Myung-Gon Kim

Damage Analysis of a Type 3 Cryogenic Propellant Tank After LN2 Storage Test

The application of composites to cryotanks has been one of the major concerns for lightweight launch vehicles. In this study, a prototype of a Type 3 cryotank was fabricated with the composite developed for cryogenic application and aluminum liner, and the cryogenic conditions were applied by filling the prototype with liquid nitrogen and then pressurizing it with gaseous nitrogen. During the experiment, delamination inside the cryotank happened. This article describes several attempts made to investigate failure through both analytical approach with thermo-elastic analysis accompanied by progressive failure and experimental approach with LN2 immersion of composite/aluminum ring specimens.

Tensile Properties of Carbon Fiber Composites with Different Resin Compositions at Cryogenic Temperatures

In this study, the tensile properties of carbon fiber reinforced polymer (CFRP) composites with different resin compositions were investigated in order to develop advanced composite materials for cryogenic use. Thermo-mechanical cyclic loading (up to 6 cycles) was applied to CFRP unidirectional laminate specimens from room temperature to –150°C. Tensile tests were then performed at –150°C using an environmental test chamber. In addition, matrix-dominant properties such as the transverse and in-plane shear characteristics of each composite model were measured at –150°C to examine the effects of resin formulation on their interfacial properties. The tensile tests showed that the composite models with large amounts of bisphenol-A epoxy and CTBN modified rubber in their resin composition had good mechanical performance at cryogenic temperatures (CTs).