Abstract: Techniques for manufacturing structures that include composite hat stringers are disclosed. In one embodiment, a method of forming a composite structure includes placing a generally cured composite hat stringer on a tool, the hat stringer having a rigid mold line conformal surface for adjoining a generally uncured skin, positioning the skin adjacent to the rigid mold line conformal surface, coupling the skin to the rigid mold line conformal surface of the composite hat stringer, including applying a pressure to a surface of the skin to urge the skin into engagement with the composite hat stringer, and curing the skin.

Abstract: Techniques for manufacturing structures that include composite hat stringers are disclosed. In one embodiment, a method of forming a composite structure includes placing a generally cured composite hat stringer on a tool, the hat stringer having a rigid mold line conformal surface for adjoining a generally uncured skin, positioning the skin adjacent to the rigid mold line conformal surface, coupling the skin to the rigid mold line conformal surface of the composite hat stringer, including applying a pressure to a surface of the skin to urge the skin into engagement with the composite hat stringer, and curing the skin.

Abstract: Apparatus and techniques for providing a closed hat stringer are disclosed. In one embodiment, a closed hat stringer for stiffening a composite structure includes opposing cavity walls situated between a first flange and a second flange, the cavity walls, first flange and second flange defining an elongated cavity, the second flange including a continuous exterior surface having a width greater than the first flange and configured for attachment to a skin.