United Technologies Corporation

Sikorsky Aircraft Corporation

Philip J Ramey

Alexander C Dublinski

Darryl Mark Toni

Thomas Arthur Carstensen

Edward Joseph Fabian

Alex C Dublinski

Gary J Jacaruso

Paul A Vallier

Robert L Faiz

Peter B Leoni

Nicholas P Flonc

Terry M Boustead

Dean Nguyen

Donald J Baumgarten

Kenneth M Adams

Matthew T Turner

William J Walker

Ronald J Cooper

A method of fabricating a low total density, stabilized ramped honeycomb core for high pressure co-cure molding of a lightweight honeycomb core composite article includes forming the honeycomb core by net shaping stabilized honeycomb core material into a ramped honeycomb core. The ramped honeycomb core is prepared for lay-up and co-cure by applying a layer of low areal weight film adhesive to the upper and lower surfaces and to each ramped surface of the ramped honeycomb core. The honeycomb core material is stabilized for the net shaping operation by applying a layer of low areal weight film adhesive to the upper and lower surfaces of the honeycomb core material in a predetermined picture frame format.

Method of fabricating a low total density, stabilized ramped honeycomb

A method for high pressure co-cure molding of lightweight honeycomb core composite articles having ramped surfaces utilizing low total density, stabilized ramped honeycomb cores. The low total density, stabilized ramped honeycomb core is formed by net shaping stabilized honeycomb core material into a ramped honeycomb core, which is prepped for lay-up and co-cure by applying a layer of low areal weight film adhesive to the upper, lower and ramped surfaces thereof. The honeycomb core material is stabilized for the net shaping operation by a layer of the low areal weight film adhesive applied to the upper and lower surfaces of the material in a predetermined picture frame format. Composite prepregs and the ramped honeycomb core are layed-up in a semi-rigid molding assembly including a rigid base member and a complementary semi-rigid mold member having at least one internal rigid reinforcement insert, which is vacuum bagged and disposed in an autoclave. The vacuum bag is evacuated, and the layed-up molding assembly is subjected to a two stage pressure, temperature cycle for high pressure co-cure. The autoclave is pressurized to a dwell pressure, and the temperature is then raised from ambient to a dwell temperature whereupon the autoclave is stabilized for a dwell period. Next, the autoclave pressure is increased to a high pressure, and the temperature is raised to a co-cure temperature whereupon the autoclave is stabilized for a co-cure period to effect curing of the lay-up. After curing is complete, the autoclave is cooled, and then depressurized for removal of the composite molding apparatus.

Method for high pressure co-cure molding of lightweight honeycomb core

A method of fabricating a structural member having a stiffener bead therein. Prepreg plies or layers of high tensile strength fabric are laid up on a conformable caul plate. A rubber-like plug is prefabricated to the shape of the stiffener bead and is urged into a stiffener bead cavity of the caul plate by a metal tool to sandwich the prepreg plies between the caul and the plug. The caul and the plug cooperate to cause the prepreg plies to conform to the desired shape of the stiffener bead.

Method of fabricating a structural member having a stiffener bead therein

A composite molding apparatus for high pressure co-cure molding of lightweight honeycomb core composite articles having ramped surfaces utilizing low total density, stabilized ramped honeycomb cores. The composite molding apparatus is a semi-rigid molding assembly that includes a rigid base member and a complementary semi-rigid mold member that is formed from a combination of layers of fiber-reinforced elastomeric material and unreinforced elastomeric material. The semi-rigid mold member further includes internal rigid reinforcement inserts formed from a structurally rigid material and having a configuration that matches the configuration of the ramped surfaces of the honeycomb composite article. The rigid reinforcement inserts are interleaved between the layers of fiber-reinforced elastomeric material and/or unreinforced elastomeric material forming the semi-rigid mold member. The rigid reinforcement inserts of the semi-rigid mold member provide symmetric pressure distribution over the ramped surfaces of the honeycomb core and the overlayed composite prepregs during the high pressure co-cure process.

Composite molding apparatus for high pressure co-cure molding of

A composite forming tool is fabricated by securing shapeable filler blocks between composite headers and contouring the blocks to match the shape of the headers, to form a support structure with a continuous surface. Layers of uncured, composite laminates are laid up over the support structure and cured. The filler blocks may be removed after curing.

Method for fabricating a composite structure

The method of fabricating a complex part made of composite material and having a plurality of panels oriented in diverse angular relationship, and utilizing a plurality of conformable cauls upon which the composite material is individually laid up and which cauls cooperate to form one of the molds used in the co-curing of the individually laid-up composite materials.

Method of fabricating a complex part made of composite material

A structural member made up of a plurality of bonded plies of high tensile strength woven fabric and molded to include at least one stiffener bead having elliptically shaped ends, and a structural part so fabricated.

Structural member having a stiffener bead therein and comprising plies

A mold, adapted for resin transfer molding of composite articles, that has a seal for maintaining a vacuum resulting in denser composite parts. A mold body has at least two openings including an opening for removing the article therethrough. There are at least two mold closures adapted for closing the openings and two of the mold closures are in mutual contact within the interior of the mold. A seal is disposed between each closure and the mold body for sealing each mold closure to the mold body to continuously seal only a single surface. The mold has an improved seal for initiating and maintaining a vacuum thus reducing part porosity.

Resin transfer mold

A method for resin transfer molding composite articles of complex configuration that have high fiber-to-resin ratios. The molding apparatus includes a compliant mold subassembly having one or more conformable cauls and a complementary, non-permeable membrane that function, in combination, as a semi-rigid molding tool. The compliant mold subassembly is relatively insensitive to bulk variations of layed-up fiber reinforcement material, facilitating fiber reinforcement material lay up and closure of the molding apparatus. The compliant mold subassembly provides uniform pressures during various molding stages, i.e., resin injection, expulsion of excess resin, curing, to enhance the homogeneity and dimensional stability of the finished composite article. The semi-rigid aspect of the compliant mold subassembly facilitates demolding of the finished composite article. The process utilizes stage pressurization transmitted through the compliant mold subassembly to enhance resin flow for complete, uniform saturation of fiber reinforcement layups and to expel excess resin prior to curing of the resin-impregnated fiber reinforcement layups.

Tooling method for resin transfer molding

A shrinkable foam mandrel that can be easily removed and composite resin transfer molding process that uses the foam mandrel. The foam is dimensionally stable at a first temperature that typically corresponds to the cure temperature of the composite resin. The foam is capable of irreversibly shrinking to less than about 0.5 said foam's original size at a second tempertaure that is above said first tempertaure. The foam is encapsulated by a non-stick elastomer skin and covered with fibers. The fiber covered elastomer encapsulated foam is disposed in a female mold cavity and resin is injected into the female mold cavity. The resin and fibers are cured and the resulting composite component is removed from the female mold. The temperature is raised to the second temperature and the elastomer encapsulated foam male mandrel irreversibly shrink to less than about 0.5 its original size. Finally the shrunken male mandrel is removed from said composite component. These mandrels are a solution to the aerospace industry's flyaway mandrel problem as they are lightweight and can easily be removed from the composite component.

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Milford, CT, United States of America

Philip J Ramey