1) Technical Field
Embodiments of the disclosure relate to the formation of a hybrid composite-metal part and, more particularly, to apparatus and methods for forming a hybrid composite-metal aircraft landing gear and engine support beams.
2) Description of Related Art
In many applications, particularly in the aviation, marine, space, and construction industries, it is important to provide parts with certain properties, such as strength, but with the least amount or at least a reduced amount of mass. Landing gears and engine support beams are commonly heavy metallic structures. For example, there is shown in
The requirements for resisting compression, bending, torsion loads, and runway debris in a landing gear have created a need for a new landing gear design. The new landing gear design must meet the standard requirements but with less mass. Prior and emerging art, using an all metal or all composite structure, have provided limited capabilities to complete these requirements. Namely, composite structures are lighter in weight than metal structures but require expensive molds or tools for their fabrication and autoclaves or presses for their cure processing. In addition, composite structures are susceptible to impact damage and may not be able to support the weight of an entire aircraft. As such, metal has remained the material of choice for the landing gear even though it has a weight disadvantage. Thus, the dead weight of the landing gear remains a problem for the aviation industry.
The requirements for the engine support beams are similar to those for the landing gear design. The engine support beams must provide enough support to effectively resist the various loads caused by the engine including pitch and side loads. As was the case for landing gears, it is desirable to reduce the weight of the engine support structure as much as possible without critically reducing the ability of the structure to achieve its load requirements. As such, the need exists for a new engine support beam design to reduce mass. Prior and emerging art have provided limited capabilities to complete the requirements. Typically, engine supports are made of metal. Metal supports do not require the expensive molds or tools used in fabrication of composite supports. As such, metal is still the material of choice for engine support beams. Thus, the weight of engine support beams continues to be a problem for designers.
It would therefore be advantageous to provide apparatus and methods for forming hybrid components that enjoy at least some of the strength offered by conventional metal components and at least some of the weight advantages offered by composite components. In addition, it would be advantageous to provide apparatus and methods to form components that decrease the overall weight of an aircraft or other vehicles without compromising its structural integrity. With less structural weight, aircraft and other vehicles would be able to carry greater payloads and realize increased fuel economy.
Embodiments of the disclosure may address the above needs and achieve other advantages by providing apparatus and methods for formation of a hybrid composite-metal part, such as a hybrid composite-metal aircraft landing gear and engine support beams. Generally, embodiments of the disclosure provide apparatus and methods for forming a hybrid composite-metal part without the need for tooling or autoclave processing while benefiting from the properties and characteristics of both composite and metal materials. In particular, hybrid composite-metal parts may be formed of metal pieces joined together with a cured composite occupying the space between the pieces.
In one embodiment, a hybrid composite-metal component includes an elongate inner metal piece, an outer metal piece disposed about at least a portion of the inner metal piece, and composite material disposed between the inner metal piece and the outer metal piece. The inner metal piece and outer metal piece may have opposed tapered and non-tapered ends. The length defined by the distance from the tapered end to the non-tapered end of the inner metal piece may be about the same as the length defined by the distance from the tapered end to the non-tapered end of the outer metal piece. The inner metal piece and outer metal piece may be joined by at least one of a seal and at least one fastener, which may be a bolt extending between the inner metal piece and outer metal piece or a plurality of fasteners spaced evenly about a section of the outer metal piece. The inner metal piece and the outer metal piece may be formed of titanium. The composite material may be formed of graphite impregnated with resin. The tapered ends of both the inner metal piece and outer metal piece may include a double taper. Also, the tapered ends of the inner metal piece and outer metal piece may be aligned, while the non-tapered ends are also aligned.
In another embodiment, a method of forming a hybrid composite-metal component is provided. The method includes mating an inner metal piece within an outer metal piece so that there is a gap therebetween, filling at least a portion of the gap with a composite material, and joining the inner metal piece and the outer metal piece. The joining of the inner metal piece and the outer metal piece may include at least one of applying a seal and attaching at least one fastener. Attaching at least one fastener may include affixing at least one bolt to the inner metal piece and the outer metal piece, as well as affixing a plurality of bolts spaced evenly about the outer metal piece. The filling at least a portion of the gap with composite material includes depositing a dry composite material within the gap and impregnating the dry composite material with a resin. The method further includes curing the composite material. The curing of the composite material may include applying heat or radiation to the composite material. Also, the method may include applying pressure to the composite material during the curing of the composite material.
In another embodiment, an aircraft component is provided. The aircraft component includes an inner metal tube, an outer metal tube disposed about at least a portion of the inner metal tube, and composite material disposed between the inner metal tube and the outer metal tube. As before, both the inner metal tube and the outer metal tube may have at least one tapered end. The tapered ends of both the inner metal tube and outer metal tube may each include a double taper.
Having thus described the embodiments of the disclosure in general terms, reference will now be made to the accompanying illustrations, which are not necessarily drawn to scale, and wherein:
The embodiments will now be described more fully hereinafter with reference to the accompanying illustrations, in which some, but not all embodiments are shown. Indeed, these embodiments may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
A hybrid composite-metal component is provided that can be employed in various applications and may serve, for example, as landing gear main posts and trucks or an engine support beam for aircraft. The hybrid composite-metal component includes an elongated inner metal piece 10 that may have a tapered end 11 and an opposed non-tapered end 12 as shown in
As shown in
Typically, the composite material 30 substantially or completely fills the gap 13. The width of the gap 13 differs depending upon the application, particularly the load requirements. For instance, larger and heavier aircraft require greater composite thicknesses to provide the necessary strength to resist loads imposed on the aircraft by hard landings at maximum gross weights. The surfaces of the metal components that contact the composite resin material may be etched and adhesive bond primed to provide high bond strengths. The outer metal piece 20 and inner metal piece 10 are also typically joined by fasteners, such as bolts 5. In one embodiment, for example, the outer metal piece 20 and inner metal piece 10 may be joined by a plurality of bolts 5 spread circumferentially about the outer metal piece 20 surface. Typically, the bolts 5 are spaced in an even manner about the circumference of the outer metal piece 20, but bolts 5 can be spaced irregularly if desired. Large diameter fasteners may be used, particularly to resist torsion and side loads. In addition or alternatively, outer metal piece 20 and inner metal piece 10 can be joined by a seal. The seal is typically a high temperature resistant seal, such as a polyimide. The inside surface of the outer metal piece 20 and outside surface of the inner metal piece 10 may have a layer of TeflonĀ® applied to shield the two surfaces. The TeflonĀ® may be removed after cure. In addition or alternatively, the outer metal piece 20 and inner metal piece 10 may include threaded metal components.
In
Many modifications and other embodiments will come to mind to one skilled in the art to which these embodiments pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. For example, one or both of the inner metal piece 10 and the outer metal piece 20 need not have tapered ends 11 and may either have cylindrical or even outwardly flared ends. Moreover, while a cylindrical inner metal piece 10 and a cylindrical outer metal piece 20 have been illustrated and described, one or both of the inner metal piece 10 and the outer metal piece 20 may have other cross sectional shapes and the inner metal piece 10 and the outer metal piece 20 may have different cross-sectional shapes so long as the inner metal piece 10 fits, at least partially, within the outer metal piece 20. Therefore, it is to be understood that the disclosure is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.