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This paper describes the experimental study of impact testing and permeability testing of CFRP laminates for application of propellant tanks considering the reliability of the tank structures associated with foreign object impact damage. Three types of quasi-isotropic laminates with different laminate thickness were prepared and subjected to transverse impact tests, nondestructive inspections, and helium gas permeation tests in series. Transverse impacts induced delaminations, matrix cracking, and fiber breakage, which caused severe through-thickness gas leakage. Effects of impact energy and laminate thickness on the permeation-after-impact properties are discussed, and the critical damage mode controlling the severe gas leakage is identified.

This paper describes the experimental assessment of gas permeability of carbon fiber/toughened epoxy laminates under cyclic loadings as a fundamental research for the development of composite cryogenic propellant tank for reusable space transportation system. A thin-ply technique, which may contribute to the enhancement of damage resistance of CFRP laminates, is introduced herein, and the damage accumulation behaviors and gas permeability are compared between thin-ply laminates and standard laminates subjected to cyclic tension and impact.