Large composite core structures formed by vacuum assisted resin transfer

Abstract

Large composite structures are produced using a vacuum assisted resin transfer molding process. The structures incorporate cores, which may be hollow cells or foam blocks. A plurality of cores, each of which may be wrapped with a fiber material, is arranged in a layer on a mold with a fiber material arranged to form face skins. The assembly is sealed under a vacuum bag to a mold surface. One or more main feeder conduits are provided in communication with a resin distribution network of smaller channels which facilitates flow of uncured resin into and through the fiber material. The resin distribution network may comprise a network of grooves formed in the surfaces or the cores and/or rounded corners of the cores. The network of smaller channels may also be provided between the vacuum bag and the fiber material, either integrally in the vacuum bag or via a separate distribution medium. Resin, introduced under vacuum, travels relatively quickly through the main feeder channel(s) and the network of smaller channels. After penetrating the fiber material to reach the surface of the cores, the resin again travels relatively quickly along the cores via the grooves in the cores or the spaces provided by the rounded corners to penetrate the fiber material between the cores, if present, and between the cores and the mold.