Experimental evaluation of gas permeability through damaged composite laminates for cryogenic tank

This paper describes some recent experimental techniques for leakage assessment in conjunction with permeability results of composite laminates with matrix cracks in relation to the application of composite laminates to cryogenic fuel tank structures. Tensile loadings were applied to CFRP tubular specimens utilizing a cryogenic loading system for leak measurement at room temperature (RT) and at liquid nitrogen temperature (LN2T). Helium gas permeability through damaged CFRP under both RT and LN2T conditions was compared. Furthermore, an experimental method for evaluating the effect of crack intersecting angle on the gas leakage was proposed, and measured results were presented.