Method for producing integrally stiffened fiber reinforced plastic panels
First Claim
1. A process for producing an integrally stiffened panel comprising a skin of fiber reinforced resin containing T-section stiffeners of fiber reinforced resin, which comprises:
- (a) producing a rubber-like form block having T-shaped grooves therein corresponding to the shape of said T-section stiffeners,(b) inserting T-section stiffeners of fiber reinforced partially cured thermosetting resin into the grooves of said form block, said T-section stiffeners comprising a leg and outwardly extending flanges,(c) introducing the resulting assembly of the form block and stiffeners into a die,(d) placing a sheet of fiber reinforced partially cured thermosetting resin forming a skin over said form block and in contact with the flanges of said T-section stiffeners.(e) and co-curing said stiffeners and said skin under heat and pressure to integrally connect said stiffeners to said skin.
1 Assignment
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Accused Products
Abstract
A method for producing T-section integrally stiffened reinforced panels formed of parallel stringers or stiffeners having a T-section, formed of fiber reinforced resin, co-cured to a skin component to be reinforced, also formed of fiber reinforced resin, comprises first forming a rubber-like, e.g., silicone rubber, form block containing T-shaped grooves corresponding to the T-section stiffeners. Lay-ups in the form of fiber reinforced partially cured thermosetting resin T-shaped stiffeners are then forced into the grooves of the rubber-like form block in spaced parallel relation therein, and the center of the T-section stiffeners between the flanges thereof is filled with unidirectional tape comprised of fiber reinforced partially cured thermosetting resin. An outer skin formed of fiber reinforced partially cured thermosetting resin fabric is then placed over the rubber-like form block and the T-section stiffeners therein. A top plate is then applied over the outer skin and the entire assembly is vacuum bagged and cured under heat and pressure to co-cure the parallel lay-ups or stiffeners in the form of T-section reinforcements, to the outer skin, to provide a uniform unwarped integrally stiffened panel.
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Citations
24 Claims
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1. A process for producing an integrally stiffened panel comprising a skin of fiber reinforced resin containing T-section stiffeners of fiber reinforced resin, which comprises:
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(a) producing a rubber-like form block having T-shaped grooves therein corresponding to the shape of said T-section stiffeners, (b) inserting T-section stiffeners of fiber reinforced partially cured thermosetting resin into the grooves of said form block, said T-section stiffeners comprising a leg and outwardly extending flanges, (c) introducing the resulting assembly of the form block and stiffeners into a die, (d) placing a sheet of fiber reinforced partially cured thermosetting resin forming a skin over said form block and in contact with the flanges of said T-section stiffeners. (e) and co-curing said stiffeners and said skin under heat and pressure to integrally connect said stiffeners to said skin. - View Dependent Claims (2, 3, 4, 5, 6, 7, 19, 20, 21, 22)
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8. A process for producing an integrally stiffened panel comprising a skin of fiber reinforced resin containing T-section stiffeners of fiber reinforced resin, which comprises:
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forming a wax layer on the bottom plate of a die having the approximate shape and thickness of said skin, positioning a plurality of model T-sections on said wax layer, said model T-sections having a leg and flanges of substantially the same size and shape as said T-section stiffeners, said flanges of said model T-sections being in contact with said wax layer, filling said die with a partially cured rubber-like thermosetting resin material and covering said model T-sections with said material, curing said thermosetting material to form a solid rubber-like resilient mass, removing said model T-sections from said rubber-like mass to form said form block containing said T-shaped grooves, inserting T-section stiffeners of fiber reinforced partially cured thermosetting resin into the grooves of said form block, said T-section stiffeners comprising a leg and outwardly extending flanges, introducing the resulting assembly of the form block and stiffeners into a die, placing a sheet of fiber reinforced partially cured thermosetting resin forming a skin over said form block and in contact with the flanges of said T-section stiffeners, and co-curing said stiffeners and said skin under heat and pressure to integrally connect said stiffeners to said skin. - View Dependent Claims (9, 10, 11)
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12. A process for producing an integrally stiffened panel comprising a skin of fiber reinforced thermosetting resin having integrally connected thereto on one surface thereof a plurality of spaced parallel T-section stiffeners of fiber reinforced resin, which comprises
(a) producing a rubber-like form block having a plurality of spaced parallel T-shaped grooves therein corresponding to the shape of said T-section stiffeners, (b) inserting T-section stiffeners of fiber reinforced partially cured thermosetting resin into the grooves of said form block, said T-section stiffeners comprising a leg and outwardly extending flanges, said flanges being positioned at the top of said form block, said T-section stiffeners being in the form of a lay-up comprising a plurality of layers of a tape of graphite fibers impregnated with partially cured epoxy resin, (c) inserting unidirectional tape of graphite fibers impregnated with partially cured epoxy resin into the center space of said T-section stiffeners between the flanges thereof, to fill said center space, (d) introducing the resulting assembly of the form block, said stiffeners and said fill tape, into a die surrounding said form block, (e) placing a sheet of fabric comprised of fiber reinforced composite material impregnated with a partially cured thermosetting resin forming a skin, in contact with the top of said form block and the flanges of said T-section stiffeners, and (f) co-curing said T-section stiffeners, said unidirectional tape and said skin in an autoclave at a temperature sufficient to integrally connect said stiffeners and said unidirectional tape to said skin with said stiffeners in spaced parallel relation.
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23. A process for producing an integrally stiffened panel comprising a skin of fiber reinforced resin containing T-section stiffeners of fiber reinforced resin, which comprises:
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producing a rubber-like form block having T-shaped grooves therein corresponding to the shape of said T-section stiffeners, inserting T-section stiffeners of fiber reinforced partially cured thermosetting resin into the grooves of said form block, said T-section stiffeners comprising a leg and outwardly extending flanges, placing a sheet of fiber reinforced partially cured thermosetting resin forming a skin in contact with the flanges of said T-section stiffeners and with the adjacent surface of said form block, and subjecting the resulting assembly of the form block, stiffeners and skin to heat and pressure in a die to co-cure said stiffeners and said skin under conditions to balance the internal pressure generated in said rubber-like form block, whereby no "hump effect" of said form block occurs and the cured integrally stiffened panel is unwarped. - View Dependent Claims (24)
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Specification