The subject matter described herein relates to manufacturing techniques and more particularly to techniques to form a T-shaped or I-shaped composite structure which includes an air gap in a region which would normally contain a radius filler.
Composite structures are used in various manufacturing and construction operations. By way of example, various structural components of aircraft may be formed from composite materials. Composite materials which are incorporated into structures that from a T-shaped or I-shaped cross section, e.g., beams or flanges, typically form a fillet at the intersection of the structures. In conventional manufacturing techniques these fillets are filled with a compound commonly referred to as a radius filler. In some circumstances the use of radius fillers creates structural issues in completed parts.
Accordingly, composite structures and methods to make the same may find utility, e.g., in the construction of vehicles such as aircraft or watercraft.
In one example, a method to form a composite part comprises joining a first structural element and a second element to form a fillet at an intersection of the first structural element and the second element, positioning an inflatable radius filler in the fillet, positioning the composite part in a vacuum chamber, venting the inflatable radius filler to an environment external to vacuum chamber, drawing a vacuum in the vacuum chamber, and curing the composite part.
In another example, a composite part comprises a first structural element and a second element formed from a composite material and joined at an intersection to define a fillet at the intersection and an inflatable radius filler positioned in the fillet.
In another example, a composite part comprises a first structural element and a second element formed from a composite material and joined at an intersection to define a fillet at the intersection, and an air radius in the fillet.
Embodiments of methods and systems in accordance with the teachings of the present disclosure are described in detail below with reference to the following drawings.
In the following description, numerous specific details are set forth to provide a thorough understanding of various embodiments. However, it will be understood by those skilled in the art that the various embodiments may be practiced without the specific details. In other instances, well-known methods, procedures, components, and circuits have not been illustrated or described in detail so as not to obscure the particular embodiments.
As described herein, composite structures may be assembled into structural components for use in a larger structure such as an aircraft, a space vehicle, or a waterborne vehicle. By way of example, aircraft structures such as wings and tails commonly include structural components formed from composite materials. Embodiments described herein allow composite structures to be assembled into T-shaped or I-shaped components without the use of radius fillers, thereby increasing the efficiency of the manufacturing process and allowing for lightweight, strong composite components.
Referring more particularly to the drawings, embodiments of the disclosure may be described in the context of an aircraft manufacturing and service method 100 as shown in
Each of the processes of method 100 may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of venders, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on. As shown in
Apparatus and methods embodied herein may be employed during any one or more of the stages of the production and service method 100. For example, components or subassemblies corresponding to production process 108 may be fabricated or manufactured in a manner similar to components or subassemblies produced while the aircraft 102 is in service. Also, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during the production stages 108 and 110, for example, by substantially expediting assembly of or reducing the cost of an aircraft 102. Similarly, one or more of apparatus embodiments, method embodiments, or a combination thereof may be utilized while the aircraft 102 is in service, for example and without limitation, to maintenance and service 116.
First structural elements 310 and second structural elements 320 may be formed from a fiber-reinforced composite material such as fiberglass, carbon fiber, Kevlar, or the like bonded by a resin such as an epoxy resin or the like. First structural elements 310 and second structural elements 320 may include one or more layers of a reinforcing metal, e.g., aluminum, titanium, or steel.
In the embodiment depicted in
In various embodiments the composite part 300 may be a structural component of an aircraft. Examples of such components include wing boxes, control surfaces, wings, skins, fuselages, doors, or the like.
As described above, in conventional practice fillets 330 have been filled with a structural material commonly referred to in the art as a radius filler. In some circumstances it may be advantageous to manufacture the composite part 300 without a radius filler disposed in the fillet(s) 330. Techniques to manufacture a composite part 300 without a radius filler will be explained with reference to
At operation 415 an inflatable radius filler 350 is positioned in the fillet.
In some embodiments at least one bag carrier may be positioned in the vacuum bag 354. One example of a bag carrier 360 is depicted in
In alternate embodiments the inflatable radius filler 350 may be implemented as tube formed from a deformable material, e.g., a suitable polymer or rubber. The tube may be cylindrical in shape, as depicted in
At operation 420 the composite part 300 is positioned in a vacuum chamber. By way of example, in some embodiments the vacuum chamber may be embodied as a second vacuum bag which is sufficiently large to hold the entire assembly of structural components. The vacuum chamber 300 may further comprise an autoclave which has an integrated vacuum bag.
At operation 425 the inflatable radius filler 350 is vented to an external environment. By way of example in some embodiments the vent 352 of the inflatable radius filler 350 may be placed in fluid communication with the ambient environment, e.g., by coupling a tube to the vent 352 and extending the tube to the ambient environment.
At operation 430 a vacuum is drawn in the vacuum chamber. As used herein the term vacuum should be construed to mean that the ambient pressure of the gas in the vacuum chamber is reduced to a level below the air pressure of the ambient environment. As used here, the term vacuum should not be construed to require the forming of a perfect vacuum in the vacuum chamber. A vacuum may be drawn by drawing the gas from the vacuum chamber using a pump or the like.
Because the inflatable radius filler 350 is vented to the ambient environment the inflatable radius filler 350 will maintain an internal pressure that corresponds approximately to the ambient environment. Thus, as a vacuum is drawn in the vacuum chamber the inflatable radius filler 350 will expand to occupy the space defined by the fillet(s) 330. The expansion of the inflatable radius filler 350 in the fillet(s) 330 applies a uniform cure pressure each of the sides 332, 334, 336 of the fillet(s) 330, thereby reducing the risk of ply distortion and voids in the layers of the composite structures 310, 320.
At operation 435 the composite part 300 is cured in the vacuum chamber. In some embodiments curing the composite part 300 may comprise heating the composite part to a temperature at which the resin and/or any adhesive used to form the composite part 300 will cure. In addition, the composite part 300 may be subjected to pressure. The specific temperature and pressure applied to the composite part 300 may be a function of the materials from which the composite part is constructed. By way of example, in composite materials used in the aerospace industry are commonly heated to a temperature range between 30 degrees centigrade and 200 degrees centigrade and are subjected to pressures between 15 and 100 psi.
At operation 440 the inflatable radius filler 350 is removed from the cured composite part 300 to provide a cured composite part 300 comprising a first structural element 310 and a second element 320 formed from a composite material and joined at an intersection to define a fillet at the intersection, and an air radius in the fillet 330.
As illustrated in
By way of example and not limitation, in some embodiments the vacuum bag 354 may be wrapped in a composite ply material such that, when cured, the composite ply material forms the reinforcement member 340. The reinforcement member 340 may be formed from the same composite material as the structural elements 310, 320 such that the composite ply material which forms the reinforcement member 340 has an elastic modulus which is approximately the same as the elastic modulus of the structural components 310, 320. The particular number of layers of composite ply material used to wrap the vacuum bag 354 is not critical. In some embodiments the vacuum bag 354 may be wrapped with 1-5 layers of composite ply material.
Thus, described herein are methods to form a composite part which includes one or more fillets 330 that include a hollow aperture, rather than a radius filler. In some embodiments the fillet 330 may be left completely hollow. In other embodiments the fillet 330 may include a reinforcement member 340 formed from one or more layers of composite ply material. In use, the fillet 330 may be used as a conduit through which wiring, cables, fluid lines, or the like may extend. Because the fillet 330 is a confined space, there may be no need for clips or housings to hold the wires, cables, or fluid lines in place.
When used in an aircraft, the composite part 300 may define a confined space which operates in pressurized and unpressurized states at different points in time, depending upon the conditions in which the aircraft is being operated.
In another example depicted in
In this embodiment, the aircraft 500 includes a fuselage 502 including wing assemblies 504, a tail assembly 506, and a landing assembly 508. The aircraft 500 further includes one or more propulsion units 510, a control system 512 (not visible), and a host of other systems and subsystems that enable proper operation of the aircraft 500. One should appreciate that composite part may be employed in any suitable portion of the aircraft 500, such as in a fuselage 502, wing assemblies 504, tail assembly 506, and any other suitable areas of the aircraft 500. In general, the various components and subsystems of the aircraft 500 may be of known construction and, for the sake of brevity, will not be described in detail herein.
Although the aircraft 500 shown in
In the description and claims, the terms coupled and connected, along with their derivatives, may be used. In particular embodiments, connected may be used to indicate that two or more elements are in direct physical or electrical contact with each other. Coupled may mean that two or more elements are in direct physical or electrical contact. However, coupled may also mean that two or more elements may not be in direct contact with each other, but yet may still cooperate or interact with each other.
Reference in the specification to “one embodiment” or “some embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least an implementation. The appearances of the phrase “in one embodiment” in various places in the specification may or may not be all referring to the same embodiment.
Although embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that claimed subject matter may not be limited to the specific features or acts described. Rather, the specific features and acts are disclosed as sample forms of implementing the claimed subject matter.
The present application claims priority from, and is a divisional application of, U.S. patent application Ser. No. 13/895,409, filed May 16, 2013, now U.S. Pat. No. 9,205,634, the contents of which is incorporated by reference herein in its entirety.
Number | Name | Date | Kind |
---|---|---|---|
4798594 | Hillstead | Jan 1989 | A |
5710414 | Matsen et al. | Jan 1998 | A |
6458309 | Allen | Oct 2002 | B1 |
6849150 | Schmidt | Feb 2005 | B1 |
8377248 | Coleman et al. | Feb 2013 | B2 |
20100080942 | McCarville et al. | Apr 2010 | A1 |
20100151162 | Dorawa et al. | Jun 2010 | A1 |
Number | Date | Country |
---|---|---|
1459873 | Sep 2004 | EP |
1762357 | Mar 2007 | EP |
2052846 | Apr 2009 | EP |
2004011169 | Feb 2004 | WO |
2013001458 | Jan 2013 | WO |
Entry |
---|
Lukosevicius, M. et al., “Reservoir Computing Approaches to Recurrent Neural Network Training,” Aug. 2009, vol. 3, No. 3, Computer Science Review, Elsivier, Amsterdam, The Netherlands, pp. 127-149. |
Extended European Search Report for European Application No. 14167906.8 dated Dec. 5, 2014, 7 pgs. |
Number | Date | Country | |
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20160160899 A1 | Jun 2016 | US |
Number | Date | Country | |
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Parent | 13895409 | May 2013 | US |
Child | 14930214 | US |