United Technologies Corporation

Richard T Reavely

Robert V Kromrey

Peter C Ogle

David N Schmaling

Wonsub Kim

David J Parker

A method of making fiber reinforced composite articles from stabilized dry fiber preforms which are impregnated with a thermosetting resin by the resin transfer molding method. The dry fiber preforms may be stabilized prior to molding by dispersing a polymeric binder between adjacent dry fabric plies of the preform. Hot air is passed through the preform after it has been compressed to fuse the binder and bind the dry fabric plies together, forming a stabilized high density fiber preform. Forming a preform by this method is significantly less labor and time intensive than methods currently in use.

Method of fabricating fiber reinforced composite articles by resin

A solid flowable polymeric material useful as a pressurizing medium that is ultraviolet detectable and is particularly adapted for use in a molding process. The polymeric material comprises a substantially uniform mixture of a solid, flowable, particulate silicone having a nominal flow rate of at least 0.6 gram per second through a 1.1 cm diameter pipe 7.6 cm long under applied pressure of 10.34 MPa at room temperature and an ultraviolet detectable compound. The polymeric material is especially useful for molding composites. A composite is disposed with a pressure vessel which is substantially filled with the above mixture. The silicone is caused to produce a substantially uniform, predetermined medium pressure on the surface of said composite prepreg. The composite prepreg is cured to form a composite which is removed from the pressure vessel and exposed to ultraviolet light.

Method of molding using a solid flowable polymer medium with U.V.

A method particularly adapted for making a complex shaped composite component that has reduced bridging defects. The method comprises disposing a composite prepreg on to a substantially flat tool. The composite prepreg has a substantially flat section and at least one prepreg member extending from and substantially perpendicular to said flat section. A layer, at least about 125% of said composite prepreg height, of a said flowable particulate silicone rubber is disposed in substantially complete contact with the composite prepreg surface. The particulate silicone rubber has a flow rate of at least 0.6 gram/second through a 1.1 cm diameter pipe 7.6 cm long under applied pressure of 10.34 MPa at room temperature. The layer of solid flowable rubber is covered with a bag to effect a gas tight seal. The bag is exposed to pressures which are transferred to said prepreg by said solid flowable polymer. The composite prepreg is exposed to temperatures to form a composite component.

Method of vacuum bagging using a solid flowable polymer

A method of fabricating a fiber reinforced resin composite article having tubular structures that has improved density and fewer voids. The method comprises laying up a prepreg that has at least two tubular structures and disposing a thermally conductive metallic support structure within and in contact with the tubular structures. The prepreg is disposed within and in substantially complete contact with a tool which has at least one hole. An expandable bag having at least one opening in communication with a tube is inserted within each tubular structure thereby forming a void space between the bag and the tubular structure. The void space is substantially filled with a solid flowable particulate silicone rubber that contacts the prepreg and the tube is sealed to edge of hole in the tool. The solid flowable rubber is caused to transfer a substantially uniform predetermined pressure to the surface of the prepreg by pressurizing the expandable bag. The composite prepreg is exposed to heat by conducting heat through the thermally conductive metallic support structure in order to cure the composite article.

Method of fabricating tubular composite structures

The present invention discloses a damage tolerant composite article comprising a plurality of layers of both graphite and polyaramide fibers. The graphite fiber layers are oriented at angles of about .+-.30.degree. and about .+-.15.degree. to the longitudinal axis while the polyaramide fiber layers are oriented at about .+-.14.degree. to the longitudinal axis. Composite structures of this construction will have increased damage tolerance while maintaining the required bending and torsional stiffness.

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Madison, CT, United States of America

Richard T Reavely