Method for producing a composite fiber preform for a disc brake

Abstract

The present invention is entitled "Method for manufacturing a composite fiber preform for a disc brake". The present disclosure relates to a method comprising winding a composite fabric around a mandrel to form a plurality of layers, the plurality of layers defining a loop extending along a central longitudinal axis, wherein the composite fabric comprises a plurality of elongated axial fibers extending substantially in an axial direction relative to the longitudinal axis and a plurality of elongated circumferential fibers extending substantially in a circumferential direction relative to the longitudinal axis; and introducing a plurality of radial fibers into at least a portion of the plurality of layers, the plurality of radial fibers extending substantially in a radial direction relative to the longitudinal axis, wherein the plurality of radial fibers mechanically bonds one or more adjacent layers of the plurality of layers.

Description

Technical Field

[0001] The present disclosure relates to the manufacture of carbon-carbon composite materials, such as the manufacture of aircraft brake discs made from carbon-carbon composite materials. Background Art

[0002] Carbon-carbon composites are composite materials that include a matrix that includes carbon reinforced with carbon fibers. Carbon-carbon (CC) composite parts can be used in many high temperature applications. For example, the aerospace industry uses CC composite parts as friction materials for commercial and military aircraft, such as friction brake materials.

[0003] Some carbon-carbon composites, such as some carbon-carbon composite brake discs used in the aerospace industry, may be manufactured from a porous preform including a carbon fiber layer, which may be densified using one or more of several processes including chemical vapor deposition / chemical vapor infiltration (CVD / CVI), vacuum / pressure infiltration (VPI), or resin transfer molding (RTM) to infiltrate the porous preform with carbon. Summary of the invention

[0004] In some examples, the present disclosure describes a fiber preform defining a ring extending along a central longitudinal axis, the fiber preform comprising a plurality of layers and a plurality of radial fibers. The plurality of layers extend in an axial direction and a circumferential direction relative to the longitudinal axis. Each of the plurality of layers is formed by a plurality of elongated fibers, the plurality of elongated fibers comprising elongated axial fibers extending substantially in an axial direction and elongated circumferential fibers extending substantially in a circumferential direction. At least about 40% of the plurality of elongated fibers extend substantially in an axial direction. The plurality of radial fibers extending substantially in a radial direction relative to the longitudinal axis mechanically bonds one or more adjacent layers of the plurality of layers.

[0005] In some examples, the present disclosure describes a fiber preform that defines a cylinder extending along a central longitudinal axis. The fiber preform includes a plurality of fiber layers and a plurality of radial fibers. The plurality of fiber layers extend in an axial direction and a circumferential direction relative to the cylinder. Each of the plurality of layers includes a woven fabric that includes a plurality of elongated axial fibers extending substantially in an axial direction and a plurality of elongated circumferential fibers extending substantially in a circumferential direction. At least 40% of the fibers of the woven fabric extend substantially in an axial direction. The plurality of radial fibers extend substantially in a radial direction relative to the cylinder and mechanically bond one or more adjacent layers of the plurality of layers.

[0006] In some examples, the present disclosure describes a carbon-carbon composite disc brake that defines a ring extending along a central longitudinal axis. The carbon-carbon composite disc brake includes a plurality of layers and a plurality of radial carbon fibers. The plurality of layers extend in an axial direction and a circumferential direction relative to the longitudinal axis. Each layer of the plurality of layers includes a plurality of elongated carbon fibers, the plurality of elongated carbon fibers including a plurality of elongated axial fibers extending substantially in the axial direction and a plurality of elongated circumferential fibers extending substantially in the circumferential direction. At least 40% of the plurality of elongated fibers extend substantially in the axial direction. The plurality of radial carbon fibers extend substantially in a radial direction relative to the longitudinal axis and mechanically bond one or more adjacent layers of the plurality of layers.

[0007] In some examples, the present disclosure describes a method that includes winding a composite fabric around a mandrel to form a plurality of layers, the plurality of layers defining a ring extending along a central longitudinal axis. The composite fabric includes a plurality of elongated axial fibers extending substantially in an axial direction relative to the longitudinal axis and a plurality of elongated circumferential fibers extending substantially in a circumferential direction relative to the longitudinal axis. The method also includes introducing a plurality of radial fibers into at least a portion of the plurality of layers, the plurality of radial fibers extending substantially in a radial direction relative to the longitudinal axis. The plurality of radial fibers mechanically bonds one or more adjacent layers of the plurality of layers.

[0008] In some examples, the present disclosure describes a method for forming a composite brake pad, the method comprising winding a carbon fiber fabric around a rotating mandrel to form a plurality of layers, the plurality of layers defining a cylinder extending along a central longitudinal axis. The carbon fiber fabric comprises a plurality of elongated carbon fibers, at least 40% of the plurality of elongated carbon fibers extending in an axial direction. The method also comprises tufting or needle punching at least one of the plurality of layers to introduce radially extending fibers into the plurality of layers to form a carbon fiber preform. The method also comprises pyrolyzing the carbon fiber preform, at least partially densifying the carbon fiber preform, and segmenting the carbon fiber preform into discs defining a plurality of composite disc brakes.

[0009] In some examples, the present disclosure describes a system including a composite fabric source and a mandrel. The composite fabric source includes a composite fabric. The mandrel is configured to wind the composite fabric around the mandrel to form a fiber preform, which defines a ring extending along a central longitudinal axis. The fiber preform includes a plurality of layers and a plurality of radial fibers. The plurality of layers extend in an axial direction and a circumferential direction relative to the longitudinal axis. Each of the plurality of layers includes a plurality of elongated fibers, the plurality of elongated fibers including a plurality of elongated axial fibers extending substantially in an axial direction and a plurality of elongated circumferential fibers extending substantially in a circumferential direction. At least 40% of the plurality of elongated fibers extend substantially in an axial direction. The plurality of radial fibers extend substantially in a radial direction relative to the longitudinal axis and mechanically bond one or more adjacent layers of the plurality of layers.

[0010] The details of one or more examples of the present disclosure are set forth in the following drawings and the description. Other features, objects, and advantages of the present disclosure will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a conceptual diagram illustrating an exemplary wheel and brake assembly that may include one or more of the disc brakes formed according to the techniques and structural features of the present disclosure.

[0012] Figure 2 is a schematic perspective view of an exemplary stator brake disk defining an inner diameter (ID) and an outer diameter (OD).

[0013] Figure 3A is a schematic perspective view of an exemplary fiber preform that may be used to make the composite friction materials described herein.

[0014] Figure 3B Yes Figure 3A Partial cross section of a portion of the indicated fiber preform.

[0015] Figure 4 is shown for manufacturing Figure 3A Conceptual diagram of an exemplary system of a fiber preform.

[0016] Figure 5A and Figure 5B is a thermal graph showing exemplary peak temperatures during a braking process for an exemplary friction composite and an exemplary nonwoven friction composite made using the techniques described herein.

[0017] Figure 6 is a graph of peak antioxidant temperature versus time for an exemplary friction composite and an exemplary nonwoven friction composite made using the techniques described herein.

[0018] Figure 7 is a flow chart illustrating an exemplary technique for manufacturing a fiber preform. DETAILED DESCRIPTION

[0019] In some examples, the present disclosure describes a fiber preform for producing a composite friction material that can be used, for example, to form a disc brake. The fiber preform described may define a ring extending along a central longitudinal axis. The fiber preform may include a plurality of layers extending in an axial direction and a circumferential direction relative to the longitudinal axis. Each of the plurality of layers may include a composite fabric. The composite fabric includes a plurality of elongated fibers extending along a long axis. In some examples, at least 40% of the long axis of the fibers in the plurality of elongated fibers extends in an axial direction relative to the longitudinal axis. For example, a majority of the fibers in the plurality of elongated fibers may extend in an axial direction relative to the longitudinal axis, and the remaining fibers may extend in a circumferential direction or a radial direction relative to the longitudinal axis. In some examples, the percentage of fibers extending in each of the axial direction, the circumferential direction, and the radial direction may be selected to improve friction characteristics, shear strength, torque strength, and combinations thereof.

[0020] Composite friction materials, such as composite aircraft brakes, wear during operation. In the example of aircraft brakes, increasing the useful life of the brake can be achieved by increasing the wear pin length, reducing the wear rate of the friction material, or both. Typically, the wear pins are already at a maximum length. Therefore, reducing the wear rate may be beneficial. Fiber orientation in a composite material can affect the wear rate and thermal conductivity. In some examples, a composite aircraft brake includes alternating layers of radial fiber segments and chord-wise fiber segments such that a majority of the fibers are located in the radial and chord-wise directions of the brake disc. Needling can be used to introduce a relatively low percentage of fibers in the axial direction.

[0021] Orienting a majority of the fibers of the composite friction material in an axial direction (e.g., perpendicular to the friction surface) relative to the longitudinal axis of the ring defined by the disc brake can reduce wear rates, increase thermal conductivity (in the axial direction), and increase the useful life of the composite friction material. Additionally or alternatively, the axial orientation of the majority of the fibers can improve thermal conductivity from the friction surface to a heat sink (such as a backing plate). For example, by better conducting heat, the axially oriented fibers can reduce peak temperatures and / or reduce the time of exposure to temperature during operation, which can increase the useful life of the friction material and / or antioxidant coating on the friction material. Additionally or alternatively, the axial orientation of the majority of the fibers can improve mid-disc densification by providing preferentially oriented fibers via a chemical vapor infiltration or chemical vapor deposition (CVI / CVD) process, which can reduce density gradients, potentially increase bulk density, thereby resulting in lower overall temperatures, and / or potentially reduce the number of CVI / CVD cycles to achieve a desired density.

[0022] Figure 1 is a conceptual diagram illustrating an exemplary wheel and brake assembly 10 that may include one or more of the disc brakes formed according to the techniques and structural features of the present disclosure. For ease of description, examples of the present disclosure will be described primarily with respect to aircraft brake assemblies formed of composite friction materials. However, the techniques of the present disclosure may be used to form composite friction materials other than aircraft brake discs. For example, the composite friction material may be used in other types of vehicles or friction material applications that may benefit from, for example, improved wear rates and / or improved thermal conductivity.

[0023] exist Figure 1 In the example of FIG. 1 , the wheel and brake assembly 10 includes a wheel 12, an actuator assembly 14, a brake stack 16, and an axle 18. The wheel 12 includes a hub 20, a wheel leg flange 22, flange seals 24A and 24B, a lug bolt 26, and a lug nut 28. The actuator assembly 14 includes an actuator housing 30, an actuator housing bolt 32, and a piston 34. The brake stack 16 includes alternating rotor brake discs 36 and stator brake discs 38; the rotor brake discs 36 are configured to move relative to the stator brake discs 38. The rotor brake discs 36 are mounted on the wheel 12, and in particular, the hub 20, by a beam key 40. The stator brake discs 38 are mounted to the axle 18 by a rack 44, and in particular, a torque tube 42. The wheel and brake assembly 10 can support any type of private, commercial, or military aircraft or other type of vehicle.

[0024] The wheel and brake assembly 10 includes a wheel 12 having a Figure 1 In the example of FIG. 1 , the wheel 12 is defined by a wheel hub 20 and a wheel leg flange 22. The wheel leg flange 22 may be mechanically secured to the wheel hub 20 by lug bolts 26 and lug nuts 28. The wheel 12 defines flange seals 24A and 24B. During assembly, an inflatable tire (not shown) may be placed over the wheel hub 20 and secured on the opposite side by the wheel leg flange 22. Thereafter, the lug nuts 28 may be tightened on the lug bolts 26, and the inflatable tire may be inflated with the flange seals 24A and 24B, thereby providing an airtight seal for the inflatable tire.

[0025] The wheel and brake assembly 10 may be mounted to a vehicle via the torque tube 42 and the axle 18. Figure 1 In the example of FIG. 1 , a torque tube 42 is attached to the shaft 18 by a plurality of bolts 46. The torque tube 42 supports the actuator assembly 14 and the stator brake disc 38. The shaft 18 may be mounted on a strut of a landing gear (not shown) or other suitable component of a vehicle to connect the wheel and brake assembly 10 to the vehicle.

[0026] During vehicle operation, braking may be required from time to time, such as during landing and taxiing procedures of an aircraft. The wheel and brake assembly 10 is configured to provide a braking function to a vehicle via an actuator assembly 14 and a brake stack 16. The actuator assembly 14 includes an actuator housing 30 and a piston 34. The actuator assembly 14 may include different types of actuators, such as, for example, one or more of an electro-mechanical actuator, a hydraulic actuator, a pneumatic actuator, etc. During operation, the piston 34 may extend away from the actuator housing 30 to axially compress the brake stack 16 against the compression point 48 for braking.

[0027] The brake stack 16 includes alternating rotor brake discs 36 and stator brake discs 38. The rotor brake discs 36 are mounted on the hub 20 for common rotation via beam keys 40. The stator brake discs 38 are mounted to the torque tube 42 via key teeth 44. Figure 1 In the example of FIG. 1 , the brake stack 16 includes four rotors and five stators. However, in other examples, a different number of rotors and / or stators may be included in the brake stack 16 .

[0028] The rotor brake discs 36 and the stator brake discs 38 may provide opposing friction surfaces for braking the aircraft. As the kinetic energy of the moving aircraft is converted into heat energy in the brake stack 16, the temperature in the brake stack 16 may increase rapidly. As such, the rotor brake discs 36 and the stator brake discs 38 forming the brake stack 16 may include strong, thermally stable materials capable of operating at very high temperatures.

[0029] In one example, the rotor brake disc 36 and / or the stator brake disc 38 are formed of a carbon-carbon (CC) composite material in the form of a ring that defines a set of opposing wear surfaces. The CC composite material can be manufactured using any suitable manufacturing technique or combination of techniques (including, for example, vacuum pressure infiltration (VPI), resin transfer molding (RTM), chemical vapor infiltration (CVI), chemical vapor deposition (CVD), additive manufacturing, machining, ablation techniques, etc.) using the fiber preform described herein as a starting substrate.

[0030] In some examples, the rotor brake disc 36 and the stator brake disc 38 may be mounted in the wheel and brake assembly 10 by beam keys 40 and racks 44, respectively. In some examples, the beam keys 40 may be spaced circumferentially around the inner portion of the hub 20. For example, the beam keys 40 may be shaped to have opposite ends (e.g., opposite sides of a rectangle), and may have one end mechanically fixed to the inner portion of the hub 20 and an opposite end mechanically fixed to the outer portion of the hub 20. The beam keys 40 may be integrally formed with the hub 20, or may be separate from the hub 20 and mechanically fixed to the hub 20, for example, to provide a thermal barrier between the rotor brake disc 36 and the hub 20. In some examples, the wheel and brake assembly 10 may include a heat shield (not shown) that extends radially outward and outwardly around the brake stack 16, for example, to limit heat transfer between the brake stack 16 and the wheel 12.

[0031] In some examples, the key teeth 44 may be spaced circumferentially around the outer portion of the torque tube 42. As such, the stator brake disc 38 may include a plurality of radially inwardly disposed lug slots along the inner diameter of the brake disc that are configured to engage with the rack 44. Similarly, the rotor brake disc 36 may include a plurality of radially inwardly disposed lug slots along the outer diameter of the brake disc that are configured to engage with the beam key 40. As such, the rotor brake disc 36 will rotate with the movement of the wheel while the stator brake disc 38 remains stationary, allowing the friction surfaces of the adjacent stator brake disc 38 and rotor brake disc 36 to engage with each other, thereby decelerating the rotation of the wheel 12.

[0032] Figure 2 is a schematic perspective view of an exemplary stator brake disc 38 defining an inner diameter (ID) and an outer diameter (OD). The stator brake disc 38 includes opposing friction surfaces 70 positioned on opposite sides of the ring. An inner radial segment 74 along the inner diameter ID of the stator brake disc 38 includes a plurality of lug grooves 72 cut into the stator brake disc 38. The lug grooves 72 are configured to engage and couple with the key teeth 44 of the wheel and brake assembly 10. For the rotor disc brake 36, the lug grooves 72 will appear along the outer radial segment 76 along the outer diameter OD of the ring. The lug grooves 72 of the rotor disc brake 36 will be configured to engage and couple with the beam key 40.

[0033] During the braking process, the key teeth 44 and the beam keys 40 may engage with the corresponding lug grooves 72 of the rotor brake disc 36 and the stator brake disc 38, thereby generating heat between adjacent friction surfaces 70 and transferring a large amount of torque into the brake disc. The heat generated during the braking process may be conducted through the fibers of the brake disc 38. In some examples, the orientation of the underlying fiber framework of the CC composite may affect the heat conduction. For example, the heat conduction parallel to the longitudinal length of the fiber may be greater than the direction transverse to the longitudinal length of the fiber. In some examples, if the majority of the fibers of the CC composite are oriented in the axial direction (relative to the circumferential direction or radial direction), more heat may be conducted between the friction surfaces 70 and / or toward the core of the brake disc 38 (in the axial direction) (e.g., away from the friction surfaces 70 in the axial direction). Transferring heat between adjacent friction surfaces and / or toward the core of the brake disc 38 may reduce localized accumulation of heat, which may otherwise increase wear, damage protective coatings, and / or reduce the service life of the disc brake 38. As such, the fiber architecture of the disc brakes 36 and 38 may be selected to reduce the wear rate, increase thermal conductivity in the axial direction, and increase the useful life of the composite friction material.

[0034] Additionally, the torque forces generated during the braking process can be transferred into the underlying fiber architecture of the CC composite. In some examples, if the fibers of the CC composite are oriented in a radial direction, the resultant force can be applied in a direction generally perpendicular to the longitudinal length of the fibers. In contrast, if the fibers are oriented in a circumferential direction (e.g., aligned perpendicular to the radial direction), the resultant force can be applied in a direction generally along the longitudinal length of the fibers. The fiber architecture of the disc brakes 36 and 38 can be selected to provide the desired torque transfer near the lug slots 72.

[0035] Figure 3A It is useful for making the composite friction material described herein (e.g., Figure 1 and Figure 2 2 is a schematic perspective view of an exemplary fiber preform 100 for a rotor brake disk 36 or a stator brake disk 38 . Figure 3B is a partial cross section of the fiber preform 100 (the cross section is Figure 3A ). The fiber preform 100 defines a ring extending along a central longitudinal axis 110 (e.g., extending parallel to the x-axis). The fiber preform includes a plurality of superimposed fiber layers 102 ("layers 102"). The layers 102 extend in an axial direction "A" and an R direction "C" relative to the longitudinal axis. Figure 3B As shown, layer 102 includes layers 102A-102G wound around longitudinal axis 110. For example, layer 102 can be continuously wound around longitudinal axis 110, such as in a continuous spiral. In other examples, layer 102 can include discrete rings. Layer 102 includes a plurality of elongated fibers 103.

[0036] In some examples, layer 102 may include a continuous fiber fabric, such as a uniaxial fabric or a biaxial fabric. For example, each layer in layer 102 may include a plurality of continuous axial fibers 104 ("axial fibers 104") extending substantially in the axial direction and a plurality of continuous circumferential fibers 106 ("circumferential fibers 106") extending substantially in the circumferential direction. As used herein, extending substantially in the axial direction, the circumferential direction, or the radial direction may refer to extending to the extent allowed by the manufacturing tolerance of a given composite fiber relative to the longitudinal axis 110 (e.g., relative to the ring) in the corresponding direction, for example, not exceeding a deviation of + / -5 degrees (such as + / -2 degrees). Continuous fibers may include fibers that are continuous and infinitely long at least throughout layer 102. In some examples, continuous fiber fabrics may include woven fabrics having any suitable weaving pattern. In some examples, layer 102 may include alternating layers of continuous fiber fabrics and nonwoven fabrics.

[0037] In some examples, the layers 102 may be tufted and / or needled together to form the fiber preform 100. The tufting process or the needling process may introduce a plurality of third fibers 108 ("radial fibers 108") extending substantially in the radial direction "R" into the fiber preform 100. The radial fibers 108 may mechanically bond the layers 102 together. For example, the radial fibers 108 may secure at least one of the layers 102 to one or more adjacent layers of the layers 102. In this way, the radial fibers 108 may increase the interlaminar shear strength of the fiber preform 100 and / or the disc brake 38 formed by the fiber preform 100. Additionally or alternatively, the tufting process or the needling process, and the resulting radial fibers 108 may partially compress the layers 102 to form a more compact fiber preform 100 compared to a preform including a similar number of layers 102 that are not tufted or needled together.

[0038] Although some of the figures described herein show a relatively small number of layers used in the corresponding fiber preform, the preform (e.g., fiber preform 100) produced by the technology described herein may include any suitable number of layers 102 to produce the desired outer diameter OD of the resulting preform. For example, each layer 102 may have a thickness of about 1 millimeter (mm) to about 2 mm measured on a radial parallel. Once the fiber preform 100 is completed, it may be in the shape of a ring defining a preform outer diameter (OD) and a preform inner diameter (ID). In some examples, the preform outer diameter (OD) of the fiber preform 100 may be about 14.5 inches (e.g., about 37 cm) to about 25 inches (e.g., about 64 cm), and the preform inner diameter (ID) of the fiber preform 100 may be about 4.5 inches (e.g., about 12 cm) to about 15 inches (e.g., about 38 cm). Therefore, in some examples, the fiber preform may include about 30 to about 520 layers. In other examples, the fiber preform may include fewer than 30 layers or more than 520 layers.

[0039] In some examples, after forming the preform 100, for example, before or after any of pyrolysis, partial densification, or densification of the preform 100, the preform 100 may be segmented (e.g., cut) along a circumferential / radial plane (e.g., parallel to the yz plane) to form brake disks (e.g., brake disk 38). In some examples, the total thickness (T) of each segmented portion of the fiber preform 100 may be about 1 inch to about 3 inches (e.g., about 2.54 cm to about 7.62 cm).

[0040] In some examples, the fiber preform 100 may be configured with lug grooves 72 ( Figure 3A 1 (not shown), the lug slots are formed into either the outer diameter (OD) or the inner diameter (ID), depending on whether the fiber preform 100 is intended to be formed as a rotor disc brake 36 or a stator disc brake 38, respectively. In some examples, an area of ​​the preform 100 at the lug slot 72, for example, having a lug slot 72 of about 3 inches (e.g., about 7.62 cm) may include more radial fibers 108 than other areas of the fiber preform 100. The greater concentration of radial fibers 108 near the lug slot 72 may improve the torque transmission strength at the lug slot 72. In some examples, the lug slots may be formed with the fiber preform 100, may be cut into the fiber preform 100 after the corresponding layers 102 have been fully wound, or may be introduced after the fiber preform 100 has undergone some or all of the subsequent pyrolysis and densification processes to convert the fiber preform 100 into a CC composite.

[0041] In some examples, the fiber preform may be in the shape of a ring (e.g., a disc) defining an inner diameter ID and an outer diameter OD. The cross section of the fiber preform ring may be divided into an inner radial segment, a central radial segment, and an outer radial segment. For example, layers 102A and 102B may define an inner radial segment, layers 102C-102E may define a central radial segment, and layers 102G and 102F may define an outer radial segment. In other examples, the inner radial segment, the central radial segment, and the outer radial segment may include any suitable number of layers. In other examples, the inner radial segment, the central radial segment, and the outer radial segment may each include about 5% to about 90% of the total width W of the ring.

[0042] In some examples, each of the inner and outer radial segments may include a greater percentage of radially extending fibers (relative to axially or circumferentially extending fibers) than the percentage of radially extending fibers in the center radial segment. In some examples, the percentage of radially extending fibers may be selected based on the location of the lug region within the final fiber preform (e.g., a region of a lug groove configured to interlock with a key tooth or beam key of a wheel and brake assembly).

[0043] The fibers 103 (e.g., axial fibers 104, circumferential fibers 106, and radial fibers 108) may include carbon fibers, fibers that are configured to be subsequently pyrolyzed into carbon fibers (hereinafter referred to as "carbon-precursor fibers"), or combinations thereof. The carbon-precursor fibers may include, for example, polyacrylonitrile (PAN) fibers, oxidized polyacrylonitrile (O-PAN) fibers, rayon fibers, and the like.

[0044] In some examples, the axial fibers 104 and / or the circumferential fibers 106 may be in the form of tows of continuous filaments (e.g., linearly aligned individual fiber bundles). Each tow may include hundreds to thousands of individual fibers aligned unidirectionally to form a single tow. In such examples, the layer 102 may include a fabric having multiple unidirectionally aligned tows within a segment, wherein each tow includes multiple fibers.

[0045] In some examples, the layer 102 may include a double-layer fabric that includes a plurality of unidirectional aligned axial fibers 104 and / or circumferential fibers 106 (e.g., aligned tows) that have been combined with a plurality of web fibers (not shown). The web fibers may include chopped, discontinuous, or cut fibers having an unspecified alignment that are relatively short compared to the axial fibers 104 and / or circumferential fibers 106 and that, when combined with the axial fibers 104 and / or circumferential fibers 106 in the double-layer fabric, entangle with the aligned axial fibers 104 and / or circumferential fibers 106 to impart integrity to each of the layers 102. The web fibers may define a random fiber orientation relative to each other and relative to the aligned axial fibers 104 and / or circumferential fibers 106.

[0046] In some examples, the formation of a double-layer fabric can be achieved by combining one or more layers of aligned tow fibers (e.g., axial fibers 104 and / or circumferential fibers 106) with one or more layers of web fibers, which are then needled into the layers of tow fibers to form a double-layer fabric. For example, a layer of web fibers can be formed by cross-combing a web to achieve a desired area weight and then needled into the layer to form a web layer. Additionally or alternatively, a web layer can be formed by air-laying the web fibers on top of a layer of unidirectional aligned fibers. A layer of unidirectional aligned fibers can be formed by spreading large continuous tows using a creel to form a sheet of desired area weight, wherein the fibers are aligned in the same direction. Both the web layer and the unidirectional aligned fiber layer can be needled together to force relatively short web fibers to entangle with the unidirectional aligned fibers to form a double-layer fabric (e.g., layer 102).

[0047] Additionally or alternatively, layer 102 may be formed as a double-layer fabric by initially combining web fibers into tows of unidirectionally aligned fibers. The described tow layer may be formed by spreading large tows using a creel to form a sheet of desired area weight. The layer may then be needled to force the relatively short web fibers to entangle with the unidirectionally aligned fibers to form a double-layer fabric.

[0048] As a result of the needling process in any of the above examples, the web fibers entangle with the aligned fibers and help to bond the aligned fibers together, thereby allowing layer 102 to be effectively handled without causing the aligned fibers to separate or break apart during subsequent processing. The resulting double-layer fabric (e.g., layer 102) can be more durable, better retain its shape, and generally easier to further manufacture than a layer of only unidirectional aligned fibers. Other techniques can also be used to form layer 102 into a double-layer fabric that includes unidirectional aligned fibers and web fibers, which fibers can be known to those skilled in the art. In all of the examples described herein, the layers 102 and fabric sections used to form the fiber preforms described herein can be composed of one or more layers of a double-layer fabric.

[0049] In some examples, in addition to holding the layers 102 together, the web fibers used to produce the double-layer fabric may ultimately be used to form or contribute to a portion of the needled fibers 104 in the fiber preform 100 as the layers 102 are superimposed (e.g., stacked on each other) and needled together. Additionally or alternatively, as the layers 102 are superimposed and needled together, at least some of the unidirectionally aligned fibers (e.g., axial fibers 104 and / or circumferential fibers 106) may be transformed into needled fibers 104 within the fiber preform 100. For example, the needle punching process may break some of the unidirectionally aligned fibers contained in the layers 102 and at least partially transfer the broken fibers to one or more adjacent layers 102 within the fiber preform 100 to form the needled fibers 104.

[0050] The web fibers and the unidirectionally aligned fibers 103 may all be formed from the same carbon fibers or carbon fiber precursor materials, may be formed from different carbon fibers or carbon fiber precursor materials, or may be formed from different combinations of carbon fibers and / or carbon fiber precursor materials. In some examples, the layer 102 may be formed to have a carbon fiber weight of about 500 g / m2 (g / m 2 ) to about 2500g / m 2 (such as about 597g / m 2 About 1346g / m 2 ) area weight.

[0051] Figure 4 is a conceptual diagram illustrating an exemplary system 400 for manufacturing a fiber preform 100. The system 400 includes a first mandrel 402 and a second mandrel 404. The system 400 is configured to wind a composite fabric 406 into the fiber preform 100.

[0052] The first mandrel 402 is configured to wind a composite fabric 406 from a fabric source 408 into a fiber preform 100. The first mandrel 402 extends along a central longitudinal axis 410. In some examples, the first mandrel 402 is coupled to a motor 412. The motor 412 is configured to controllably rotate the first mandrel 402 to wind the composite fabric 406 around the first mandrel 402. In some examples, the motor 412 may include a variable speed motor communicatively coupled to a controller (not shown). The controller may be configured to control the rotation speed of the mandrel 402.

[0053] In some examples, the first mandrel 402 can include a material that can be heated to between about 1900° C. and about 2500° C. For example, the first mandrel 402 can include a graphite mandrel. In some examples, the first mandrel 402 can include a graphite ring removably attached to a metal rod.

[0054] In some examples, the fabric source 408 can be wound around the second mandrel 404. The second mandrel 404 can be coupled to a tensioner 414. The tensioner 414 can include, for example, an electric motor or a brake system configured to provide a selected tension on the composite fabric 406 when the first mandrel 402 rotates to wind the composite fabric 406 onto the first mandrel 402. In other examples, the system 400 can include one or more tensioning rollers configured to provide a selected tension on the composite fabric 406 when the first mandrel 402 rotates to wind the composite fabric 406 onto the first mandrel 402. In some examples, the selected tension can affect the density of the fiber preform 100, such as the fiber volume relative to the total volume of the fiber preform 100. For example, a greater tension during winding can result in a denser fiber preform 100 than a smaller tension. In some examples, the tension can be selected to produce a selected fiber volume relative to the total volume of the fiber preform 100. For example, the tension may be selected to result in a percentage of fiber volume relative to the total volume of the fiber preform 100 of between about 15% and about 50%, such as about 22% and about 25%.

[0055] The system 400 may also include a needle punch 416. As discussed above, the needling process using the needle punch 416 may introduce a plurality of fibers that extend, for example, in a radial direction relative to the central longitudinal axis 410. For example, needling using the needle punch 416 may cause at least a portion of the fibers of the composite fabric to break and at least partially divert the broken fibers to extend in a radial direction.

[0056] The needle punch 416 may include a curved member 418 having a plurality of needles 420. The curved member 418 has a radius of curvature R. The radius of curvature R of the curved member 418 may be selected to correspond to the radius of curvature of the fiber preform 100. For example, as discussed above, the fiber preform 100 may include an inner radial segment, a central radial segment, and an outer radial segment. The radius of curvature of the curved member 418 may be the same or substantially similar to the radius of curvature of the fiber preform 100 during winding of the inner radial segment (e.g., the inner diameter ID of the fiber preform 100), the radius of curvature of the fiber preform 100 during winding of the outer radial segment (e.g., the outer diameter OD of the fiber preform 100), or a radius between the inner diameter ID and the outer diameter OD.

[0057] In some examples, the system 400 may include a plurality of needlers 416. For example, the system 400 may include a first needler having a first radius that is the same as or substantially similar to the radius of curvature of the fiber preform 100 during the winding of the inner radial segment (e.g., the inner diameter ID of the fiber preform 100). Additionally, the system 400 may include a second needler having a second radius (different from the first radius) that is the same as or substantially similar to the radius of curvature of the fiber preform 100 during the winding of the outer radial segment (e.g., the outer diameter OD of the fiber preform 100).

[0058] In some examples, the needle punch 416 may be coupled to a piston or mechanical actuator (not shown) that is configured to controllably press the needle 420 into the fiber preform 100 when the composite fabric 406 is wound onto the first mandrel 402. In some examples, the frequency and / or timing of the pressing may be controlled to provide a selected amount of radial fibers in a selected area of ​​the fiber preform 100. For example, during the winding of the inner radial segment, a pressing of a first frequency may provide a greater amount of radial fibers relative to a central radial segment wound with a pressing of a second frequency, the second frequency being less than the first frequency. Similarly, during the winding of the outer radial segment, a pressing of a third frequency greater than the second frequency may provide a greater amount of radial fibers relative to the central radial segment. In this way, the fiber preform 100 may be formed with a selected amount (e.g., percentage) of radially extending fibers relative to the axially and / or circumferentially extending fibers.

[0059] In addition to or as an alternative to the needle punch 416, the system 400 may include a tufting device (not shown). The tufting device may include one or more needles configured to introduce one or more fibers extending in a radial direction into the fiber preform 100. For example, the needles of the tufting device may introduce loops of fibers in the radial direction. Tufting to introduce fibers extending in the radial direction may reduce damage to the fibers of the composite fabric 100 while still providing fibers extending in the radial direction to mechanically bond one or more adjacent layers of the plurality of layers of the fiber preform 100. Additionally or alternatively, tufting to introduce fibers extending in the radial direction may be faster and / or cheaper than other processes for introducing radial fibers, such as three-dimensional weaving or three-dimensional braiding.

[0060] Figure 5A and Figure 5B 5 are thermal diagrams 500A and 500B of an exemplary rotor brake disc and adjacent stator brake disc interface. Figure 5AAs shown, the rotor brake disc 502A and the adjacent stator brake disc 504A may define a friction surface interface 506A. The rotor brake disc 502A and the stator brake disc 504A include a non-woven friction composite material. During the braking process, the friction between the rotor brake disc 502A and the stator brake disc 504A at the friction surface interface 506A generates heat. As shown in the heat map 500A, the temperature of the friction surface interface 506A is about 2800°F. In some examples, such temperatures may increase the wear of the rotor brake disc 502A and the stator brake disc 504A, damage the protective coating on the rotor brake disc 502A and the stator brake disc 504A, and / or reduce the service life of the rotor brake disc 502A and the stator brake disc 504A.

[0061] like Figure 5B As shown, rotor brake disc 502B and adjacent stator brake disc 504B may define a friction surface interface 506B. Rotor brake disc 502B and stator brake disc 504B material 502B include a friction composite material manufactured using the techniques described herein. As indicated by thermal map 500B, during the braking process, the temperature of friction surface interface 506B is less than 2800°F, such as less than about 2400°F. This reduction in temperature (e.g., relative to Figure 5A In one example, the friction composite material may reduce wear of the rotor brake disc 502B and the stator brake disc 504B and / or improve the service life of protective coatings (such as antioxidant coatings on the rotor brake disc 502B and the stator brake disc 504B). In this way, the brake disc including the friction composite material manufactured using the techniques described herein may increase the service life of the brake disc.

[0062] Figure 6 600 is a graph of peak antioxidant (AO) temperature versus time for an exemplary friction composite and an exemplary nonwoven friction composite made using the techniques described herein. Line 602 shows the temperature of the exemplary nonwoven friction composite. Figure 6 As shown, the peak temperature reaches about 2800° F. during the fracture process. After reaching a peak temperature of about 2800° F., the brake cools over time. Line 604 shows the temperature of an exemplary friction composite material made using the techniques described herein.

[0063] Compared to nonwoven friction composites, friction composites provide lower thermal gradients due to the axial fibers. Figure 6As shown, the peak temperature of the described friction composite reaches less than about 2400°F during the fracture process. In some examples, the peak temperature of the described friction composite can be about 550°F lower than the peak temperature of the nonwoven friction composite. In some examples, the antioxidant surface peak temperature of the described friction composite can be about 350°F lower than the peak temperature of the nonwoven friction composite. In addition, the described friction composite spends less time above 2000°F than the nonwoven friction composite.

[0064] The fiber preforms and disc brakes described herein may be formed using any suitable technique. Figure 7 1 is a flow chart illustrating an exemplary technique for manufacturing a fiber preform and a disc brake. Figure 7 The techniques shown; however, other fiber preforms or disc brakes may be formed using the described techniques, and other techniques may be used to form the fiber preform 100 and the disc brake 38.

[0065] Figure 7 An exemplary technique includes winding a composite fabric onto a mandrel to form a fiber preform 100 in the shape of a ring (700); introducing radial fibers into the fiber preform 100 (702); pyrolyzing the fiber preform 100 (704); and densifying the resulting preform 100 to produce a disc brake 38 (706).

[0066] The technology includes winding a composite fabric onto a mandrel to form a fiber preform 100 (700) in the shape of a ring. The composite fabric is wound to define each layer in the layer 102. As discussed above, each layer in the layer 102 includes axial fibers 104 and circumferential fibers 106. The resulting fiber preform 100 includes fibers extending primarily in the axial direction and the circumferential direction. In some examples, winding the composite fabric onto the mandrel may include selecting an outer diameter of the mandrel to correspond to a selected inner diameter ID of the fiber preform 100. In some examples, winding the composite fabric onto the mandrel may include controlling the number of windings to achieve a selected outer diameter OD of the fiber preform 100. In some examples, winding the composite fabric onto the mandrel may include controlling the tension of the composite fabric during winding. For example, as described above with reference to Figure 4 As discussed, a second mandrel or tension rod may be used to control the tension of composite fabric 406 .

[0067] The technology also includes introducing radial fibers 108 into the fiber preform 100 (702). The radial fibers 108 can be introduced by needling, tufting, or a combination of the two. In some examples, introducing the radial fibers 108 into the fiber preform 100 can include determining and / or controlling the frequency and / or timing of needling and / or tufting. For example, as discussed above, the frequency and / or timing of needling and / or tufting can be controlled to provide a selected amount of radial fibers in a selected area of ​​the fiber preform 100. The radial fibers 108 can mechanically bond the layers 102 together, partially compress the layers 102 to form a more compact fiber preform 100, or both. In this way, the introduction of the radial fibers 108 can increase the interlaminar shear strength of the fiber preform 100 and / or the disc brake 38 produced using the fiber preform 100.

[0068] Once the fiber preform 100 has been formed, the technique may include pyrolyzing the fiber preform 100 (704). Pyrolyzing the fiber preform 100 may convert any carbon precursor material into carbon through a thermal degradation process to effectively burn out any non-carbon material. For example, the fiber preform 100 may be carbonized by heating the fiber preform 100 in a distiller under inert or reducing conditions to remove non-carbon components (hydrogen, nitrogen, oxygen, etc.) from the fiber 103. Carbonization may be performed using a distiller, such as an autoclave, a furnace, a hot isostatic press, a uniaxial hot press, etc. In each of these techniques, the fiber preform 100 may be heated in an inert atmosphere at a temperature in the range of, for example, about 600° C. to about 1000° C., while optionally being mechanically compressed. Mechanical compression may be used to define the geometry (e.g., thickness (T)) of the fiber preform 100. In some examples, the distiller may be purged with nitrogen for about 1 hour, then slowly heated to about 900° C. over a period of about 10 hours to about 20 hours, and then the temperature is raised to about 1050° C. over about 1 hour to about 2 hours. The distiller may then be maintained at about 1050° C. for about 3 hours to about 6 hours, and then the carbonized preform is allowed to cool. In some examples, the carbonization step may be performed at even higher temperatures, including up to about 1800° C. or up to about 2600° C.

[0069] After pyrolysis, the technology also includes densifying the resulting preform 100 to produce the disc brake 38 (706). The fiber preform 100 may be subjected to one or more densification cycles to form a CC composite. An exemplary densification cycle may include, for example, densification by applying one or more cycles of chemical vapor infiltration / chemical vapor deposition (CVI / CVD) of a carbonaceous gas. Any suitable carbonaceous gas may be used during the CVI / CVD process, including, for example, a carbon-based gas such as natural gas, methane, ethane, propane, butane, propylene, or acetylene, or a combination thereof. In some examples, applying a carbonaceous gas via CVI / CVD to densify the fiber preform 100 may occur substantially in a vacuum space (e.g., a container having an internal environment of less than 100 Torr (e.g., 13.33 kPa)) or in an inert gas environment to control the chemical deposition reaction. In some examples, during the application of the CVI / CVD gas, the environment including the fiber preform 100 may be heated to an elevated temperature, such as about 900° C. to about 1200° C., to promote the chemical deposition reaction.

[0070] In some examples, the axial fibers 104 may increase the penetration of carbonaceous gases into the fiber preform 100. For example, a fiber preform 100 having a greater percentage of axial fibers 104 relative to the total fibers 103 may have better carbonaceous gas penetration than a preform having a relatively lower percentage of axial fibers. Better penetration of carbonaceous gases may improve the final density and / or reduce the overall time required for a desired densification.

[0071] In other examples, the fiber preform 100 can be densified (706) using other suitable techniques, including, for example, resin infiltration and carbonization via a resin transfer mold (RTM) process, a vacuum pressure infiltration (VPI) process, a high pressure infiltration (HPI), etc. In some examples, the densification step (706) can produce a densified CC composite substrate having a final density of about 1.60 g / cc to about 1.95 g / cc, such as about 1.65 g / cc to about 1.85 g / cc.

[0072] In some examples, the fiber preform 100 can be segmented into a plurality of segments having a selected thickness before or after pyrolysis (704) or partial or complete densification (706). For example, the fiber preform 100 can be cut into a plurality of segments using any suitable cutting method, which in some examples can then be pyrolyzed or densified.

[0073] In some examples, during or after densification of the fiber preform 100, the primary friction surface of the resulting CC composite can be sculpted into a desired shape, such as a final brake disc shape. For example, the CC composite substrate can be ground in the shape of a densified CC composite disc brake having a final thickness T (e.g., about 1.4 inches). Additionally or alternatively, lug grooves 72 can be formed at this time.

[0074] In some examples, after densification (706), the technique can include applying one or more coatings to the disc brake 38. For example, the technique can include applying an antioxidant coating, such as a phosphorus-based penetrant system and / or a barrier system, to the disc brake 38. In some examples, the one or more coatings can improve the performance of the disc brake 38 and / or improve the service life of the disc brake 38.

[0075] The following clauses illustrate exemplary subject matter described herein.

[0076] Item 1. A method comprising: winding a composite fabric around a core shaft to form a plurality of layers, the plurality of layers defining a ring extending along a central longitudinal axis, wherein the composite fabric comprises: a plurality of elongated axial fibers, the plurality of elongated axial fibers extending substantially in an axial direction relative to the longitudinal axis; and a plurality of elongated circumferential fibers, the plurality of elongated circumferential fibers extending substantially in a circumferential direction relative to the longitudinal axis; and introducing a plurality of radial fibers into at least a portion of the plurality of layers, the plurality of radial fibers extending substantially in the radial direction relative to the longitudinal axis, wherein the plurality of radial fibers mechanically bonds one or more adjacent layers of the plurality of layers.

[0077] Clause 2. The method of Clause 1, further comprising controlling tension in the composite fabric while winding the composite fabric.

[0078] Clause 3. The method of Clause 2, wherein controlling the tension of the composite fabric comprises providing a resistive tension to a second mandrel of a roll comprising the composite fabric.

[0079] Clause 4. The method of Clause 2 or 3, wherein controlling the tension of the composite fabric comprises controlling the percentage of fiber volume relative to the total volume of the fiber preform to be between about 15% and about 50%.

[0080] Clause 5. The method of any one of Clauses 1 to 4, wherein introducing the plurality of radial fibers comprises needling the fiber preform during winding.

[0081] Clause 6. The method of any one of Clauses 1 to 5, wherein introducing the plurality of radial fibers comprises tufting the fiber preform during winding.

[0082] Clause 7. The method of Clause 5 or 6, wherein introducing the plurality of radial fibers further comprises controlling a frequency and timing of at least one of needling or tufting.

[0083] Clause 8. The method of any one of Clauses 1 to 7, further comprising: pyrolyzing the fiber preform to carbonize at least a portion of the composite fabric; and densifying the carbonized fiber preform to form a densified carbon-carbon composite material.

[0084] Clause 9. The method of any one of clauses 1 to 8, further comprising: at least partially densifying the carbon fiber preform; and dividing the at least partially densified carbon fiber preform into disks defining a composite brake pad.

[0085] Item 10. A method for forming a composite brake pad, the method comprising: winding a carbon fiber fabric around a rotating mandrel to form a plurality of layers, the plurality of layers defining a cylinder extending along a central longitudinal axis, wherein the carbon fiber fabric comprises a plurality of elongated carbon fibers, wherein at least 40% of the fibers of the plurality of elongated carbon fibers extend in an axial direction; tufting or needling at least one of the plurality of layers to introduce radially extending fibers into the plurality of layers to form a carbon fiber preform; pyrolyzing the carbon fiber preform; at least partially densifying the carbon fiber preform; and dividing the carbon fiber preform into disks defining a plurality of composite brake disks.

[0086] Item 11. A system comprising: a composite fabric source, the composite fabric source comprising a composite fabric; and a mandrel, the mandrel being configured to wind the composite fabric around the mandrel to form a fiber preform, the fiber preform defining a ring extending along a central longitudinal axis, the fiber preform comprising: a plurality of layers, the plurality of layers extending in an axial direction and a circumferential direction relative to the longitudinal axis, wherein each of the plurality of layers comprises a plurality of elongated fibers, the plurality of elongated fibers comprising: a plurality of elongated axial fibers, the plurality of elongated axial fibers extending substantially in an axial direction; and a plurality of elongated circumferential fibers, the plurality of elongated circumferential fibers extending substantially in the circumferential direction, wherein at least 40% of the plurality of elongated fibers extend substantially in the axial direction; and a plurality of radial fibers, the plurality of radial fibers extending substantially in the radial direction relative to the longitudinal axis, wherein the plurality of radial fibers mechanically bond one or more adjacent layers of the plurality of layers.

[0087] Clause 12. The system of clause 11, further comprising: a motor coupled to the mandrel, wherein the motor is configured to rotate the mandrel; and a controller communicatively coupled to the motor, wherein the controller is configured to control a rotational speed of the mandrel.

[0088] Clause 13. The system of Clause 11 or 12, wherein the mandrel comprises a graphite mandrel.

[0089] Clause 14. The system of Clause 11 or 12, wherein the mandrel comprises a metal rod and a graphite ring coupled to at least a portion of the metal rod.

[0090] Clause 15. The system of any of Clauses 11 to 14, wherein the source of composite fabric comprises a second mandrel, wherein the composite fabric is wound onto the second mandrel.

[0091] Clause 16. The system of Clause 15, further comprising a tensioner coupled to the second mandrel, wherein the tensioner is configured to control tension in the composite fabric during winding of the composite fabric onto the first mandrel.

[0092] Clause 17. The system of any of Clauses 11 to 16, further comprising at least one tensioning rod configured to control tension in the composite fabric during winding of the composite fabric onto the first mandrel.

[0093] Clause 18. The system of any of Clauses 11 to 17, further comprising a needler configured to introduce the plurality of radial fibers into a selected layer of the plurality of layers.

[0094] Item 19. A system according to Item 18, wherein the needle punch is a first needle punch, and the system also includes a second needle punch, which is configured to introduce the plurality of radial fibers into a selected layer of the plurality of layers, wherein the first needle punch includes a first curved member having a first radius of curvature, wherein the second needle punch includes a second curved member having a second radius of curvature, and wherein the second radius of curvature is greater than the first radius of curvature.

[0095] Clause 20. The system of any of Clauses 11 to 19, further comprising a tufting device configured to introduce a plurality of radial fibers into a selected layer of the plurality of layers.

[0096] Various embodiments have been described. These and other embodiments are within the scope of the following claims.

Claims

1. A method comprising: winding a composite fabric by a second mandrel comprising a roll of composite fabric about the first mandrel to form a fiber preform comprising a plurality of layers defining a loop extending along a central longitudinal axis, wherein the composite fabric comprises: a plurality of elongated axial fibers extending in a substantially axial direction relative to the longitudinal axis; and a plurality of elongated circumferential fibers extending substantially in a circumferential direction relative to the longitudinal axis; controlling tension in the composite fabric while the composite fabric is wound by the second mandrel about the first mandrel, wherein controlling tension in the composite fabric comprises providing tension to the second mandrel comprising the roll of the composite fabric to resist rotation; and introducing a plurality of radial fibers into at least a portion of the plurality of layers, the plurality of radial fibers extending substantially in a radial direction relative to the longitudinal axis, wherein the plurality of radial fibers mechanically bonds one or more adjacent layers of the plurality of layers, Wherein the ring comprises an inner radial segment, a central radial segment, and an outer radial segment, each of the inner radial segment and the outer radial segment comprising a greater percentage of radial fibers than a percentage of radial fibers in the central radial segment. 2 . The method of claim 1 , wherein controlling the tension of the composite fabric comprises controlling a percentage of fiber volume relative to a total volume of the fiber preform to be between 15% and 50%.

3. The method of claim 1 , wherein introducing the plurality of radial fibers comprises: During winding, at least one of: needling the fiber preform or tufting the fiber preform is performed; as well as The frequency and timing of at least one of needling or tufting is controlled.

4. The method according to claim 1, further comprising: pyrolyzing the fiber preform to carbonize at least a portion of the composite fabric; as well as The carbonized fiber preform is densified to form a densified carbon-carbon composite material.

5. The method according to claim 1, wherein the fiber preform comprises a carbon fiber preform, the method further comprising: at least partially densifying the carbon fiber preform; as well as The at least partially densified carbon fiber preform is segmented into disks defining a composite brake pad.

6. A system comprising: a composite fabric source, the composite fabric source comprising a composite fabric wound around a second mandrel; and a first mandrel configured to wrap the composite fabric around the first mandrel by the second mandrel to form a fiber preform, the fiber preform defining a loop extending along a longitudinal axis; and a tensioner coupled to the second mandrel, wherein the tensioner is configured to control tension in the composite fabric by applying tension to the second mandrel that resists rotation while the composite fabric is being wound onto the first mandrel, wherein the fiber preform comprises: a plurality of layers extending in an axial direction and a circumferential direction relative to the longitudinal axis, wherein each layer of the plurality of layers comprises a plurality of elongated fibers, the plurality of elongated fibers comprising: a plurality of elongated axial fibers extending substantially in the axial direction; a plurality of elongated circumferential fibers extending substantially in the circumferential direction, wherein at least 40% of the plurality of elongated fibers extend substantially in the axial direction; and a plurality of radial fibers extending substantially in a radial direction relative to the longitudinal axis, wherein the plurality of radial fibers mechanically bonds one or more adjacent layers of the plurality of layers, Wherein the ring comprises an inner radial segment, a central radial segment, and an outer radial segment, each of the inner radial segment and the outer radial segment comprising a greater percentage of radial fibers than a percentage of radial fibers in the central radial segment.

7. The system according to claim 6, further comprising: a motor coupled to the first spindle, wherein the motor is configured to rotate the spindle; and A controller is communicatively coupled to the motor, wherein the controller is configured to control a rotational speed of the first spindle.

8. The system of claim 6, further comprising a needling or tufting device configured to introduce the plurality of radial fibers into selected ones of the plurality of layers.

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