U.S. patent application number 16/375179 was filed with the patent office on 2020-10-08 for monolithic composite blade and platform.
The applicant listed for this patent is General Electric Company. Invention is credited to Gregory Carl Gemeinhardt, Nicholas Joseph Kray, Andreas Mastorakis.
Application Number | 20200318486 16/375179 |
Document ID | / |
Family ID | 1000004626618 |
Filed Date | 2020-10-08 |
United States Patent
Application |
20200318486 |
Kind Code |
A1 |
Gemeinhardt; Gregory Carl ;
et al. |
October 8, 2020 |
Monolithic Composite Blade and Platform
Abstract
A component for a gas turbine engine. The component includes a
continuous fiber blade including an airfoil extending radially
between a root and a tip and a blade attachment feature positioned
at or adjacent to the root. The component further includes a
platform coupled to the root of the continuous fiber blade. The
platform includes a plurality of chopped fibers. Additionally, the
component includes a thermoplastic polymer contained in both the
continuous fiber blade and the platform. Moreover, the continuous
fiber blade and platform are coupled together such that the
continuous fiber blade and platform form a monolithic composite
body.
Inventors: |
Gemeinhardt; Gregory Carl;
(Park Hills, KY) ; Kray; Nicholas Joseph; (Mason,
OH) ; Mastorakis; Andreas; (Corona, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
1000004626618 |
Appl. No.: |
16/375179 |
Filed: |
April 4, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F05D 2230/50 20130101;
F05D 2300/603 20130101; F05D 2300/614 20130101; F01D 5/282
20130101; F05D 2220/32 20130101; F02C 3/04 20130101 |
International
Class: |
F01D 5/28 20060101
F01D005/28; F02C 3/04 20060101 F02C003/04 |
Claims
1. A component for a gas turbine engine, the component comprising:
a continuous fiber blade including an airfoil extending radially
between a root and a tip and a blade attachment feature positioned
at or adjacent to the root; a platform coupled to the root of the
continuous fiber blade, the platform including a plurality of
chopped fibers; and a thermoplastic polymer contained in both the
continuous fiber blade and the platform, wherein the continuous
fiber blade and platform are coupled together such that the
continuous fiber blade and platform form a monolithic composite
body.
2. The component of claim 1, wherein the continuous fiber blade is
formed, at least in part, by molding of a continuous fiber
thermoplastic composite.
3. The component of claim 1, wherein the platform is formed, at
least in part, by at least one of compression molding or injection
molding of the plurality of chopped fibers.
4. The component of claim 3, wherein the platform is coupled to the
continuous fiber blade via injection molding at an interface
between the platform and the continuous fiber blade.
5. The component of claim 3, wherein the platform is coupled to the
continuous fiber blade simultaneously with the molding of the
platform.
6. The component of claim 1, wherein the thermoplastic polymer
includes a bonding layer between the continuous fiber blade and the
platform.
7. The component of claim 1, wherein the continuous fiber blade
defines a pressure side and a suction side, and wherein the
platform is coupled to the pressure side or suction side of the
continuous fiber blade.
8. The component of claim 1, wherein the continuous fiber blade
defines a pressure side and a suction side, and wherein the
platform comprises two platforms, a first platform coupled to the
pressure side of the continuous fiber blade, and a second platform
coupled to the suction side of the continuous fiber blade.
9. The component of claim 1, wherein the platform comprises a split
platform defining a notch such that the continuous fiber blade is
received within the notch and coupled to the split platform at the
notch.
10. The component of claim 1, wherein the thermoplastic polymer
comprises at least one of PEKK, PEEK, PAEK, or PEI.
11. A gas turbine engine defining a centerline, the gas turbine
engine comprising: an engine shaft extending along the centerline;
a compressor attached to the engine shaft and extending radially
about the centerline; a combustor positioned downstream of the
compressor to receive a compressed fluid therefrom; a turbine
mounted on the engine shaft downstream of the combustor to provide
a rotational force to the compressor; and a monolithic composite
component connected to the engine shaft, the monolithic composite
component comprising: a continuous fiber blade including an airfoil
extending radially outward from a root to a tip and a blade
attachment feature positioned at or adjacent to the root; a
platform coupled to the root of the continuous fiber blade, the
platform including a plurality of chopped fibers; and a
thermoplastic polymer contained in both the continuous fiber blade
and the platform, wherein the continuous fiber blade and platform
are coupled together such that the continuous fiber blade and
platform form a monolithic composite body.
12. The gas turbine engine of claim 11, wherein the thermoplastic
polymer includes a bonding layer between the continuous fiber blade
and the platform.
13. The gas turbine engine of claim 11, wherein the continuous
fiber blade defines a pressure side and a suction side, and wherein
the platform is coupled to the pressure side or suction side of the
continuous fiber blade.
14. The gas turbine engine of claim 11, wherein the platform
comprises a split platform defining a notch such that the
continuous fiber blade is received within the notch and coupled to
the split platform at the notch.
15. The gas turbine engine of claim 11, wherein the gas turbine
engine includes a plurality of monolithic composite components,
wherein a portion of the monolithic composite components are
arranged circumferentially about the centerline to form a
stage.
16. The gas turbine engine of claim 15, wherein the platforms of
each of the plurality of monolithic composite components extend at
least partially in a circumferential direction relative to the
centerline, and wherein the platform of at least two adjacent
monolithic composite components of the portion of the monolithic
composite components define a butt joint therebetween in the
circumferential direction.
17. A method of forming a monolithic composite component for a gas
turbine engine, the method comprising: molding a continuous fiber
thermoplastic composite into a continuous fiber blade including an
airfoil extending radially outward from a root to a tip and a blade
attachment feature positioned at or adjacent to the root; forming a
plurality of chopped fibers into a platform containing a
thermoplastic polymer; and coupling the platform to the root of the
continuous fiber blade such that the platform and continuous fiber
blade form the monolithic composite component.
18. The method of claim 17, wherein forming the plurality of
chopped fibers into the platform comprises at least one of
compression molding or injection molding of the chopped fibers.
19. The method of claim 17, wherein coupling the platform to the
root of the continuous fiber blade comprises utilizing injection
molding at an interface between the platform and the continuous
fiber blade.
20. The method of claim 18, wherein coupling the platform to the
root of the continuous fiber blade comprises simultaneously
coupling the platform to the continuous fiber blade while molding
the platform.
Description
FIELD
[0001] The present subject matter relates generally to monolithic
composite components and, more particularly, to monolithic
composite blades and platforms for gas turbine engines.
BACKGROUND
[0002] A gas turbine engine generally includes a fan and a core
arranged in flow communication with one another. Additionally, the
core of the gas turbine engine generally includes, in serial flow
order, a compressor section, a combustion section, a turbine
section, and an exhaust section. In operation, air is provided from
the fan to an inlet of the compressor section where one or more
axial compressors progressively compress the air until it reaches
the combustion section. Fuel is mixed with the compressed air and
burned within the combustion section to provide combustion gases.
The combustion gases are routed from the combustion section to the
turbine section. The flow of combustion gases through the turbine
section drives the turbine section and is then routed through the
exhaust section, e.g., to atmosphere.
[0003] The compressor section of the gas turbine engine typically
includes a number of airfoils or blades attached to a rotor of the
gas turbine engine. Further, the compressor section generally
includes platforms positioned between the airfoils in order to
define an inner boundary for the air provided from the fan section
to the inlet of the compressor. Accordingly, at least some known
gas turbine engines include airfoils and platforms formed
separately and removably coupled together and attached to the rotor
of the gas turbine engine. However, such airfoil-platform
assemblies require additional process steps in order to couple the
airfoils and platforms together, such as secondary bonding or
fastening. Additionally, sealing may be required between the
components of the airfoil-platform assembly. Further, such sealing
may include leaks that reduce the efficiency of the gas turbine
engine.
[0004] As such, there is a need for an airfoil-platform assembly
that enables a reduction in the number of process steps and an
increased efficiency of a gas turbine engine.
BRIEF DESCRIPTION
[0005] Aspects and advantages will be set forth in part in the
following description, or may be obvious from the description, or
may be learned through practice of the invention.
[0006] In one aspect, the present subject matter is directed to a
component for a gas turbine engine. The component includes a
continuous fiber blade including an airfoil extending radially
between a root and a tip and a blade attachment feature positioned
at or adjacent to the root. The component further includes a
platform coupled to the root of the continuous fiber blade. The
platform includes a plurality of chopped fibers. Additionally, the
component includes a thermoplastic polymer contained in both the
continuous fiber blade and the platform. Moreover, the continuous
fiber blade and platform are coupled together such that the
continuous fiber blade and platform form a monolithic composite
body.
[0007] In an additional embodiment, the continuous fiber blade may
define a pressure side and a suction side. Further, the platform
may be coupled to the pressure side or suction side of the
continuous fiber blade. In another embodiment, the platform may
include two platforms. A first platform may be coupled to the
pressure side of the continuous fiber blade, and a second platform
may be coupled to the suction side of the continuous fiber blade.
In another embodiment, the platform may include a split platform
defining a notch such that the continuous fiber blade is received
within the notch and coupled to the split platform at the
notch.
[0008] In another embodiment, the continuous fiber blade may be
formed, at least in part, by molding of a continuous fiber
thermoplastic composite. In a further embodiment, the platform may
be formed, at least in part, by at least one of compression molding
or injection molding of the plurality of chopped fibers. In one
such embodiment, the platform may be coupled to the continuous
fiber blade via injection molding at an interface between the
platform and the continuous fiber blade. In another such
embodiment, the platform may be coupled to the continuous fiber
blade simultaneously with the molding of the platform. In a further
embodiment, the thermoplastic polymer may include a bonding layer
between the continuous fiber blade and the platform. In a still
further embodiment, the thermoplastic polymer may include at least
one of PEKK, PEEK, PAEK, or PEI.
[0009] In another aspect, the present subject matter is directed to
a gas turbine engine defining a centerline. The gas turbine engine
includes an engine shaft extending along the centerline, a
compressor attached to the engine shaft and extending radially
about the centerline, a combustor positioned downstream of the
compressor to receive a compressed fluid therefrom, and a turbine
mounted on the engine shaft downstream of the combustor to provide
a rotational force to the compressor. The gas turbine engine
further includes a monolithic composite component connected to the
engine shaft. The monolithic composite component includes a
continuous fiber blade including an airfoil extending radially
outward from a root to a tip and a blade attachment feature
positioned at or adjacent to the root. The monolithic composite
component further includes a platform coupled to the root of the
continuous fiber blade. The platform includes a plurality of
chopped fibers. Additionally, the monolithic composite component
includes a thermoplastic polymer contained in both the continuous
fiber blade and the platform. Moreover, the continuous fiber blade
and platform are coupled together such that the continuous fiber
blade and platform form a monolithic composite body.
[0010] In one embodiment, the gas turbine engine may include a
plurality of monolithic composite components. In such an
embodiment, a portion of the monolithic composite components may be
arranged circumferentially about the centerline to form a stage. In
one such embodiment, the platforms of each of the plurality of
monolithic composite components may extend at least partially in a
circumferential direction relative to the centerline. Further, the
platform of at least two adjacent monolithic composite components
of the portion of the monolithic composite components may define a
butt joint therebetween in the circumferential direction. It should
be further understood that the gas turbine engine may further
include any of the additional features as described herein.
[0011] In another aspect, the present subject matter is directed to
a method of forming a monolithic composite component for a gas
turbine engine. The method includes molding a continuous fiber
thermoplastic composite into a continuous fiber blade including an
airfoil extending radially outward from a root to a tip and a blade
attachment feature positioned at or adjacent to the root. The
method additionally includes forming a plurality of chopped fibers
into a platform containing a thermoplastic polymer. Further, the
method includes coupling the platform to the root of the continuous
fiber blade such that the platform and continuous fiber blade form
the monolithic composite component.
[0012] In one embodiment, forming the plurality of chopped fibers
into the platform may include at least one of compression molding
or injection molding of the chopped fibers. In another embodiment,
coupling the platform to the root of the continuous fiber blade may
include utilizing injection molding at an interface between the
platform and the continuous fiber blade. In a still further
embodiment, coupling the platform to the root of the continuous
fiber blade may include simultaneously coupling the platform to the
continuous fiber blade while molding the platform. It should be
further understood that the method may further include any of the
additional features as described herein.
[0013] These and other features, aspects and advantages will become
better understood with reference to the following description and
appended claims. The accompanying drawings, which are incorporated
in and constitute a part of this specification, illustrate
embodiments of the invention and, together with the description,
serve to explain certain principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] A full and enabling disclosure of the present invention,
including the best mode thereof, directed to one of ordinary skill
in the art, is set forth in the specification, which makes
reference to the appended FIGS., in which:
[0015] FIG. 1 illustrates a cross-sectional view of one embodiment
of a gas turbine engine that may be utilized within an aircraft in
accordance with aspects of the present subject matter, particularly
illustrating the gas turbine engine configured as a high-bypass
turbofan jet engine;
[0016] FIG. 2 illustrates one embodiment of a monolithic composite
component for a gas turbine engine in accordance with aspects of
the present subject matter, particularly illustrating two
monolithic composite components arranged circumferentially about a
centerline to form a stage;
[0017] FIG. 3 illustrates an exploded perspective view of an
exemplary monolithic composite component in accordance with aspects
of the present subject matter, particularly illustrating the
monolithic composite component including a blade and platforms;
[0018] FIG. 4 illustrates an exploded perspective view of an
alternative exemplary monolithic composite component in accordance
with aspects of the present subject matter, particularly
illustrating a blade and a split platform;
[0019] FIG. 5 illustrates another view of an exemplary monolithic
composite component in accordance with aspects of the present
disclosure, particularly, FIG. 5 illustrates a partially exploded
view of the monolithic composite component where one platform is
separated from a blade while another platform is shown
monolithically formed to the blade; and
[0020] FIG. 6 illustrates a flow diagram of one embodiment of a
method of forming a monolithic composite component for a gas
turbine engine in accordance with aspects of the present
disclosure.
[0021] Repeat use of reference characters in the present
specification and drawings is intended to represent the same or
analogous features or elements of the present invention.
DETAILED DESCRIPTION
[0022] Reference now will be made in detail to embodiments of the
invention, one or more examples of which are illustrated in the
drawings. Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing
from the scope of the invention. For instance, features illustrated
or described as part of one embodiment can be used with another
embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
[0023] As used herein, the terms "first", "second", and "third" may
be used interchangeably to distinguish one component from another
and are not intended to signify location or importance of the
individual components.
[0024] The terms "upstream" and "downstream" refer to the relative
direction with respect to fluid flow in a fluid pathway. For
example, "upstream" refers to the direction from which the fluid
flows, and "downstream" refers to the direction to which the fluid
flows.
[0025] The terms "coupled," "fixed," "attached to," and the like
refer to both direct coupling, fixing, or attaching, as well as
indirect coupling, fixing, or attaching through one or more
intermediate components or features, unless otherwise specified
herein.
[0026] The terms "communicate," "communicating," "communicative,"
and the like refer to both direct communication as well as indirect
communication such as through a memory system or another
intermediary system.
[0027] A monolithic composite component for a gas turbine engine
and associated methods for forming the same are generally provided.
The component may include a continuous fiber blade including an
airfoil extending radially between a root and a tip. The continuous
fiber blade may further include a blade attachment feature
positioned at or adjacent to the root. Additionally, the component
may include one or more platforms coupled to the root of the
continuous fiber blade. The platform(s) may include a plurality of
chopped fibers. Additionally, the component may include a
thermoplastic polymer contained in both the continuous fiber blade
and the platform. The thermoplastic polymer may allow for the
platform(s) containing the chopped fibers to be monolithically
formed to the continuous fiber blade. Moreover, the continuous
fiber blade and platform(s) may be coupled together such that the
continuous fiber blade and platform(s) form a monolithic composite
body. For instance, in certain embodiments, the platform(s) may be
coupled to the blade utilizing injection molding, or the
platform(s) may be formed to the blade during a molding process of
the platform(s). As such, the composite components of the present
disclosure may reduce the process steps involved in assembing
multiple separate parts before or simultaneously with attaching the
component within the gas turbine engine. Further, a monolithic
composite component, as described herein, may reduce the number of
seals required within the engine, potentially increasing the
efficiency of the gas turbine engine. Moreover, the platform(s)
formed from chopped fibers may be more easily formed into complex
shapes desired within the platform(s), while the continuous fibers
of the blade may allow for greater strength to withstand the
aerodynamic loads on the blade.
[0028] Referring now to the drawings, FIG. 1 illustrates a
cross-sectional view of one embodiment of a gas turbine engine 10
that may be utilized within an aircraft in accordance with aspects
of the present subject matter. More particularly, for the
embodiment of FIG. 1, the gas turbine engine 10 is a high-bypass
turbofan jet engine, with the gas turbine engine 10 being shown
having a longitudinal or axial centerline axis 12 extending
therethrough along an axial direction A for reference purposes. The
gas turbine engine 10 further defines a radial direction R
extending perpendicular from the centerline 12. Further, a
circumferential direction C (shown in/out of the page in FIG. 1)
extends perpendicular to both the centerline 12 and the radial
direction R. Although an exemplary turbofan embodiment is shown, it
is anticipated that the present disclosure can be equally
applicable to turbomachinery in general, such as an open rotor, a
turboshaft, turbojet, or a turboprop configuration, including
marine and industrial turbine engines and auxiliary power
units.
[0029] In general, the gas turbine engine 10 includes a core gas
turbine engine (indicated generally by reference character 14) and
a fan section 16 positioned upstream thereof. The core engine 14
generally includes a substantially tubular outer casing 18 that
defines an annular inlet 20. In addition, the outer casing 18 may
further enclose and support a low pressure (LP) compressor 22 for
increasing the pressure of the air that enters the core engine 14
to a first pressure level. A multi-stage, axial-flow high pressure
(HP) compressor 24 may then receive the pressurized air from the LP
compressor 22 and further increase the pressure of such air. The
pressurized air exiting the HP compressor 24 may then flow to a
combustor 26 within which fuel is injected into the flow of
pressurized air, with the resulting mixture being combusted within
the combustor 26. The high energy combustion products 60 are
directed from the combustor 26 along the hot gas path of the gas
turbine engine 10 to a high pressure (HP) turbine 28 for driving
the HP compressor 24 via a high pressure (HP) shaft or spool 30,
and then to a low pressure (LP) turbine 32 for driving the LP
compressor 22 and fan section 16 via a low pressure (LP) drive
shaft or spool 34 that is generally coaxial with HP shaft 30. After
driving each of turbines 28 and 32, the combustion products 60 may
be expelled from the core engine 14 via an exhaust nozzle 36 to
provide propulsive jet thrust.
[0030] Additionally, as shown in FIG. 1, the fan section 16 of the
gas turbine engine 10 generally includes a rotatable, axial-flow
fan rotor 38 configured to be surrounded by an annular fan casing
40. In particular embodiments, the LP shaft 34 may be connected
directly to the fan rotor 38 or rotor disk (not shown), such as in
a direct-drive configuration. In alternative configurations, the LP
shaft 34 may be connected to the fan rotor 38 via a speed reduction
device 37 such as a reduction gear gearbox in an indirect-drive or
geared-drive configuration. Such speed reduction devices may be
included between any suitable shafts/spools within the gas turbine
engine 10 as desired or required. Additionally, the fan rotor 38
and/or rotor disk may be enclosed or formed as part of a fan hub
41.
[0031] It should be appreciated by those of ordinary skill in the
art that the fan casing 40 may be configured to be supported
relative to the core engine 14 by a plurality of substantially
radially-extending, circumferentially-spaced outlet guide vanes 42.
As such, the fan casing 40 may enclose the fan rotor 38 and its
corresponding fan rotor blades (fan blades 44). Moreover, a
downstream section 46 of the fan casing 40 may extend over an outer
portion of the core engine 14 so as to define a secondary, or
by-pass, airflow conduit 48 that provides additional propulsive jet
thrust.
[0032] During operation of the gas turbine engine 10, it should be
appreciated that an initial airflow (indicated by arrow 50) may
enter the gas turbine engine 10 through an associated inlet 52 of
the fan casing 40. The air flow 50 then passes through the fan
blades 44 and splits into a first compressed air flow (indicated by
arrow 54) that moves through the by-pass conduit 48 and a second
compressed air flow (indicated by arrow 56) which enters the LP
compressor 22. The LP compressor 22 may include a plurality of
rotor blades (LP rotor blades 45) enclosed by the outer casing 18.
The pressure of the second compressed air flow 56 is then increased
and enters the HP compressor 24 (as indicated by arrow 58).
Additionally, the HP compressor 24 may include a plurality of rotor
blades (HP rotor blades 47) enclosed by the outer casing 18. After
mixing with fuel and being combusted within the combustor 26, the
combustion products 60 exit the combustor 26 and flow through the
HP turbine 28. Thereafter, the combustion products 60 flow through
the LP turbine 32 and exit the exhaust nozzle 36 to provide thrust
for the gas turbine engine 10.
[0033] Referring now to FIG. 2, one embodiment of a monolithic
composite component 100 for a gas turbine engine 10 is illustrated
in accordance with aspects of the present subject matter. More
particularly, FIG. 2 illustrates two monolithic composite
components 100 arranged circumferentially about the centerline 12
to form a stage 102. It should be appreciated that monolithic, as
used herein, means irreversibly coupled together or formed together
in order to create one indivisible component. Though two monolithic
composite components 100 of the stage 102 are illustrated in FIG. 2
for exemplary purposes, it should be appreciated that the stage 102
may include three or more monolithic composite components 100 such
that the monolithic composite components are equally spaced about
the centerline 12 in the circumferential direction C. Generally, as
illustrated in FIG. 2, the monolithic composite component 100 will
be described as a component of the LP compressor 22 including LP
rotor blade 45 as described generally in reference to FIG. 1.
However, it should be appreciated that the following description
may be equally applicable to any other airfoil or blade of the gas
turbine engine 10, such as a fan blade 44 or an HP rotor blade 47.
In particular embodiments, the monolithic composite component 100
may include one of the first several HP rotor blades 47 of the HP
compressor 24. However, in other embodiments, the monolithic
composite component 100 may include a blade and/or airfoil of the
HP turbine 28 or the LP turbine 32. Further, it should be
appreciated that, in general, the disclosed monolithic composite
component 100 may generally be utilized with any suitable gas
turbine engine having any suitable configuration.
[0034] FIG. 2 additionally illustrates a partial cutaway view of an
example compressor rotor 104 of the LP compressor 22, according to
at least some aspects of the present disclosure, in order to place
the monolithic composite component 100 in an exemplary field of
use. However, the rotor may be one of an HP compressor rotor, HP
turbine rotor, LP turbine rotor, or the fan rotor 38 in another
context. The compressor rotor 104 may include the LP shaft 34,
which may include a generally radially outward facing,
circumferentially oriented shaft attachment feature 106, such as,
but not limited to, a circumferentially oriented dovetail slot 108.
Individual blades 110 may be releasably mounted to LP shaft 34 to
extend radially outward, such as by engagement of a generally
circumferentially oriented blade attachment feature 112 with shaft
attachment feature 106. For example, dovetail slot 108 may be
configured to slidably receive blade attachment feature 112
therein.
[0035] Referring now to FIG. 3, an exploded perspective view of an
example monolithic composite component 100 is illustrated in
accordance with aspects of the present subject matter.
Particularly, FIG. 3 illustrates the blade 110 and platforms 114,
116, according to at least some aspects of the present disclosure.
It should be appreciated that though the blade 110 and platforms
114, 116 are shown separated for illustrative purposes in FIG. 3,
the blade 110 and at least one of the platforms 114, 116 may be
inseperably coupled together to form the monolithic composite
component 100. The blade 110 may include a composite blade panel
118, which may include at least one of an airfoil 120 or blade
attachment feature 112. As described in more detail below in regard
to FIG. 5, the airfoil 120 and/or blade attachment feature 112 may
be a continuous fiber airfoil and a continuous fiber attachment
feature formed together. More particularly, the composite blade
panel 118 may be a continuous fiber composite blade panel formed
integrally. Airfoil 120 may be arranged such that its span 122
extends generally radially outward with respect to the gas turbine
engine 10 centerline 12 (FIGS. 1 and 2) from a root 142 to a tip
144. The blade 110 may define a pressure side 124 and a suction
side 126. More particularly, the airfoil 120 may include at least
one of a pressure side 124 or a suction side 126. Blade attachment
feature 112 may be disposed radially inward from the airfoil 120
with respect to centerline 12 such that the attachment feature 112
is positioned at or adjacent to the root 142 and/or may be
circumferentially oriented with the centerline 12. Further, the
platform(s) 114, 116 may be inseperably coupled to the root 142 of
the blade 110, such as at the blade attachment feature 112.
[0036] Blade attachment feature 112 may be generally shaped as a
dovetail and may include at least one of a neck 128, a forward lobe
130, or an aft lobe 132. Forward lobe 130 and/or aft lobe 132 may
be radially inward from the neck 128 with respect to the centerline
12 (FIG. 1). Blade attachment feature 112 may have a substantially
uniform cross-section in the circumferential direction with respect
to centerline 12. Platform 114 may be disposed generally adjacent
to the pressure side 124. Further, platform 116 may be disposed
generally adjacent to the suction side 126. Alternatively, platform
114 may be disposed generally adjacent to the pressure side 124 and
platform 116 may be disposed generally adjacent to the suction side
126. Platforms 114, 116 may extend generally circumferentially from
blade panel 118 with respect to the centerline 12 (FIG. 1).
Further, the platform(s) 114, 116 may be coupled to the root 142 of
the blade 110 (e.g., monolithically and irreversibly formed to the
blade 110) in order to form a monolithic composite body. As
described in more detail in regard to FIG. 5, the platform(s) 114,
116 may include a plurality of chopped fibers. Platforms 114, 116
may include radially outward facing flowpath surfaces 134, 136,
respectively, each of which may be generally shaped as a segment of
a cylinder. Platforms 114, 116 may include radially inwardly
extending attachment features 138, 140, respectively, which may be
configured to releasably engage shaft attachment feature 106 (FIG.
2). Attachment features 138, 140 of platforms 114, 116 may be
constructed to have substantially the same circumferential
cross-sections as blade attachment feature 112. Further, in one
arrangement, the platform 114 of a first monolithic composite
component 100 may define a butt joint 146 with the platform 116 of
an adjacent monolithic composite component 100 in the
circumferential direction C (see FIG. 2). Moreover, the monolithic
composite components 100 may be in sealing engagement at one or
more butt joints 146 between adjacent monolithic composite
components 100 (e.g., adjacent monolithic composite components 100
in a stage 102).
[0037] Referring now to FIG. 4, an exploded perspective view of an
alternative example of the monolithic composite component 100 is
illustrated in accordance with aspects of the present subject
matter. Particularly, FIG. 4 illustrates the blade 110 and a split
platform 148 according to at least some aspects of the present
disclosure. It should be appreciated that though the blade 110 and
split platform 148 are shown separated for illustrative purposes in
FIG. 4, the blade 110 and the split platform 148 may be inseperably
coupled together to form the monolithic composite component 100.
For instance, the split platform 148 may be inseperably coupled to
the root 142 of the blade 110, such as at the blade attachment
feature 112.
[0038] As shown in FIG. 4, the split platform 148 may extend
generally circumferentially from the blade panel 118 on both the
pressure side 124 and suction side 126 of the blade 110 with
respect to the centerline 12 (FIG. 1). For instance, the split
platform 148 may include radially outward facing pressure side
flowpath surface 150 and suction side flowpath surface 152, each of
which may be generally shaped as a segment of a cylinder. Further,
the pressure and suction side flowpath surfaces 150, 152 may define
a notch 154 therebetween in order to receive the blade 110 and/or
to be formed onto the blade 110. As described in more detail in
regard to FIG. 5, the split platform 148 may include a plurality of
chopped fibers. The split platform 148 may include radially
inwardly extending pressure side attachment feature 156 and suction
side attachment feature 158, each of which may be configured to
releasably engage shaft attachment feature 106 (FIG. 2). Attachment
features 156, 158 of the split platform 148 may be constructed to
have substantially the same circumferential cross-sections as blade
attachment feature 112.
[0039] Referring now to FIG. 5, another view of an exemplary
monolithic composite component 100 is illustrated in accordance
with aspects of the present disclosure. Particularly, FIG. 5
illustrates a partially exploded view where the platform 114 is
separated from the blade 110 while the platform 116 is shown
monolithically formed to the blade 110. Though the monolithic
composite component 100 of FIG. 5 is shown including the platforms
114, 116, in other embodiments the monolithic composite component
100 may include one of the platforms 114, 116, or any other
suitable platform, such as split platform 148 of FIG. 4. As shown,
the blade 110 and/or the blade attachment feature 112 may include a
plurality of continuous fibers 160 (several of which are shown for
illustrative purposes). For instance, one or more of the continuous
fibers 160 may extend from the root 142 to the tip 144. As such,
blade 110 may be a continuous fiber blade including a continuous
fiber blade panel 118. As additionally shown in FIG. 5, the
platforms 114, 116 may include a plurality of chopped fibers 162
(several of which are shown for illustrative purposes). As further
explained below, the monolithic composite component 100 may include
a thermoplastic polymer 164 in both the continuous fiber blade 110
and the chopped fiber platforms 114, 116.
[0040] Composite materials generally comprise a fibrous
reinforcement material embedded in matrix material, such as polymer
or ceramic material. The reinforcement material serves as a
load-bearing constituent of the composite material, while the
matrix of a composite material serves to bind the fibers together,
and also acts as the medium by which an externally applied stress
is transmitted and distributed to the fibers. Many polymer matrix
composite (PMC) materials are fabricated with the use of prepreg,
which is a fabric or unidirectional tape that is impregnated with
resin. Multiple layers of prepreg are stacked to the proper
thickness and orientation for the part, and then the resin is cured
and solidified to render a fiber reinforced composite part. Resins
for matrix materials of PMCs can be generally classified as
thermosets or thermoplastics. Thermoplastic resins are generally
categorized as polymers that can be repeatedly softened and flowed
when heated and hardened when sufficiently cooled due to physical
rather than chemical changes. Notable example classes of
thermoplastic resins include nylons, thermoplastic polyesters,
polyaryletherketones, and polycarbonate resins. Specific example of
high performance thermoplastic resins that have been contemplated
for use in aerospace applications include, polyetheretherketone
(PEEK), polyetherketoneketone (PEKK), polyetherimide (PEI),
polyaryletherketone (PAEK), and polyphenylene sulfide (PPS). In
contrast, once fully cured into a hard rigid solid, thermoset
resins do not undergo significant softening when heated, but
instead thermally decompose when sufficiently heated. Notable
examples of thermoset resins include epoxy, bismaleimide (BMI), and
polyimide resins.
[0041] A variety of fibrous reinforcement materials have been used
in PMCs, for example, carbon (e.g., AS4), glass (e.g., S2), polymer
(e.g., Kevlar.RTM.), ceramic (e.g. Nextel.RTM.) and metal fibers.
Fibrous reinforcement materials can be used in the form of
relatively short chopped fibers, generally less than two inches in
length, and more preferably less than one inch, or long continuous
fibers, the latter of which are often used to produce a woven
fabric or unidirectional tape. PMC materials can be produced by
dispersing dry fibers into a mold, and then flowing matrix material
around the reinforcement fibers, or by using prepreg as previously
described.
[0042] Another complication is the type of reinforcement system
required by PMC materials in aircraft engine applications.
Generally, to achieve the mechanical properties required for
aircraft engine applications, parts would require the use of
continuous fiber-reinforced PMC materials to achieve the high
performance mechanical requirements (particularly strength and
fatigue properties) dictated by aircraft engine applications (e.g.,
blades 110). However, the manufacturing processes involved in the
fabrication of continuous fiber reinforcement composite parts
further complicate the ability to produce structures that have
complex shapes. On the other hand, chopped fiber reinforcement
systems, whether in a thermoplastic or thermoset resin matrix, are
not ideal solutions for highly loaded parts due to their lower
mechanical performance. However, it is possible to fabricate
complex-shaped parts with chopped fiber material solutions with
net-shaped molding methods, and therefore these material systems
can be used for lightly-loaded secondary structures and
non-structural engine components (e.g., the platforms 114, 116, and
148).
[0043] As engine performance continues to be pushed to limits, it
is desirable to have parts of complex geometries that are capable
of being highly loaded to aid or improve such performance. Many
times, these complex geometries are non-structural features that
help with, for example, aerodynamic performance. Therefore, taking
a hybrid approach, a monolithic part is provided with hybrid fiber
reinforcement to achieve structural loading yet providing for the
complex shaped (lightly loaded) features, for example
aero-features.
[0044] Referring back to the exemplary embodiment of FIG. 5,
thermoplastic polymer 164 may include a bonding layer 166 between
the continuous fiber blade 110 and the platform(s) 114, 116 (only
one bonding layer 166 is shown for clarity). In certain
embodiments, the thermoplastic polymer 164 may include one or more
of PEKK, PEEK, PAEK, or PEI. In certain embodiments, thermoplastic
polymer 164 may be the same within the blade 110 and platform(s)
114, 116 in order to reduce thermal gradients within the parts of
the monolithic composite component 100.
[0045] Further, in one embodiment, the continuous fiber blade 110
may be formed, at least in part, by molding of a continuous fiber
thermoplastic composite. For instance, the continuous fiber blade
110 may be constructed by laying up continuous fiber portions that
are in a fabric, unidirectional tape, or braided architecture and
the thermoplastic polymer 164 within a mold to define the
aerodynamic profile of the blade 110. Further, the continuous fiber
blade 110 may be formed of, for non-limiting examples,
unidirectional prepreg, woven fabric prepreg, a braided prepreg, or
a dry reinforcement fiber with filaments or fibers of thermoplastic
polymer. Additionally, the platform 114, 116, 148 may be formed, at
least in part, by at least one of compression molding or injection
molding of the plurality of chopped fibers 162. In at least some
embodiments, the chopped fibers 162 may be included in
unidirectional tape that has been chopped to a short fiber length.
The thermoplastic polymer 164 used in the chopped fiber
unidirectional tape may be the same thermoplastic polymer 164 that
is used in the continuous fiber blade 110. The use of the same
thermoplastic polymer 164 within the blade 110 and platforms 114,
116, 148 may allow the component to be fabricated as the monolithic
composite component 100 as depicted herein.
[0046] For example, the continuous fiber material may be continuous
fibers 160 of individual fibers or fiber tows arranged parallel
(unidirectional) with the matrix material, or individual fibers or
fiber tows arranged to have multiple different orientations (e.g.,
multiple layers of unidirectional fibers or fiber tows to form
bi-axial or tri-axial architecture) within the matrix material, or
individual fibers or fiber tows, woven to form a mesh or fabric
within the matrix material. The fibers, tows, braids, meshes, or
fabrics can be arranged to define a single ply within the PMC or
any suitable number of plies. Particularly suitable continuous
fiber reinforcement materials include carbon, glass polymer,
ceramic, and metal fibers.
[0047] According to one embodiment, the PMC material is defined in
part by prepreg, which is a reinforcement material preimpregnated
with a matrix material, such as thermoplastic resin desired for the
matrix material. Non-limiting examples of processes for producing
thermoplastic prepregs include hot melt prepregging in which the
fiber reinforcement material is drawn through the molten bath of
resin and powder prepregging in which a resin is deposited onto the
fiber reinforcement material (for example electrostatically) and
then adhered to the fiber (for example, in an oven or with the
assistance of heated rollers). The prepregs can be in the form of
unidirectional tapes or woven fabrics, which are then stacked on
top of one another to create the number of stacked plies desired
for the part. According to an alternative option, instead of using
a prepreg, with the use of thermoplastic polymers it is possible to
have a woven fabric that has, for example, dry carbon fiber woven
together with thermoplastic polymer fibers or filaments.
Non-prepreg braided architectures can be made in a similar fashion.
With this approach, it is possible to tailor the fiber volume of
the part by dictating the relative concentrations of the
thermoplastic fibers and reinforcement fibers that have been woven
or braided together. Additionally, different types of reinforcement
fibers can be braided or woven together in various concentrations
to tailor the properties of the part. For example, glass fiber,
carbon fiber, and thermoplastic fiber could all be woven together
in various concentrations to tailor the properties of the part. The
carbon fiber provides the strength of the system, the glass may be
incorporated to enhance the impact properties, which is a design
characteristic for parts located near the inlet of the engine, and
the thermoplastic fibers are the matrix that will be flowed to bind
the reinforcement fibers.
[0048] The ply stack may next undergo a consolidation operation, in
which heat and pressure are applied to the ply stack to flow the
resin and consolidate the ply stack into the part. In addition to
creating parts using prepreg, an alternative approach is to lay-up
dry fabric in a suitably shaped mold cavity and then infuse the dry
fabric with molten resin. For instance, PMC materials can be
produced by dispersing dry fibers into a mold, and then flowing
matrix material around the reinforcement fibers.
[0049] According to the instant embodiment, the continuous fiber
blade 110 or chopped fiber platform(s) 114, 116, 148 may be loaded
into compression molds. Within these molds may be cavities
corresponding to the shape of blade 110 or platform 114, 116, 148
respectively. Additionally, the platform(s) 114, 116, 148 may be
coupled to the continuous fiber blade 110 via injection molding at
an interface 168 between the continuous fiber blade 110 and the
platform(s) 114, 116, 148 in order to form the bonding layer 166
and the monolithic composite component 100 as shown in FIG. 5. In
another embodiment, the platform(s) 114, 116, 148 may be coupled to
the continuous fiber blade 110 simultaneously with the molding of
the platform(s) 114, 116, 148. For instance, the platform(s) 114,
116, 148 may be directly molded onto the continuous fiber blade 110
as to form the bonding layer(s) 166 at the interface(s) 168 of
monolithic composite component 100.
[0050] Referring now to FIG. 6, a flow diagram of one embodiment of
a method 200 of forming a monolithic composite component for a gas
turbine engine is illustrated in accordance with aspects of the
present disclosure. In general, the method 200 will be described
herein with reference to the gas turbine engine 10 and monolithic
composite component 100 described above in reference to FIGS. 1-5.
However, it should be appreciated by those of ordinary skill in the
art that the disclosed method 200 may generally be utilized to form
any suitable monolithic composite component in connection with any
gas turbine engine having any suitable configuration. In addition,
although FIG. 6 depicts steps performed in a particular order for
purposes of illustration and discussion, the methods discussed
herein are not limited to any particular order or arrangement. One
skilled in the art, using the disclosures provided herein, will
appreciate that various steps of the methods disclosed herein can
be omitted, rearranged, combined, and/or adapted in various ways
without deviating from the scope of the present disclosure.
[0051] As depicted in FIG. 6, the method 200 may include (202)
molding a continuous fiber thermoplastic composite into the
continuous fiber blade 110 including the airfoil 120 extending
radially outward from the root 142 to the tip 144 and the blade
attachment feature 112 positioned at or adjacent to the root 142.
The method 200 may additionally include (204) forming a plurality
of chopped fibers 162 into the platform (e.g., any of the platforms
114, 116, 148) containing the thermoplastic polymer 164. In one
embodiment, forming the plurality of chopped fibers 162 into the
platform may include at least one of compression molding or
injection molding of the chopped fibers 162.
[0052] Further, the method 200 may include (206) coupling the
platform to the root 142 of the continuous fiber blade 110 such
that the platform and continuous fiber blade 110 form the
monolithic composite component 100. In one particular embodiment,
coupling the platform to the root 142 of the continuous fiber blade
110 may include utilizing injection molding at the interface 168
between the platform and the continuous fiber blade 110. In an
additional and/or alternative embodiment, coupling the platform to
the root 142 of the continuous fiber blade 110 may include
simultaneously coupling the platform to the continuous fiber blade
110 while molding the platform.
[0053] This written description uses exemplary embodiments to
disclose the invention, including the best mode, and also to enable
any person skilled in the art to practice the invention, including
making and using any devices or systems and performing any
incorporated methods. The patentable scope of the invention is
defined by the claims, and may include other examples that occur to
those skilled in the art. Such other examples are intended to be
within the scope of the claims if they include structural elements
that do not differ from the literal language of the claims, or if
they include equivalent structural elements with insubstantial
differences from the literal languages of the claims.
* * * * *