United Technologies Corporation

Peter B Leoni

David A Kovalsky

Philip J Ramey

Gary J Jacaruso

Alexander C Dublinski

A two-stage co-cure method for fabricating a composite article having a box-beam cross-sectional configuration wherein an outer shell portion of the composite article is fabricated and configured in the first stage to function as the tooling for completing the fabrication of composite article in the second stage. The first stage includes a step wherein a molding assembly is configured to define the outer margin line surface of the outer shell, a step wherein prepreg plies forming the outer shell are layed-up in the molding assembly, a step wherein the layed-up molding assembly is vacuum bagged and evacuated in preparation for curing, a curing step, an optional step wherein the molding assembly is reconfigured as required so that the reconfigured molding assembly and the outer shell in combination define a foam injection cavity, an injecting step wherein a high temperature, high pressure foam is injected into the foam injection cavity to form an outer shell, cured foam core stabilized combination that functions as the tooling for the second stage, and a disassembly step. The second stage includes an application step wherein a film adhesive is applied to the outer shell, cured foam core stabilized combination, a step wherein prepreg plies forming an inner cap are layed-up onto the adhesive coated outer shell, cured foam core stabilized combination, a step wherein layed-up outer shell, cured foam core stabilized combination is vacuum bagged for curing, and a curing step.

Two-state co-cure method for fabricating a composite article

The method of fabricating selectively shaped dog-leg plies of composite material comprising unidirectionally extending high tensile strength fibers or filaments extending for the full length of the ply and embedded in a resin matrix comprising winding high tensile strength filament onto a mandrel of generally cylindrical shape but having circumferentially extending frustoconical projections extending radially therefrom so that the filament wound onto the cylindrical portion of the mandrel forms the straight legs of the dog-leg ply and so that the filament wound on the frustoconical projection of the mandrel form the arcuate central portion of the dog-leg ply.

Method of manufacturing a dog-leg shaped ply of composite material and

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 method of making tubular composite structures that simplifies vacuum bag sealing. The method comprises disposing a prepreg structure within a tool that has at least one hole. The prepreg is disposed adjacent a mandrel. The mandrel comprises an inner bag containing a solid filler core that comprises about 75% to about 95% of the volume of the inner bag. The hole is enclosed with a vacuum bag thereby forming a void space between said vacuum bag and said prepreg. The void space is evacuated. The vacuum bag applies a predetermined pressure to the inner bag thus causing the inner bag to apply a substantially uniform predetermined pressure to the surface of the prepreg. The prepreg is exposed to heat.

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Bethany, CT, United States of America

Peter B Leoni