# US 11,028,696 B2 · Ceramic matrix composite airfoil repair

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- Number: US 11,028,696 B2
- Document ID: US11028696B2
- Status: Granted
- Kind: B2
- Application number: 15/670,151
- Filed: 2017-08-07
- Published: 2019-02-07
- Granted: 2021-06-08
- Earliest claimed: 2017-08-07
- Assignees: General Electric Company
- Applicants: General Electric Company
- Inventors: Herbert Chidsey Roberts; Glenn Curtis Taxacher
- Web page: https://patentgrep.com/patent/US11028696B2

## CPC

- F01D 5/005: {Repairing methods or devices}
- F01D 5/147: {Construction, i.e. structural features, e.g. of weight-saving hollow blades (F01D5/148, F01D5/16 and F01D5/20 take precedence; blade shape F01D5/141; blades with cooling or heating channels or cavities F01D5/18; heating, heat-insulating or cooling means on blades F01D5/18)}
- F01D 5/282: {Selecting composite materials, e.g. blades with reinforcing filaments}
- F01D 5/284: {Selection of ceramic materials}
- B23P 6/005: {using only replacement pieces of a particular form}
- B29C 73/04: using preformed elements
- F05D 2230/10: by removing material
- F05D 2230/23: by permanently joining parts together
- F05D 2230/80: Repairing, retrofitting or upgrading methods
- F05D 2240/10: Stators
- F05D 2240/24: for turbines
- F05D 2260/36: by a form fit connection, e.g. by interlocking
- F05D 2300/6033: Ceramic matrix composites [CMC]
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- B23P: METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS (arrangements for copying or controlling B23Q)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

Methods for repairing composite components are provided. For instance, one exemplary method includes machining an interlocking feature into an existing component. A replacement material or core having an interlocking feature complementary to the interlocking feature of the existing component is then joined with the component. The interlocking features interlock to form a joint. The joint is then overlaid with one or more plies to rebuild the outer surface of the component and seal the joint. A bonding process can be used to chemically bond the newly joined parts together. Repaired composite components are also provided.

## Claims

### Claim 1

A method for repairing a component having a damaged region, the component formed from a composite material and defining a span length that extends from a first end of the component to a second end of the component, and a reference line that is defined midway between the first end and the second end, the damaged region being closer to the second end than the first end, wherein the component is an airfoil for use in a gas turbine engine, the method comprising:
joining a replacement material with the component, the replacement material having a tip end, a connection end, a leading edge, and a trailing edge, wherein the component comprises an interlocking feature and the connection end of the replacement material comprises an interlocking feature complementary to the interlocking feature of the component, wherein when the replacement material is joined with the component, the interlocking features of the replacement material and the component interlock to form a joint that defines a joint width and a joint length, the joint width being perpendicular to the joint length and the joint length spanning a width of the component;
overlaying the joint with a plurality of plies, wherein overlaying the joint comprises laying a first ply over the joint on a pressure side of the airfoil and laying a second ply over the joint on a suction side of the airfoil; and
bonding the component with the replacement material and bonding the plurality of plies with the component and the replacement material;
wherein the joint is only between the reference line and the first end of the component;
wherein the first ply extends beyond the leading edge of the replacement material;
wherein overlaying the joint with a plurality of plies comprises laying one or more ply layers on the pressure side of the airfoil and laying one or more ply layers on the suction side of the airfoil, wherein the number of ply layers on the pressure side of the airfoil does not equal the number of ply layers on the suction side of the airfoil.

### Claim 2 (depends on 1)

The method of claim 1, wherein at least one of the plurality of plies extends from a center of the joint width in a first direction a distance equal to the joint width and extends from the center of the joint width in a second direction a distance equal to the joint width, the first direction opposite the second direction.

### Claim 3 (depends on 1)

The method of claim 1, wherein the component is formed from a polymer matrix composite (PMC) material.

### Claim 4 (depends on 1)

The method of claim 1, wherein the interlocking feature of the component is one or more dovetails and the interlocking feature of the replacement material is one or more dovetails.

### Claim 5 (depends on 1)

The method of claim 1, wherein the interlocking feature of the component and the interlocking feature of the replacement material are configured to counteract tensile forces.

### Claim 6 (depends on 1)

The method of claim 1, wherein the interlocking feature of the component and the interlocking feature of the replacement material are configured to counteract shear forces.

### Claim 7 (depends on 1)

The method of claim 1, wherein the step of bonding comprises inserting the component, the replacement material, and the plurality of plies in an autoclave to cause the component to chemically bond with the replacement material and the plurality of plies to chemically bond with the component and the replacement material.

### Claim 8 (depends on 1)

The method of claim 1, wherein the first ply mates with the second ply.

### Claim 9 (depends on 1)

The method of claim 1, wherein at least one of the plurality of plies has a different length than another one of the plurality of plies.

### Claim 10 (depends on 1)

The method of claim 1, further comprising machining the component and the replacement material after boding the component with the replacement material.