Patent Description:
Aircraft are typically equipped with interior components and flight control surfaces. Flight control surfaces are utilized to maneuver the aircraft during flight as well as provide high lift surfaces to increase lift at low airspeed. Interior components vary significantly but often utilize hollow structures to reduce weight and decrease manufacturing costs. Vibration welding is utilized to couple a hollow structure to an adjacent component. Vibration welding operates at lower frequencies and higher amplitudes relative to ultrasonic welding. Additionally, a large clamping force is typically applied to each flange of a hollow structure that is being welded to an adj acent component.

<CIT> discloses a manufacturing method for a bonded body.

A method for forming a fiber-reinforced thermoplastic hollow structure according to an aspect of the invention is disclosed in claim <NUM>. Embodiments of this aspect of the invention are provided in claims dependent from claim <NUM>.

A fiber-reinforced thermoplastic hollow structure according to an aspect of the invention is disclosed in claim <NUM>. Embodiments of this aspect of the invention are provided in claims dependent from claim <NUM>.

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the inventions, it should be understood that other embodiments may be realized and that logical changes and adaptations in design and construction may be made in accordance with this invention and the teachings herein. Thus, the detailed description herein is presented for purposes of illustration only and not for limitation. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Surface shading lines may be used throughout the figures to denote different parts but not necessarily to denote the same or different materials.

In general, the example shells and mating components used to form a hollow structure as described herein may be used with control surfaces, such as aircraft wings, stabilizers, or elevators, among other aerodynamic surfaces of an aircraft. Some examples of common names for these surfaces known to those practiced in the arts include but are not limited to flaps, ailerons, rudders, elevators, stabilators, elevons, spoilers, lift dumpers, speed brakes, airbrakes, trim tabs, slats, flaperons, spoilerons, and canards. These are henceforth referred to as control surfaces. In general, control surfaces may direct air flow during maneuvering and in-flight aircraft attitude adjustments. The example control surfaces described herein may provide increased resistance to impact damage than some known control surface constructions. Further, the example methods for manufacturing control surfaces described herein include fewer and lighter components than some known control surfaces. Thus, the example control surfaces described herein provide increased fuel efficiency and/or range to aircraft. Still further, the example control surfaces may be manufactured using an automated skin/stiffener manufacturing process, as described herein, which optimizes material usage and reduces cycle time.

Although described with respect to control surfaces, the present disclosure is not limited in this regard. For example, shells and mating components coupled together in accordance with the systems and methods disclosed herein may be used for aircraft interior components like seat backs, urban aerial mobility (UAM) components, or the like.

A thermoplastic material including a fiber-reinforced structure, as described herein, includes a structural body comprising skin members. In various embodiments, the skin members include a continuous fiber reinforced fabric, or unidirectional tape based laminate, and a thermoplastic resin. The reinforcing fiber, or a combination of reinforcing fibers, to be used for the fiber-reinforced structure has no particular limitations with respect to the type thereof, and examples thereof include metal fibers, such as an aluminum fiber, a brass fiber, and a stainless steel fiber, carbon fibers (including graphite fibers), such as polyacrylonitrile (PAN)-based carbon fibers, rayon-based carbon fibers, lignin-based carbon fibers, and pitch-based carbon fibers, insulating fibers, such as glass fiber, organic fibers, such as aramid fibers, polyparaphenylene benzoxazole (PBO) fibers, polyphenylene sulfide fibers, polyester fibers, acrylic fibers, nylon fibers, and polyethylene fibers, and inorganic fibers, such as silicon carbide fibers and silicon nitride fibers. Fibers prepared by applying surface treatment to these fibers are also available. Examples of the surface treatment include treatment with a coupling agent, treatment with a sizing agent, treatment with a binder, and adhesion treatment with an additive in addition to deposition treatment with conductive metal.

In the disclosure, the thermoplastic resin to be used for a mating component and/or a shell may be either semi-crystalline or amorphous.

Examples of the semi-crystalline thermoplastic resin include polyester, polyolefin, polyoxymethylene (POM), polyamide (PA), polyarylene sulfide, polyketone (PK), polyetherketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyaryletherketone (PAEK), polyether nitrile (PEN), fluororesin, and liquid crystal polymer (LCP). Examples of the polyester include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terphthalate (PTT), polyethylene naphthalate (PEN), and liquid crystal polyester. Examples of the polyolefin include polyethylene (PE), polypropylene (PP), and polybutylene. Examples of the polyarylene sulfide include polyphenylene sulfide (PPS). Examples of the fluororesin include polytetrafluoroethylene.

Examples of the amorphous thermoplastic resin include polystyrene, polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), polyphenylene ether (PPE), polyimide (PI), polyamide imide (PAI), polyetherimide (PEI), polysulfone (PSU), polyether sulfone (PES), and polyarylate (PAR). The thermoplastic resin to be used for the control surface also may be phenoxy resin, polystyrene, polyolefin, polyurethane, polyester, polyamide, polybutadiene, polyisoprene, fluorine resin, acrylonitrile, and other thermoplastic elastomers, and copolymers and modified resin thereof.

Disclosed herein is a method of vibration welding without applying a direct load to a flange that is welded to a mating component. The flange is an element of a shell being coupled to the mating component via vibration welding. The flange is compressed, via the method disclosed herein, from a nearby area, which generates a force on a weld area of the flange and the mating component sufficient to weld the flange to the mating component. In this regard, tooling costs may be reduced, a vibration welding process may be simplified, and/or a high weld strength between the flange and the mating component may be maintained.

Referring now to <FIG>, a perspective view of a shell <NUM> and a mating component <NUM> prior to vibration welding is illustrated in accordance with various embodiments. In various embodiments, the shell <NUM> and the mating component <NUM> both comprise a fiber reinforced thermoplastic material. The shell <NUM> may be formed from a first continuous fiber reinforced fabric or uni-directional tape based laminate, as described herein. The mating component <NUM> may be formed from a second continuous fiber reinforced fabric, as described herein. In various embodiments, the second continuous fiber reinforced fabric is the same or similar material as the first continuous fiber reinforced fabric. In various embodiments, the shell <NUM> and/or the mating component <NUM> may both be formed of multiple layers of fiber reinforced fabric. The present disclosure is not limited in this regard. In various embodiments, one of the shell <NUM> and the mating component <NUM> may comprise a fiber-reinforced thermoplastic material and the remaining component may comprise any other material, such as a metal alloy (e.g., nickel-based alloy, titanium-based alloy, aluminum-based alloy, iron-based alloy, etc.). The present disclosure is not limited in this regard.

In various embodiments, the shell <NUM> and the mating component <NUM> may be formed by combining fiber fillers and thermoplastic resin at a pre-selected ratio to form a thermoplastic composite material with continuous fiber reinforcement. For example, the shell <NUM> and/or mating component <NUM> may be formed using automated fiber placement or automated tape laying. The pre-selected ratio may have any percentage or ratio of fiber filler to resin, such as <NUM>% fiber filler and <NUM>% resin. The mixture may range from <NUM>% fiber filler and <NUM>% resin to <NUM>% fiber filler and <NUM>% resin. In this regard, shell <NUM> and/or the mating component <NUM> may be continuous fiber reinforced. However, it is contemplated herein that shell <NUM> and the mating component <NUM> may be discontinuous fiber reinforced, in accordance with various embodiments.

In various embodiments, the shell <NUM> comprises a first flange <NUM> and a second flange <NUM>. The first flange <NUM> and the second flange <NUM> are configured to be vibration welded to the mating component <NUM> without a direct load being applied to the first flange <NUM> as described further herein.

In various embodiments, the shell <NUM> further comprises sidewalls <NUM>. With reference now to <FIG>, internal surfaces of the sidewalls <NUM> and an internal surface of the mating component <NUM> define a cavity <NUM> of a hollow structure <NUM> in response to being coupled together via the systems and methods disclosed herein. Although illustrated as comprising perpendicular sidewalls to form a substantially square cross-section for the cavity <NUM>, the present disclosure is not limited in this regard. For example, sidewalls <NUM> may comprise acute or obtuse angles and/or may define various types of cross-sections, such as trapezoidal, polygonal, hexagonal, or the like and still be within the scope of this disclosure. In various embodiments, each flange (e.g., first flange <NUM> and second flange <NUM>) extends laterally (i.e., in the X-direction) from an adjacent sidewall (e.g., sidewall <NUM> for first flange <NUM> and sidewall <NUM> for flange <NUM>). In various embodiments, a centerline through the cavity <NUM> (i.e., in the Z direction) may define a longitidudinal axis for the hollow structure <NUM> from <FIG>.

Referring now to <FIG>, a system <NUM> for coupling the shell <NUM> to the mating component <NUM> via vibration welding is illustrated, in accordance with various embodiments. With combined reference to <FIG> and <FIG>, a method <NUM> of coupling the shell <NUM> to the mating component <NUM> comprises abutting a first surface <NUM> of the first flange <NUM> and a second surface <NUM> of the second flange <NUM> with the mating component <NUM> (step <NUM>). In various embodiments, the first surface <NUM> and the second surface <NUM> may abut a single surface (e.g., a singular planar surface <NUM>) of the mating component <NUM>; however, the present disclosure is not limited in this regard. For example, with brief reference to <FIG>, a first surface <NUM> of a first flange <NUM> of a shell <NUM> may abut a first surface <NUM> of a mating component <NUM> and a second surface <NUM> of a second flange <NUM> of the shell <NUM> may abut a second surface <NUM> of the mating component (i.e., where the second surface <NUM> is in a different plane from the first surface <NUM>) and still be within the scope of this disclosure.

The method <NUM> further comprises disposing an end block <NUM> laterally adjacent to the first flange <NUM> (i.e., the flange where a load will not be applied) of the shell <NUM> (step <NUM>). Although illustrated as being disposed adjacent to the first flange <NUM>, the present disclosure is not limited in this regard. For example, the first flange <NUM> could be oriented inward (i.e., into the cavity <NUM> from <FIG>) and still be within the scope of this disclosure. In this regard, the end block <NUM> would be disposed laterally adjacent to a sidewall <NUM> of the sidewalls <NUM>. The end block <NUM> is configured to restrain lateral movement (i.e., movement in the -X direction) during vibration welding as described further herein. In this regard, a lateral position of a weld line may remain constant during the welding process, in accordance with various embodiments.

The method <NUM> further comprises applying a first load F1 to a sidewall <NUM> of the sidewalls <NUM> and a second load F2 to the second flange <NUM> (step <NUM>). Each of the loads F1 and F2 may be at least generally directed toward the mating component <NUM>. In various embodiments, the first load F1 applied to the sidewall <NUM> may be substantially perpendicular to a plane defined by the sidewall <NUM>. In various embodiments, in response to the plane defined by the sidewall <NUM> being contoured, a plurality of local forces may be applied which may be substantially perpendicular to the sidewall <NUM> at a local point where the force is applied. "Substantially perpendicular" as defined herein is between <NUM>° and <NUM>°, or between <NUM>° and <NUM>°, or between <NUM>° and <NUM>°. In various embodiments, a contact surface of the sidewall <NUM> configured to receive the first load F1 may be substantially co-planar with the first surface <NUM> of the first flange <NUM>. "Substantially co-planar" as referred to herein is between <NUM>° and <NUM>°, or between <NUM>° and <NUM>°, or between <NUM>° and <NUM>°, in accordance with various embodiments.

Although illustrated as applying the first load F1 and the second load F2 in a similar direction, the present disclosure is not limited in this regard. For example, with brief reference to <FIG>, a load F3 may be applied substantially perpendicular to sidewall <NUM> and a load F4 may be applied substantially perpendicular to the second flange <NUM> during the method <NUM> for forming the hollow structure <NUM>. In this regard, the load applied to the sidewall (e.g., a non-mating flange), may be substantially perpendicular to a mating surface of a non-loaded wall (e.g., first surface <NUM> of first flange <NUM>. In this regard, the load F3 supplied to sidewall <NUM> supplies a sufficient force, combined with an end block <NUM> from <FIG> positioned against the side of flange <NUM> and component <NUM> preventing lateral motion of the first flange <NUM>, to join the first flange <NUM> to the mating component <NUM> during step <NUM> as described further herein.

The method <NUM> further comprises vibrating the mating component <NUM> while keeping the shell <NUM> stationary (step <NUM>). Although described as vibrating the mating component <NUM> relative to the shell <NUM>, the present disclosure is not limited in this regard. For example, in various embodiments, the shell <NUM> may be vibrated while the mating component <NUM> is kept stationary. In various embodiments, "vibrating" as described herein refers to translating a component (e.g., the mating component <NUM> or the shell <NUM>) relative to the other component back and forth (e.g., oscillating) in a longitudinal direction (i.e., alternating between the Z direction and the -Z direction in <FIG>) to generate friction heat between the first surface <NUM> of the first flange <NUM> and the mating component <NUM> and the second surface <NUM> of the second flange <NUM> and the mating component <NUM>. In this regard, the friction heat fuses at least a portion of the first surface <NUM> of the first flange <NUM> and the second surface <NUM> of the second flange <NUM> to the mating component <NUM>.

In various embodiments, a weld formed on the non-loaded flange (e.g., the first flange <NUM>) may only be a partial lateral length (i.e., measured in the X direction from an adjacent sidewall) of the flange. For example, welding a shell <NUM> with a flange length of <NUM> inches (<NUM>) may result in a weld seam of approximately <NUM> inches (<NUM>). In various embodiments, a weld seam may be between <NUM>% and <NUM>% of a lateral length (i.e., in the X-direction) of a non-loaded flange, or between <NUM>% and <NUM>%, or between <NUM>% and <NUM>% by the method <NUM> disclosed herein. Although the entire flange of the non-loaded flange (e.g., first flange <NUM>) may not weld to the mating component, the partial weld seam may be sufficient for loading of the hollow structure <NUM> from <FIG>. For example, in some real cases the torsional test data of a resultant hollow structures <NUM> formed via method <NUM> from <FIG> resulted in the hollow structure <NUM> buckling, and ultimately failing, prior to disbond of the weld seam formed from the method <NUM>. In this regard, the decrease in weight and cost of manufacturing the hollow structure <NUM> outweigh any reduction in structural capabilities of the weld formed by the method <NUM> disclosed herein. In contrast to the non-loaded flange, the weld formed on the loaded flange (e.g., the second flange <NUM>) is between <NUM>% and <NUM>% of a lateral length of the flange. For example, the weld formed on the loaded flange may be between <NUM>% and <NUM>% of a lateral length of the flange, or approximately an entire lateral length of the flange, in accordance with various embodiments.

In various embodiments, by not having to apply a direct load to a flange (e.g., first flange <NUM>) that is being friction welded to a mating component <NUM>, more complex hollow structures (e.g., hollow structure <NUM> from <FIG>) may be manufactured in a simpler manner and/or at a lower expense relative to typical vibration welding processes.

Claim 1:
A method for forming a fiber-reinforced thermoplastic hollow structure (<NUM>; <NUM>), comprising:
abutting a first surface (<NUM>; <NUM>) of a first flange (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>) of a shell (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>) and a second surface (<NUM>; <NUM>) of a second flange (<NUM>; <NUM>) of the shell (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>) with a mating component (<NUM>; <NUM>);
configuring an end block (<NUM>) to restrain lateral movement of the shell (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>);
applying a first load (F1) to a sidewall (<NUM>; <NUM>; <NUM>) of the shell (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>);
applying a second load (F2) to the second flange (<NUM>; <NUM>) of the shell (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>); and
vibrating one of the shell (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>) or the mating component (<NUM>; <NUM>) while keeping a non-vibrating component (<NUM>) stationary, the non-vibrating component (<NUM>) including one of the shell (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>) or the mating component (<NUM>; <NUM>) the method characterised in that a direct load is not applied to the first flange (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>).