Abstract: A structure and a method of producing such structure which includes a fiber reinforced composite article in which the surface of the article will generate a visible indication thereon upon impact of the surface by another object. The method comprises laying up multiple layers of a first material into the shape of the desired composite article. A relatively thin layer of a second filamentary material is then layed up on and bonded to the surface of the base structure formed by the layers of the first material. The second filamentary material forms a thin outer layer on the composite article, and upon impact of the outer layer with another object, the outer layer delaminates and forms a discoloration in the form of a whitened patch or spot in the immediate vicinity of the impact. The articles so produced can be visually inspected for damage, and only those articles showing a surface discoloration need be subjected to nondestructive testing.

Abstract: A high pressure vessel construction in the form of an elongate tank includes a plurality of layers of resin impregnated graphite fibers and a plurality of layers of a hybrid of resin impregnated glass and polymer fibers, with the glass and polymer fiber layers alternating with the graphite fiber layers. The outermost layers are hoop wound and the innermost layers are helically wound. A layer of elastomer material is joined to the interior surface of the innermost layer of fibers, and a layer of stiff composite material is joined to the interior surface of the elastomer layer.

Abstract: A method of manufacture of large high pressure composite bottles. In accordance with the method, polar caps are placed on the ends of a reusable mandrel, which is then coated with an appropriate mold release and then coated or at least covered with a material which will become the internal protective coating for the finished bottle, and then coated with an impervious liner material. Thereafter, a few layers of windings of high strength resin impregnated filament are put on the mandrel and the resin is cured to make the internal protective coating and liner self-supporting. The resulting thin shell is then cut circumferentially near the middle thereof and the two halves are removed from the mandrel, then rebonded together so that the thin shell may act as a self-supporting mandrel over which the structural shell of the bottle is subsequently wound. This allows the original mandrel to be used over and over again as desired. Various details and variations of the method are disclosed.