Composite tube assemblies and manufacturing process

Abstract

A composite tube assembly includes a first composite tube with a first tubular core and a first outer composite material. The first outer composite material is bonded to a first outer face of the first tubular core. The composite tube assembly further includes a second composite tube having a second tubular core and a second outer composite material. The second outer composite material is bonded to a second outer face of the second tubular core. The second composite tube is coupled to the first composite tube.

Description

Title of the invention: Composite tube assemblies and manufacturing method Technical field

[0001] The present invention relates to composite tube assemblies comprising one or more composite tubes coupled to a reinforced joint. STATE OF PRIOR ART

[0002] Modern machines, such as airplanes, automobiles, boats, rockets, space vehicles, or industrial equipment, may be subjected to extreme operating conditions, including high temperatures, high pressures, and high speeds. Reinforced ceramic matrix composites (“CMCs”) comprising fibers dispersed in continuous ceramic matrices of the same or different composition are well-suited for structural applications due to their toughness, thermal resistance, high-temperature strength, and chemical stability. These composites generally exhibit a high strength-to-weight ratio and retain this attribute over a wide temperature range that exceeds that of metal alloys.This makes them attractive in applications where weight is a concern and where high-temperature structural attributes severely limit element and system design, such as in aerospace and spacecraft applications. Their high-temperature stability makes CMCs highly suitable for applications where elements are in contact with high-temperature gas, such as in a gas turbine engine and in spacecraft reentry conditions in terrestrial and non-terrestrial environments. Brief description of the drawings

[0003] A complete and useful disclosure of the present invention, including the best mode thereof, intended for a person skilled in the art having ordinary skill in the art, is set forth in the specification, which refers to the accompanying figures, in which:

[0004] [Fig.l] illustrates a cross-sectional view of a composite tube having a partially hollow tubular core, in accordance with embodiments of the present invention;

[0005] [Fig.2] illustrates a cross-sectional view of a composite tube having a core solid tubular, in accordance with embodiments of the present invention;

[0006] [Fig. 3] illustrates a partially exploded cross-sectional view of a composite tube assembly in accordance with embodiments of the present invention;

[0007] [Fig.4] illustrates the composite tube assembly shown in [Fig.3] assembled in accordance with embodiments of the present invention;

[0008] [Fig.5] illustrates a partially exploded cross-sectional view of a composite tube assembly in accordance with embodiments of the present invention;

[0009] [Fig.6] illustrates the composite tube assembly shown in [Fig.5] assembled in accordance with embodiments of the present invention;

[0010] [Fig.7] illustrates a partially exploded cross-sectional view of a tube assembly in accordance with embodiments of the present invention;

[0011] [Fig.8] illustrates the composite tube assembly shown in [Fig.7] assembled in accordance with embodiments of the present invention;

[0012] [Fig.9] illustrates a partially exploded cross-sectional view of a composite tube assembly in accordance with embodiments of the present invention;

[0013] [Fig. 10] illustrates the composite tube assembly shown in [Fig. 9] assembled in accordance with embodiments of the present invention; and

[0014] [Fig. 11] is a flowchart of an exemplary method of manufacturing a composite tube assembly in accordance with embodiments of the present invention. DETAILED DESCRIPTION

[0015] Reference will now be made in detail to certain embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and alphabetical designations to refer to features of the drawings. In the drawings and description, like or similar designations have been used to refer to like or similar parts of the disclosure.

[0016] The term "exemplary" is used herein to mean "serving as an example, case, or illustration." Any implementation described herein "as an example" should not necessarily be construed as preferred or advantageous over other embodiments. Furthermore, unless otherwise specifically indicated, all embodiments described herein should be considered exemplary.

[0017] For the purposes of the following description, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “upper”, “lower”, “lateral ", "longitudinal" and their derivatives refer to the embodiments as oriented in the figures of the drawings. However, it is understood that the embodiments may take various variations, unless expressly indicated otherwise. It is also understood that the specific devices illustrated in the accompanying drawings and described in the following specification are only mere embodiments of the present invention given by way of example. Therefore, the specific dimensions and other physical characteristics related to the embodiments described herein should not be considered as limiting.

[0018] The term "radially" means the relative direction that is substantially perpendicular to the central axis of the centerline of a particular element, the term "axially" means the relative direction that is substantially parallel and / or coaxially aligned with the axial central axis of a particular element, and the term "circumferentially" means the relative direction that extends around the axial central axis of a particular element.

[0019] As used herein, the terms "first," "second," and "third" may be used interchangeably to distinguish one element from another and are not intended to designate the location or importance of individual elements.

[0020] The singular forms "un", "une", "la" and "le" include plural references, unless the context otherwise clearly indicates otherwise.

[0021] The expression "at least one of" in the context of, for example, "at least one of A, B, and C" refers to only A, only B, only C, or any combination of A, B, and C.

[0022] Herein and throughout the specification and claims, range limitations are combined and interchanged, such ranges are identified and include all subranges within them, unless the context or language otherwise indicates otherwise. For example, all ranges referred to herein include endpoints, and endpoints may be combined independently of each other.

[0023] The term "turbomachine" or "turbomachinery" refers to a machine comprising one or more compressors, a heat generating section (e.g., a combustion section), and one or more turbines that together generate an output torque.

[0024] The term "gas turbine engine" means an engine in which all or part of the power source is a turbomachine. Examples of gas turbine engines include turbofan engines, turboprop engines, turbojet engines, turboshaft engines, etc., as well as hybrid-electric versions of one or more of these engines.

[0025] The chemical elements are described herein using their common chemical abbreviation, as generally found in the periodic table of elements. For example, hydrogen is represented by its common chemical abbreviation H; helium is represented by its common chemical abbreviation He; and so on.

[0026] As used herein, the term "ceramic matrix composite" or "CMC" refers to a category of materials that includes a reinforcing material (e.g., reinforcing fibers) surrounded by a ceramic matrix phase. In general, the reinforcing fibers provide the structural integrity of the ceramic matrix. Some examples of matrix materials of CMCs may include, but are not limited to, non-oxide silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), oxide ceramics (e.g., silicon oxycarbides, silicon oxynitrides, aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates, or mixtures thereof), or mixtures thereof.Optionally, ceramic particles (e.g., oxides of Si, Al, Zr, Y and combinations thereof) and inorganic fillers (e.g., pyrophyllite, wollastonite, mica, talc, kyanite and montmorillonite) may also be included in the CMC matrix.

[0027] Some examples of CMC reinforcing fibers may include, but are not limited to, non-oxidized silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), non-oxidized carbon-based materials (e.g., carbon, silicon carbide, zirconium carbide), oxide ceramics (e.g., silicon oxycarbides, silicon oxynitrides, aluminum oxide (A12O3), silicon dioxide (SiO2), aluminosilicates, such as mullite, or mixtures thereof), or mixtures thereof.

[0028] Generally, particular CMCs may be referred to by their fiber type / matrix type combination. For example, C / SiC for carbon fiber reinforced silicon carbide; SiC / SiC for silicon carbide fiber reinforced silicon carbide, SiC / SiN for silicon carbide fiber reinforced silicon nitride; SiC / SiC-SiN for silicon carbide / silicon nitride fiber reinforced silicon carbide matrix mixture, etc. In other examples, CMCs may include a matrix and reinforcing fibers comprising oxide-based materials such as aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates, and mixtures thereof. Aluminosilicates may include crystalline materials, such as mullite (3Al2O3-2SiO2), as well as glassy aluminosilicates.

[0029] In some embodiments, the reinforcing fibers may be bundled or coated prior to inclusion within the matrix. For example, fiber bundles may be in the form of a reinforced ribbon, such as a unidirectional reinforced ribbon. A plurality of ribbons may be assembled to form a preform element. The fiber bundles may be impregnated with a slurry composition before or after formation of the preform. The preform may then undergo a thermal treatment, such as curing or burning to obtain a substantial char residue in the preform, and a subsequent chemical treatment, such as melt infiltration with silicon, to arrive at a member formed from a CMC material having a desired chemical composition.

[0030] Such materials, like certain monolithic ceramics (i.e., ceramic materials without reinforcing material), are particularly suitable for high temperature applications. In addition, these ceramic materials are lightweight compared to superalloys, but can still provide strength and durability to the element made from them.Therefore, these materials are currently being considered for many gas turbine, spacecraft and propulsion structure components used in high-temperature sections, such as airfoils (e.g., turbines and blades), combustors, fairings and similar components, nozzles, transition ducts, thermal protection systems, TPSs, aerodynamic control surfaces and leading edges that would benefit from the lighter weight and higher temperature resistance these materials can provide.

[0031] As used herein, the term "additive manufacturing" generally refers to a manufacturing technology in which features are manufactured layer by layer. An exemplary additive manufacturing machine may be designed to use any suitable additive manufacturing technology. The additive manufacturing machine may use an additive manufacturing technology that includes powder bed fusion (PBF) technology, such as direct metal laser melting (DMLM) technology, selective laser melting (SLM) technology, directed metal laser sintering (DMLS) technology, or selective laser sintering (SLS) technology.In one exemplary PBF technology, thin layers of powdered material are sequentially applied to a build plane and then selectively melted or fused together, layer by layer, to form one or more three-dimensional objects. Additively manufactured objects are typically monolithic in nature and may have a variety of integrated sub-components.

[0032] Additionally or alternatively, suitable additive manufacturing technologies may include, for example, Binder Jet technology, FDM (Fused Deposition Modeling) technology, DED (Direct Energy Deposition) technology, LENS (Laser Engineered Net Shaping) technology, LNSM (Laser Net Shape Manufacturing) technology, DMD (Direct Metal Deposition) technology, DLP (Digital Light Processing) technology, and other additive manufacturing technologies that utilize an energy beam or other energy source to solidify an additively manufactured material such as a powder material. In fact, any suitable additive manufacturing modality may be used with the subject matter of the present invention.

[0033] Additive manufacturing technology can generally be described as the fabrication of objects by building objects point by point, line by line, layer by layer, generally in a vertical direction. Other manufacturing methods are contemplated and are within the scope of the present invention. For example, although this document refers to the addition of material to form successive layers, the disclosed subject matter can be accomplished using any additive manufacturing technology or other manufacturing technology, including layer-adding processes, layer-subtracting processes, or hybrid processes.

[0034] The additive manufacturing methods described herein may be used to form features using any suitable material. For example, the material may be metal, ceramic, polymer, epoxy, photopolymer resin, plastic, or any other suitable material that may be in solid, powder, material, wire, or other suitable form, or combinations thereof. Additionally, or alternatively, exemplary materials may include metals, ceramics, or binders, as well as combinations thereof. Exemplary ceramics may include ultrahigh temperature ceramics or precursors of ultrahigh temperature ceramics, such as polymer precursors.Each successive layer may be, for example, between about 10 qm and 200 qm, although the thickness may be determined on the basis of any number of parameters and may be of any suitable size.

[0035] As used herein, the term "build plane" means a plane defined by a surface onto which an energy beam penetrates to selectively irradiate and thereby consolidate a powder material during an additive manufacturing process. In general, the surface of a powder bed defines the build plane. During irradiating a respective layer of the powder bed, a previously irradiated portion of the respective layer may define a portion of the build plane. Before dispensing the powder material onto a build module, a build plate that supports the powder bed typically defines the build plane.

[0036] As used herein, the term "consolidate" or "consolidating" refers to the densification and solidification of the powder material following irradiation of the powder material, including by way of melting, sintering, or other similar processes.

[0037] The joining of one CMC sub-element, or preform, to another CMC or ceramic sub-element to form a complete element structure is of particular interest in the field of CMCs. For example, joining one CMC sub-element to another may occur when the complexity of the shape of a complete overall structure is too great to be laminated into a single piece. Another instance where joining one CMC sub-element to another may occur is where a large complete structure is difficult to assemble into a single piece, and multiple sub-elements, or preforms, are fabricated and joined to form the large complete structure. The manufacture of complex composite elements may require complex tooling and may involve the formation of fibers over small radii, which poses manufacturability issues.Current procedures for bonding CMC sub-elements include, but are not limited to, diffusion bonding, reaction forming, melt infiltration, brazing, adhesives, or the like. Separation or failure of the joint formed during the assembly procedure, under the influence of applied loads, is of particular concern in these CMC element structures formed from joined sub-elements.

[0038] Thus, an improved joint and method for joining a CMC sub-element, or preform, to another monolithic ceramic sub-element or CMC sub-element to form a complete structure is desired and appreciated in the art.

[0039] The present invention generally relates to composite tube assemblies comprising one or more composite tubes joined together. A composite tube may comprise an unreinforced core (which may be additively manufactured with one or more hollow cells and one or more interlocking features) and one or more composite plies bonded to the core. Although some composite materials, such as CMCs, provide good toughness, high thermal insulation, high temperature resistance and chemical stability, the raw material and processing techniques can become expensive. Current structures capable of withstanding extreme operating conditions may be bulky, expensive, or have a short lifespan. Consequently, a lighter, stronger, and more cost-effective structure would be welcome in technology. Composite panels can provide similar properties while reducing the weight of the element, and in particular the amount of composite material used in the element.

[0040] Referring now to the drawings, in which like numerals indicate like elements in the figures, [Fig. 1] and 2 each illustrate a cross-sectional view of a composite tube 100 having a tubular core 102 and a first outer composite material 104. The composite tube 100 and the composite tube assembly 200 discussed below with reference to [Fig. 3] through [Fig. 10] may each define a cylindrical coordinate system having an axial direction A extending along an axial centerline 150, a radial direction R perpendicular to the axial centerline 150, and a circumferential direction C extending about the axial centerline 150. The first outer composite material 104 may annularly surround and couple to the tubular core 102.

[0041] The tubular core 102 may define a first face 106 (e.g., a radially outer surface) and a second face 108 (e.g., a radially inner surface). In many embodiments, the first outer composite material 104 may be bonded to the first face 106 of the tubular core 102. The second face 108 may define a passage 110 (such as a fluid passage), through which fluids, cables, or other elements may extend. In some embodiments (not shown), the composite tube 100 may further include an inner composite material bonded to the second face 108 of the tubular core 102.

[0042] The first outer composite material 104 and the tubular core 102 may comprise a combination of different materials to meet the structural and mechanical requirements of the composite tube 100. The first outer composite material 104 may comprise any composite material such as a ceramic matrix composite material, described above. Composite materials generally comprise a fibrous reinforcing material embedded in a matrix material. The reinforcing material serves as a load-bearing constituent of the composite material, while the matrix of a composite material serves to bind the fibers together and act as a medium through which externally applied stress is transmitted and distributed to the fibers. In general, CMCs are well suited for structural applications due to their toughness, heat resistance, high temperature strength, and chemical stability.These composites can have a high strength-to-weight ratio which makes them attractive in applications where weight is a concern, such as in aerospace applications. In addition, their high temperature stability makes CMCs very suitable for applications. where the elements are in contact with a high temperature gas, for example in a gas turbine engine.

[0043] Exemplary CMC materials may include silicon carbide (SiC), silicon, silica, carbon, or alumina matrix materials and combinations thereof. Ceramic fibers may be incorporated into the matrix, such as oxidation-stable reinforcing fibers comprising monofilaments, such as sapphire and silicon carbide (e.g., SCS-6 from Textron), as well as rovings and yarns comprising silicon carbide (e.g., NICALON® from Nippon Carbon, TYRANNO® from Ube Industries, and SYLRAMIC® from Dow Corning), alumina silicates (e.g., Nextel 440 and 480 from 3M), and chopped rovings and fibers (e.g., Nextel 440 and SAFFIL® from 3M), and optionally ceramic particles (e.g., oxides of Si, Al, Zr, Y, and combinations thereof) and inorganic fillers (e.g., pyrophyllite, wollastonite, mica, talc, kyanite, and montmorillonite).For example, in some embodiments, the fiber bundles, which may include a coating of refractory ceramic material, are formed as a reinforced ribbon, such as a unidirectional reinforced ribbon. A plurality of ribbons may be assembled (e.g., as batts) together to form a preform element. The fiber bundles may be impregnated with a slurry composition before or after forming the preform (e.g., prepreg batts) or after forming the preform. The preform may then undergo a thermal treatment, such as curing or burning to achieve a substantial char in the preform, and a subsequent chemical treatment, such as melt infiltration with silicon, to result in a member formed from a CMC material having a desired chemical composition.In other embodiments, the CMC material may be formed, for example, from a carbon fiber fabric rather than a ribbon.

[0044] The tubular core 102 may be made of a different material compared to the first outer composite material 104. By way of non-limiting example, the tubular core 102 may be made of a less dense material than the material of the first outer composite material 104. However, even if the material of the tubular core 102 is different, it is compatible with the first outer composite material 104 to produce sufficient bonding between the elements, including under extreme operating conditions, such as high temperatures. In exemplary embodiments, the tubular core 102 may be an unreinforced material, i.e., one devoid of fibers. In particular, the use of an unreinforced material reduces the total amount of coated fibers, thereby reducing the overall material cost of the composite tube 100. The tubular core 102 may comprise silicon, silicon carbide, alumina, carbon or aluminosilicates, or combinations thereof.

[0045] Referring more specifically to [Fig. 1], in some embodiments, the tubular core 102 includes a plurality of hollow cells 130 defined by a plurality of lattice walls 132 extending between the inner face 108 and the outer face 106. As illustrated in [Fig. 1], the plurality of lattice walls 132 of the plurality of hollow cells 130 defines the shape, and more specifically the cross-sectional geometry, of each of the plurality of hollow cells 130. In other words, the plurality of lattice walls 132 creates a partially enclosed structure to define a hollow interior 149 to form a cross-sectional geometry for each of the plurality of hollow cells 130. The cross-sectional geometry may include a variety of different shapes within each of the plurality of hollow cells 130. For example, as shown in the embodiment of [Fig.l], the cross-sectional geometry of each hollow cell 130 may be a square along the entire length of each hollow cell 130, including at the respective ends of the hollow cell 130 (not shown), but the cross-sectional geometry of the plurality of hollow cells 130 may be a hexagon, a circle, a triangle, or other non-limiting examples. In other embodiments, as shown in [Fig. 2], the tubular core 102 may be solid. As used herein, the term "solid" may refer to one or more elements that do not have significant cavities or voids.

[0046] [Figs. 3] to 10 illustrate each embodiment of a composite tube assembly 200 according to the present invention. In particular, [Figs. 3] and 4 illustrate a composite tube assembly 200 according to a first embodiment of the present invention; [Figs. 5] and 6 illustrate a composite tube assembly 200 according to a second embodiment of the present invention; [Figs. 7] and 8 illustrate a composite tube assembly 200 according to a third embodiment of the present invention; and [Figs. 9] and 10 illustrate a composite tube assembly 200 according to a fourth embodiment of the present invention.

[0047] As generally indicated for the composite tube assemblies of [Fig. 3]-10, the composite tube assembly 200 may include a first composite tube 100A having a first tubular core 102A and a first outer composite material 104A. The first tubular core 102A may define a first outer face 106A (e.g., a radially outer surface) and a first inner face 108A (e.g., a radially inner surface). In many embodiments, the first outer composite material 104A may be bonded to the first outer face 106A of the first tubular core 102A. The first face The inner core 108A may define a first passage 110A (such as a fluid passage), through which fluids, cables, or other elements may extend. The first composite tube 100A may extend from a front end 101A to a rear end 103A. The first tubular core 102A may extend (e.g., axially) between a first end 107A at the front end 101A of the first composite tube 100A and a second end 109A at the rear end 103A of the first composite tube 100A. Further, in some embodiments, the first outer composite material 104A may extend (e.g., axially) between a first end 11 IA at the forward end 101A of the first composite tube 100A and a second end 113A at the rearward end 103A of the first composite tube 100A.

[0048] The composite tube assembly 200 may further include a second composite tube 100B with a second tubular core 102B and a second outer composite material 104B. The second tubular core 102B may define a second outer face 106B (e.g., a radially outer surface) and a second inner face 108B (e.g., a radially inner surface). In many embodiments, the second outer composite material 104B may be bonded to the second outer face 106B of the second tubular core 102B. The second inner face 108B may define a second passage 110B (such as a fluid passage), through which fluids, cables, or other elements may extend. The second composite tube 100B may extend from a forward end 101B to a rearward end 103B.The second tubular core 102B may extend (e.g., axially) between a first end 107B at the forward end 101B of the second composite tube 100B and a second end 109B at the rear end 103B of the second composite tube 100B. Further, in some embodiments, the second outer composite material 104B may extend (e.g., axially) between a first end 111B at the forward end 101B of the second composite tube 100B and a second end 113B at the rear end 103B of the second composite tube 100B.

[0049] In exemplary embodiments, the first composite tube 100A may be coupled to the second composite tube 100B at a joint 202. In some embodiments, the rear end 103A of the first composite tube 100A may be coupled to the front end 101B of the second composite tube 100B, such that the passages 110A, 110B are aligned and fluidly connected to each other. The first composite tube 100A and the second composite tube 100B may share a central axis of the centerline 150. Although it is understood that this does not necessarily have to be the case.

[0050] Referring more specifically to the embodiment shown in [Fig. 3] and 4, [Fig. 3] illustrates a partially exploded view of the composite tube assembly 200, and [Fig. 4] illustrates a fully assembled view of the composite tube assembly 200, in accordance with embodiments of the present invention. As illustrated, the second composite tube 100B may be coupled to the first composite tube via one or more couplers 204. The one or more couplers 204 may be coupled to an outer surface (e.g., a radially outer surface) of the outer composite materials 104A, 104B at the joint 202. In particular, the one or more couplers 204 may be centered on the joint 202, such that an equal portion of the coupler 204 is attached to both the first outer composite materials 104A and the second outer composite materials 104B. Although it is understood that this does not necessarily have to be the case.The at least one coupler 204 may extend axially between a first end 208 coupled to the first outer composite material 104A and a second end 210 coupled to the second outer composite material 104B. Further, the at least one coupler 204 may include a first portion 212 coupled to the first outer composite material 104A and extending between the first end 208 and the seal 202 and a second portion 215 coupled to the second outer composite material 104B and extending between the seal 202 and the second end 210.

[0051] In a non-limiting example, the coupler(s) 204 may comprise a composite web 206, which may be formed from the same material as the outer composite materials 104A, 104B. In other words, the composite web 206 may be made from any composite material, such as a ceramic matrix composite web. In some embodiments, the one or more couplers 204 may be a single coupler 204 that annularly surrounds the outer composite materials 104A, 104B at the joint 202. In other embodiments, the one or more couplers 204 may be a plurality of couplers 204 circumferentially spaced apart from one another and each coupled to the outer composite materials 104A, 104B at the joint 202. The composite web 206 may be processed to couple the outer composite materials 104A, 104B, for example, by curing, bonding, heat treating, or any other combination of these methods.The 206 composite web adds thickness to the 200 composite tube assembly, which can improve toughness and reduce deformation or cracking.

[0052] Referring more specifically to the embodiment shown in [Fig. 5] and 6, [Fig. 5] illustrates a partially exploded view of a composite tube assembly 300, and [Fig. 6] illustrates a fully assembled view of the composite tube assembly 300, in accordance with embodiments of the present invention. As illustrated, the second composite tube 100B may be coupled to the first composite tube via one or more couplers 302. The one or more couplers 302 may be coupled to an outer surface (e.g., a radially outer surface) of the outer composite materials 104A, 104B and to an axial surface of the outer composite materials 104A, 104B to form a seal 304. In some embodiments, the one or more couplers 302 may be a single coupler 302 that annularly surrounds the outer composite materials 104A, 104B. In other embodiments, the one or more couplers 302 may be a plurality of couplers 302 circumferentially spaced apart from each other and each coupled to the outer composite materials 104A, 104B.

[0053] As illustrated, the coupler(s) 302 may include a composite coupler 306 with a core 308 and a composite portion 310 bonded to the core 308. The core 308 may also be unreinforced. As a non-limiting example, the core 216 may be formed of the same material as the tubular cores 102A, 102B (which may include silicon, silicon carbide, alumina, carbon, or aluminosilicates, or combinations thereof). The composite portion 310 may be formed of a material similar to the outer composite materials 104A, 104B (e.g., formed of a ceramic matrix composite material). In exemplary embodiments, the core 308 of the composite coupler 306 has a main portion 312 and a tab 314 extends (e.g., extends radially inward) from the main portion 312.In such embodiments, the composite portion 310 may be coupled to the main portion 312 of the core 308 (e.g., a radially outer surface of the main portion 312).

[0054] In many embodiments, the tab 314 may be positioned between the rear end 103A of the first composite tube 100A and the front end 101B of the second composite tube 100B. For example, the tab 314 may be positioned between and contact the second end 109A of the first tubular core 102A and the first end 107B of the second tubular core 102B. Similarly, the tab 314 may be positioned between and contact the second end 113A of the first outer composite material 104A and the first end 111B of the second outer composite material 104B.

[0055] Referring now to the embodiment shown in [Fig. 7] and 8, [Fig. 7] illustrates a partially exploded view of a composite tube assembly 400, and [Fig. 8] illustrates an assembled view of the composite tube assembly 400, in accordance with embodiments of the present invention. As illustrated, a first composite tube 401A with a first tubular core 402A may have a first main portion 414A and a first flange 416A extending away from the first main portion 414A. For example, the first flange 416A may extend radially outward from the first main portion 414A to a terminal end. Similarly, a second composite tube 401B with a second core Tubular 402B may include a second main portion 414B and a second flange 416B extending away from the second main portion 414B. For example, the second flange 416B may extend radially outward from the second main portion 414B to a terminal end.

[0056] A first outer composite material 404A may be bonded to both the first main portion 414A and the first flange 416A. The first flange 416A may define a front face 420A and a rear face 422A. The first outer composite material 404A may have a first portion coupled to the first outer surface 406A of the first main portion 414A and a second portion coupled to the front face 420A of the first flange 416A. Similarly, the second outer composite material 404B may be bonded to both the second main portion 414B and the second flange 416B. The second flange 416B may define a front face 420B and a rear face 422B. The second external composite material 404B may include a first portion coupled to the second external surface 406B of the second main portion 414B and a second portion coupled to the rear face 422B of the second flange 416B.

[0057] In exemplary embodiments, the first flange 416A may be coupled to the second flange 416B. By way of non-limiting example, the first composite tube 401A and the second composite tube 401B may each define an opening 426A, 426B (as indicated by the dotted lines in [Fig. 7] and 8) through the outer composite material 404A, 404B and the flanges 416A, 416B. In such embodiments, a fastener may be inserted through the openings 426A, 426B to couple the flanges 416A, 416B and form a joint 428. By way of non-limiting example, a bolt or pin may be inserted and retained therein. The openings 426A, 426B may be generally axially oriented and radially disposed between the main portion 414A, 414B and a terminal end of the flanges 416A, 416B.The openings 426A, 426B may be circumferentially spaced around the flanges 416A, 416B such that when fasteners are inserted into the openings 426A, 426B, the flanges 416A, 416B are secured to each other in a substantially equal manner. The backside 422A of the first flange 416A may contact the frontside 420B of the second flange 416B. By integrating the flanges 416A, 416B into the composite cores 402A, 402B, the flanges 416A, 416B facilitate integration of the composite tubes 401A, 401B with other members.

[0058] Referring now to the embodiment shown in [Fig. 9] and 10, [Fig. 9] illustrates a partially exploded view of the composite tube assembly 500, and [Fig. 10] illustrates an assembled view of the composite tube assembly 500, in accordance with embodiments of the present invention. As illustrated, In some embodiments, a first composite tube 501A with a first tubular core 502A has a first main portion 552A and a first tapered portion 554A that extends from the first main portion 552A. In particular, the first main portion 552A may extend axially from a first end 507A to the first tapered portion 554A. The first tapered portion 554A may extend axially from the first main portion 552A to a first rear end 509A. In such embodiments, a first outer surface 506A of the first tubular core 502A converges radially inward (e.g., to a generally axially oriented first inner surface 508A) as the first tapered portion 554A extends from the first main portion 552A to a rear end 503A of the first composite tube 501A.

[0059] Similarly, a second composite tube 501B with a second tubular core 502B may include a second main portion 552B and a second tapered portion 554B extending from the second main portion 552B. In particular, the second tapered portion 554B may extend axially from a first end 507B to the second main portion 552B. A second inner surface 508B of the second tubular core 502B may diverge radially outwardly (e.g., to a generally axially oriented second outer surface 506B) as the second tapered portion 554B extends from a front end 505B of the second composite tube 501B to the second main portion 552B.

[0060] In exemplary embodiments, as shown in [Fig. 10], the first tapered portion 554A may extend into the second tapered portion 554B such that the first outer composite material 504A is positioned between (e.g., radially between) the outer surface 506A of the first tubular core 502A and the inner surface 508B of the second tubular core 502B. In some embodiments, the first outer composite material 504A may be adhered (e.g., with an adhesive) to both the outer surface 506A of the first tubular core 502A and the inner surface 508B of the second tubular core 502B.

[0061] By way of non-limiting example, an adhesive may at least partially bond the first composite tube 501A to the second composite tube 501B. In such embodiments, the adhesive may be silicon, silicon alloys, matrix precursors, sealing glasses, or combinations thereof. The adhesive may be disposed between the first composite tube 501A and the second composite tube 501B.

[0062] As another non-limiting example, not shown in FIG., the first composite tube 501A may have threads that mate with a tapped region of the second tubular core 502B. In this case, the threads and the tapped area may form a sealed connection that secures the first composite tube 501A to the second composite tube 501B. In other words, the threads and the tapped area may be sized so that when the threads engage the tapped area, fluid can flow through the passages 510A, 510B without leakage.

[0063] Referring now to [Fig. 11], a flow diagram of one embodiment of a method 1100 for manufacturing a composite tube assembly is illustrated in accordance with the embodiments of the present subject matter. In general, the method 1100 will be described herein with reference to the composite tube 100 and composite tube assemblies 200, 300, 400, 500 described above with reference to [Figs. 1]-10. However, those of ordinary skill in the art will appreciate that the disclosed method 1100 may generally be used with any suitable composite tube assembly. Furthermore, although [Fig. 11] depicts the steps performed in a particular order for purposes of illustration and discussion, the methods discussed herein are not limited to any particular order or arrangement unless otherwise indicated in the claims.Those skilled in the art, using the disclosures provided herein, will appreciate that the various steps of the methods disclosed herein may be omitted, rearranged, combined and / or adapted in various ways without departing from the scope of the present invention. The dotted boxes may indicate optional steps of the method 1100.

[0064] As illustrated, the method 1100 may comprise (1102) manufacturing a first composite tube and a second composite tube. The manufacturing at (1102) may further comprise at (1104) manufacturing a first tubular core and a second tubular core. This may further comprise additively manufacturing the first tubular core or the second tubular core. For example, all or a portion of the first tubular core or the second tubular core may be additively manufactured, for example by means of binder jetting or a similar process to produce an additively manufactured core. In particular, the core shown in [Fig. 1] may be additively manufactured to produce the plurality of hollow cells. In this manner, the plurality of lattice walls may be additively manufactured by building up all or a portion of the plurality of lattice walls layer by layer, for example by using a powder feed material.

[0065] In such embodiments, additive manufacturing of the plurality of lattice walls may result in a residual amount of unconsolidated powder remaining within the interior of each of the plurality of hollow cells. Thus, in some embodiments, the method may further comprise removing the powder charge from at least one of the plurality of hollow cells. For example, the powder charge may be poured or aspirated through an opening of the hollow cell. Removing the powder charge may also allow the unused powder charge to be recycled and used to manufacture cores for additional composite tubes or other portions of the composite panel.

[0066] Although additive manufacturing is presented as an exemplary method of manufacturing the core, it should be noted that other ceramic processing techniques may also be used within the scope of the present invention, such as, for example, extrusion processing. Depending on the materials used, the manufacturing process, or other manufacturing variables, the core may be ready for use in the composite panel or require one or more additional intermediate processing steps. For example, in some embodiments, the core may be in a green state after additive manufacturing. Thus, in such embodiments, the method may further comprise curing the core to remove moisture or sintering the core.

[0067] In some embodiments, the manufacturing (1102) may further comprise (1106) bonding a first outer composite material to the first tubular core and a second outer composite material to the second tubular core. The bonding may comprise any process suitable for mechanically integrating the outer composite materials to the tubular cores. For example, the bonding to (1106) may comprise adhesive bonding. In some embodiments, the bonding step (1106) may comprise one or more manufacturing steps used in the manufacture of ceramic matrix composites, such as infiltrating the ceramic material or curing.

[0068] In exemplary embodiments, the method 1100 may further comprise (1108) coupling the first composite tube to the second composite tube. In some embodiments, the joining at (1108) may further comprise at (1110) attaching a coupler to the first composite tube and the second composite tube. The coupler may be a composite web ([Fig. 3] and 4) or a composite coupler ([Fig. 5] and 6). In other embodiments, the joining at (1108) may further comprise at (1112) inserting a first tapered portion of a first tubular core of the first composite tube into a second tapered portion of a second tubular core of the second composite tube. In many embodiments, the first tapered portion may be bonded to the second tapered portion.In still other embodiments, the assembly at (1108) may comprise at (1114) coupling a first flange of a first tubular core of the first composite tube to a second flange of a second tubular core of the second composite tube. This may include aligning the flanges and inserting a bolt through the openings defined in both flanges. It will be appreciated that any or all of these elements that connect the first composite tube and the second composite tube may be used in any combination for a suitable connection.

[0069] The composite tube assembly 200, 300, 400, 500 as disclosed and described herein, may be used in a variety of industrial machines, including, but not limited to limited to one or more turbomachinery elements. Furthermore, the composite tube assembly 200, 300, 400, 500 disclosed and described herein may provide a more economical, lighter, and potentially stronger alternative to solid composite structures. However, the composite tubes disclosed and described herein provide improved bonding between the core and the composite materials.

[0070] This written description uses examples to describe the present invention, including the best mode, and also to enable a person skilled in the art to practice the disclosure, including the manufacture and use of any devices or systems and the performance of any methods incorporated therein. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

[0071] Other aspects are provided by the subject matter of the following clauses:

[0072] A composite tube assembly comprising a first composite tube with a first tubular core and a first outer composite material, the first outer composite material being bonded to a first face of the first tubular core, and a second composite tube with a second tubular core and a second outer composite material, the second outer composite material being bonded to a second face of the second tubular core, the second composite tube being coupled to the first composite tube.

[0073] The composite tube assembly of one of the preceding clauses, wherein the second composite tube is coupled to the first composite tube via one or more couplers.

[0074] The composite tube assembly of one of the preceding clauses, wherein the coupler(s) comprise at least one composite sheet coupled to the first outer composite material and to the second outer composite material.

[0075] The composite tube assembly of one of the preceding clauses, wherein the coupler(s) comprise a composite coupler with an unreinforced ceramic coupler core and a composite material bonded to the unreinforced ceramic coupler core.

[0076] The composite tube assembly of any of the preceding clauses, wherein the unreinforced ceramic coupler core comprises a main portion and a tab extending from the main portion, and wherein the composite material is coupled to the main portion of the unreinforced ceramic coupler core.

[0077] The composite tube assembly of one of the preceding clauses, wherein, when coupled, the tab is positioned between the first composite tube and the second composite tube.

[0078] The composite tube assembly of one of the preceding clauses, wherein the first tubular core comprises a first main portion and a first flange extending radially from the first main portion, and wherein the second tubular core comprises a second main portion and a second flange extending radially from the second main portion.

[0079] The composite tube assembly of one of the preceding clauses, wherein the first outer composite material is bonded to both the first main portion and the first flange, and wherein the second outer composite material is bonded to both the second main portion and the second flange.

[0080] The composite tube assembly of one of the preceding clauses, wherein the first flange is coupled to the second flange by a fastening element.

[0081] The composite tube assembly of one of the preceding clauses, wherein the first tubular core comprises a main portion having a first tapered portion and wherein the second tubular core comprises a second tapered portion forming a socket.

[0082] The composite tube assembly of one of the preceding clauses, wherein, when coupled, the first tapered portion extends into the second tapered portion such that the first outer composite material is positioned between an outer surface of the first tubular core and an inner surface of the second tubular core.

[0083] The composite tube assembly of one of the preceding clauses, further comprising an adhesive, the adhesive adapted to at least partially bond the first composite tube to the second composite tube, and wherein the adhesive is one of silicones, silicon alloys, matrix precursors, sealing glasses, or combinations thereof.

[0084] The composite tube assembly of one of the preceding clauses, wherein at least one of the first outer composite material or the second outer composite material comprises a ceramic matrix composite material.

[0085] The composite tube assembly of one of the preceding clauses, wherein at least one of the first tubular core or the second tubular core comprises silicon, silicon carbide, alumina, carbon, aluminosilicates or combinations thereof.

[0086] The composite tube assembly of one of the preceding clauses, wherein at least one of the first tubular core or the second tubular core is an additively manufactured core.

[0087] A method of manufacturing the composite tube assembly of one of the preceding clauses, comprising manufacturing a first composite tube and a second composite tube and coupling the first composite tube to the second composite tube.

[0088] The method of one of the preceding clauses, wherein manufacturing the first composite tube and the second composite tube, comprises manufacturing at least one of a first tubular core or a second tubular core, and bonding an external composite material to the first tubular core or the second tubular core.

[0089] The method of one of the preceding clauses, wherein coupling the first composite tube to the second composite tube, comprises attaching a coupler to the first composite tube and the second composite tube, the coupler comprising a composite web or a composite coupler.

[0090] The method of one of the preceding clauses, wherein coupling the first composite tube to the second composite tube, comprises inserting a first tapered portion of a first tubular core of the first composite tube into a second tapered portion of a second tubular core of the second composite tube.

[0091] The method of one of the preceding clauses, wherein joining the first composite tube to the second composite tube, comprises coupling a first flange of a first tubular core of the first composite tube to a second flange of a second tubular core of the second composite tube.

Claims

Claims

1. 1 A composite tube assembly comprising: a first composite tube having a first tubular core and a first outer composite material, the first outer composite material being bonded to a first face of the first tubular core; and a second composite tube having a second tubular core and a second outer composite material, the second outer composite material being bonded to a second face of the second tubular core, the second composite tube being coupled to the first composite tube.

2. 2 A composite tube assembly according to claim 1, wherein the second composite tube is coupled to the first composite tube via one or more couplers.

3. 3 A composite tube assembly according to claim 2, wherein the coupler(s) comprise at least one composite sheet coupled to the first outer composite material and to the second outer composite material.

4. 4 A composite tube assembly according to claim 2, wherein the one or more couplers comprise a composite coupler with an unreinforced ceramic coupler core and a composite material bonded to the unreinforced ceramic coupler core.

5. 5 A composite tube assembly according to claim 4, wherein the unreinforced ceramic coupler core has a main portion and a tab extending from the main portion, and wherein the composite material is coupled to the main portion of the unreinforced ceramic coupler core.

6. 6 A composite tube assembly according to claim 5, wherein, when coupled, the tab is positioned between the first composite tube and the second composite tube.

7. 7 A composite tube assembly according to claim 1, wherein the first tubular core has a first main portion and a first flange extending radially from the first main portion, and wherein the second tubular core has a second main portion and a second flange extending radially from the second main portion.

8. 8 A composite tube assembly according to claim 7, wherein the first outer composite material is bonded to both the first main portion and the first flange, and wherein the second external composite material is bonded to both the second main portion and the second flange.

9. 9 A composite tube assembly according to claim 7, wherein the first flange is coupled to the second flange with a fastener.

10. 10 A composite tube assembly according to claim 1, wherein the first tubular core comprises a main portion having a first tapered portion and wherein the second tubular core comprises a second tapered portion forming a socket.

11. 11 The composite tube assembly of claim 10, wherein, when coupled, the first tapered portion extends into the second tapered portion such that the first outer composite material is positioned between an outer surface of the first tubular core and an inner surface of the second tubular core.

12. 12 The composite tube assembly of claim 1, further comprising an adhesive, the adhesive configured to at least partially bond the first composite tube to the second composite tube, and wherein the adhesive is one of silicon, silicon alloys, matrix precursors, sealing glasses, or combinations thereof.

13. 13 The composite tube assembly of claim 1, wherein at least one of the first outer composite material or the second outer composite material comprises a ceramic matrix composite.

14. 14 The composite tube assembly of claim 1, wherein at least one of the first tubular core or the second tubular core comprises silicon, silicon carbide, alumina, carbon, aluminosilicates, or combinations thereof.

15. 15 The composite tube assembly of claim 1, wherein at least one of the first tubular core or the second tubular core is an additively manufactured core.

16. 16 A method of manufacturing the composite tube assembly of claim 1, the method comprising: manufacturing a first composite tube and a second composite tube; and coupling the first composite tube to the second composite tube.

17. 17 The method of claim 16, wherein manufacturing the first composite tube and the second composite tube comprises: manufacturing at least one of a first tubular core or a second tubular core; and bonding an external composite material to the first tubular core or the second tubular core.

18. 18 The method of claim 16, wherein coupling the first composite tube to the second composite tube comprises: attaching a coupler to the first composite tube and the second composite tube, the coupler comprising a composite web or a composite coupler.

19. 19 The method of claim 16, wherein coupling the first composite tube to the second composite tube comprises: inserting a first tapered portion of a first tubular core of the first composite tube into a second tapered portion of a second tubular core of the second composite tube.

20. 20 The method of claim 16, wherein joining the first composite tube to the second composite tube comprises: coupling a first flange of a first tubular core of the first composite tube to a second flange of a second tubular core of the second composite tube.

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