because these materials are conductive, there is an induced current (RF field) if the sample is studied with Radio frequencies used in MR. This produces strong distortions of the images. We were able to compensate for those artefacts using special imaging coils (IBMT-production, and home built probe holder) and a certain orientation of the materials studied, with respect to the coils RF-field orientation(s). In general we can conclude that a low but non-negligible amount of water penetrates the CFCs materials (and the resins) and forms detectable clusters of "water rich" regions. Thinking in long terms using those materials in aircraft and ship construction, we have to consider drastically changes in temperature and moisture (e.g. condensation of water) for aircraft that might slowly weaken the materials properties. Especially, in the case of strong heat and/or ice formation, those water clusters might become starting points for material defects. This project shows ways, how to select the best material and how the final finishing of the materials (e.g. sealing) could be done. Thermal conductivity of CFRPs The transient hot-strip (THS) method for measuring the thermal conductivity of solids has been successfully applied to dry and moist carbon fibre reinforced composites (CFRP's). The investigation of electrically conducting CFRP samples has been carried out by inserting a thin insulating polymer layer between the metal strip and the specimen. Although the insulation leads to additional thermal contact resistance between specimen and hot-strip, the method yields reliable results as long as the layer thickness does not exceed a particular critical value. When the THS method is applied to the non-isotropic CFRP's, the measured thermal conductivity shows systematic differences depending on the kind of orientation of the carbon fibres with respect to the strip sensor. To measure the quantity of heat transmitted in a direction normal to the surface of a CFRP board, strip and fibres must be aligned parallel to each other. Depending on the type of material analysed, maximum water absorption capabilities between 0.8% and 1.6% have been found while the actual moisture content of a particular sample directly relates to the ambient humidity. The difference in measured thermal conductivities between a dry and a moist specimen lies almost within the measurement uncertainty of the THS method. Searching for OpenAIRE data... 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