Investigation of Smooth-Bonded Metal Liners for Glass Fiber Filament-Wound Pressure Vessels.

Filament-wound fiberglass has been recognized for some time as a potential structure for storing fluids under pressure in a cryogenic environment. The highest potential is realized with a thin, smooth-bonded, metallic liner. The number of cycles that can be achieved with such a liner, however, is dependent upon the ability of the adhesive to prevent the liner from buckling and upon the ability of the liner to resist fracture when subjected to high, plastic, tensile-compressive strains. The goal of this investigation was the development of a liner-adhesive system, which when incorporated into a vessel, would withstand repeated cyclic loadings over a temperature range of 75 deg F to -423 deg F. Various adhesive systems were evaluated in preliminary coupon testing. A blended polyurethaneepoxy 7030 pbw resin with a glass scrim cloth system was selected for further testing in a 11 biaxial pressure vessel. A thin aluminum liner performed well 100 pressure cycles to 2 strain with the adhesive at -423 deg F, but at ambient temperature, aluminum liners and a nickel liner buckled and failed. On the basis of these results, a reorientation was made to further develop an adhesive system to satisfactorily bond the liner at both ambient temperature and -423 deg F. The use of a thin nylon scrim in the adhesive, in place of the glass scrim, improved the ambient temperature performance of the 7030 blend adhesive, while at the same time, it did not cause a degradation in the -423 deg F performance 10 pressure cycles to 2 strain this was with aluminum liners nickel work was discontinued. An 8020 blend adhesive with nylon scrim also performed satisfactorily. The primary liner in all cases remained satisfactorily bonded to the structural wall. However, at -423 F, in all cases, leakage occurred through the bonded longitudinal seam. MM