Process and apparatus for the production of high strength polymer composite structures

An apparatus for use in the production of fiber reinforced polymer composite structures includes a mold having a mold surface and a fiber construction on the mold surface including at least one layer of resin absorbing fibrous lay up material. A stiffener on the fiber construction is constructed of a resin absorbing material. A flexible, resin impervious vacuum bag lays over the mold surface and is marginally sealed to the mold surface to define an enclosure for the fiber construction and stiffener. The vacuum bag has a resin inlet to permit introduction of a resin into the enclosure. A vacuum is drawn upon the enclosure to draw the vacuum bag against the fiber construction and stiffener. The stiffener spaces the vacuum bag from the fiber construction when the vacuum bag is drawn against the fiber construction and stiffener to facilitate the distribution of resin uniformly throughout the fiber construction. The stiffener is integrated with the fiber construction upon curing of the resin.