Use for connecting components

Abstract

Associated structure (30), encompassing: a first component (32) formed from a fiber-reinforced material and having a hole (38) that defines an axis (A); comprising a second component (34) next to the first component (32) and having a hole (40) aligned with the hole (38) of the first component (32); and an insert (36) positioned in the hole (38) of the first component (32), the insert (36) comprising an inner layer (42) having a tubular shape around the axis (A), a middle layer (44) concentric to the inner layer (42) around the axis (A) and an outer layer (46) concentric to the middle layer (44) around the axis (A); wherein the layers (42, 44, 46) are formed from fiber-reinforced materials; and wherein a boundary (50) between the inner and middle layer and a boundary (52) between the middle and outer layer has a non-linear profile in a direction parallel to the axis (A).

Description

GENERAL STATE OF THE ART

[0001] Motor vehicles and other complex assemblies can contain components made of fiber-reinforced plastic and components made of metal. Fiber-reinforced plastic is a composite material, meaning it is made from two or more materials with significantly different physical or chemical properties. Fiber-reinforced plastic is made from a polymer matrix reinforced with fibers. A fiber is elongated, meaning its length is much greater than its thickness. Among other applications, fiber-reinforced plastic can be used in body panels, particularly in vehicles.

[0002] Metals, such as steel and aluminium, are widely used in vehicles, for example in the frame, body panels, engine, drivetrain, etc.

[0003] From FR 2 974 867 A1, a fastener is known that comprises three layers of fiber-reinforced materials and is used to join two parts of an aircraft, both parts having a hole. US 8 393 068 B2 relates to a fastener for mechanically joining components, including components made of non-metallic material. US 8 739 388 B2 relates to a component for fastening composite parts, wherein a self-piercing riveting tool is used to join a first part and a second part by inserting a rivet into the first and second parts, such that its tubular section forms a recess in the first and second parts. From US 9 327 446 B2, a connection between a metal element and a composite body is known, wherein the top of the metal element has tree-like fastening projections extending from the surface to connect the metal element to the composite body. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a perspective view of a first component and a second component. Fig. Figure 2 is a perspective view of the first component, the second component, an insert, and a fastener. Fig. Figure 3 is a cross-sectional view of the first component, the second component, the insert, and the fastener along line 3-3 in Fig. 2. Fig. Figure 4 is a cross-sectional view of the first component, the second component, and the insert along line 3-3 in Fig. 2, with the fastening element removed for illustration. Fig. Figure 5 is a sectional view of the deployment along line 3-3 in Fig. 2. Fig. Figure 6 is a cross-sectional view of the deployment along line 3-3 in Fig. 2. Fig. Figure 7 is a sectional view of a first embodiment of the insert. Fig. Figure 8 is a sectional view of a second embodiment of the insert. DETAILED DESCRIPTION

[0004] Referring to the figures, in which identical reference symbols denote identical parts in the different views, a connected structure 30 comprises a first component 32, a second component 34, and an insert 36. (The adjectives "first" and "second" are used in this text as identifiers and are not intended to indicate meaning or order.) The first component 32 is formed from a fiber-reinforced material and has a hole 38 that defines an axis A. The second component 34 is located adjacent to the first component 32 and has a hole 40 that is aligned with the hole 38 of the first component 32. The insert 36 is positioned in the hole 38 of the first component 32.The insert 36 comprises an inner layer 42 with a tubular shape around axis A, a middle layer 44 concentrically adjacent to the inner layer 42 around axis A, and an outer layer 46 concentrically adjacent to the middle layer 44 around axis A. The layers 42, 44, 46 are made of fiber-reinforced materials. A boundary 50 between the inner and middle layers 42, 44 and a boundary 52 between the middle and outer layers 44, 46 have a non-linear profile in a direction parallel to axis A.

[0005] The insert 36 allows the first component 32, which is made of a fiber-reinforced material, to be joined to the second component 34 with a reduced risk of corrosion. The second component 34, or a fastener 48 connecting the first to the second component 32, 34, can be made of metal. If fibers in a fiber-reinforced material are exposed to metal, the fibers can cause galvanic corrosion in the metal, which can impair the strength of the connection, e.g., of the fastener 48. The insert 36 reduces the exposure of the fibers in the fiber-reinforced material to parts made of metal; for example, it reduces the exposure of fibers 56 of the first component 32 to the metal of the fastener 48 and / or the second component 34.The insert 36 can also provide additional energy absorption when the first and second components 32, 34 are subject to opposing forces, thereby reducing the risk of the connected structure 30 failing, i.e. separating.

[0006] With reference to the Fig. 1-4 The first component 32 can have a sheet-like or plate-like shape, meaning that its length and width are much greater than its thickness. The sheet-like shape of the first component 32 can be curved, bent, or shaped according to the purpose of the first component 32. As an example, the first component 32 can be a body panel of a vehicle (not shown), such as a passenger or commercial vehicle, like a car, truck, van, SUV, station wagon, etc. In particular, the first component 32 can be an outer body panel of the vehicle. The first component 32 can have a Class A surface, meaning a surface intended to be exposed to a customer and specifically manufactured to have a finished, aesthetically pleasing appearance of high quality and free from defects.Other examples include the first component 32 being a structural element of the vehicle, e.g. a body reinforcement, a frame element, a pillar, a roof rack, a roof rail, a rocker, a frame cross member, etc.

[0007] The first component 32 is made of a fiber-reinforced material; in other words, the first component 32 is a fiber-reinforced material. The fiber-reinforced material of the first component 32 can be, for example, a fiber-reinforced plastic or a fiber-reinforced polymer. The fiber-reinforced material contains fibers 56. The fibers 56 can be made of, for example, carbon, aramid, glass, polyacrylonitrile, viscose, etc. The fiber-reinforced material includes a matrix material, and the fibers 56 are cured in the matrix material. The matrix material of the first component 32 can be, for example, polyester, epoxy, polyamide, polycarbonate, polypropylene, vinyl, any type of polymer, etc. With reference to the Fig. 1 and Fig. 4. The first component 32 has the hole 38. The hole 38 may be cut through the thickness of the first component 32. For example, the hole 38 may have been cut after the formation of the first component 32, resulting in exposed ends of the fibers 56 around the hole 38. At least some of the fibers 56 of the first component 32 may be exposed in the hole 38; that is, at least some of the fibers 56 are located at a surface of the hole 38, instead of being covered by, for example, the matrix material. Thus, the fibers 56 may pose a risk of causing corrosion in any metal parts that come into contact with the fibers 56.

[0008] With reference to the Fig. Figures 1-4 include the connected structure 30 and the second component 34. The second component 34 can have a sheet-like or plate-like shape, meaning that its length and width are much greater than its thickness. The sheet-like shape of the first component 32 can be curved, bent, or shaped according to the purpose of the first component 32. For example, the first component 32 can be a body panel in a vehicle (not shown). As other examples, the second component 34 can be a structural element of the vehicle, such as a body reinforcement, frame element, pillar, roof beam, roof rail, rocker, frame crossmember, etc.

[0009] The second component 34 is located next to the first component 32, meaning that there is nothing between the first component 32 and the second component 34, and the second component 34 can touch the first component 32. The second component 34 can be located directly next to the first component 32. In particular, a region 58 surrounding the hole 38 of the first component 32 can touch a region 60 surrounding the hole 40 of the second component 34. The regions 58 and 60 can be broad surfaces of the first and second components 32 and 34, respectively, that are orthogonal to the thickness of the first and second components 32 and 34.

[0010] The second component 34 can be made of any material with suitable strength and durability for its purpose; in other words, the second component 34 is such a material. For example, the second component 34 can be made of a metal, such as steel or aluminum, a plastic, a fiber-reinforced material, as described for the first component 32, etc.

[0011] With reference to the Fig. 1 and Fig. In section 4, the second component 34 has a hole 40 that is aligned with the hole 38 of the first component 32. For example, the axis A defined by the hole 38 of the first component 32 can be the same as an axis defined by the hole 40 of the second component 34. The directions of holes 38 and 40 can be parallel.

[0012] With reference to Fig. Figure 2 defines the hole 38 of the first component 32 as axis A. Axis A can be the basis of a cylindrical coordinate system. In the cylindrical coordinate system, a position P is specified in three dimensions: an axial dimension z parallel to axis A, a radial direction r directed perpendicularly away from axis A, and a circumferential dimension θ around axis A. The axial dimension z and the radial dimension r are distances, and the circumferential dimension is an angle. An axial direction is a direction parallel to axis A, meaning that the axial dimension z increases or decreases, while the radial dimension r and the circumferential dimension θ remain constant. A radial direction is a direction orthogonal to and away from axis A, meaning that the radial dimension r increases or decreases, while the axial dimension z and the circumferential dimension θ remain constant.A circumferential direction orbits the axis A in a plane orthogonal to the axis A, meaning that the circumferential dimension θ increases or decreases, while the axial dimension z and the radial dimension r remain constant.

[0013] With reference to Fig. 4. Insert 36 is positioned in hole 38 of the first component 32. Insert 36 can be positioned outside hole 40 of the second component 34, as shown in Fig. 4 shown, or the insert 36 can extend into the hole 40 of the second component 34. The insert 36 can have a cylindrical shape aligned with axis A.

[0014] With reference to the Fig. 4-6, the insert 36 includes the inner layer 42 with a tubular shape around the axis A. In other words, the inner layer 42 can have a round shape elongated along the axis A and can have a bore 62 extending through the inner layer 42 parallel to or aligned with the axis A. The inner layer 42 can extend axially from a first end 64 to a second end 66. The second end 66 can contact the second component 34, and the first end 64 can be spaced apart from the second component 34 and can be positioned at one end of the hole 38 of the first component 32 opposite the second component 34.

[0015] The middle layer 44 is located concentrically next to the inner layer 42 around axis A, i.e., the middle layer 44 is located next to the inner layer 42 around a full circumference of axis A. The middle layer 44 can have a tubular shape. The middle layer 44 can have a circular shape elongated along axis A and can surround the inner layer 42 around axis A. The middle layer 44 can extend axially from a first end 68 to a second end 70. The middle layer 44 can be axially congruent with the inner layer 42; that is, the first end 68 of the middle layer 44 can be located at the first end 64 of the inner layer 42, and the second end 70 of the middle layer 44 can be located at the second end 66 of the inner layer 42. The middle layer 44 can extend from the first end 64 of the inner layer 42 to the second end 66 of the inner layer 42.The second end 70 of the middle layer 44 can touch the second component 34 and the middle layer 44 can extend axially away from the second end 70 to the first end 68 of the middle layer 44.

[0016] The middle layer 44 and the inner layer 42 can have a boundary 50 between them. The boundary 50 can be a common surface of the inner layer 42 and the middle layer 44. The boundary 50 can have a non-linear profile in a direction parallel to axis A, that is, along the axial dimension. In other words, the boundary 50 does not follow a straight line between the first end 64 of the inner layer 42 and the second end 66 of the inner layer 42. The shape of the boundary 50 can be a surface of revolution, that is, a surface formed by rotating a curvature in a plane around a straight line in the plane. The boundary 50 can be a surface of revolution of the non-linear profile rotated about axis A.

[0017] With continued reference to the Fig. 4-6 The outer layer 46 can have a tubular section 72 and a flanged section 74. The tubular section 72 is located concentrically next to the middle layer 44 around axis A, i.e., the tubular section 72 is located next to the middle layer 44 around a full circumference of axis A. The tubular section 72 has a tubular shape. The tubular section 72 can have a round shape elongated along axis A and can surround the middle layer 44 around axis A. The tubular section 72 can extend axially from a first end 76 to a second end 78. The first end 76 of the tubular section 72 can connect to the flanged section 74.The tubular section 72 can be axially congruent with the middle layer 44 and / or the inner layer 42; that is, the first end 76 of the tubular section 72 can be located at the first end 64, 68 of the middle layer 44 and / or the inner layer 42, and the second end 78 of the tubular section 72 can be located at the second end 66, 70 of the middle layer 44 and / or the inner layer 42. The tubular section 72 can extend from the first end 64, 68 of the middle layer 44 and / or the inner layer 42 to the second end 66, 70 of the middle layer 44 and / or the inner layer 42. The second end 78 of the tubular section 72 can touch the second component 34 and the tubular section can extend axially away from the second end 78 to the first end 76 of the tubular section 72.

[0018] The middle layer 44 and the tubular section 72 of the outer layer 46 can have the boundary 52 between them. The boundary 52 can be a common surface of the middle layer 44 and the outer layer 46. The boundary 52 can have a non-linear profile in a direction parallel to the axis A, that is, along the axial dimension. In other words, the boundary 52 does not follow a straight line along the axial dimension between the first end 68 of the middle layer 44 and the second end 70 of the middle layer 44. The shape of the boundary 52 can be a surface of revolution, that is, a surface formed by rotating a curvature in a plane about a straight line in the plane. The boundary 52 can be a surface of revolution of the non-linear profile rotated about the axis A.

[0019] With continued reference to the Fig. 4-6 The flange section 74 of the outer layer 46 can extend radially outwards from the tubular section 72 relative to the axis A, that is, it can extend in a radial direction away from the axis A. The flange section 74 can have an outer diameter that is larger than the outer diameter of the tubular section 72 of the outer layer 46. The flange section 74 can have a chamfer 80 that extends circumferentially around the outer diameter of the flange section 74.

[0020] The flange section 74 can extend radially inwards relative to axis A from the tubular section 72 next to the first end 64 of the inner layer 42, that is, it can extend in a radial direction towards axis A. The flange section 74 can be located next to the middle layer 44. The flange section 74 can have an inner diameter that is smaller than the inner diameter of the tubular section 72. The inner diameter of the flange section 74 can be the same size as the inner diameter of the inner layer 42, that is, the same size as the diameter of the bore 62 of the inner layer 42.

[0021] The flange section 74 of the outer layer 46 has a boundary 54 with the first end 64 of the inner layer 42 and the first end 68 of the middle layer 44. The boundary 54 can be a common surface of the flange section 74 and the inner layer 42 or the middle layer 44. The boundary 54 can have a non-linear profile in a direction orthogonal to the axis A, that is, along the radial dimension. In other words, the boundary 54 does not follow a straight line along the radial dimension from the inner diameter of the flange or the inner layer 42 at the first end 64 to the inner diameter of the tubular section 72 at the first end 76. The shape of the boundary 54 can be a surface of revolution, that is, a surface formed by rotating a curve in a plane about a straight line in the plane. The boundary 54 can be a surface of revolution of the non-linear profile rotated about the axis A.

[0022] With reference to the Fig. 7 and Fig. In section 8, layers 42, 44, and 46 are formed from fiber-reinforced materials; that is, layers 42, 44, and 46 are fiber-reinforced material. Layers 42, 44, and 46 can be formed from the same or different fiber-reinforced materials, or any two of the three layers 42, 44, and 46 can be formed from the same fiber-reinforced material, i.e., the same type of fiber-reinforced material. As another example, all three layers 42, 44, and 46 can be formed from different fiber-reinforced materials, i.e., different types of fiber-reinforced materials. As stated above, the fiber-reinforced materials can be, for example, fiber-reinforced plastic or fiber-reinforced polymer, such as carbon fiber, glass fiber, or aramid fiber. The fiber-reinforced materials each contain fibers 82, 84, and 86. Fibers 82, 84, 86 can be made from, for example, carbon, aramid, glass, polyacrylonitrile, viscose, etc.The fiber-reinforced materials each contain a matrix material, and the fibers 82, 84, and 86 are cured within the matrix materials. The matrix materials of layers 42, 44, and 46 can be, for example, polyester, epoxy, polyamide, polycarbonate, polypropylene, vinyl, or any other type of polymer.

[0023] Layers 42, 44, and 46 can be formed in one piece, i.e., simultaneously as a single unit. Alternatively, any one of layers 42, 44, or 46 can be formed separately from the others and then attached to them.

[0024] The fibers 84 of the fiber-reinforced material of the middle layer 44 extend in a direction relative to axis A different from the fibers 82, 86 of the fiber-reinforced material of the inner layer 42 and the outer layer 46. For example, if the fibers 84 of the middle layer 44 extend radially, then the fibers 82, 86 of the inner layer 42 or the outer layer 46 extend axially, circumferentially, or at an angle relative to the axial or circumferential direction. Each fiber is elongated, that is, it extends much further in one direction than in any other direction. The direction of a collection of fibers, such as the fibers 82, 84, 86 of one of the layers 42, 44, 46, is an aggregate direction of the individual fibers 82, 84, 86, in particular a direction in which the majority of the fibers 82, 84, 86 are oriented.

[0025] The density of fibers 82, 84, 86 can vary between different positions in layers 42, 44, 46. For example, in Fig. As shown in Figure 7, the fibers 82 can be denser at an outer diameter of the flange section 74 of the outer layer 46 than at an inner diameter of the flange section 74 of the tubular section 72. The density of the fibers 82, 84, 86 is the number of fibers per unit volume.

[0026] With reference to the Fig. 4-8 A lining 88 can line the bore 62. The lining 88 can be the matrix material of the fiber-reinforced material that forms the inner layer 42; that is, the fibers 86 of the fiber-reinforced material of the inner layer 42 can be spaced apart from the bore 62 by the lining 88. Alternatively, the lining 88 can be a different material than the matrix material of the inner layer 42.

[0027] With reference to the Fig. 2 and Fig. Figure 3 includes the connected structure 30 and the fastener 48. The fastener 48 can be positioned through the bore 62 of the inner layer 42 and the hole 40 of the second component 34. The fastener 48 connects the first component 32 to the second component 34; that is, it holds the first component 32 and the second component 34 together. Due to the insert 36, the fastener 48 does not touch any of the fibers 56 of the fiber-reinforced material of the first component 32 during assembly. The fastener 48 can be a rivet, as shown in the Fig. 2 and Fig. Figure 3 shows that when mounted on the first component 32 and the second component 34, the fastener 48 can have heads 90 at both ends that press the inner layer 42 and the outer layer 44 together. Alternatively, the fastener 48 can have any type of holding the first component 32 and the second component 34 together, e.g., a threaded fastener, a pin, a clip, etc.

[0028] If the first component 32 and the second component 34 are subjected to forces acting in opposite directions, the fastener 48 can prevent the components 32 and 34 from separating. The forces will press the fastener 48 against one side of the bore 62 of the insert 36. If the forces are sufficiently large, the insert 36 may deform or break. The different orientation of the fibers in the middle layer 44 compared to the inner or outer layers 42 and 46 allows the middle layer 44 to compress and thereby absorb energy without breaking the insert 36.

[0029] With reference to Fig. 7 can include a first embodiment of the insert 36 in which the fibers 82 of the outer layer 46 extend circumferentially relative to the axis A, the fibers 84 of the middle layer 44 extend axially relative to the axis A, and the fibers 86 of the inner layer 42 extend along a direction that is diagonal between circumferential and axial relative to the axis A. In other words, the fibers 82 of the outer layer 46 extend in a circumferential direction, that is, the axial dimension z and the radial dimension r are constant with respect to the circumferential dimension θ for each fiber. The fibers 84 of the middle layer 44 extend parallel to the axis A, that is, the radial dimension r and the circumferential dimension θ are constant with respect to the axial dimension z.The fibers 86 of the inner layer 42 extend along a spiral of constant radius around the axis A, that is, the radial dimension r is constant and the axial dimension is a linear function of the circumferential dimension θ, i.e., z = kθ, where k is constant. The inner layer 42 can contain a first set of fibers 86a, which runs diagonally between the circumferential and the axial dimensions, and a second set of fibers 86b, which runs diagonally oppositely between the circumferential and the axial dimensions. Thus, for the first set 86a of fibers, r is constant and z = kθ, and for the second set of fibers 86b, r is constant and z = -jθ, where j and k are positive constants.

[0030] With reference to Fig.8 can include a second embodiment of the insert 36 in which the fibers 82 of the outer layer 46 extend circumferentially relative to the axis A, the fibers 84 of the middle layer 44 extend radially relative to the axis A, and the fibers 86 of the inner layer 42 extend circumferentially relative to the axis A. In other words, the fibers 82 of the outer layer 46 and the inner layer 42 extend in a circumferential direction, that is, the axial dimension z and the radial dimension r are constant with respect to the circumferential dimension θ for each fiber. The fibers 84 of the middle layer 44 extend orthogonally to the axis A, that is, the axial dimension z and the circumferential dimension θ are constant with respect to the radial dimension r.

[0031] The revelation has been described in an illustrative manner, and it is understood that the terminology used is intended to serve description rather than limitation. In light of the foregoing teachings, many modifications and variations of the present revelation are possible, and the revelation can be implemented differently than specifically described.

Claims

[1] Associated structure (30), comprising: a first component (32) formed from a fiber-reinforced material and having a hole (38) that defines an axis (A); comprising a second component (34) next to the first component (32) and having a hole (40) aligned with the hole (38) of the first component (32); and an insert (36) positioned in the hole (38) of the first component (32), the insert (36) comprising an inner layer (42) having a tubular shape around the axis (A), a middle layer (44) concentric to the inner layer (42) around the axis (A) and an outer layer (46) concentric to the middle layer (44) around the axis (A); wherein the layers (42, 44, 46) are formed from fiber-reinforced materials; and wherein a boundary (50) between the inner and middle layer and a boundary (52) between the middle and outer layer has a non-linear profile in a direction parallel to the axis (A). [2] Composite structure (30) according to claim 1, wherein the inner layer (42) has a bore (62), further comprising a lining (88) which lines the bore (62). [3] Composite structure (30) according to claim 1, wherein the fiber-reinforced material of the first component (32) has fibers (86) and at least some of the fibers (86) are exposed in the hole (38) of the first component (32). [4] Composite structure (30) according to claim 1, wherein the fiber-reinforced materials of the layers (42, 44, 46) each have fibers (86, 84, 82) and the fibers (84) of the fiber-reinforced material of the middle layer (44) extend differently relative to the axis (A) than the fibers of the fiber-reinforced material of one of the inner layer (42) and the outer layer (46). [5] Composite structure (30) according to claim 4, wherein the fibers (82) of the outer layer (46) extend circumferentially relative to the axis (A). [6] Composite structure (30) according to claim 5, wherein the fibers (84) of the middle layer (44) extend radially or axially relative to the axis (A). [7] Composite structure (30) according to claim 6, wherein the fibers (86) of the inner layer (42) extend along a direction that runs diagonally between circumferential and axial relative to the axis (A). [8] Composite structure (30) according to claim 1, wherein the outer layer (46) has a tubular section (72) concentrically adjacent to the middle layer (44) around the axis (44) and a flanged section (74) extending radially outwards from the tubular section (72) relative to the axis (A). [9] Composite structure (30) according to claim 8, wherein the inner layer (42) has a first end (64) and the flange section (74) extends radially inwards relative to the axis (A) from the tubular section (72) next to the first end (64) of the inner layer (42). [10] A connected structure (30) according to claim 9, wherein a boundary (54) between the flange section (74) of the outer layer (46) and the first end (64) of the inner layer (42) has a non-linear profile in a radial dimension relative to the axis (A). [11] Use (36), encompassing: an inner layer (42) with a tubular shape that defines an axis (A); a middle layer (44) concentric next to the inner layer (42) around the axis (A); and an outer layer (46) concentric next to the middle layer (44) around the axis (A); wherein the layers (42, 44, 46) are formed from fiber-reinforced materials; and wherein a boundary (50) between the inner and middle layer and a boundary (52) between the middle and outer layer has a non-linear profile in a direction parallel to the axis (A). [12] Insert (36) according to claim 11, wherein the inner layer (42) has a bore (62), further comprising a lining (88) which lines the bore (62). [13] Insert (36) according to claim 11, wherein the fiber-reinforced materials of the layers (42, 44, 46) each have fibers (86, 84, 82) and the fibers (84) of the fiber-reinforced material of the middle layer (44) extend differently relative to the axis (A) than the fibers (86, 82) of the fiber-reinforced material of one of the inner layer (42) and the outer layer (46). [14] Insert (36) according to claim 13, wherein the fibers (82) of the outer layer (46) extend circumferentially relative to the axis (A). [15] Insert (36) according to claim 14, wherein the fibers (84) of the middle layer (44) extend radially or axially relative to the axis (A). [16] Insert (36) according to claim 15, wherein the fibers (86) of the inner layer (42) extend along a direction that runs diagonally between circumferential and axial relative to the axis (A). [17] Insert (36) according to claim 11, wherein the outer layer (46) has a tubular section (72) concentrically adjacent to the middle layer (44) around the axis (A) and a flanged section (74) extending radially outwards from the tubular section (72) relative to the axis (A). [18] Insert (36) according to claim 17, wherein the inner layer (42) has a first end (64) and the flange section (74) extends radially inwards relative to the axis (A) from the tubular section (72) next to the first end (64) of the inner layer (42). [19] Insert (36) according to claim 18, wherein a boundary (54) between the flange section (74) of the outer layer (46) and the first end (64) of the inner layer (42) has a non-linear profile in a radial dimension relative to the axis (A). [20] Use (36), encompassing: an inner layer (42) with a tubular shape defining an axis (A) and extending from a first end (64); a middle layer (44) concentric next to the inner layer (42) around the axis (A) and extending from the first end (64); and an outer layer (46) with a tubular section (72) concentrically adjacent to the middle layer (44) around the axis (A) and a flanged section (74) extending radially inwards and outwards from the tubular section (72) relative to the axis (A), the flanged section (74) being located adjacent to the first end (64) of the inner layer (42); wherein the layers (42, 44, 46) are formed from fiber-reinforced materials.

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