GB2539249A

GB2539249A - Method of manufacturing a composite component

Info

Publication number: GB2539249A
Application number: GB1510239.5A
Authority: GB
Inventors: K Lander James; Calvert Peter; Davies Ben; Bowyer James; Bowyer Michael
Original assignee: Rolls Royce PLC; Composite Technology and Applications Ltd
Current assignee: Rolls Royce PLC; Composite Technology and Applications Ltd
Priority date: 2015-06-12
Filing date: 2015-06-12
Publication date: 2016-12-14
Also published as: GB201510239D0

Abstract

A method of reinforcing a fibre reinforced resin matrix composite structure and a rig thereof comprises providing a composite structure having one or more holes formed therein; and inserting a reinforcement rod 38 into a hole provided in the composite structure using a rod insertion device 64. Rod is supplied to the rod insertion device from a rod supply system 62 that includes a reel 68 of rod material. Tension is removed from the reinforcement rod between the rod supply system and the rod insertion device preferably by feeding the rod from the supply system into an unsupported loop 72 and then into the rod insertion device. The rod insertion device may include a gripper (58, fig 5) for pulling rod from the supply system and directing a predetermined length into a hole of the composite structure. The rod supply system may comprise one or more tensioning systems and a tension monitoring system 80. The tension removal arrangement may include one or more sensors 76 to detect the amount of rod in the unsupported loop and a control system 82 for increasing the amount of rod in the loop when required.

Description

Method of manufacturing a composite component

Technical Field

The present disclosure concerns a method of reinforcing a composite structure, a method of manufacturing a composite component, and/or a rig for reinforcing a composite structure.

Background

Gas turbine engines are typically employed to power aircraft. Typically a gas turbine engine will comprise an axial fan driven by an engine core. The engine core is generally made up of one or more turbines which drive respective compressors via coaxial shafts. The fan is usually driven via one of the turbines.

The fan may comprise an array of radially extending fan blades mounted on a rotor. The fan blades may be manufactured from metallic or composite materials. Generally composite fan blades include a body formed from a plurality of composite structured plies that include fibres within a resin matrix.

During operation of the gas turbine engine, the fan blades may be impacted by a foreign object (such as a bird) or if a failure occurs the fan blade may be impacted by another fan blade that has been released from the remainder of the fan. In such impact events the integrity of the fan blade should be maintained. A failure mechanism of concern for composite fan blades is delamination.

To resist delamination the fan blade may be reinforced. One method of reinforcing a composite component such as a fan blade is to use through thickness reinforcement rods or pins.

EP2581201 discloses a method by which reinforcement rods can be positioned in a composite component. In the method described in EP2581201, a composite material is heated and holes are formed in the material, reinforcement elements are then provided in each of the holes.

Summary of disclosure

The present disclosure is concerned with further developing and enhancing the method described in EP2581201.

In a first aspect there is provided a method of reinforcing a composite structure. The method comprises providing a composite structure having one or more holes formed therein. A reinforcement rod is inserted into a hole provided in the composite structure using a rod insertion device. Rod is supplied to the rod insertion device from a rod supply system that includes a reel of rod material.

The method may comprise removing tension in the reinforcement rod between the rod supply system and the rod insertion device.

Tension may be removed from the rod by feeding the rod from the supply system into an unsupported loop and feeding rod from the unsupported loop to the rod insertion device. Rollers (e.g. two drive rollers) may be provided to guide the rod into the unsupported loop. Alternatively, another gripping and/or feeding mechanism may be used.

The method may comprise detecting the amount of rod in the unsupported loop. The method may further comprise increasing the length of rod in the loop when the length of the loop drops below a predetermined length. For example, sensors may be provided to detect the amount of rod in the loop. A control system may be provided, and the control system may be operable to feed rod into the loop depending upon the signal received from the sensors.

The method may comprise pulling the rod towards the rod insertion device using a gripper.

The method may include pulling rod from the reel and directing a predetermined length into a hole of the composite structure. For example, a gripper may be provided and the gripper may grip the rod and pull the rod towards the hole of the composite structure. The gripper may take any suitable form, for example a jaw or a pair of rollers.

The method may include tensioning the rod from the reel and then removing tension in the rod before pulling the rod and directing the rod into a hole of the composite structure. At a point in time, a first section of the rod adjacent the reel will be in tension, and a second section of the rod between the first section and the rod insertion device will be substantially free from tension.

The supply system may include a series of rollers and the method may comprise guiding and directing the rod via the rollers. When a series of rollers are provided, the method may comprise removing tension in the rod after the rod has travelled between the rollers. When a gripper is provided, the method may comprise removing tension in a section of the rod before said section of rod is gripped by the gripper.

The method may include monitoring the tension in the rod from the reel before the tension is removed from the rod (e.g. monitoring the tension in the rod supply system). The method may comprise detecting when the tension in the rod in the supply system drops below a predetermined level. The method may comprise stopping insertion of the rod into the holes of the composite structure if the tension goes below a predetermined tension. The method may comprise shutting down the supply system when the tension drops below a predetermined level.

The composite structure may comprise a plurality of holes. The method may comprise inserting a length of rod into one hole of the composite structure, cropping said length of rod, and inserting a length of rod into another hole of the composite structure from the same reel of rod.

The method may comprise providing a plurality of rods from an array of reels. A rod supply system may provide the plurality of reels. The method may comprise positioning an array for rods in an array of holes in the composite structure. In such a method, a plurality of grippers may be provided. In such a method, the tension removal arrangement may be arranged to remove tension from a plurality of rods or alternatively a plurality of tension removal arrangements may be provided.

The method may further comprise heating a composite structure to a predetermined temperature and forming one or more holes in the composite structure.

The composite structure may be heated to a pre-determined temperature over and/or for a pre-determined time period, the pre-determined temperature and time period being selected such that the gel point of the composite structure is not reached. The composite structure may be heated to a temperature greater than room temperature. The temperature may be selected so as to ease formation of holes in the composite structure.

The one or more holes may be formed by inserting a needle or piercing member into the composite structure. The needle may have a conical shaped tip. The needle may be rotated during insertion into the composite structure.

The composite structure may be a polymeric matrix material. The composite structure may comprise a fibre reinforced resin matrix.

The rod may be made from any suitable reinforcement material, for example carbon, glass, metallic materials, ceramic materials, plastic materials or a composite arrangement of such materials.

The method may comprise cropping the reinforcement rod to a desired length. The reinforcement rod may be cropped to a desired length when the rod is positioned in a hole of the composite structure. The reinforcement rod may be cropped using a shearing mechanism, e.g. by impacting the rod with a plate having a tapered portion.

The method may comprise cropping the reinforcement rod at a position spaced from the surface of the composite structure and tamping the cropped reinforcement rod into the hole of the composite structure such that the cropped rod is flush with the surface of the composite structure.

A guide may be provided to guide the rod in a region between the gripper and the composite structure.

In a second aspect there is provided a method of manufacturing a composite component, the method comprising providing a composite structure and reinforcing the composite structure using the method according to the first or second aspect.

The composite component may be a fan blade for a gas turbine engine.

In a third aspect there is provided a rig for reinforcing a composite structure. The rig comprises a rod insertion device for inserting a reinforcement rod into a hole provided in a composite structure. A rod supply system is provided for supplying rod to the rod insertion device from a reel of rod material.

The rod insertion device may include a gripper for pulling rod from the supply system and directing a predetermined length of the rod into a hole of the composite structure.

The rod supply system may include one or more tensioning systems such that the rod is fed through the supply system in tension. The tensioning system may include a motor. The motor may be configured to drive in a direction opposite to the direction in which the rod is fed through the supply system.

The rig may comprise a tension removal arrangement for removing tension in the rod between the insertion device and the rod supply system.

The tension removal arrangement may include guides arranged to form an unsupported loop of rod between the supply system and the insertion device.

Two or more drive rotors may be provided to guide the rod into the unsupported loop. In alternative embodiments alternative mechanisms may be provided to drive the rod through the system.

The tension removal arrangement may include one or more sensors to detect the amount of rod in the unsupported loop. The rig may further include a control system for increasing the amount of rod in the loop when required.

The rig may comprise a tension monitoring system for monitoring the tension in the rod supply system. The tension monitoring system may be configured to shut down part or the entirety of the rig if the tension goes below a predetermined tension.

The rig of the third aspect may be used in the method of the first and/or second aspect and may have any one or more of the optional features described with reference to the first, second or third aspects.

The skilled person will appreciate that except where mutually exclusive, a feature described in relation to any one of the above aspects of the invention may be applied mutatis mutandis to any other aspect of the invention.

Description of the drawings

Embodiments of the invention will now be described by way of example only, with reference to the Figures, in which: Figure 1 is a sectional side view of a gas turbine engine; Figure 2 is a schematic cross section through a composite structured composite component reinforced with pins; Figure 3 is a schematic of a rig including a rod supply system, a rod insertion device and a tension removal arrangement Figure 4 is a schematic cross section of a needle of a rod insertion device of the rig of Figure 3 forming a hole in a composite structure; Figure 5 is a schematic cross section of a portion of the rod insertion device of Figure 3 positioning a rod in a hole of a composite structure; Figure 6 is a schematic cross section of a foot for pushing a cropped rod into a hole of a composite structure; and Figure 7 is a schematic of the tension removal arrangement of Figure 3.

Detailed Description

With reference to Figure 1, a gas turbine engine is generally indicated at 10, having a principal and rotational axis 11. The engine 10 comprises, in axial flow series, an air intake 12, a propulsive fan 13, an intermediate pressure compressor 14, a high-pressure compressor 15, combustion equipment 16, a high-pressure turbine 17, and intermediate pressure turbine 18, a low-pressure turbine 19 and an exhaust nozzle 20. A nacelle 21 generally surrounds the engine 10 and defines both the intake 12 and the exhaust nozzle 20.

The gas turbine engine 10 works in the conventional manner so that air entering the intake 12 is accelerated by the fan 13 to produce two air flows: a first air flow into the intermediate pressure compressor 14 and a second air flow which passes through a bypass duct 22 to provide propulsive thrust. The intermediate pressure compressor 14 compresses the air flow directed into it before delivering that air to the high pressure compressor 15 where further compression takes place.

The compressed air exhausted from the high-pressure compressor 15 is directed into the combustion equipment 16 where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines 17, 18, 19 before being exhausted through the nozzle 20 to provide additional propulsive thrust. The high 17, intermediate 18 and low 19 pressure turbines drive respectively the high pressure compressor 15, intermediate pressure compressor 14 and fan 13, each by suitable interconnecting shaft.

The fan blades of the fan 14 and/or the casing 24 surrounding the fan may be made from a composite material, for example, plies of a fibre reinforced resin matrix. To improve structural integrity and resist delamination the fan blades and/or casing may need to be reinforced in a direction tangential to plies of a composite structure defining the fan blades or casing. One method of reinforcing a composite component is to pin the component.

A composite component is indicated generally at 26 in Figure 2. The composite component 26 includes a plurality of plies 28 stacked to define a composite structure 30. The composite component is reinforced by rods or pins 32, 32' and 32". The pins extend through the composite component in a direction perpendicular to the direction of the plies. As illustrated in Figure 2, a pin 32 can extend through the entire thickness of the component, or a pin 32', 32" can extend through part of the thickness of the component and the pins may be arranged on the same side or on opposite sides of the component.

A method of forming a component similar to the component 26 will now be described in more detail.

Referring now to Figure 3, a rig for use in reinforcing a composite structure is indicated generally at 60. The rig includes a rod insertion device 64, a rod supply system 62 for supplying rod 38 to the insertion device 64, and a tension removal arrangement 66 for removing tension from the rod 38 between the supply system 62 and the rod insertion device 64.

The rod insertion device 64 and the method of operation of the rod insertion device will now be described in more detail with reference to Figures 4 to 6. In the present example the rod insertion device forms holes in the composite structure, but alternatively the composite structure may be provided with holes formed therein.

In the present example, the composite structure is a laminated structure and is formed by laying plies on top of each other. The method of forming a composite structure is well understood in the art, so will not be described in detail here, but may include laying the plies by hand or forming a ply using tape that may be laid using an automated fibre placement machine.

In the present example, the composite structure is heated to a pre-determined temperature for a pre-determined length of time. The pre-determined temperature and length of time is dependent upon the matrix material of the composite structure, and is selected such that the gel point of the matrix material is not reached so as to avoid curing the composite structure. The gel point can be defined as the start of the cure reaction for the matrix material, i.e. the point at which the molecules of the matrix material begin linking together (or gelling) and the material starts to harden.

The temperature the composite structure is heated to is selected so as to soften the material of the composite structure. Once the material is softened one or more holes are formed in the composite structure. Referring to Figure 4, the rod insertion device is provided with a needle 34. A hole 36 is formed in the composite structure 30 using the needle 34. The needle 34 includes a conical end to ease initial formation of the hole. The needle 34 may be rotated during formation of the hole. The method of heating the composite structure and forming a hole in said composite structure is explained in detail in EP2581201A1 incorporated herein by reference, for example the method is described in detail in paragraphs [0050] to [0064] of EP2581201A1 incorporated herein by reference.

Once a hole 36 is formed in the composite structure 30 a reinforcement rod is inserted into the hole using the arrangement illustrated in Figure 5. As illustrated in Figure 5, the insertion device of the rig includes a gripper 58 for gripping the rod 38 and pulling and directing the rod into the hole 36. The gripper 58 includes two jaws or rollers or other features capable of gripping or pinching the rod. In an example arrangement, the gripper jaws move together to pinch or grip the rod. The jaws then move towards the composite structure so as to direct a desired length of rod into the hole in the composite structure. The jaws are releasable from the rod and returnable to the original position so as to grip and move subsequent portions of rod into the composite structure.

A guide 40, e.g. in the form of a tube, is provided to support and further direct the rod into the hole. Once a desired length of rod is positioned in the hole 36 the rod is cropped. In the present example, the rod is made from fibrous carbon and is cut using a shearing mechanism, but in alternative embodiments the rod may be cut using alternative cutting mechanisms. The insertion device includes a cropper in the form of a plate 42 that has a tapered portion 46. The plate 42 is operable to slide relative to the guide 40 and impact the rod 38 so as to initiate shear.

Referring now to Figure 6, once a cropped rod 50 of a desired length is positioned in the hole 36, the cropped rod (which may be referred to as a pin) 50 is pushed so as to be flush with a surface of the composite structure 30, or to protrude a desired amount from the surface of the structure 30. The insertion device is provided with a foot 52 operable to push the cropped rod (pin) 50 into the hole 36 of the composite structure.

Figures 4 to 6 illustrate the components for insertion of a single rod into a single hole. However, as will be appreciated by the person skilled in the art the described components of the insertion device can be modified or provided in a plurality so that a plurality of rods can be inserted into a plurality of holes in a composite structure at one time.

Referring back to Figure 3, the rod supply system will be explained in more detail. In the supply system shown in Figure 3 four reels 68 are shown (only one labelled), but any number of reels may be provided depending on the number of rods to be inserted by the insertion device 64 at any one time. The reinforcement rod 38 is provided on a reel 68. The reel 68 is arranged to rotate so as to release the rod from the reel. Rollers 70 (only one labelled) associated with each reel are provided to guide the rod 38. In the present example only one or two rollers 70 per reel are shown, but in alternative embodiments any number of rollers may be provided.

A motor 84 is provided. The motor is connected to one or more reels and/or rollers of the feed system. The motor can be configured to drive in a direction reverse to that of the travel of the rod 38 through the feed system so as to tension the rod. For example, the rod may be gripped at one point in the rig 60 and the motor may oppose this gripping force to create a tension T in the rod. As will be described later the rod may be gripped by drive rotors 74 and the motor 84 may be driven to rotate a spool to oppose said drive rotors.

A tension detection device 80 may be provided. The tension detection device monitors a tension T in the rod whilst the rod is in the supply system 62. If the tension in any one of the rods drops below a predetermined tension, the detection device sends a signal to a rig control system 82 to temporarily stop insertion of the rod into the composite structure. In this way, faults in the supply system can be detected and addressed.

The rod 38 is tensioned by a tension T when in the supply system 62. However, when the gripper 58 of the insertion device 64 pulls the rod for insertion into a composite structure, problems can arise in the operation of the rig if the gripper needs to pull a rod in tension. To improve the operation of the rig 60, a tension removal arrangement 66 is provided.

The tension removal arrangement 66 will now be described in more detail with reference to Figure 3 and Figure 7.

The tension removal arrangement is configured to form a loop 72 of rod that is unsupported and substantially free from tension. Rod 38 is fed from the supply system 62 to the loop. When the gripper of the insertion device 64 pulls the rod to direct a portion of the rod into a hole of a composite structure, the gripper pulls rod that is substantially free from tension from the loop 72. In this way, the gripper does not "see" the rod tension T of the supply system.

A series of sensors 76, in this example lasers, are provided to monitor the position of the rod in the loop 72. When the material in the loop drops below a predefined position more rod is fed into the loop.

Two drive rotors 74 are provided to direct the rods to form the loops 72. The drive rotors 74 grip the rod and feed the rod into the loop. Guides may be provided to guide the rod into and out of the loop. The guides may be stationary supports or may be rollers.

The described rig 60 having a rod supply system 62, a rod insertion device 64 and a tension removal arrangement 66 permits the rig to be used to insert reinforcement rods into a plurality of holes, either singularly or in arrays, multiple times, and so can be used in a mass production environment.

It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.

For example, the composite component has been described with reference to a fan blade and/or a fan case of a gas turbine engine, but it will be understood that the method described herein is applicable to any composite component that is reinforced using reinforcing rods.

Claims

Claims 1. A method of reinforcing a fibre reinforced resin matrix composite structure, the method comprising: providing a composite structure having one or more holes formed therein; inserting a reinforcement rod into a hole provided in the composite structure using a rod insertion device; supplying rod to the rod insertion device from a rod supply system that includes a reel of rod material; and removing tension in the reinforcement rod between the rod supply system and the rod insertion device.
2. The method according to claim 1, wherein tension is removed from the rod by feeding the rod from the supply system into an unsupported loop and feeding rod from the unsupported loop to the rod insertion device.
3. The method according to claim 2, comprising detecting the amount of rod in the unsupported loop and increasing the amount of rod in the loop when the length of the loop drops below a predetermined length.
4. The method according to any one of claims 1 to 3, comprising tensioning the rod in the supply system, detecting when the tension in the rod in the supply system drops below a predetermined level, and shutting down the supply system when the tension drops below a predetermined level.
5. The method according to any one of claims 1 to 4, comprising pulling the rod towards the rod insertion device using a gripper.
6. The method according to any one of the previous claims, wherein the composite structure comprises a plurality of holes, and the method includes inserting a length of rod into one hole of the composite structure, cropping said length of rod, and inserting a length of rod into another hole of the composite structure from the same reel of rod.
7. A method of reinforcing a composite structure, the method comprising: providing a composite structure having one or more holes formed therein; inserting a length of reinforcement rod into one or more of the holes of the composite structure; and supplying said reinforcement rod from a reel of rod material.
8. A method of manufacturing a composite component comprising providing a composite structure and reinforcing the composite structure using the method according to any one of the previous claims.
9. The method according to claim 8, wherein the composite component is a fan blade for a gas turbine engine.
10.A rig for reinforcing a composite structure, the rig comprising: a rod insertion device for inserting a reinforcement rod into a hole provided in a composite structure; and a rod supply system for supplying rod to the rod insertion device from a reel of rod material.
11.The rig according to claim 10, wherein the rod insertion device includes a gripper for pulling rod from the supply system and directing a predetermined length of the rod into a hole of the composite structure.
12.The rig according to claim 10 or 11, wherein the rod supply system includes one or more tensioning systems such that the rod is fed through the supply system in tension.
13. The rig according to claim 12 as dependent on claim 11, comprising a tension removal arrangement for removing tension in the rod between the insertion device and the rod supply system.
14. The rig according to claim 13, wherein the tension removal arrangement includes guides arranged to form an unsupported loop of rod between the supply system and the insertion device.
15. The rig according to claim 14, wherein two drive rotors are provided to guide the rod into the unsupported loop.
16.The rig according to claim 14 or 15, wherein the tension removal arrangement includes one or more sensors to detect the amount of rod in the unsupported loop and the rig comprises a control system for receiving signals from the sensors and increasing the amount of rod in the loop when required.
17.The rig according to any one of claims 10 to 16, comprising a tension monitoring system for monitoring the tension in the rod supply system and shutting down the rig if the tension goes below a predetermined tension.
18. A method and/or rig substantially as hereinbefore described with reference to and as shown in the accompanying drawings.