Not applicable.
Not applicable.
Structural components in aircraft are often subjected to high forces and/or loads when in motion. In some instances, structural aircraft components are subjected to occasional impact from objects. These structural components must be designed to be lightweight while handling the forces and resisting impact damage. Accordingly, structural aircraft components are frequently constructed from a core having a matrix of adjoining hollow cells and an attached outer skin to maintain structural integrity of the components while also minimizing weight. Current systems and methods for constructing such structural aircraft components include using a fiber-reinforced thermoset skin bonded to a fiber-reinforced thermoset core. However, these thermoset components present many challenges, such as requiring complex surface preparation procedures prior to bonding, which can leave the bonds predisposed to failure if not performed properly.
For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description.
In this disclosure, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of this disclosure, the devices, members, apparatuses, etc. described herein may be positioned in any desired orientation. Thus, the use of terms such as “above,” “below,” “upper,” “lower,” or other like terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the device described herein may be oriented in any desired direction.
This invention relates generally to constructing a thermoplastic component. More specifically, this disclosure relates to constructing a thermoplastic component by adhering a fiber-reinforced thermoplastic skin to a fiber-reinforced thermoplastic core. Thermoplastics, by definition, rely on a phase-change when processed by melting and re-solidifying upon cooling. Thermoplastic materials begin in a first solid state that is melted into a second semi-liquid or liquid state, consolidated with another component, and then re-solidified when cooled to create a single “welded,” “melt-bonded,” and/or “fusion-bonded” thermoplastic component. As such, constructing a thermoplastic component in accordance with this disclosure requires melting a surface and/or surface element of each of thermoplastic skin and a thermoplastic core at an interface between the two, consolidating the skin and core at the interface via contact and/or an application of pressure, and then cooling the skin and core at the interface to create the single unitary thermoplastic component.
Referring now to
In some embodiments, heat source 106 may comprise a vibratory mechanism that selectively vibrates at least one of the thermoplastic skin 102 and the thermoplastic core 104 to generate heat 108 via friction between the interfaces 102, 104. To generate heat 108 through friction, it will be appreciated that the interfaces 103, 105 are in contact prior to the heat source 106 applying the vibration. In other embodiments, heat source 106 may be configured to generate inductive heat 108, radiant heat 108, and/or any other type of heat 108 to melt the thermoplastic skin 102 and the thermoplastic core 104 to melt at their respective interfaces 103, 105. Accordingly, in some embodiments, the interfaces 103, 105 may be in contact prior to applying the inductive, radiant, and/or other type of heat 108. However, in some embodiments, the interfaces 103, 105 may be separated prior to application of the inductive, radiant, and/or other type of heat 108.
When inductive, radiant, and/or other type of heat 108 is employed, the heat 108 may be directed onto the interfaces 103, 105 from the top, bottom, and/or sides of the thermoplastic skin 102 and/or the thermoplastic core 104 until each of the interfaces 103, 105 reaches its melting temperature. By directing the heat 108 at the interfaces 103, 105, the structure of the thermoplastic skin 102 and the thermoplastic core 104 maintain their structural integrity. The heat 108 transfers sufficient energy to bring the interfaces 103, 105 to the melting temperature and at least partially melt the thermoplastic skin 102 and the thermoplastic core 104 at their respective interfaces 103, 105. As the interfaces 103, 105 at least partially melt, the interfaces 103, 105 of the thermoplastic skin 102 and the thermoplastic core 104 undergo a phase-change from a solid to liquid. In one example, the interfaces 103, 105 may be subjected to heat 108 and begin to soften at about 360 to 380 degrees Fahrenheit. Each of the interfaces 103, 105, may continue to soften until the temperature reaches about 600 degrees Fahrenheit, at which temperature each of the interfaces 103, 105 is considered fully melted.
To reach the fully melted state of the interfaces 103, 105, the heating rate at the interfaces 103, 105 must be sufficiently rapid to ensure that the structure and stiffness of a majority of the thermoplastic skin 102 and thermoplastic core 104 retain their shapes and structural integrity such that melting only occurs at the interfaces 103, 105. Then, upon reaching the fully melted state, the thermoplastic skin 102 and the thermoplastic core 104 are consolidated by forcing the thermoplastic skin 102 and the thermoplastic core 104 into contact through gravity, pressure, and/or another external force. However, in embodiments where the thermoplastic skin 102 and thermoplastic core 104 are in contact prior to applying heat 108, the interfaces 103, 105 may consolidate automatically. Consolidation occurs when the melted interfaces 103, 105 remain in contact and re-solidify upon cooling. In some embodiments, the interfaces 103, 105 may be allowed to cool naturally at room temperature by selectively ceasing the application of heat 108 to the interfaces 103, 105. However, in some embodiments, a thermal mass having high thermal conductivity (e.g. aluminum) may be applied to the thermoplastic component 120. The thermal mass may quickly extract heat from the thermoplastic component 120, which may further retain the integrity and/or structure of thermoplastic core 104.
Upon consolidation, the interfaces 103, 105 undergo a second phase-change, changing from a liquid to a solid, re-solidifying and recrystallizing and/or reorganizing to form a single “welded” and/or “fusion-bonded” unitary thermoplastic component 120. Accordingly, the thermoplastic skin 102 and the thermoplastic core 104 are joined by the welding and/or fusion-bonding process that requires no adhesive. The interfaces 103, 105 of the thermoplastic skin 102 and the thermoplastic core 104 are simply melted, consolidated, and then cooled to form the thermoplastic component 120. By eliminating the need for adhesive to form the bond between the thermoplastic skin 102 and the thermoplastic core 104, costly and complex surface preparation procedures necessary in bonding thermoset components are eliminated. Further, the reticulation formed by thermoset components is also emulated through process 100. Additionally, it will be appreciated that fiber-reinforced thermoplastic components 120 exhibit improved damage tolerance, better strength after impact, and other structurally desirable characteristics as compared to most current thermoset components.
Referring now to
In some embodiments, thermoplastic skin 202 may generally be formed from a fiber-reinforced thermoplastic material that is impregnated with a constituent 207 that enhances heat transfer between the heat source 206 and the thermoplastic skin 202. Constituent 207 comprises an interspersed metallic component and/or other material component that enhances heat transfer by more readily responding to inductive, radiant, and other type of heat 208. Accordingly, when heat 208 is applied from heat source 206, constituent 207 allows the interface 203 of the thermoplastic skin 202 to reach its melting temperature prior to the interface 205 of the thermoplastic core 204 reaching its melting temperature. The material of the thermoplastic skin 202 may be selected, designed, and/or otherwise impregnated with constituent 207 such that the interface 203 of the thermoplastic skin 202 reaches its melting temperature just prior to that of the interface 205 of the thermoplastic core 204. This lowers the risk of the thermoplastic core 204 receiving too much heat 208, thereby protecting and preserving the structural integrity of the thermoplastic core 204 when heat 208 is applied to join the thermoplastic skin 202 and the thermoplastic core 204.
Referring now to
To join the thermoplastic skin 302 to the thermoplastic core 304, heat 308 may be directed to the thermoplastic film 310 while also directed heat 308 to the interfaces 303, 305. When fully melted, the thermoplastic film 310 may flow between the at least partially melted interfaces 303, 305. The thermoplastic skin 310 may be sandwiched between the thermoplastic skin 302 and the thermoplastic core 104 by forcing the thermoplastic skin 102 and the thermoplastic core 104 into contact through gravity, pressure, and/or another external force. Upon cooling, the thermoplastic film 310 joins the thermoplastic skin 102 and the thermoplastic core 104 by the welding and/or fusion-bonding provided by the thermoplastic film 310, thereby forming the thermoplastic component 320. Similarly to processes 100, process 300 eliminates the need for adhesive and the costly and complex surface preparation procedures necessary in bonding thermoset components.
Referring now to
In some embodiments, thermoplastic film 410 may generally be formed from a fiber-reinforced thermoplastic material that is impregnated with a constituent 407 substantially similar to constituent 207 that enhances heat transfer between the heat source 406 and the thermoplastic film 410. Constituent 407 may comprise an interspersed metallic component and/or other material component that enhances heat transfer by more readily responding to inductive, radiant, and other type of heat 408. However, in some embodiments, constituent 407 may be configured to react to an induced electromagnetic field (EMF). Accordingly, when heat 408 is applied from heat source 406, constituent 407 allows the thermoplastic film 410 to reach its melting temperature prior to the interfaces 403, 405 reaching its melting temperature. The material of the thermoplastic film 410 may therefore be selected, designed, and/or otherwise impregnated with constituent 407 such that the thermoplastic film 410 reaches its melting temperature just prior to that of the interfaces 403, 405. This lowers the risk of the thermoplastic skin 402 and the thermoplastic core 404 receiving too much heat 408, thereby protecting and preserving the structural integrity of the thermoplastic core 404 when heat 408 is applied to join the thermoplastic skin 202 and the thermoplastic core 404 and form the thermoplastic component 420.
Referring now to
Referring now to
Referring now to
Accordingly, in a first step of process 700, the thermoplastic skin 710 is joined to the thermoplastic core 704 to form an intermediate thermoplastic component 719. In a second step of process 700, the thermoplastic skin 702 is joined to the intermediate thermoplastic component 719. However, in alternative embodiments, the thermoplastic skin 702 and the thermoplastic core 704 may be joined in a single step substantially similar to process 400. The material of the thermoplastic film 710 may therefore be selected, designed, and/or otherwise impregnated with constituent 707 such that the thermoplastic film 710 reaches its melting temperature just prior to that of the interfaces 703, 705. This lowers the risk of the thermoplastic skin 702 and the thermoplastic core 704 receiving too much heat 708, thereby protecting and preserving the structural integrity of the thermoplastic core 704 when heat 708 is applied to the interfaces 703, 705 to join the thermoplastic skin 702 and the thermoplastic core 704 and form the thermoplastic component 720.
Referring now to
The compressed interface 805″ thereby emulates the reticulation caused by surface tension in current thermoset components that employ adhesive between a skin and core and/or aluminum crushed core components. Thus, only the interface 805′ is compressed to form the compressed interface 805″, while the remainder of the thermoplastic core 804 retains its structural integrity. Further, it will be appreciated that thermoplastic core 804 may be representative of thermoplastic cores 104, 204, 304, 404, 504, 607, 704. Additionally, the compressed interface 805″ creates a larger footprint than other non-crushed portions of the thermoplastic core 804 for an increased surface contact area between the thermoplastic core 804 and a subsequent thermoplastic skin 102, 202, 302, 402, 502, 602, 702 that may be joined thereto. The compressed interface 805″ created by process 800 thus strengthens the joint between a thermoplastic core 104, 204, 304, 404, 504, 604, 704, 804 and a thermoplastic skin 102, 202, 302, 402, 502, 602, 702 and/or an optional thermoplastic film 310, 410, 510, 610, 710. Accordingly, process 800 may be used prior to any of processes 100, 200, 300, 400, 500, 600, 700 to form a compressed interface 805″ on the thermoplastic cores 104, 204, 304, 404, 504, 607, 704.
Furthermore, while processes 100, 200, 300, 400, 500, 600, 700, 800 are described in terms of applying a single thermoplastic skin 102, 202, 302, 402, 502, 602, 702 to a thermoplastic core 104-804, it will be appreciated that multiple thermoplastic skins 102, 202, 302, 402, 502, 602, 702 and/or thermoplastic films 310, 410, 510, 610, 710 may be applied to a thermoplastic core 104, 204, 304, 404, 504, 607, 704, 804. Further it will be appreciated that multiple thermoplastic skins 102, 202, 302, 402, 502, 602, 702 and/or thermoplastic films 310, 410, 510, 610, 710 to substantially encapsulate the thermoplastic core 104, 204, 304, 404, 504, 604, 704, 804 to form a thermoplastic component 120, 220, 320, 420, 520, 620, 720.
Referring now to
Referring now to
Referring now to
Furthermore, in some embodiments, processes 100, 200, 300, 400, 500, 600, 700, 800 may be used to construct components 120, 220, 320, 420, 520, 620, 720 of military vehicles and sea craft, commercial and/or residential buildings, and/or any other structures or components. The large cell thermoplastic core 900 used to form thermoplastic components 120, 220, 320, 420, 520, 620, 720 comprises increased strength both before and after impact as compared to thermoset components. Further, the large cell thermoplastic core 900 used to form thermoplastic components 120, 220, 320, 420, 520, 620, 720 will not propagate in high cycle fatigue applications. As such, the thermoplastic components 120, 220, 320, 420, 520, 620, 720 may be used in high-energy dissipating materials or structures that are prone to impact such as leading edges of rotor blades 1008, 1110, tail rotors 1010, and wings 1104, other flight control surfaces of a helicopter 1000, tiltrotor 1110 and/or other aircraft, and/or a fuselage 1002, 1102 of an aircraft 1000, 1100 that are subject to impact damage.
Referring now to
Referring now to
Method 1300 continues as block 1308 by applying pressure to at least one of the thermoplastic skin 102, 202, 302, 402, 502, 602, 702 and the thermoplastic core 104, 204, 304, 404, 504, 604, 704, 804 to make contact between the thermoplastic film 310, 410, 510, 610, 710 and each of the interfaces 103, 203, 303, 403, 503, 603, 703 and 105, 205, 305, 405, 505, 605, 705, 805″. Method 1300 concludes at block 1310 by cooling the thermoplastic film 310, 410, 510, 610, 710 and the interfaces 103, 203, 303, 403, 503, 603, 703 and 105, 205, 305, 405, 505, 605, 705, 805″ below the melting point of each of the thermoplastic skin 102, 202, 302, 402, 502, 602, 702, the thermoplastic film 310, 410, 510, 610, 710, and the thermoplastic core 104, 204, 304, 404, 504, 604, 704, 804 to consolidate the thermoplastic skin 102, 202, 302, 402, 502, 602, 702, the thermoplastic film 310, 410, 510, 610, 710, and the thermoplastic core 104, 204, 304, 404, 504, 604, 704, 804 into a unitary thermoplastic component 120, 220, 320, 420, 520, 620, 720.
At least one embodiment is disclosed, and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of this disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of this disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, Rl, and an upper limit, Ru, is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=Rl+k*(Ru−Rl), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . 50 percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 95 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed.
Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention. Also, the phrases “at least one of A, B, and C” and “A and/or B and/or C” should each be interpreted to include only A, only B, only C, or any combination of A, B, and C.