Thermally induced stress analysis of composite/aluminum ring specimens at cryogenic temperature

In this study, the characteristics of filament wound composite/aluminum ring specimens were investigated at cryogenic temperature. Ring specimens were manufactured using carbon fiber and Type B epoxy resin which had been developed for cryogenic use. By measuring the thermal strain at −150 °C, it was found that compressive thermal stress was induced in the composite part, while the tensile thermal stress in aluminum part, which was about 32% of yield stress, in turn caused aluminum to yield at a lower load level. In addition, the thermal strain from a finite element analysis showed good agreement with this measure in an experiment. After six mechanical loading cycles were applied to the ring specimen at −150 °C, tensile tests were performed at −150 °C using split disk fixtures. The results of these tests showed that the composite strength in a liner-composite tank structure for use in a cryogenic propellant tank is decreased by the applied auto-frettage pressure.