Abstract: Forming a cured composite structure may include assembling pre-cure members about a variable volume support member to form a pre-cure assembly, applying an internal pressure from within the pre-cure assembly by maintaining the variable volume support member at an expanded volume, and curing the pre-cure members by applying heat while the variable volume support member is in the expanded volume to form a cured composite structure.

Abstract: Composite tooling is fabricated with low cost dry fabrics and a neat resin instead of expensive prepregs. Dry, three-dimensional woven joint preforms are placed on a dry tool substrate and dry, 3D preforms are also placed between pre-cured egg crate-like junctions. The entire tool substrate and substrate-to-support structure joints are then resin-infused simultaneously through the use of rota-molded tooling aids, providing an additional reduction in cost. Tight control of resin content and distribution with vacuum infusion is thereby provided. This process eliminates the primary cause of structural weakness and cooling distortion, which typically occur at the attachment interface when existing methods are used. The preforms provide significantly greater pull-off strengths at interfaces than do hand-laid tie plies. Issues with tool surface durability are addressed through the use of ceramic-filled face coat.