Fiber-placed composite grid-stiffened structures

Composite grid-stiffened structures axe less expensive to fabricate than widely used honeycomb-core structures. They impose no weight penalty and provide improved damage tolerance and no moisture infiltration problems, and the stiffening can be tailored to fit local geometric variations and cutouts. The cost savings comes from the use of the automated fiber placement process which generates a unitized structure complete with skin and stiffeners, in contrast to honeycomb structures that require the purchase, forming and machining of core, hand layup of adhesive film and core pieces, and potting of edges and seams. Recent developments have simplified the tooling and manufacturing process for composite grid-stiffened structures providing the opportunity to apply them to large shell structures traditionally made with honeycomb core. A current application for a payload fairing is described. Other potential applications include aerodynamic fairings, cowlings and fuselages.