Strain measurements in a cryogenic environment using fiber optic sensors and strain gauges

Abstract

To achieve the ambitious goal of CO2-neutral aviation by 2050, new propulsion systems and fuels must be considered. One promising candidate is liquid hydrogen. However, the storage of liquid hydrogen is a complex challenge. Although storage in the liquid phase allows a thin-walled design at pressures of 1 to 4 bar, it also places high demands on materials and design. The required temperature of -253 °C also requires very good insulation. Mechanical loads and thermal residual stresses are superimposed in the tank, which can lead to high stress peaks. It is therefore important to know the exact stresses and strains in order to design the material and avoid damage. To this end, TMLA specimens are produced to experimentally determine the thermal expansion properties of CFRP laminates and then compare them with simulated values. For this purpose, the specimens are prepared with fibre optic sensors and strain gauge strips to measure the strains.