The use of glass-fiber reinforced plastic (GRP) can reduce the weight of tanks significantly. By replacing steel with GRP in tanks for gases (propane, etc.) a weight reduction of up to 50 % was reached. In this project not only the material should be optimized, but also the design. Previous tanks consist of a double-walled structure with an insulation layer between the two shells (e.g. vacuum). Goal of this project is to realize a single-walled construction of GRP with an insulation layer on the outside. To determine the temperature dependent material values, two different experiments are performed: In the first experiment, temperature dependent material properties of liquid nitrogen found in literature research are validated in a simple setup. The level of liquid nitrogen in a small jar is measured over the experiment time. Numerical simulation shows the change of nitrogen level with sufficient precision. In the second experiment, a liquid nitrogen is applied on one side of a GRP plate. Temperature is measured with thermocouples on top and bottom of the GRP plate, as well as in the middle of the plate. By use of numerical simulation, temperature dependent thermal conductivity is determined. In the third experiment, a test stand is designed to examine different insulation materials. In this test stand, the insulation material can easily be changed. A numerical simulation, in which the determined material data is used, is performed as well for this test stand. The experiments show, that GRP can be used in cryogenic environments. Multiphase simulations are a suitable tool to describe the energy absorption of thermal energy due to thermal phase change. Results on different insulation materials will follow.

To reduce the emission of carbondyoxide (CO2) of combustion engines, liquefied naturalgas (LNG) is used as an alternative fuel. LNG is transported via truck, ship or railway for longdistances. Double walled stainless steel tanks are used for transportation, which are heavy and expensive.The vacuum insulation between the two walled structure ensures that the LNG stays liquid overthe transportation time (boiling point of LNG: −162 °C). This causes a high temperature differencebetween the transported good and the ambient air. A simplified tank construction is used to reduce the weight and price of the tank. Instead of stainlesssteel, glass fiber reinforced plastic (GFRP) is used. The designed is changed to a single walledconstruction with a solid insulation material outside on the GFRP structure. Goal of this work is the characterization of a suitable insulation material and configuration as wellas the analysis of the mechanical properties of GFRP under cryogenic conditions. Several experimentsare carried out. Numerical models of these experiments can then be used for parameter studies.

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