Abstract: A method for resin transfer molding composite articles of complex configuration that have high fiber-to-resin ratios. The molding apparatus includes a compliant mold subassembly having one or more conformable cauls and a complementary, non-permeable membrane that function, in combination, as a semi-rigid molding tool. The compliant mold subassembly is relatively insensitive to bulk variations of layed-up fiber reinforcement material, facilitating fiber reinforcement material lay up and closure of the molding apparatus. The compliant mold subassembly provides uniform pressures during various molding stages, i.e., resin injection, expulsion of excess resin, curing, to enhance the homogeneity and dimensional stability of the finished composite article. The semi-rigid aspect of the compliant mold subassembly facilitates demolding of the finished composite article.

Abstract: A shrinkable foam mandrel that can be easily removed and composite resin transfer molding process that uses the foam mandrel. The foam is dimensionally stable at a first temperature that typically corresponds to the cure temperature of the composite resin. The foam is capable of irreversibly shrinking to less than about 0.5 said foam's original size at a second tempertaure that is above said first tempertaure. The foam is encapsulated by a non-stick elastomer skin and covered with fibers. The fiber covered elastomer encapsulated foam is disposed in a female mold cavity and resin is injected into the female mold cavity. The resin and fibers are cured and the resulting composite component is removed from the female mold. The temperature is raised to the second temperature and the elastomer encapsulated foam male mandrel irreversibly shrink to less than about 0.5 its original size. Finally the shrunken male mandrel is removed from said composite component.