FILAMENT-WINDING PLASTICS. PART 2. ROLE OF THE RESIN IN GLASS-FIBER-REINFORCED STRUCTURES UNDER TENSILE STRESS

A study was conducted on amine-cured epoxy resins and the effects on the ultimate burst strength of internally loaded glass-reinforced filament-wound vessels when these resins were used as the plastic matrices. The tensile properties of the matrix were changed by systematically altering the molecular structure of the amine-cured epoxy resin. It was found that resin tensile properties had an insignificant effect on the ultimate burst strength of a well- designed and wellfabricated vessel. However, it was also found that a matrix of good tensile properties improved the reliability of the burst pressure by providing a healing effect on minor winding errors. The glass stresses at burst of the test vessels were 400,000-psi range, which is about the ultimate tensile strength of bundles of E glass. A summary discusses the state of the art and unsolved problems relevant to the plastic matrix in glass-reinforced filament- wound vessels. In particular, the deleterious effect of voids on externally loaded structures and the necessity of removing these voids is discussed.