Methods for forming integral composite parts with a smp apparatus

ES 2 548 827 T3

DESCRIPTION

Methods for forming integral composite parts with an SMP apparatus

Background

Countryside

The present invention relates to systems and methods for using a reusable shape memory polymer (SMP) apparatus to manufacture composite parts.

Related art

Composite parts, such as those used in aircraft manufacturing, can be constructed using various production methods, such as filament winding, taping, outer braiding, movable fiber cutting, coating, hand molding, or other manufacturing techniques. composite material processing and curing processes. Most of these processes use a rigid curing tool or mandrel onto which the composite material is applied and then cured into a rigid composite part. Removal of the rigid curing tool or mandrel from the cured composite part is generally difficult, expensive, and / or time consuming, particularly if the resulting composite part has capture geometry that prevents easy removal of the part. One known method of removing the mandrel requires sacrificing or destroying the mandrel by cutting, dissolving, blasting, or otherwise disintegrating the mandrel into small pieces that can be removed from within the composite part. Destruction of the mandrel obviously prevents it from being used again for subsequent parts and can be damaged on an internal surface of the composite part.

Another method uses a segmented mandrel that can be disassembled and removed after the composite part is cured. However, these mandrels are expensive and require a great deal of time to install and remove. Additionally, these segmented mandrels are each typically designed to fabricate a specific composite part and are not easily reconfigured for use in fabricating other composite parts.

Still another method uses flammable mandrels that can be removed by deflating after the composite part is cured. However, this method typically involves balloon-like mandrels that can only be used as a bagging aid due to their relative lack of strength and rigidity during composite molding.

Another alternative method involves a silicone coated foam mandrel or tool. This foam tool can be covered with a silicone bag and then wrapped with the uncured composite material. During curing, the silicone bag inflates and the foam tool melts. After it cures, the silicone bag can be removed and reused. However, the foam tool is not reusable, as a new foam tool must be machined from each cure cycle of the new foam.

US-B-7727458 describes a method for manufacturing a composite part, the method comprises:

TO. fabricate a composite part with integrated stiffening agents wherein a final part comprising flanges is molded, activate a shape memory polymer (SMP) apparatus to a malleable state, shape an SMP apparatus in a malleable state to correspond to a configuration desired of a first surface of the composite part to be manufactured, which includes one or more cavities configured for the placement of stiffening agents there; and activating the SMP apparatus to a rigid state.

In accordance with the foregoing, there remains a need for improved methods for manufacturing composite parts.

Resume

Embodiments of the present invention provide methods for manufacturing composite parts using shape memory polymer (SMP) apparatus. An exemplary method may comprise applying the composite material to at least a portion of an SMP apparatus, triggering a change in the modulus of the SMP apparatus from a rigid state to a malleable state, heating the composite material to a material cure temperature. composite, and inducing a differential pressure that drives the SMP apparatus, in its malleable state, toward the composite material prior to and / or during curing to compress the composite against a rigid mold. The change in module can be activated by applying at least one of a temperature change, an electrical current, water, and turning on the SMP apparatus. Once curing is complete, pressure can be released and the SMP apparatus can be removed from within the resulting cured composite part.

ES 2 548 827 T3

Another example method of manufacturing a composite part may comprise the steps of applying the composite material in at least one part of an SMP apparatus, putting the composite material and SMP apparatus in a cavity within a rigid molding tool, in such a way that at least a part of the composite material rests against the rigid molding tool, put an impermeable sheet of material on the composite material and SMP apparatus, and sealing the impermeable sheet of material to the rigid molding tool and / or the SMP apparatus. This method may then comprise heating the composite material to a composite curing temperature, activating the SMP apparatus to change the module from a rigid state to a malleable state, and inducing a differential pressure sufficient to actuate the waterproof sheet of material and the SMP apparatus, in a malleable state, towards the composite material, thereby compressing at least a portion of the composite against the rigid mold before and during curing of the composite within the composite.

In yet another embodiment of the present invention, a method for manufacturing a composite part with integrated stiffening agents may comprise the steps of activating an SMP apparatus to a malleable state, shaping an SMP apparatus in a malleable state to correspond to a desired configuration of a first surface of the composite part to be manufactured, which includes shaping the SMP apparatus to have one or more cavities configured for placing stiffening agents there, activating the SMP apparatus to a rigid state, placing the stiffening agents within the cavities, applying the composite material in the SMP apparatus, and the exposed surfaces of the stiffening agents resting within the cavities, and cooking or bonding the stiffening agents with the composite material on the SMP apparatus by means of pressure and heat to make the composite part.

In another embodiment of the present invention, a method of removing an SMP apparatus from within a cured composite part may comprise the steps of activating the SMP apparatus from a rigid state to a malleable state, inducing a differential pressure that actuates the SMP apparatus, in a malleable state, away from the cured composite part and towards an internal mandrel tool, and removing the inner mandrel tool with the SMP apparatus resting on it outside of the cured composite part. The inner mandrel tool may comprise an outer surface that has varied contours such that a surface area of ​​the outer surface is sufficiently large to prevent the SMP apparatus from bending back on itself or folding when directed toward the punching tool. internal chuck. A maximum straight line distance between points on the outer surface may be small enough to allow the inner mandrel tool to clear for removal of the cured composite part.

In yet another embodiment of the present invention, a method for manufacturing a composite part with integrated stiffening agents may comprise the steps of shaping or casting an SMP apparatus to correspond to a desired configuration of a first surface of the composite part to be to form, shape or cast the SMP apparatus to include one or more cavities configured for the placement of the stiffening agents there, placing the stiffening agents within the cavities, applying the composite material on the SMP apparatus and the exposed surfaces of the stiffening agents resting within the cavities, and co-curing or bonding the stiffening agents with the composite material on the SMP apparatus by pressure and heat medium to make the composite part. In this embodiment of the invention, the SMP apparatus can remain in a rigid state through co-curing or co-adhesion of the stiffening agents with the composite material.

This summary is provided to introduce a selection of concepts in a simplified form which are further described later in the detailed description. This summary is not intended to identify the key features or essential characteristics of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying figures.

Brief description of the figures

Embodiments of the present invention are described in detail below with reference to the accompanying drawings, wherein:

FIGURE 1 is a perspective view of an SMP apparatus constructed in accordance with one embodiment of the present invention and is shown used as a mandrel with the composite material placed thereon;

FIGURE 2 is a vertical cross-sectional elevation view of the SMP apparatus of Figure 1, with the SMP apparatus inflated outwardly to act as an air chamber, pressing the composite material over it toward an external mold;

FIGURE 3 is a perspective view of another embodiment of an SMP apparatus in a rigid, inflated state;

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FIGURE 4 is a perspective view of an internal chuck tool constructed in accordance with one embodiment of the present invention;

FIGURE 5 is an exploded perspective view of the SMP apparatus of Figure 3 after it is slid over the inner mandrel tool illustrated in Figure 4 and heated to contract against the inner mandrel tool, and also illustrates end seals configured to seal the SMP apparatus to the internal mandrel tool at each end thereof;

FIGURE 6a is a perspective view of internal stiffening agents constructed in accordance with embodiments of the present invention and configured to be bonded or co-cured to a composite part;

FIGURE 6b is a fragmentary perspective view of a false skin and false stiffening agents constructed in accordance with one embodiment of the present invention to aid the formed SMP apparatus of Figure 5 within a desired rigid tool configuration;

FIGURE 7 is a fragmentary perspective view of the false skin and false stiffeners of Figure 6, further illustrating stiffening agent inserts placed on and in the false stiffening agents;

FIGURE 8 is an exploded perspective view of the internal mandrel tool of Figure 5 placed within a rigid external tool constructed in accordance with one embodiment of the present invention;

FIGURE 9 is a perspective view of the SMP apparatus of Figure 5 in the desired rigid tool configuration with the internal false stiffening agents resting in the cavities formed there;

FIGURE 10a is a perspective view of the SMP apparatus of Figure 9 in the desired rigid tool configuration with internal stiffening agents removed from cavities formed there;

FIGURE 10b is a perspective view of the SMP apparatus of Figure 5 in the desired rigid tool configuration with the internal stiffening agents of Figure 6a resting in the cavities formed there;

FIGURE 11 is a perspective view of the SMP apparatus of Figure 9 with the composite material applied over it and around the internal stiffening agents;

FIGURE 12 is a fragmentary perspective view of the SMP apparatus and the composite of Figure 11 after the composite is cured, illustrating the space between the SMP apparatus and the cured composite after the SMP apparatus is heated and heated. contracts toward inner chuck tool;

FIGURE 13 is a perspective view of the composite of Figure 12 and the internal stiffening agents of Figure 6 are cooked or bonded within a rigid fuselage, with the internal mandrel tool, the rigid external tool, and the apparatus. SMP withdrawn from this;

FIGURE 14 is a flow chart of a method for forming the SMP apparatus into a desired rigid tool configuration in accordance with one embodiment of the present invention;

FIGURE 15 is a flow chart of a method for manufacturing a fuselage using the SMP apparatus in accordance with one embodiment of the present invention;

FIGURE 16 is a fragmentary cross-sectional view of a J-shaped crossbar that is formed between two SMP appliances and a rigid mold tool, each constructed in accordance with one embodiment of the present invention; Y

FIGURE 17 is a flow chart of a method for making a composite stiffening agent using the SMP apparatus in accordance with one embodiment of the present invention.

The figures do not limit the present invention to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis is placed rather than being placed to clearly illustrate the principles of the invention.

Detailed description:

The following detailed description of the invention refers to the accompanying drawings that illustrate specific embodiments in which the invention may be practiced. Embodiments are intended to describe aspects

ES 2 548 827 T3 of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be used and changes can be made without departing from the scope of the present invention. Therefore, the following detailed description is not taken in a limiting sense. The scope of the present invention is defined only by the appended claims.

Elaboration of Composite Parts with an SMP Apparatus

One embodiment of the present invention is a method of making composite parts. This embodiment of the invention may be implemented with a shape memory polymer (SMP) apparatus 12, as best shown in Figures 1-2, and / or a rigid external tool 28, as finally described herein and illustrated. in Figure 2. The SMP apparatus 12 can be used as a chuck or rigid tool to apply the composite 14 over it, as illustrated in Figure 1, and an air chamber to provide outward pressure to the composite 14 during curing of the composite 14. within a hardened composite part, as illustrated in Figure 2.

The SMP apparatus 12 can be formed from casting the SMP material into any memory shape. For example, SMP apparatus 12 can be cast into a hollow and / or elongated configuration having one or more open ends using any method known in the art, such as methods for forming an SMP cylinder described in U.S. Patent No. 7,422,714 . For example, the SMP apparatus 12 may be a preformed SMP barrel or cylinder open at two opposite ends. Alternatively, the SMP apparatus 12 may have any cross-sectional shape, such as a trapezoid, rectangle, square, or triangle, or it may be cast into a non-hollow configuration. The cast shape of the SMP apparatus is referred to herein as its memory shape.

The SMP material used to form the SMP apparatus 12 may be reinforced or unreinforced SMP material. Specifically, the SMP material used to form SMP apparatus 12 can be an epoxy, an epoxy-based SMP, a styrene copolymer-based SMM, or any other type or combination of SMPs, such as cyanate ester, polyurethane, homopolymer of polyethylene, styrene-butadiene, polyisoprene, copolymers of stearyl acrylate and acrylic acid or methyl acrylate, homopolymers or copolymers of norbonne or dimethanooctahydronaphthalene, and malemide. For example, the SMP material used in SMP apparatus 12 can be any of the SMPs described in US Patent No. 7,422,714, US Patent No. 6,986,855, US Patent No. 7,276,195, US Patent Application Publication No. 2008/0021188, US Patent Application Publication No. 2008/0021166, and / or US Patent Application Publication No. 2008/0269420. However, there are numerous other types of SMPs and they can be tailored to meet specific temperature requirements and tolerances.

The module of various SMP materials can be changed through various different methods, such as a change in temperature, an electric current, water, and / or ignition. However, the example methods described here describe the use of temperature changes to transform the SMP apparatus 12 from a malleable state to a rigid state and vice versa. However, any of the activations listed above to change the SMP material modulus of the SMP apparatus 12 can be used for the composite part manufacturing methods described herein without departing from the scope of the invention.

A glass transition temperature (Tg) of an SMP material is defined herein as a threshold temperature at and / or above which the SMP material begins to transition to a lower modulus state, becoming soft and / or malleable for the purpose of be deformed. Therefore, the SMP apparatus 12 of the present invention can be configured to begin to become flexible and formable when heated above its Tg and to become rigid when cooled to a temperature below its Tg. If the SMP apparatus 12 is deformed at a temperature above Tg and then remains in that deformed state when its temperature drops below Tg, then the SMP apparatus 12 is hardened in that deformed state. When heated again, the SMP apparatus 12 can generally return to its original memory melt shape unless otherwise acted upon by some other force. While the modulus change of the SMP apparatus 12 may start at Tg, it may be in a range of transition temperatures through which the SMP apparatus 12 can become increasingly malleable.

The SMP apparatus 12 can be made of an SMP material having any appropriate Tg for use and the methods described herein. In some embodiments of the invention, Tg may be equal to or less than the curing temperature for the composite material 14, such that the SMP apparatus 12 can be used as an expandable bladder during curing of the composite part. In other embodiments of the invention, Tg may be greater than the cure temperature for composite material 14 such that SMP apparatus 12 remains rigid during composite portion cure.

While the SMP apparatus 12 can be designed to have any Tg, in some example embodiments of the invention, Tg can be a temperature between 100 ° F and 700 ° F (38-371 ° C). Specifically, Tg can be a temperature between 100 ° F and 200 ° F, 200 ° F and 300 ° F, or between 300 ° F and 400 ° F (between 36 and 93, 93 and 149, or between 149 and 204 ° C ). More specifically, Tg can be a temperature between 125 ° F and 175 ° F, 250 ° F and 300 ° F, or 350 ° F and 400 ° F

ES 2 548 827 T3 between 52 and 79, 121 and 149 or 177 and 204 ° C. In one embodiment of the invention, Tg of SMP apparatus 12 may be approximately equal to 143 ° F, 275 ° F, or 375 ° F, 62, 135, or 191 ° C. The 12 SMP apparatus can become increasingly malleable when heated through a temperature transition range beginning at or centered around Tg and can gradually harden to its rigid cooled state through the temperature transition range at a temperature. a or below Tg.

The rigid outer tool 28 may have any desired shape or configuration to manufacture the composite part. In some embodiments of the invention, the rigid outer tool 28 may have a hollow space within which the SMP apparatus 12 and composite material 14 can be placed. For example, the rigid outer tool 28 can be a barrel tool or a folding tool. The rigid outer tool 28, as illustrated in Figure 2, can form an outer surface of the composite part. In alternative embodiments of the invention, the rigid outer tool 28 can be replaced with any type of mold shape and is configured to form an inner or outer surface of a composite part. In some embodiments of the invention, the rigid outer tool 28 may also be used to aid the shape or form of the SMP apparatus 12. For example, faux fur 22, internal false stiffening agents 23, and / or reinforcing inserts 26 may be placed in or adhered to rigid outer tool 28, as described in detail below, to provide a desired mold configuration for the 12 SMP device.

The composite material 14 placed on the SMP apparatus 12 to form the composite part may comprise or be in the form of a low temperature resin, high temperature resin, hardened resin, prepreg, wet processed fiber, dry fiber, continuous fiber, staple fiber, fibers. cut, glass, KEVLAR (RTM), carbon, and / or core. The core is defined here as any offset component that separates two layers of the composite material. For example, the core can comprise foam, thermoplastic materials, honeycomb materials, aluminum, phenolic fiberglass material, carbon, Nomex, etc. The core can also be referred to as core panels, honeycomb core, or sandwich core panel. Additionally, the chemical makeup of composite 12 may include epoxy, BMI, benzoxazine, vinyl, acrylic, polyester, polyamide, phthalonitrile, and any other similar substances known in the art. Composite material 14 can be placed in SMP apparatus 12 using automatic cloth placement, automatic fiber placement, automatic filament winding, cloth placement, manual casting, or any other method known in the art. The composite material 14 can be configured to be hardened or cured, such as in an autoclave, outside of an autoclave, by means of a low temperature curing process, and / or by means of a high temperature curing process.

In use, the SMP apparatus 12 can be formed into a rigid tool configuration and then the composite material 14 can be applied over it. For example, SMP apparatus 12 may be formed by one or more internal molds placed within SMP apparatus 12 and / or one or more external molds (such as rigid external tool 28) placed outside SMP apparatus 12. The internal or external molds may comprise any number of integrally formed or assembled components to provide a desired shape to the SMP apparatus 12, such as the false skin 22, internal false stiffening agents 23, and / or reinforcing inserts 26 placed within or on the rigid outer tool 28 in any desired configuration. However, any method of the formed SMP apparatus 12 can be used without departing from the scope of the invention.

In some embodiments of the invention, the SMP apparatus 12 can be sealed in the external or internal molds, heated, and then pressed against the external or internal molds. For example, the SMP apparatus 12 may be pressed against the molds via an induced differential pressure by inflation, vacuum, and / or. any other method known in the art for pushing the SMP apparatus 12 into the mold. Specifically, the SMP apparatus 12 can be heated and inflated toward the outer mold within a configuration to form an inner surface of a composite part. Once the SMP apparatus 12 cools into the rigid tool configuration, as illustrated in Figure 1, the SMP apparatus 12 can be removed from the external or internal molds and the composite material 14 can be placed in the SMP apparatus 12 using any method known in the art, such as fiber placement. The SMP apparatus 12 may be referred to herein as in the rigid tool configuration after it is formed into the desired shape for the composite material 14 to be applied thereto.

In some embodiments of the invention, cavities 40 may be formed in the SMP apparatus 12 such that components (such as internal stiffening agents such as composite structures, studs, or cores) can be placed within the cavities to bond or cure. to composite material 14. The composite material 14 can then be placed on and / or in the SMP apparatus 12 and the components bonded or cured. These cavities 40 can hold the components to be bonded or cured in the composite 14 in place during the application of the composite 14 without the need for any mechanical adhesions. Additionally or alternatively, various restraints can be used to keep the internal stiffening agents in place during the application of the composite material 14. Then pressure through the SMP apparatus 12 can compress these internal components or stiffening agents against the composite material during curing, however they co cure or bond together,

Additionally or alternatively, the size and shape of the SMP apparatus 12 may be configured to allow the composite 14 or additional layers of the composite 14 to be applied over it to thicken.

ES 2 548 827 T3 in select locations. For example, the SMP apparatus 12 may have a part with a smaller cross-sectional area and a part with a larger cross-sectional area. The part of the SMP apparatus 12 with the smallest cross-sectional area can allow a larger amount of the composite material 14 to be applied over it. In general, the SMP apparatus 12 may be shaped and configured to provide sufficient clearance or offset between the SMP apparatus 12 and the rigid outer tool 28 such that a desired thickness of the composite material 14 and / or the stiffening agents internal parts can fit within this gap.

Once the composite material is applied, the SMP apparatus 12 and the composite material 14 may have heat and pressure applied thereto for the purpose of curing the composite 14 and / or to co cure or bond other internal components or stiffening agents to the material. 14 compound. Additionally, heat can also be used to change the 12 SMP device module. For example, the SMP apparatus 12 and the composite material 14 can be placed in the hollow space of the rigid outer tool 28 and heated and pressurized as required to cure the composite material 14. In some embodiments, the heat used during this curing process may be greater than Tg of SMP apparatus 12, causing SMP apparatus 12 to convert to its malleable state, and a differential pressure applied from within and / or without apparatus 12 SMP (eg, by autoclaving) can cause SMP apparatus 12 to be pushed towards rigid outer tool 28. Specifically, heat can transform the SMP apparatus 12 from the rigid tool configuration into an air chamber configuration in which the SMP apparatus 12 becomes flexible and inflatable, which acts as an internal air chamber to compress the composite material. 12 against rigid outer tool 28, as illustrated in Figure 2. Additionally, in some embodiments of the invention, a small differential pressure or pressurization may be applied to the SMP apparatus 12 until its temperature exceeds Tg, at which the pressure point can be stepped up to the full amount of pressure desired.

The SMP apparatus 12 can therefore be used to press the composite material 14 against the rigid outer tool 28 or any alternative rigid mold surface. Differential pressure, as described herein, can be induced using a variety of methods, with the SMP apparatus 12 sealed in an airtight manner to one of the rigid tools or molds described herein, such that the SMP apparatus 12 is inflates into the composite and / or pulls against the composite 14 during cure. In some embodiments of the invention, the differential pressure is entered by means of an autoclave.

Alternatively, in some embodiments of the invention, a vacuum bag or other impermeable sheet of material may be applied in such form to push the SMP apparatus 12, in its malleable state, toward a rigid surface to compress the composite material 14 between the apparatus. 12 SMP and the rigid surface. In this embodiment of the invention, the vacuum bag or other impermeable sheet of material can be sealed in one of the rigid tools or molds described herein, such as the rigid outer tool 28. This can be particularly useful if the SMP apparatus 12 is not impermeable, comprises any gaps or tears there, and / or cannot be sealed to another surface such that a differential pressure can be induced between the SMP apparatus 12 and the surface to be the one that is sealed. For example, the vacuum bag can be sealed in the rigid outer tool 28 and can be used to drive the SMP apparatus 12, in its malleable state, in a desired direction via a differential pressure applied to the vacuum bag.

As described above, SMP apparatus 12 can be configured to undergo a change in module in response to activations other than heat, such as electrical current, water, and / or ignition. Therefore, in some embodiments of the invention, one of the other activations may also be applied to the SMP apparatus 12 as the composite material 14 to be cured, such that the SMP apparatus 12 is sufficiently malleable to inflate or deform. otherwise compressing the composite material 14 against the rigid outer tool 28.

Once the composite material 14 cures, the differential pressure can be substantially equalized while the temperature remains above Tg, and then the SMP apparatus 12 in the flexible bladder configuration can be removed from within the part. composite cured. Alternatively, once the composite 14 cures, a sufficient differential pressure can be induced to push the SMP apparatus 12 away from the cured composite. In some embodiments of the invention, the SMP apparatus 12 can be collapsed into its original shape or memory shape, which allows easy removal of the SMP apparatus 12 from within the resulting composite part. In other embodiments of the invention, as finally described herein, an internal mandrel placed within SMP apparatus 12 may be configured to pull SMP apparatus 12 (still in its malleable state) away from the composite part. In some embodiments of the invention, the SMP apparatus 12 can be pushed away from the cured composite part while it is still in a malleable state, then allowed to cool and / or become at least somewhat rigid or completely rigid before being removed from within. of the cured composite part.

The SMP apparatus 12 can be used to form a variety of composite parts of various geometries, such as composite parts with capture geometries. For example, the composite parts can be aircraft fuselages, wings, nacelles, panels, ducts, and aircraft structural supports or stiffening agents. Examples of aircraft structural supports may include cross members, frames, stiffening agents with

ES 2 548 827 T3 trapezoidal hat shape, flared stiffening agents, inverted hat stiffening agents, J-shaped stiffening agents, F-shaped stiffening agents, paddle stiffening agents, stiffening agents with I-shaped, and C-shaped stiffening agents. Additionally, composite parts formed with the 12 SMP apparatus can include helicopter parts, support structures, heat shields, hoops, inlets, ailerons, wingtips, vertical and horizontal stabilizers, helicopter structures, empennage, cross members, flanges, tubular fuselage structures, control surfaces, nose sections, fuselage, fins, ailerons, deflectors, slats, torque tubes, drive shafts, hoods, engine inlets, exhaust nozzles, exhaust cones, thrusters, gearboxes, transmission housings, sleeves, rotor blades, fuel tanks, landing gear, landing gear wells, doors, substructures, side members, trays of wire, shock absorbers, brackets, frame stabilizers, part mounts, control stands, instrument consoles, etc. These composite parts can be formed using the SMP apparatus 12 by first placing the composite material 14 against at least a portion of the SMP apparatus 12 when the SMP apparatus 12 is in its rigid tool configuration. The composite material 14 can then be compressed against and / or by the SMP apparatus 12 into a rigid state or malleable state during curing of the composite material 14 within the composite part. In some embodiments of the invention, more than one SMP apparatus 12 may be used to manufacture the composite part, as described hereinafter. In some embodiments of the invention where a plurality of SMP apparatuses are used to form the composite part, the SMP apparatuses can be configured to have different temperatures Tg or different triggers to change the module of the different SMP apparatuses, as described above. .

Additionally, the internal stiffening agents can be co-cured or bonded with any composite part, such as the composite parts listed above, using the 12 SMP apparatus, as described below. The term "co-cure" is defined herein as simultaneously curing and adhesion of two uncured composite parts. The term "bonding" is defined herein as simultaneously cured an uncured composite part while adhering the uncured composite part to a hardened part or a previously cured composite part. Internal stiffening agents can include, for example, frames, studs, or core, as defined above. The structures and beams can elongate structural stiffening agents that extend laterally and / or perpendicular to a length of a composite part. In some embodiments of the invention, the structures can cross the cross members in a grid-like configuration. Examples of some specific types of frames and beams may include trapezoid hat-shaped stiffening agents, bell-shaped stiffening agents, inverted hat-shaped stiffening agents, J-shaped stiffening agents, F, paddle stiffening agents, I-shaped stiffening agents, and C-shaped stiffening agents. Additionally, the 12 SMP apparatus can be used to form a variety of other composite parts, such as trailers, car lines and manifolds, hose, tires, turbochargers, tanks, automobiles, racing vehicles, boats, yachts, bicycles, canoes, etc. kayaks, paddles, sporting goods, weapons, grips, crossbows and accessories, golf clubs and related components, fishing rods, guitars, pipes, poles, construction supplies, wind turbine blades, engine components, furniture, sail masts, electronic enclosures, trusses, transmission shafts, satellites, missiles, and the aircraft. These composite parts can be formed using methods similar to any of the methods described here.

Manufacture a fuselage with the SMP apparatus

Another embodiment of the present invention is a method of manufacturing an aircraft fuselage 15 with integrated internal stiffening agents 24, as illustrated in Figure 13. The method of this embodiment can be implemented with the SMP apparatus 12, as described above, together with an internal mandrel tool 16, seals 18, 20, end-skin false 22, internal stiffening agents 24, inserts 26 reinforcement, and rigid outer tool 28, as best illustrated in Figures 2-12.

In this embodiment of the invention, the SMP apparatus 12, as illustrated in Figure 3, may have the features and characteristics described below with reference to the embodiment of the invention illustrated in Figures 1-2. Additionally, SMP apparatus 12 may have a barrel, bottle, funnel, cone, or cylinder shape as its fused memory shape. However, any other molten memory shape can be used without departing from the scope of the invention. In some embodiments of the invention, the SMP apparatus 12 may be received in an inflated state. Specifically, the SMP apparatus 12 can be made previously heated and inflated to a diameter greater than that of its memory shape and then cooled and hardened in that inflated state. The SMP apparatus 12 may comprise one or two open ends. In some embodiments of the invention, the SMP apparatus 12 may be about 1 inch to 35 feet in diameter and about 1 foot to 75 feet in length. However, the SMP apparatus 12 may have any dimensions without departing from the scope of the invention.

The inner mandrel tool 16, as illustrated in Figure 4, can be made of any rigid durable material that remains rigid through a compound cure cycle. In some embodiments of the invention, the inner mandrel tool 16 may be substantially cylindrical. Additionally, the inner mandrel tool 16 may be hollow, has a cylindrical wall 30 and two opposite ends 32, 34 which may comprise openings (not shown) in the hollow space within the inner mandrel tool 16.

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In some embodiments of the invention, one or more inflation openings 36 may be provided through the cylindrical wall 30 such that a compressed gas can be forced into the hollow inner mandrel tool 16, such as via lines. (not shown), thereby providing outward inflation force for the inner mandrel tool 16. The inflation openings 36 may also be configured to suck the SMP apparatus 12 against the inner mandrel tool 16 during various stages of manufacturing the fuselage 15, as described below.

In some embodiments of the invention, an outer surface of the inner mandrel tool 16 may also comprise varied contours. For example, the varied contours may include a series of protrusions 38 and / or indentations for use in retrieving the SMP apparatus 12 after the composite portion is cured. Specifically, as illustrated in Figure 4, an outer surface of the cylindrical wall 30 may comprise protrusions 38 in the form of a plurality of circumferentially or axially spaced edges or ridges arranged substantially parallel to one another. Each of the edges or ridges may extend between the opposite ends 32, 34 of the inner chuck tool 16 and can be formed with a wavy or sinusoidal pattern extending between the opposite ends 32, 34 of the chuck tool 16 internal, as illustrated in Figure: 4. Additionally or alternatively, the protrusions 38 may be one or more concentric rings formed around the inner mandrel tool 16, or they may have any other configuration. The protrusions 38 may be integrally formed or otherwise adhered to the inner mandrel tool 16.

The purpose of the varied contours or protrusions 38 is to introduce a greater amount of deformation of the SMP apparatus 12 into a smaller cross-sectional area. Specifically, when the SMP apparatus 12 is pushed by differential induced pressure toward the internal mandrel tool 16 that is withdrawn from within a cured composite part, the varied contours or protrusions 38 prevent the SMP apparatus 12 from bending back on itself. For example, after its outward expansion during curing, as described below, the SMP apparatus 12 can be stretched. The axial and / or hoop deformation induced by the varied contours or protrusions 38 can prevent the SMP apparatus 12 from bending on itself or bending and damaging the SMP material.

Thus essentially the varied contours, protrusions 38, and / or inventions provide a greater surface area for the SMP apparatus 12 to contract without requiring an increase in size and / or cross section of the internal mandrel tool 16. In the embodiment illustrated in Figure 4, if the radius of the inner chuck tool 16 is r, and the length is L, then the equation for the surface area would normally be 2n * r * L. However, because the protrusions 38 extend from the surface of the inner mandrel tool 16 in Figure 4, the surface area of ​​the inner mandrel tool 16 in Figure 4 is greater than 2n * r * L.

As illustrated in Figure 5, the end seals 18, 20 may be any end fittings, seals, and / or seal configurations to provide an airtight seal between the SMP apparatus 12 and the internal mandrel tool 16 in or near the ends 32, 34 of the SMP apparatus 12. For example, the end seals 18, 20 may be in the form of lock dies and is configured to join the ends 32, 34 of the internal mandrel tool 16 on portions of the SMP apparatus 12 near the open ends of the SMP apparatus 12. , therefore forming a pressure vessel within SMP apparatus 12. Due to the nature of the SMP material, heat may be required to form a proper seal between the end seals 18, 20, the SMP apparatus 12, and / or the internal mandrel tool 16. In some embodiments of the invention, the end seals 18, 20 may be substantially circular lock dies. Inflation pressure can be introduced by pumping compressed gas into SMP apparatus 12 via one or more overhead lines (not shown) loaded through end seals 18, 20 in some embodiments of the invention. However, pressure applied to SMP apparatus 12 may be provided through any openings in end seals 18, 20, inner mandrel tool 16, and / or rigid outer tool 28 without departing from the scope of the invention. Note that in some embodiments of the invention, the end seals 18, 20 may be omitted or may be configured to additionally or alternatively seal the SMP apparatus 12 to the rigid outer tool 28.

The false skin 22, as illustrated in Figures 6b and 7, can be made of any material and can have a thickness that corresponds to the thickness of the uncured composite 14 that is placed in the SMP apparatus 12. The faux fur 22 can be made from composite material shapes, metal, unreinforced plastics, or any material that exhibits good dimensional stability under heat and pressure. For example, the faux skin 22 can be formed from the composite material, such as a graphite fiber reinforced epoxy composite laminate. The dummy skin 22 is configured to be placed within the rigid outer tool 28, as described below, during deformation of the SMP apparatus 12 into the rigid tool configuration. In some embodiments of the invention, the false skin 22 may also include or is integrally formed with the internal false stiffening agents 23.

The internal dummy stiffeners 23, as illustrated in Figure 6b and 7 may be rigid structures of a size and shape substantially identical to the internal stiffening agents 24 and disposed on the dummy skin 22 to represent the internal stiffening agents 24. cured and uncured during deformation of the SMP apparatus

ES 2 548 827 T3 within the rigid tool configuration. The internal dummy stiffening agents 23 may alternatively be shaped and sized to represent the internal stiffening agents and reinforcing inserts 26 during deformation of the SMP apparatus 12 into the rigid tool configuration.

The internal stiffening agents 24, as illustrated in Figure 6a and 10b, can be any substructure stiffening agents configured to be bonded and / or co-cured in the composite material 14 of the fuselage or other composite part. The internal stiffening agents 24 can be elongated structural components curved to match the contour of an internal surface of the fuselage. The internal stiffening agents 24 may comprise cured composite material or uncured composite material in the form of internal frame parts, such as frames and cross members. The internal stiffening agents 24 can be held in a desired shape during cure by means of the reinforcing inserts 26, as described below. Some examples of internal stiffening agents 24 include, but are not limited to, trapezoidal hat stiffening agents, flared stiffening agents, inverted hat stiffening agents, J-shaped stiffening agents, F-shaped stiffening agents, paddle stiffening agents, I-shaped stiffening agents, C-shaped stiffening agents, core stiffening agents, sandwich core panel, honeycomb core, and the like. In some embodiments of the invention, the internal stiffening agents 24 may include structures about 8 inches high & crossbars about 3 inches high. However, any dimensions can be used without departing from the scope of this invention.

In some embodiments of the invention, the structures can be configured to intersect the cross members in a grid-like configuration within the finished fuselage 15. For example, the studs can be formed to overlap the frames and / or the frames can be formed to overlap the studs, as illustrated in Figure 6a. The overlapping of the internal stiffening agents 24 can be accomplished by sizing and shaping the internal stiffening agents 24 to fit like puzzle pieces. The same configurations can also be used for the internal dummy stiffening agents 23, as illustrated in Figures 6b, 7, 8, and 9.

The reinforcing inserts 26, as illustrated in Figure 7, can be made of a rigid material, such as a nickel steel alloy such as INVAR, and can contact and / or engage parts of the internal stiffening agents 24 and / or the internal dummy stiffening agents 23 facing the SMP apparatus 12. The reinforcing inserts 26 can be configured to alleviate sharp corners and ends of internal stiffening agents 24 and / or internal false stiffening agents 23 to better facilitate the formation of the SMP apparatus 12. Specifically, the reinforcing inserts 26 can be configured to engage with or rest within one or more angles presented by one or more of the internal stiffening agents 24 and / or internal false stiffening agents 23. For example, if one of the internal stiffening agents 24 or false internal stiffening agents 23 exhibits a right angle, one of the reinforcing inserts 26 may have two surfaces that meet at a right angle and is configured to engage the angle. right of that internal reinforcement 24 or false internal reinforcement 23. The reinforcement inserts 26 also have surfaces that face away from the internal reinforcement 24 or false internal reinforcement 23 that are substantially flat and / or have more gradual angles. For example, one or more of the reinforcing inserts 24 may have at least one angled or chamfered surface and / or rounded edges that may contact the SMP apparatus 12 when it is pushed out toward the rigid outer tool 28, as shown. described later. The reinforcing inserts 26 may also be curved, longitudinally, to substantially match a curve of the internal stiffening agents 24, the internal false stiffening agents 23, and / or the internal surface of the rigid external tool 28.

Internal stiffening agents 24 and / or internal dummy stiffening agents 23, together with reinforcing inserts 26 can be configured to form cavities 40, such as grooves or channels, within SMP apparatus 12, as illustrated in Figure 10 and described hereinafter. In some embodiments of the invention, internal dummy stiffening agents 23 and / or reinforcing inserts 26 can be configured to form cavities 40 within SMP apparatus 12, and can then be replaced with internal stiffening agents 24. For example, once the SMP apparatus 12 is in the rigid tool configuration, the dummy skin 22, the internal dummy stiffening agents 23, and / or reinforcing inserts 26 can be removed from the cavities 40 and replaced with the stiffening agents. Uncured internal rigidity 24, is set against reinforcing inserts 26, which are to be cured within fuselage 15. Alternatively, once the SMP apparatus 12 is in the rigid tool configuration, the dummy skin 22, internal dummy stiffening agents 23, and / or reinforcing inserts 26 can be removed from the cavities 40 and replaced with internal stiffening agents 24. Pre-cured, it is configured against the reinforcement inserts 26 mating with the fuselage 15.

In an exemplary embodiment of the invention, as illustrated in Figures 6a, 6b, and 7, the internal stiffening agents 24 and / or the internal dummy stiffening agents 23 may comprise J-shaped stiffening agents 42 supported on at least two sides by corresponding reinforcing inserts 26. Additionally, the internal stiffening agents 24 and / or the internal false stiffening agents 23 in this exemplary embodiment may comprise structures 44 having a substantially T-shaped cross section, with the structures 44 also each being supported on by at least two sides by corresponding reinforcing inserts 26. As illustrated in Figure 7, the reinforcing inserts 26 and / or portions of the stiffening agents 23

ES 2 548 827 T3 dummy trim can be held in place and held by mechanical fasteners 46, such as straps and splice bolts. However, the internal stiffening agents 24 and / or the false internal stiffening agents 23 can have any known configurations and the reinforcing inserts 26 can be of any shape and configuration to engage them.

Rigid outer tool 28, as illustrated in Figure 8, may be a rigid tool that has an inner surface configured to shape an outer surface of the fuselage 15. For example, rigid outer tool 28 may be a folding tool. , as illustrated in Figure 2 or as illustrated in Figure 8, and can have two halves, including a lower cover and an upper cover. Together, the two halves can form a hollow cylindrical shape joined by the inner surface of the rigid outer tool 28. However, the rigid outer tool 28 may comprise any plurality of parts which, when joined, may form an inner surface that is configured to form the shape of the outer surface of the fuselage 15.

In general, a method of manufacturing the fuselage 15 may include the steps of forming the SMP apparatus 12 into the rigid tool configuration with the cavities 40 by the internal stiffening agents 24, putting the internal stiffening agents 24 cured or uncured and reinforcing inserts 26 into cavities 40 in SMP apparatus 12, put the uncured composite material 14 in SMP apparatus 12, then put that SMP apparatus 12 and the uncured composite material 14 into the rigid outer tool 28. The method may then include the steps of curing the composite 14 by means of pressure and heat while simultaneously inflating or otherwise expanding the SMP apparatus 12 to compress the composite 14 against the rigid outer tool 28 during the curing process, then, once the composite material 14 cures, push the SMP apparatus 12 to a reduced cross section, and extract the SMP apparatus 12 from within the resulting fuselage. The internal stiffening agents 24 can therefore be bonded and / or cured with the composite fuselage, eliminating the need for mechanical fasteners to bond the internal stiffening agents 24 to the fuselage. The methods described herein for curing or bonding the stiffening agents 24 internal to the fuselage can also be used to cure or bonding the stiffening agents or other components to any composite part known in the art, such as any of the various aircraft components mentioned. here.

The flow chart in Figure 14 describes the steps of an example method 1400 for forming the SMP apparatus 12 within the rigid tool configuration used to fabricate the airframe 15. In some alternative implementations, the functions observed in the various blocks may occur out of the order described in Figure 14. For example, two blocks shown in succession in Figure 14 may in fact run substantially concurrently, or the blocks may sometimes run in reverse order depending on the functionality involved.

The method 1400 may comprise the steps of receiving the SMP apparatus 12 in the inflated state, as illustrated in Figure 3, or receiving the SMP apparatus 12 in its memory form and then heating and inflating the SMP apparatus 12 into its state. inflated, as described in block 1402. This expansion of the SMP apparatus 12 can also be accomplished using various other activations to change the module of the SMP apparatus 12 and / or various other forces or techniques to expand the SMP apparatus 12 to the desired size. SMP apparatus 12 can then be large enough to slide over internal mandrel tool 16. Alternatively, the SMP apparatus 12 may be cast into a memory shape large enough to fit over the internal mandrel tool 16. The next step of method 1400 can either slide inner chuck tool 16 into SMP apparatus 12 or slide SMP apparatus 12 into inner chuck tool 16, as described in block 1404. In yet another alternative embodiment of the invention, the SMP apparatus 12 may be received in a collapsed state and may be formed into the inner mandrel tool 16 of Figure 4.

Once SMP apparatus 12 is positioned over internal mandrel tool 16, method 1400 may comprise heating SMP apparatus 12 above Tg at which the SMP material becomes malleable and formable, as described in block 1406. Above the threshold temperature Tg, the SMP apparatus 12 can naturally contract back to its original shape with memory and size, causing the SMP apparatus 12 to contract around and form an internal chuck tool 16, as illustrated in Figure 5. Additionally or alternatively, vacuum may be applied from within the inner mandrel tool 16, via the inflation openings, and the hot, malleable SMP apparatus 12 may be drawn against the inner mandrel tool 16. In some embodiments of the invention, the inner mandrel tool 16 may have angled or chamfered portions 48 at each of the opposite ends 32, 34 that the SMP apparatus 12 may be shaped to. Any excess material that extends outward beyond the angled or chamfered portions 48 may need to be trimmed.

The method 1400 may further comprise the step of applying the end seals 18, 20 to the SMP apparatus 12 and the inner mandrel tool 16, as described in block 1408, creating a pressure vessel between the inner mandrel tool 16 and the 12 SMP apparatus. Specifically, when the SMP apparatus 12 is contracted, the end portions of the SMP apparatus 12 may be pressed inward toward the inner chuck tool 16 and / or its angled or chamfered portions 48 and locked by the end seals 18, 20. such as lock dies. In some embodiments of the invention, the end seals 18, 20 may be coupled with the

ES 2 548 827 T3 angled or chamfered portions 48 of the inner mandrel tool 16, the interleaving portions of the SMP apparatus 12 between the end seals 18, 20 and the inner mandrel tool 16 to form an airtight seal. In some alternative embodiments of the invention, the step of applying the end seals 18, 20 may be omitted or the SMP apparatus 12 may be sealed in other ways or on other surfaces to allow a differential pressure to act on the SMP apparatus 12.

The next step of method 1400 may comprise placing the internal dummy stiffening agents 23 and / or reinforcing inserts 26 in the dummy skin 22 in a configuration that corresponds to desired locations of the internal stiffening agents 24 within the fuselage, as described. at block 1410 and is illustrated in Figure 7. The false skin 22, the internal false stiffening agents 23, and / or the reinforcing inserts 26 may be covered with a thin film or some other substance to prevent them from sticking to each other and / or to the SMP apparatus 12. The method 1400 may then comprise placing the fake skin 22 inside the rigid outer tool 28, as described in block 1412. Specifically, the dummy skin 22 can be applied to the inner surface of the rigid outer tool 28 for the purpose of mimicking or serving as a placeholder for the thickness of the composite material 14 to be placed in the SMP apparatus 12. This ensures that the SMP apparatus 12 with the composite material 14 applied over it in a desired thickness still fits within the rigid outer tool 28.

The reinforcing inserts 26 can be positioned in the dummy skin 22 that rests on the rigid outer tool 28 along with the internal dummy stiffening agents 23, which can be formed and configured to emulate the size and configuration of the stiffening agents 24 internal cured or not cured. The internal dummy stiffening agents 23 can then be removed from the cavities 40 and replaced with the cured or uncured internal stiffening agents 24. The cured or uncured internal stiffening agents 24 together with the reinforcing inserts 26 can then be placed within the grooves or cavities 40 to bond or co-cure the internal stiffening agents 24 with the composite material 14 thereby fabricating the fuselage 15.

As noted above, the internal dummy stiffening agents 23 can be omitted and / or replaced with the internal stiffening agents 24 in any of the steps described herein in a cured or uncured state. For example, internal stiffening agents. 24 and / or reinforcing inserts can be used to form cavities 40. In one embodiment of the invention, internal stiffening agents 24 may be precured and / or cured during shaping of SMP apparatus 12 and then bonded to composite 14 during cure, thereby fabricating fuselage 15.

The method 1400 may further comprise the steps of placing the SMP apparatus 12, along with the inner mandrel tool 16, within the rigid outer tool 28, as described in block 1414 and illustrated in Figure 8, and then heating and pressurizing SMP apparatus 12, as described in block 1416. Heat and pressure can force the SMP apparatus 12 to inflate and press against the false skin 22, internal false stiffening agents 23, internal stiffening agents 24, and / or reinforcing inserts 26. As mentioned above, the SMP apparatus 12 can be heated to or above Tg for the purpose of changing the module of the SMP apparatus 12 to make it formable and expandable. However, other methods can also be used to change the 12 SMP appliance module, as described here. Additionally, in alternate embodiments of the invention, method steps 1410-1414 can be replaced with a step of placing the SMP apparatus 12 within any rigid external mold shape and configured to mimic an internal surface of the composite part that forms. and comprising protrusions to form desired cavities 40 within SMP apparatus 12.

Pressure or differential pressure can be induced in a number of ways, such as by means of a forced compressed gas applied through the inflation openings 36 of the internal mandrel tool 16, as illustrated in Figure 4. For example The pressure required to expand the SMP apparatus 12 may depend on the overall thickness and / or size of the SMP apparatus 12. Additionally, the type of SMP material used and / or the design of the SMP apparatus 12 may also affect how easy or difficult it is to tension the SMP apparatus 12. In some embodiments of the invention, pressure in the range of 1-150 pounds of force per square inch (psig) or pressure in a narrower range of 30-90 psig can be applied to inflate the 12 SMP apparatus. For example, approximately 45 psig can be applied into SMP apparatus 12 to inflate SMP apparatus 12. Additionally, in any of the method steps described herein where the SMP apparatus 12 is heated and pressurized, a low differential pressure that can be induced with heat is increased to or above Tg to prevent the SMP apparatus 12 from collapsing away. of the composite material 14 when it begins to soften. Then, at some point after SMP apparatus 12 exceeds Tg, the differential pressure can build up to the full desired amount. For example, a low pressure of about 5 to 10 psi (0.34-0.69 Bar) can be applied within the SMP apparatus 12 until enough heat has been applied to make the SMP apparatus 12 sufficiently malleable, in which the Pressure point applied there can be stepped up to cure cycle pressure, such as 30-90 psi (2.07-6.20 Bar).

Then, the method 1400 may comprise cooling the SMP apparatus 12 to harden it into the rigid tool configuration, as described in block 1418. The inflation pressure may continue to be applied when the temperature of the SMP apparatus 12 cools to a point. below Tg such that the SMP apparatus hardens in its inflated rigid tool configuration. The 12 SMP apparatus is therefore formed according to

ES 2 548 827 T3 with the false skin 22, the internal false stiffening agents 23, internal stiffening agents 24, and / or reinforcing inserts 26, which form the cavities 40, cavities, or grooves within the SMP apparatus 12. As described in block 1420, method 1400 may then comprise removing SMP apparatus 12 and inner chuck tool 16 from rigid outer tool 28. The false skin 22 can also be removed from the SMP apparatus 12, as illustrated in Figure 9. Figure 10a further illustrates the resulting SMP apparatus 12 in the rigid tool configuration after the internal false stiffening agents 23 are removed, thereby revealing the cavities 40 formed by method 1400. Figure 10b illustrates the resulting SMP apparatus 12 in the rigid tool configuration with the internal stiffening agents 24 positioned where the internal false stiffening agents 23 are located in Figure 9.

The flow chart of Figure 15 describes the steps of an example method 1500 for manufacturing the airframe 15 using the SMP apparatus 12 in more detail. In some alternative implementations, the functions observed in the various blocks may occur out of the order described in Figure 15. For example, two blocks shown in succession in Figure 15 can actually run substantially concurrently, or the blocks can sometimes run in reverse order depending on the functionality involved.

As illustrated in Figure 15, method 1500 may first include the 12 SMP apparatus formation step within the rigid tool configuration, as described in block 1502 and in the method steps of Figure 14. As shown indicated above, this step may require the formation of the cavities 40 in the SMP apparatus 12 in a configuration that corresponds to the desired locations of the internal stiffening agents 24 within the finished fuselage 15. A variety of methods can be used to form the SMP apparatus 12 into the desired rigid tool configuration with the cavities 40, cavities, or grooves formed therein.

Once the SMP apparatus 12 is formed within the rigid tool configuration, the method 1500 for fabricating the fuselage 15 may include the step of placing the cured or uncured internal stiffening agents 24 and reinforcing inserts 26 within the cavities in SMP apparatus 12, as described at block 1504 and illustrated in Figure 10b. However, in some embodiments of the invention, if the internal stiffening agents 24 were already positioned on or between the reinforcing inserts 26 during heating and the SMP apparatus 12 was formed within the rigid tool configuration, then the stiffening agents Internal stiffness 24 and reinforcing inserts 26 may remain within the resulting cavities 40, cavities, or grooves that are created in SMP apparatus 12, and step 1504 may be omitted.

In some embodiments of the invention, the internal stiffening agents 24 may be uncured material applied to and / or wrapped around one or more SMP reinforcing apparatus, made of SMP material as described below for SMP apparatus 12. In this way, the internal stiffening agents 24 and the composite part or fuselage 15 can be co-cured using the SMP material. However, the SMP material used for the reinforcement SMP apparatuses may have a different activator and / or a different Tg than the SMP apparatus 12 used to form the fuselage 15. Thus the reinforcement SMP apparatus or the SMP apparatus for the Fuselage 15 can remain rigid during cure while the other reinforcing SMP apparatus and SMP apparatus 12 is used as an internal air chamber during cure.

The method 1500 may then comprise a step to apply a portion of the uncured composite material 14 to the SMP apparatus 12, as described in block 1506 and illustrated in Figure 11. Specifically, the composite material 14 can be applied to the SMP apparatus 12 and the internal stiffening agents 24 that rest in the cavities 40, such that at least a portion of the internal stiffening agents 24 contact and can cure or bonding to the composite material 14 of the fuselage 15, as described below. The uncured composite material 14 can be placed in the SMP apparatus 12 using any method known in the art, such as automatic fabric placement, automatic fiber placement, filament winding, and / or manual casting. As mentioned above, the composite material 14 may comprise or be in the form of low temperature resin, high temperature resin, hardened resin, prepreg, wet processed fiber, dry fiber, continuous fiber, staple fiber, staple fibers, KEVLAR of 'glass', carbon, and / or core. In some embodiments of the invention, a barrier and / or release agent may be placed between the SMP apparatus 12 and the composite 14, such that they may be easier to separate after cure from the composite 14. The barrier or release agent can be a film, a plastic, etc. The barrier or release agent can also, for example, have an adhesive side and a releasable side.

The method 1500 for fabricating the fuselage 15 may then comprise placing the SMP apparatus 12 and the uncured composite material 14 within the rigid outer tool 28, as described in block 1508. The method may then include the steps of curing the composite 14 by means of pressure and heat, as described in block 1510, while simultaneously inflating the SMP apparatus 12 to compress the composite 14 during the curing process, as described in 1512. In some embodiments of the invention, inflation pressure can be provided by internal mandrel tool 16 and heat can be raised to a compound cure temperature above Tg. Inflation of the sMp apparatus 12 can compress the composite 14 during the cure cycle, and compress the cured or uncured internal stiffening agents 24 between the SMP apparatus 12 and the rigid outer tool 28. Additionally or alternatively, inflation

ES 2 548 827 T3 of apparatus 12 SMP can apply pressure directly to one or more of the reinforcing inserts 26 such that the reinforcing inserts 26 apply compressive force directly to the bearings of the internal stiffening agents 24 positioned between the reinforcement inserts 26. Inflation of the SMP apparatus 12 may also compress the cured or uncured internal stiffening agents 24 within the composite material 14 of the fuselage, thereby bonding or co-curing the internal stiffening agents 24 to the fuselage.

In another embodiment of the invention, a seal may be formed between the rigid outer tool 28 and the SMP apparatus 12 using mechanical seals, adhesive, or any other known method of sealing peripheral portions of the SMP apparatus 12 to the rigid outer tool 28. The rigid outer tool 28 may be vented to further improve the pressure differential created by autoclaving during curing of the composite material 14. This can eliminate the need for an airtight seal with the internal mandrel tool 16. Note that other methods of compressing the SMP apparatus 12 against the composite material 14 can be used without departing from the scope of the invention. Additionally, the heat and differential pressure described herein can be provided by autoclaving (not shown) or any other combination of known heating and pressure techniques for fabricating composite parts.

Once the composite 14 cures, the method 1500 may comprise removing the inflation pressure from within the SMP apparatus 12, as described in block 1514, and removing the SMP apparatus 12 out from within the resulting fuselage, as described. at block 1516. SMP apparatus 12 can contract around inner mandrel tool 16 once pressure is removed, while heat remains above Tg. For example, vacuum can be applied from within the inner mandrel tool 16 to suck the SMP apparatus 12 against the inner mandrel tool 16. As illustrated in Figure 12, the SMP apparatus 12 is therefore withdrawn away from the cured composite 14. However, removal of the inner mandrel tool 16 from within the cured fuselage and the internal stiffening agents 24 results in removal of the SMP apparatus 12 which contracts against the inner mandrel tool 16 after inflation pressure is removed.

Finally, the method 1500 may comprise the steps of removing the reinforcing inserts 26 from the cured internal stiffening agents 24, as described in block 1518, and removing the fuselage from the rigid external tool 28, as described in block 1520. For example, the parts of the rigid outer tool 28 can be mechanically disconnected from each other, allowing the fuselage 15 and its integrated inner stiffening agents 24 to lift out of the rigid outer tool 28.

In an alternative embodiment of the invention, the SMP apparatus 12 may remain rigid during cure. For example, once uncured composite material 14 is applied to SMP apparatus 12, it can be vacuum packed or sealed within a flexible, impermeable material (not shown) and cured. In this alternative embodiment, the temperature of the cured composite 14 may be less than the temperature Tg at which the SMP apparatus 12 begins to become malleable, such that the SMP apparatus 12 remains rigid throughout the cure cycle. So instead of using the 12 SMP apparatus as an air chamber During curing, the 12 SMP apparatus can remain rigid During curing, with compression force from the vacuum bag or waterproof material that is used to cure or bond the material 14 composed of the fuselage and the internal stiffening agents 24. Then, once the composite material 14 cures, the vacuum bag can be removed from around the resulting fuselage, and the temperature of the SMP apparatus 12 can be raised above Tg such that the SMP apparatus 12 can be malleable and / or shrink into its memory shape that is withdrawn from within the fuselage.

Manufacture of stiffening agents with the SMP apparatus

Another embodiment of the invention, as best illustrated in Figures 16-17, is a method of fabricating a reinforcement 50, such as the internal stiffening agents 24, described above, a frame, and / or a cross member. In this embodiment of the invention, the method can be implemented using the SMP apparatus 12, a rigid mold tool 52, and an impermeable sheet of material 54 such as a vacuum bag to fabricate the reinforcement, as illustrated in Figure 16. .

The SMP apparatus 12 illustrated in Figure 16 may have the same features and characteristics as the SMP apparatus 12 described for the embodiment of the invention illustrated in Figures 1-2. Additionally, the SMP apparatus 12 can be formed into a desired rigid tool configuration using any desired method, such as the techniques described above. In some embodiments of the invention, the SMP apparatus 12 may be cast into a memory shape that substantially corresponds to a desired shape or contour of at least one surface of the resulting reinforcement 50. For example, if the reinforcement 50 to be manufactured is a cross member with a trapezium-shaped cross section, then the SMP apparatus 12 can be cast into a memory shape having a substantially trapezoidal cross-section . Alternatively, the SMP apparatus 12 may be cast into any elongated shape and then inserted into a hollow mold, heated, and inflated there, then cooled and hardened into the shape provided by the hollow mold.

Rigid casting tool 52 may be similar or identical in functionality and design to rigid outer tool 28 described below and may be made of any material capable of remaining rigid during cure.

ES 2 548 827 T3 of composite material 14, such as steel. Alternatively, the rigid molding tool 52 can be made of an SMP material that is configured to remain rigid during the cure of the composite material 14. For example, the rigid casting tool 52 may be the SMP apparatus 12 illustrated in Figure 10a and the Tg of the SMP apparatus 12 illustrated in Figure 16 may differ from the Tg of the rigid casting tool 52 in this alternate embodiment of the invention. . Rigid molding tool 52 can be configured to form at least one desired outer surface of the reinforcement. For example, the rigid molding tool 52 may comprise a cavity 56 formed there into which the uncured composite material 14 can be placed, at least one wall of the reinforcement 50 is formed. As illustrated in Figure 16, cavity 56 may be a channel with a bottom and two side walls extending at different angles of 90 ° from the bottom.

The waterproof sheet of material 54 can be a vacuum bag or any other flexible, waterproof material that can be sealed in the rigid molding tool 52 and / or the SMP apparatus 12. For example, the waterproof sheet of material 54 can be placed over the composite material 14 and sealed in the rigid molding tool 52, creating a substantially airtight seal between the impermeable sheet of material 54 and the rigid mold tool 52. The impermeable sheet of material 54 may also comprise a vacuum port (not shown) extending through it to allow evacuation and ventilation of air. When air is withdrawn from between the rigid molding tool 52 and the material impermeable sheet 54, the material impermeable sheet 54 can compress the composite material 14 placed between it. Additionally or alternatively, the SMP apparatus 12 may be pressurized by autoclaving and / or compressed gas, thereby inflating the SMP apparatus 12 toward the rigid molding tool 52 and the impermeable sheet of material 54. Additionally, a pressed sheet (not shown ) can be placed between the waterproof sheet of material 54 and the composite material 14 to better control the contour and surface finish of the composite material 14. Other compound bagging techniques known in the art can also be used herein without departing from the scope of the invention.

In an alternative embodiment of the invention, the sheet 54 of impermeable material can be replaced with a permeable sheet of material that can be placed over the composite material 14 and the SMP apparatus 12. In this embodiment of the invention, the permeable sheet of material can be physically pressed into the composite material 14 while the pressure of the SMP apparatus 12 during cure compresses the composite material 14. In yet another alternative embodiment of the invention, the waterproof sheet of material 54 can be replaced with a rigid covering tool that can be permeable or impermeable and can be clamped, pressed into, or mechanically attached to the rigid molding tool 52. and on composite material 14.

The flow chart of Figure 17 describes the steps of an example method 1700 for making a composite reinforcement using SMP apparatus 12. In some alternative implementations, the functions observed in the various blocks may occur out of the order described in Figure 17. For example, two blocks shown in succession in Figure 17 can actually run substantially concurrently, or the blocks can sometimes run in reverse order depending on the functionality involved.

Method 1700 for fabricating reinforcement 50 using SMP apparatus 12 may comprise the steps of forming SMP apparatus 12 into the rigid tool configuration, as described in block 1702, and then applying at least a portion of apparatus 12 SMP with composite 14, as described in block 1704. In some embodiments of the invention, the rigid tool configuration of the SMP apparatus 12 may correspond to an internal shape and / or angle of the reinforcement 50 to be formed thereon. In other embodiments of this invention, material 14 may be placed in or wrapped in SMP apparatus 12 first, and then SMP apparatus 12 may be formed into the rigid tool configuration, using any molding techniques described herein or known in the art. The technique.

Then method 1700 may comprise placing SMP apparatus 12 applied with composite material 14 into cavity 56 of rigid molding tool 52, as described in block 1706. Alternatively, the composite material 14 can be fixed in the cavity 56 of the rigid molding tool 52 and then the SMP apparatus 12 in the rigid tool configuration can be placed on top of the composite material 14 within the cavity 56 of the rigid molding tool 52.

However, a number of techniques can be employed to place the composite material 14 in contact with the SMP apparatus 12, and to place it in the cavity of the rigid molding tool 52, without departing from the scope of this invention. Additionally, in some embodiments of the invention, more than one SMP apparatus may be used to fabricate the reinforcement 50. For example, as illustrated in Figure 16, two SMP apparatus 58,60 have the properties of the SMP apparatus 12, as described above, they are formed or molded to support opposite surfaces of the composite material 14 to make the reinforcement 50 in a J-shaped crossbar configuration. Specifically, the reinforcement 50 may be an elongated reinforcement having a substantially J-shaped cross section. The composite material 14 can be positioned between the two SMP apparatus 58,60 and the rigid casting tool 52 as illustrated in Figure 16 using manual casting or any other method known in the art. Then, a skin laminate 62 can be placed over the two SMP apparatuses 58, 60, which make contact with the upper end of the composite material 14 making the J-shaped cross section

ES 2 548 827 T3 of reinforcement 50. In this embodiment of the invention, the leather laminate 62 and the composite material 14 may be bonded, as described below.

Thus, in general, the method 1700 may comprise the step of placing another layer of the composite material or skin laminate 62 on the SMP apparatus 12, which contacts at least a portion of the composite material 14 that rests within the cavity 56 of rigid molding tool 52, as described in block 1708. The method may then comprise placing the waterproof sheet of material 54 over the composite material 14 and / or the skin laminate 62, as described in block 1710, and sealing the waterproof sheet of material 54 to the rigid molding tool 52. , as described in block 1712, thereby forming an airtight boundary around the composite material 14. The airtight boundary can also be formed over and / or against the SMP apparatus 12, while leaving at least one ventilation opening (not shown) for the SMP apparatus 12, such that the space within the apparatus 12 SMP remains exposed to the atmosphere outside the air-tight limit.

The method 1700 may then comprise a step of inducing a differential pressure to push the impermeable sheet of material 54 toward the rigid molding tool 52, as described in block 1714. For example, this step may involve the removal of air from between the impermeable sheet of material 54 and the rigid molding tool 52, such as via a vacuum, which can press the impermeable sheet of material 54 towards or against the composite material 14. and / or the leather laminate 62. Then or simultaneously with the step described in block 1714, method 1700 may comprise the step of heating the composite 14 and SMP apparatus 12 to a temperature for curing the composite 14, as described in block 1716. The temperatures Compound cure times can be greater than Tg, such that the SMP apparatus 12 can become malleable and can push or inflate outward, pressing against the composite material 14. The SMP apparatus 12 can therefore behave similar to an internal vacuum bag. Additionally or alternatively, gas or air pressure may be introduced into the SMP apparatus to cause or assist its outward inflation to compress the composite material 14.

In some alternative embodiments of the invention, at least one of the 58,60 SMP apparatus can be replaced with a rigid tool in the same way. In other alternative embodiments of the invention, the SMP apparatus 58, 60 can be replaced with rigid tools of the same shape and the rigid molding tool 52 can be replaced with the SMP apparatus 12 of Figure 10a. In general, any combination of SMP apparatus and rigid molding tools can be used to form the composite parts described and disclosed herein.

Once the composite material 14 is cured, the method may comprise the steps of removing the impermeable sheet of material 54 from the rigid molding tool 52, as described in block 1718. In some embodiments of the invention, the method 1700 also It may comprise either continuing to heat or reapplying heat to SMP apparatus 12, as described in block 1720, such that SMP apparatus 12 can be contracted or otherwise pushed away from cured reinforcement 50. If gas or air pressure is introduced to aid inflation of the 12 SMP, this pressure can also be removed. The SMP 12 is naturally collapsible to its original memory shape, which remains soft and pliable until cooled. Thus, method 1700 may include a step of removing the SMP apparatus 12 from the cured composite 14 or reinforcement 50 while it is in a soft, malleable state, as described in block 1722. Alternatively, the SMP apparatus 12 may be contracted or pushed away from the cured reinforcement 50 while it is in its malleable state, but is then cooled and hardened before being removed from within the cured reinforcement 50.

Note that, once removed from the cured reinforcement 50, the SMP apparatus 12 can then be reconfigured into any desired rigid tool configuration within the deformation limitations of the SMP apparatus 12 and reused to make another reinforcement. In general, the SMP 12 apparatus is reconfigurable and reusable. In contrast, internal mandrel bags known in the art cannot be reused or do not offer desired durability and are more prone to failure. The inner mandrel bags do not have the necessary stiffening agents that can be used as a molding tool to apply the composite material 14 to it. Specifically, other types of mandrels used in traditional reinforcement forming applications are frequently required to be cut out or washed out of the cured reinforcement and are therefore also not reusable. Advantageously, the SMP apparatus 12 can be used as the rigid mold tool for molding the composite material and as an inner bag or bladder during curing of the composite material 14, and can then be removed and reused for multiple cycles.

Although the invention has been described with reference to the preferred embodiment illustrated in the accompanying drawings, it is noted that equivalents may be employed and substitutions are made herein without departing from the scope of the invention as mentioned in the claims. For example, any instance of vacuum or inflation force applied in or out of SMP apparatus 12, as described herein, is exemplary only and can be replaced with any techniques known in the art to create a differential pressure capable of pushing the SMP apparatus 12 into a desired mold and / or composite 12. Additionally, while various shapes, configurations, and tools have been described herein for forming the SMP apparatus 12 within a

ES 2 548 827 T3 desired rigid tool configuration, note that any mold or combination of molds and rigid tool can be used to define a shape of the SMP apparatus 12 using one or more of the method steps described herein.

Additionally, while the Figures and example embodiments provided herein describe the manufacture of composite parts for aircraft, the training tools and methods described herein can be used to manufacture composite parts for automobiles, boats, sporting goods, and the like without departing from the scope of the invention.

The following numbered paragraphs define the particular embodiments of the present invention:

1. A method for manufacturing a composite part with built-in stiffening agents, the method comprises:

forming or melting a shape memory polymer (SMP) apparatus to correspond to a desired configuration of a first surface of the composite part to be formed;

shaping or casting the SMP apparatus to include one or more cavities configured for placement of the stiffening agents there;

putting the stiffening agents into the cavities;

applying the composite material to the SMP apparatus and the exposed surfaces of the stiffening agents that rest within the cavities; and baking or bonding the stiffening agents with the composite material on the SMP apparatus by means of pressure and heat to manufacture the composite part, wherein the SMP apparatus remains in a rigid state through the co-curing or coadhesion of the stiffening agents with composite material.

two. The method of paragraph 1, wherein the co-cure or coadhesion of the stiffening agents with the composite material comprises:

sealing an impermeable sheet of material around the composite material;

compressing the impermeable sheet of material against the composite material by inducing a differential pressure outward and / or inward of the impermeable sheet of material; and heating the composite material to a composite cure temperature, with the SMP apparatus in a rigid state while the impermeable sheet of material is compressed against the composite material.

3. The method of paragraph 1, wherein the stiffening agents include at least one of frames, stringers, composite core, and additional layers of the composite material.

Four. The method of paragraph 1, wherein the stiffening agents are precured prior to placement in the cavities.

5. The method of paragraph 1, where the stiffening agents are not cured prior to placement in the cavities.

6. The method in paragraph 1, further comprising:

activating the SMP apparatus from the rigid state to a malleable state; and removing the SMP apparatus from within the composite part.

7. The method of paragraph 6, wherein the SMP apparatus is configured to be activated to the malleable state when heated above a temperature Tg, wherein the curing temperature of the composite material is less than Tg, such that the SMP apparatus remains rigid during curing of the composite material within the composite part.

8. The method of paragraph 1, further comprising placing rigid reinforcing inserts within the cavities between the SMP apparatus and the internal stiffening agents prior to applying the composite material to the SMP apparatus, wherein the cavities are sized and shaped to allow rigid reinforcing inserts and internal stiffening agents rest there.

ES 2 548 827 T3

9. A method for manufacturing a composite part with built-in stiffening agents, the method comprises:

activating a shape memory polymer (SMP) apparatus to a malleable state;

forming an SMP apparatus in a malleable state to correspond to a desired configuration of a first surface of the composite part to be formed;

shaping the SMP apparatus to include one or more cavities configured for placement of the stiffening agents there;

activating the SMP apparatus to a rigid state;

putting the stiffening agents into the cavities;

applying the composite material to the SMP apparatus and the exposed surfaces of the stiffening agents that rest within the cavities; and cooking or bonding the stiffening agents with the composite material on the SMP apparatus by means of pressure and heat to manufacture the composite part, which includes the steps of:

sealing an impermeable sheet of material around the composite material;

compressing the impermeable sheet of material towards the composite material by inducing a differential pressure outward and / or inward of the impermeable sheet of material; and heating the composite material to a composite cure temperature, with the SMP apparatus in a rigid state while the impermeable sheet of material compresses the composite material.

10. The method in paragraph 9, where the stiffening agents are internal stiffening agents.

eleven. The method of paragraph 9, wherein the stiffening agents include at least one of additional frames, stringers, core, and layers of the composite material.

12. The method of paragraph 9, wherein the composite part is a monolithic aircraft fuselage, a wing, a nacelle, an aircraft panel, an aircraft duct, aircraft structural supports, an aircraft component made of solid laminates, integrally rigid laminates, or rigid core sandwich structure, or internal stiffening agents for an aircraft component.

13. The method of paragraph 9, where the stiffening agents are precured prior to placement in the cavities.

14. The method of paragraph 9, where the stiffening agents are not cured prior to placement in the cavities.

fifteen. The method in paragraph 9, further comprising:

removing the impermeable sheet of material after the composite material cures;

activating the SMP apparatus from the rigid state to the malleable state; and removing the SMP apparatus from within the composite part while the SMP apparatus is in a malleable state.

16. The method of paragraph 9, wherein the SMP apparatus is configured to change to the malleable state when heated above a temperature Tg, where the curing temperature of the composite material is less than Tg, such that the apparatus SMP remains rigid during curing of the composite material within the composite part.

17. The method of paragraph 9, where the SMP apparatus is formed to correspond to the first surface of the composite part to be formed on it, comprises:

putting the SMP apparatus on an internal chuck tool;

seal the ends of the SMP apparatus to the internal mandrel tool;

ES 2 548 827 T3 putting the SMP apparatus and internal chuck tool inside an external mold;

heating the SMP apparatus above a temperature Tg at which the SMP apparatus begins to become malleable and inflating the SMP apparatus towards the outer mold;

cool the SMP apparatus below Tg; and removing the SMP apparatus in its rigid state from the outer mold.

18. The method of paragraph 9 further comprises placing rigid reinforcing inserts within the cavities between the SMP apparatus and the stiffening agents prior to applying the composite material to the SMP apparatus, wherein the cavities are sized and shaped to allow the inserts stiff reinforcement and stiffening agents rest there.

19. A method for manufacturing a composite part with built-in reinforcing characteristics, the method comprises:

activating a shape memory polymer (SMP) apparatus to a malleable state;

forming an SMP apparatus in a malleable state to generally correspond to a desired configuration of a first surface of the composite part to be formed;

shaping the SMP apparatus to include one or more cavities configured for placement of internal stiffening agents there;

activating the SMP apparatus to a rigid state;

putting the internal stiffening agents into the cavities;

applying the composite material to the SMP apparatus and the exposed surfaces of the internal stiffening agents that rest within the cavities;

cocuring or bonding the internal stiffening agents with the composite material on the SMP apparatus by means of pressure and heat to fabricate the composite part, which includes the steps of:

sealing an impermeable sheet of material around the composite material, compressing the impermeable sheet of material towards the composite material by inducing a differential pressure outward and / or inward of the impermeable sheet of material, and heating the composite material to a curing temperature made of composite, with the SMP apparatus in a rigid state while the impermeable sheet of material compresses the composite material;

removing the waterproof sheet of material from the composite part;

activating the SMP apparatus from the rigid state to the malleable state; and removing the SMP apparatus from within the composite part while the SMP apparatus is in a malleable state.

twenty. The method of paragraph 19, wherein the internal stiffening agents include at least one of additional structures, struts, core, and layers of the composite material.

twenty-one. The method of paragraph 19, where the SMP apparatus is set to begin to change to the malleable state when heated above a temperature Tg, where the curing temperature of the composite material is less than Tg, such that the SMP apparatus remains rigid during curing of the composite material within the composite part.

22. The method of paragraph 19 further comprises placing rigid reinforcing inserts into the cavities between the SMP apparatus and the internal stiffening agents prior to applying the composite to the SMP apparatus, wherein the cavities are sized and shaped to allow the rigid reinforcing inserts and internal stiffening agents rest there.