U.S. patent application number 13/728880 was filed with the patent office on 2014-07-03 for hybrid continuous fiber chopped fiber polymer composite structure.
This patent application is currently assigned to General Electric Company. The applicant listed for this patent is GENERAL ELECTRIC COMPANY. Invention is credited to James Michael Kostka.
Application Number | 20140186166 13/728880 |
Document ID | / |
Family ID | 51017391 |
Filed Date | 2014-07-03 |
United States Patent
Application |
20140186166 |
Kind Code |
A1 |
Kostka; James Michael |
July 3, 2014 |
Hybrid Continuous Fiber Chopped Fiber Polymer Composite
Structure
Abstract
An engine component having a monolithic composite body, the body
having a continuous fiber portion, a chopped fiber portion, a
thermoplastic polymer contained in both the continuous fiber
portion and the chopped fiber portion and between the continuous
and chopped fiber portions.
Inventors: |
Kostka; James Michael;
(Mason, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GENERAL ELECTRIC COMPANY |
Schenectady |
NY |
US |
|
|
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
51017391 |
Appl. No.: |
13/728880 |
Filed: |
December 27, 2012 |
Current U.S.
Class: |
415/182.1 |
Current CPC
Class: |
B32B 2262/02 20130101;
B29L 2031/7504 20130101; B64C 11/14 20130101; B32B 2262/0276
20130101; B32B 2262/106 20130101; F01D 5/143 20130101; F05D
2250/232 20130101; B29C 70/081 20130101; Y02T 50/672 20130101; B32B
5/26 20130101; B32B 5/024 20130101; B32B 2605/18 20130101; B32B
2262/101 20130101; B32B 2260/021 20130101; B32B 2307/546 20130101;
B32B 2307/558 20130101; B32B 2307/544 20130101; Y02T 50/60
20130101; F05D 2300/603 20130101; B32B 2260/046 20130101; F01D
5/146 20130101; F01D 5/282 20130101; B32B 2307/542 20130101; Y02T
50/673 20130101 |
Class at
Publication: |
415/182.1 |
International
Class: |
F01D 25/00 20060101
F01D025/00 |
Claims
1. An aircraft engine component, comprising: a monolithic composite
body; said body having: a continuous fiber portion; a chopped fiber
portion; a thermoplastic polymer contained in both said continuous
fiber portion and said chopped fiber portion and between said
continuous and chopped fiber portions.
2. The aircraft engine component of claim 1, wherein said
thermoplastic polymer is one of PEEK, PPS, PEKK, and PEI.
3. The aircraft engine component of claim 1, wherein the fiber is
one of carbon fiber, glass fiber and a mixture of said carbon fiber
and said glass fiber.
4. The aircraft engine component of claim 1, wherein said
continuous fiber is one a braid, woven fiber and a unidirectional
tape.
5. The aircraft engine component of claim 1, wherein said chopped
fiber constituent is formed of a unidirectional preimpregnated
tape.
6. The aircraft engine component of claim 5, wherein said chopped
fiber length is less than one inch (1'').
7. The aircraft engine component of claim 1 further comprising one
or more co-molded metallic features.
8. The aircraft engine component of claim 7, said co-molded
metallic features being one of a flange, bushing and threaded
insert.
9. The aircraft engine component of claim 1, said continuous fiber
of said composite body carrying a hoop load.
10. The aircraft engine component of claim 1, wherein said
continuous fiber is a braided preform that contains at least one of
fibers of carbon, glass and thermoplastic.
11. The aircraft engine component of claim 10 wherein said at least
one of fibers is dry carbon fiber and thermoplastic fiber.
12. The aircraft engine component of claim 10 wherein said at least
one of fibers is dry carbon fiber, glass fiber and thermoplastic
fiber.
13. The aircraft engine component of claim 1, wherein said chopped
fiber portion fails to carry a structural load.
14. The aircraft engine component of claim 1, wherein said chopped
fiber portion is adjacent to an engine air flowpath.
15. The aircraft engine component of claim 14 further comprising an
erosion protection layer on an outermost surface of said chopped
fiber portion.
16. The aircraft engine component of claim 1, said component being
a rotating part.
17. The aircraft engine component of claim 16, said rotating part
being a spinner nose cone.
18. The aircraft engine component of claim 16, said rotating part
being a spinner support ring.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] None
BACKGROUND
[0002] The disclosed embodiments generally pertain to aircraft
engine parts.
[0003] More particularly, but not by way of limitation, present
embodiments relate to aircraft engine parts formed of hybrid
composite materials to form more complicated geometries.
[0004] A typical gas turbine engine generally possesses a forward
end and an aft end with its several core or propulsion components
positioned axially therebetween. An air inlet or intake is at a
forward end of the engine. Moving toward the aft end, in order, the
intake is followed by a compressor, a combustion chamber, a
turbine, and a nozzle at the aft end of the engine. It will be
readily apparent from those skilled in the art that additional
components may also be included in the engine, such as, for
example, low-pressure and high-pressure compressors, and
high-pressure and low-pressure turbines. This, however, is not an
exhaustive list. An engine also typically has an internal shaft
axially disposed along a center longitudinal axis of the engine.
The internal shaft is connected to both the turbine and the air
compressor, such that the turbine provides a rotational input to
the air compressor to drive the compressor blades.
[0005] In operation, air is pressurized in a compressor and mixed
with fuel in a combustor for generating hot combustion gases which
flow downstream through turbine stages. These turbine stages
extract energy from the combustion gases. A high pressure turbine
first receives the hot combustion gases from the combustor and
includes a stator nozzle assembly directing the combustion gases
downstream through a row of high pressure turbine rotor blades
extending radially outwardly from a supporting rotor disk. In a two
stage turbine, a second stage stator nozzle assembly is positioned
downstream of the first stage blades followed in turn by a row of
second stage rotor blades extending radially outwardly from a
second supporting rotor disk. The turbine converts the combustion
gas energy to mechanical energy.
[0006] It is always desirable to reduce the weight of a gas turbine
engine utilized in the aviation industry. Such weight reduction
results in higher efficiency of the engine, which reduces costs for
operators. In attempting to reach this goal, designers have turned
to alternative materials in producing parts. In areas where
temperatures are reduced, engine designers have attempted to
utilize parts formed of polymer composite materials. This has led
to at least two design issues to overcome.
[0007] First, designers desire to create parts or components that
can withstand the rigors of high speed aircraft engine operation.
Second, designers are limited by the shape and geometry of the
parts being created, as related to strength and performance
requirements for those parts. Complicated geometries are difficult
to create from composites that have continuous fiber reinforcement,
which is required for higher strength applications. In sum, it is
difficult to manufacture aircraft engine composite components
having high loading capabilities and complex shapes.
[0008] As may be seen by the foregoing, it would be desirable to
overcome these and other deficiencies with gas turbine engines
components.
SUMMARY
[0009] According to present aspects, a hybrid composite
architecture is disclosed which enables the design and
manufacturing of high-performance monolithic structural parts that
have complex secondary features. Notable, but non-limiting,
examples of such include spinner cones and aft support rings,
although various other parts may be formed.
[0010] According to still other aspects of this disclosure, an
engine component may be produced which exhibits mechanical,
chemical and thermal properties (including strength, fatigue
resistance, maximum temperature capability and chemical/fluid
resistance) suitable for use in aircraft applications.
[0011] According to still other aspects of the disclosure, polymer
composite aircraft parts may be formed being constructed of first
portions formed of continuous fiber reinforcement and second
portions formed of chopped fibers.
[0012] According to at least some embodiments, an aircraft engine
component, comprises a monolithic composite body, the body having a
continuous fiber portion, a chopped fiber portion, a thermoplastic
polymer contained in both the continuous fiber portion and the
chopped fiber portion and between the continuous and chopped fiber
portions. The aircraft engine component wherein the thermoplastic
polymer is one of PEEK, PPS, PEKK, and PEI. The aircraft engine
component wherein the fiber is one of carbon fiber, glass fiber and
a mixture of the carbon fiber and said glass fiber. The aircraft
engine component wherein the continuous fiber is one a braid, woven
fiber and a unidirectional tape. The aircraft engine component
wherein the chopped fiber constituent is formed of a unidirectional
preimpregnated tape. The aircraft engine component wherein the
chopped fiber length is less than one inch (1''). The aircraft
engine component further comprising one or more co-molded metallic
features. The aircraft engine component wherein the co-molded
metallic features are one of a flange, bushing and threaded insert.
The aircraft engine component wherein the continuous fiber of the
composite body carries a hoop load. The aircraft engine component
wherein the continuous fiber is a braided preform that contains at
least one of fibers of carbon, glass and thermoplastic. The
aircraft engine component wherein the at least one of fibers is dry
carbon fiber and thermoplastic fiber. The aircraft engine component
wherein the at least one of fibers is dry carbon fiber, glass fiber
and thermoplastic fiber. The aircraft engine component wherein the
chopped fiber portion fails to carry a structural load. The
aircraft engine component wherein the chopped fiber portion is
adjacent to an engine air flowpath. The aircraft engine component
further comprising an erosion protection layer on an outermost
surface of said chopped fiber portion. The aircraft engine
component wherein the component is a rotating part. The aircraft
engine component wherein the rotating part is a spinner nose cone.
The aircraft engine component wherein the rotating part being a
spinner support ring.
[0013] All of the above outlined features are to be understood as
exemplary only and many more features and objectives of the
invention may be gleaned from the disclosure herein. Therefore, no
limiting interpretation of this summary is to be understood without
further reading of the entire specification, claims, and drawings
included herewith.
BRIEF DESCRIPTION OF THE ILLUSTRATIONS
[0014] Embodiments of the invention are illustrated in the
following illustrations.
[0015] FIG. 1 is a side section view of a gas turbine engine.
[0016] FIG. 2 is an isometric view of an exemplary composite
component.
[0017] FIG. 3 is an isometric view of a second exemplary composite
component.
[0018] FIG. 4 is a side section of the exemplary embodimentn
including the component of FIG. 3.
[0019] FIG. 5 is a sectional view of the aerodynamic feature of the
component of FIG. 4.
DETAILED DESCRIPTION
[0020] Reference now will be made in detail to embodiments
provided, one or more examples of which are illustrated in the
drawings. Each example is provided by way of explanation, not
limitation of the disclosed embodiments. In fact, it will be
apparent to those skilled in the art that various modifications and
variations can be made in the present embodiments without departing
from the scope or spirit of the disclosure. For instance, features
illustrated or described as part of one embodiment can be used with
another embodiment to still yield further embodiments. 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.
[0021] Referring to FIGS. 1-5 various embodiments of structures
constructed of polymer matrix composite (PMC) materials and
processes are taught. More specifically, hybrid continuous
fiber-chopped fiber polymer composite structures for aircraft
engine applications are shown and described capable of use in a
wide range of applications, for example, aircraft engine
components, and more particularly, fan areas and by-pass portions
of gas turbine engines. The hybrid polymer composite structures are
suitable for use in a variety of locations and according to the
non-limiting examples are utilized in areas wherein temperatures
and loading requirements may be met through the use of the
composite structures. The hybrid polymer composite structures are
monolithic and may be formed of both continuous and chopped fibers
wherein the continuous fibers may be laid for shapes which are of
more simple geometric shape while more complicated geometries, not
readily formable with continuous fiber composites, are formed with
the chopped fiber composites. The term monolithic is utilized to
mean that the same polymer is used in the continuous fiber
reinforced section(s) and the chopped fiber reinforced section(s).
As a result, the two fiber types are joined by polymers common to
both fiber types, for example thermoplastic resin.
[0022] As used herein, the terms "axial" or "axially" refer to a
dimension along a longitudinal axis of an engine. The term
"forward" used in conjunction with "axial" or "axially" refers to
moving in a direction toward the engine inlet, or a component being
relatively closer to the engine inlet as compared to another
component. The term "aft" used in conjunction with "axial" or
"axially" refers to moving in a direction toward the engine nozzle,
or a component being relatively closer to the engine nozzle as
compared to another component.
[0023] As used herein, the terms "radial" or "radially" refer to a
dimension extending between a center longitudinal axis of the
engine and an outer engine circumference. The use of the terms
"proximal" or "proximally," either by themselves or in conjunction
with the terms "radial" or "radially," refers to moving in a
direction toward the center longitudinal axis, or a component being
relatively closer to the center longitudinal axis as compared to
another component. The use of the terms "distal" or "distally,"
either by themselves or in conjunction with the terms "radial" or
"radially," refers to moving in a direction toward the outer engine
circumference, or a component being relatively closer to the outer
engine circumference as compared to another component.
[0024] As used herein, the terms "lateral" or "laterally" refer to
a dimension that is perpendicular to both the axial and radial
dimensions.
[0025] Referring initially to FIG. 1, a schematic side section view
of a gas turbine engine 10 is shown having an engine inlet end 12
wherein air enters the propulsor 13 which is defined generally by a
compressor 14, a combustor 16 and a multi-stage high pressure
turbine 20. Collectively, the propulsor 13 provides thrust or power
during operation. The gas turbine 10 may be used for aviation,
power generation, industrial, marine or the like.
[0026] In operation air enters through the air inlet end 12 of the
engine 10 and moves through at least one stage of compression where
the air pressure is increased and directed to the combustor 16. The
compressed air is mixed with fuel and burned providing the hot
combustion gas which exits the combustor 16 toward the high
pressure turbine 20. At the high pressure turbine 20, energy is
extracted from the hot combustion gas causing rotation of turbine
blades which in turn cause rotation of the shaft 24. The shaft 24
passes toward the front of the engine to continue rotation of the
one or more compressor stages 14, a turbofan 18 or inlet fan
blades, depending on the turbine design. The turbofan 18 is
connected by the shaft 28 to a low pressure turbine 21 and creates
thrust for the turbine engine 10. A low pressure turbine 21 may
also be utilized to extract further energy and power additional
compressor stages. The low pressure air may be used to aid in
cooling components of the engine as well.
[0027] The gas turbine 10 is axis-symmetrical about engine axis 26
or shaft 24 so that various engine components rotate thereabout.
The axis-symmetrical shaft 24 extends through the turbine engine
forward end into an aft end and is journaled by bearings along the
length of the shaft structure. The shaft rotates about a centerline
26 of the engine 10. The shaft 24 may be hollow to allow rotation
of a low pressure turbine shaft 28 therein and independent of the
shaft 24 rotation. Shafts 28 also may rotate about the centerline
axis 26 of the engine. During operation the shaft 28 rotates along
with other structures connected to the shaft such as the rotor
assemblies of the turbine in order to create power or thrust for
various types of turbines used in power and industrial or aviation
areas of use.
[0028] At the forward end 12 of the engine 10, forward of the turbo
fan blades 18 is a nose cone, also referred to as a spinner 30. The
spinner 30 is generally attached to a fan hub in a variety of
fashions including but not limited to a number of circumferentially
spaced bolts. The spinner 30 is utilized to provide a smooth flow
of air to the core or radially inner portions of the fan 18.
Smoothing of the airflow increases efficiency of the engine 10 and
therefore improves performance not only of the fan 18, but of
downstream components as well. For example, the spinner 30 shape
may reduce drag, correct velocity profile into the core, reduce
turbulence into the core, as well as provide a means for shedding
ice and/or deflect foreign objects toward the fan/bypass ducts
rather than allowing passage through the core, which can damage
engine components. The parts or components such as the spinner 30
and aft support ring 50 of the instant disclosure are formed of
hybrid polymer matrix composites, wherein a first portion is formed
of a first fiber type and a second portion is formed of a second
fiber type. One of the first fiber type and second fiber type is
used to form less complex shapes that have higher loading while the
other of the first and second fiber types is used to form more
complex shapes that have lighter loading. Despite the two fiber
types, the aircraft components being formed are monolithic.
[0029] 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 reinforeced 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
thermosplastic 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) 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.
[0030] 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.
[0031] Whether a PMC material is suitable for a given application
depends on its matrix and reinforcement materials, the requirements
of the particular application, and the feasibility of fabricating a
PMC article having the required geometry. Due to their considerable
potential for weight savings, various applications have been
explored for PMCs in aircraft gas turbine engines. However, a
challenge has been the identification of material systems that have
acceptable properties yet can be produced by manufacturing methods
to yield a cost-effective PMC component. In particular, it is well
known that aircraft engine applications have high performance
mechanical requirements, for example, strength and fatigue
properties (necessitated by vibrations in the engine environment),
as well as high temperature properties, chemical/fluid resistance,
etc. Though considerable weight savings could be realized by
fabricating engine parts from PMC materials, performance
requirements as well as the size and complexity of such components
have complicated the ability to produce components from these
materials.
[0032] 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.
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
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.
[0033] 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.
[0034] Referring now to FIG. 2, a part is shown which is used
toward the fan end of the engine 10. Although components of the fan
end of the engine are shown and described, other engine parts may
be formed using the design shown and described herein and the
exemplary parts should not be considered limiting. The spinner 30
is generally formed of a conical shape formed of a sidewall 32
which is generally continuous. The conical shaped sidewall 32
tapers from a first end 36 to a larger second end 38. The sidewall
32 may be linear moving from the larger end of the cone to the
smaller end of the cone. Alternatively, the sidewall 32 may be
curvilinear as shown. The spinner 30 is symmetrical about the axis
34, shown in broken line. The spinner 30 is generally hollow to
reduce weight and is capable of receiving bolts, fixtures or other
components of the fan hub (not shown).
[0035] At the forward end 12 of the engine 10 (FIG. 1), the engine
temperatures are lower which permits the use of PMC materials for
the spinner 30. The spinner 30 has significant loading
requirements. Design characteristics include, for example,
aerodynamic loading, high speed revolution fatigue and foreign
object strikes. Accordingly, the spinner 30 is formed of polymer
matrix composite and more specifically may be formed of continuous
fiber polymer composite material. The continuous fiber polymer
composites may provide the conical or parabolic conical shape
desired for the spinner 30 as these shapes are easily formed with
polymer composite materials. According to this design, the spinner
weight may exhibit significant weight reduction, for example
between 5 to 20 pounds over a metallic design, depending on the
engine type. For example, the shape of the cone spinner 30 is
generally consistent without sharp changes from the forward end 36
of the cone toward the aft end 38. Accordingly, much of the spinner
30 may be formed by laying up continuous fiber portions that are in
a fabric, unidirectional tape, or braided architecture. Each of the
continuous fiber portions may be rotated to a preselected angle
layer by layer to achieve the strength required for the part.
[0036] At the aft end 38 of the spinner 30 are a plurality of
circumferentially spaced aero-features or second features 40. These
second features 40 extend from the surface 32 of the spinner 30 and
provide a geometry which is complicated to form by continuous fiber
composite fabrication methods. For example, the aero-features 40
extend from the surface 32 at various angles and may be of varying
thickness making difficult the use of continuous fiber composites
as well as known techniques for manufacturing with such continuous
fiber composite. Accordingly, in order to form a monolithic part,
such as the spinner 30 depicted, the aero-features 40 are formed of
thermoplastic polymer unidirectional tape that has been chopped to
a short fiber length. The thermoplastic polymer used in the chopped
fiber unidirectional tape, is the same thermoplastic polymer that
is used in the continuous fiber portion of the part, for example,
spinner 30. This allows the first fibers, second fibers and polymer
to be fabricated as the monolithic part depicted. The cone sidewall
or body 32 may be formed of, for non-limiting example,
unidirectional prepreg, woven fabric prepreg, a braided prepreg, or
a dry reinforcement fiber with filaments or fibers of thermoplastic
polymer. For example the continuous fiber material may be
continuous fibers 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 thermoplastic matrix materials include PEEK, PEKK, PEI and
PPS and particularly suitable continuous fiber reinforcement
materials include carbon, glass polymer, ceramic and metal fibers.
Suitable fiber content may be at least 35 percent by volume and not
more than 75 percent by volume, with a preferred range believed to
be about 50 to about 65 percent by volume.
[0037] 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 processed 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 over 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.
[0038] 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
dray fabric with molten resin.
[0039] According to the instant embodiment, due to its shape, the
spinner cone 30 continuous fiber preform architecture is loaded
into a compression mold. Within this mold are cavities
corresponding to the shape of features 40 wherein chopped fiber
unidirectional tape prepreg flakes are loaded into the mold
cavities to form the aero-features 40. The combination of
continuous and chopped fibers are then molded into a final part
rendering, for example, a monolithic spinner cone 30, including the
continuous fiber and chopped fiber sections.
[0040] Additionally, the part 30 may be machined if necessary such
as by conventional machining, waterjet cutting, and laser cutting
techniques. For example, the part 30 may be formed to include
slots, holes or other features with which a component or assembly
structure, etc., could be mounted to gas turbine engine through the
use of conventional mechanical fasteners and/or attachment
mechanisms. Additionally, metallic features may be co-molded with
the part 30 to enable more robust mechanical fastening.
Non-limiting examples include co-molded metallic bushings,
co-molded metallic attachment rings, and co-molded metallic
threaded inserts. Another advantage of thermoplastic composite
materials is that they can undergo various joining processes
including, but not limited to, infrared (IR) welding, resistive
implant welding, ultrasonic welding, and vibration welding.
[0041] As a result of the construction, a load-bearing part is
formed which benefits from weight savings but also has requisite
capability and characteristics for withstanding mechanical and
environmental conditions associated with aircraft engines.
Additionally, a monolithic hybrid composite structure may be
fabricated which can withstand high loadings yet contain complex
secondary features.
[0042] Referring now to FIG. 3, an isometric view of a second part
or component 50 is depicted which is according to the described
embodiment capable of being formed of a first portion formed of
continuous fiber and a second portion of more complex geometry
formed of chopped fiber. According to the instant embodiment, the
part 50 is an aft support ring. The aft support ring 50 is
generally circular in cross-section and includes a body or first
surface 52 extending aft from a forward flange 54. The flange 54
includes a plurality of fastening apertures 56 through which the
aft support ring 50 may be connected to the aft end 38 of the
spinner 30. The arm 52 includes a plurality of flow path scallops
58 which aid to improve aerodynamic flow of the air leaving the
spinner 30 and moving across the aft support ring 50 from the
forward end toward the aft end of the ring 50.
[0043] Referring now to FIG. 4, a section view of the aft support
ring 50 is depicted in an assembly. At the forward end of the aft
support ring 50 is a portion of the spinner 30 which is fastened to
the flange 54 through aperture 56. The aft support ring 50 includes
the flange 54, curved arm 60, the body or arm 62, a lug 64 and the
flow path scallop 58. The lug 64 and the scallop 58 define the
interface wherein the continuous fibers reinforcement section
transitions to the chopped fiber reinforcement section.
[0044] In manufacturing, the flange 54, curved arm 60, the body 62
and lug 64 may be formed of continuous fiber reinforcement to carry
the high loads that the part is subjected to. The preformed
architecture of the flange 54, curved arm 60, body 62 and lug 64
may be formed of dry carbon fiber and thermoplastic polymer fibers
braided into the preformed structure. Further, for example, glass
fibers may be added to the preform to improve impact
characteristics. The flow path scallops 58 are formed on the lug 64
and the body 62 with chopped fiber unitape prepreg flakes. Such
continuous fiber preform is loaded into a compression mold and the
chopped fiber unitape prepreg flakes are loaded into flow path
scallop cavities in the mold to define the flow path scallop 58
shape. The compression molding is a non-limiting example as other
methods may be utilized. For example an autoclave may be an
alternative method. These chopped fiber unitape flakes may be less
than 1''.times.1'', for example, 1/2''.times.1/2'', in size
although alternate shapes and sizes may be utilized. The
combinations of continuous fiber preform architecture and chopped
fiber unitape are compression molded into the final shape of the
part, rendering a monolithic part with both continuous fiber and
chopped fiber sections. During the compression molding process, the
thermoplastic polymer in the continuous fiber reinforced section
and chopped fiber reinforced section flow together to create a
monolithic part that is made from one polymer type, while having
the two fiber types.
[0045] As shown in FIG. 5, a schematic section view is depicted for
the aft support ring 50. The scallop 58 is curved from the surface
52 to an upper height 59. The scallop 58 is disposed above the lug
64. As shown at the interface of the lug 64 and the scallop 58, the
different cross-hatchings depict the interface or joining area of
the continuous fibers 66 of the lug 64 and the chopped fibers 68.
Between the fibers 66, 68 are where the thermoplastic resin 70
flows to bind the continuous fibers 66 to the chopped fibers 68.
Also the thermoplastic 70 flows between like fiber types to provide
for the monolithic part.
[0046] The present hybrid continuous fiber-chopped fiber polymer
composite provides various benefits. The continuous fibers and
chopped fibers utilize the same resin or polymer, thereby
eliminating compatibility issues when transitioning from the
continuous fiber reinforced section to the chopped fiber reinforced
section. The component precludes the need to make aero features
separately and a subsequent joining process step to bond the two
portions of the component, for example by adhesive bonding or
mechanical fastening. Since the parts or structures may be formed
as a single monolithic structure, in certain situations this will
enable a reduction in part count and eliminate surface preparation
that would be needed in joining the two components in alternative
designs. Further, the hybrid monolithic polymer composite may be
formed to improve impact resistance at complex secondary feature
locations, as the strength of the thermoplastic polymer is
typically higher than that of an adhesive bond between two
different materials that would be used in alternative designs.
Additionally, the polymer composite may be tailored to the desired
impact properties by incorporating mixtures of carbon and/or glass
fiber into the continuous fiber preform. Even further, an erosion
protection layer may be deposited on an outermost surface of any of
the exemplary parts described.
[0047] Related to the reduction of parts described above, the
hybrid polymer composite enables co-molding of metallic features as
well as thermoplastic welding and these various benefits and
applications may be utilized with numerous parts including but not
limited to the spinner 30 and the aft support ring 50 described
herein. For example, metallic inserts may be utilized to aid
strength and provide an advantage to eliminate mechanical fastening
directly on the composite parts, for example, at the interface of
the spinner 30 and aft support ring 50 (FIG. 4).
[0048] The foregoing description of structures and methods has been
presented for purposes of illustration. It is not intended to be
exhaustive or to limit the structures and methods to the precise
forms and/or steps disclosed, and obviously many modifications and
variations are possible in light of the above teaching. Features
described herein may be combined in any combination. Steps of a
method described herein may be performed in any sequence that is
physically possible. It is understood that while certain forms of
composite structures have been illustrated and described, it is not
limited thereto and instead will only be limited by the claims,
appended hereto.
[0049] While multiple inventive embodiments have been described and
illustrated herein, those of ordinary skill in the art will readily
envision a variety of other means and/or structures for performing
the function and/or obtaining the results and/or one or more of the
advantages described herein, and each of such variations and/or
modifications is deemed to be within the scope of the embodiments
described herein. More generally, those skilled in the art will
readily appreciate that all parameters, dimensions, materials, and
configurations described herein are meant to be exemplary and that
the actual parameters, dimensions, materials, and/or configurations
will depend upon the specific application or applications for which
the inventive teachings is/are used. Those skilled in the art will
recognize, or be able to ascertain using no more than routine
experimentation, many equivalents to the specific inventive
embodiments described herein. It is, therefore, to be understood
that the foregoing embodiments are presented by way of example only
and that, within the scope of the appended claims and equivalents
thereto, inventive embodiments may be practiced otherwise than as
specifically described and claimed. Inventive embodiments of the
present disclosure are directed to each individual feature, system,
article, material, kit, and/or method described herein. In
addition, any combination of two or more such features, systems,
articles, materials, kits, and/or methods, if such features,
systems, articles, materials, kits, and/or methods are not mutually
inconsistent, is included within the inventive scope of the present
disclosure.
[0050] Examples are used to disclose the embodiments, including the
best mode, and also to enable any person skilled in the art to
practice the apparatus and/or method, including making and using
any devices or systems and performing any incorporated methods.
These examples are not intended to be exhaustive or to limit the
disclosure to the precise steps and/or forms disclosed, and many
modifications and variations are possible in light of the above
teaching. Features described herein may be combined in any
combination. Steps of a method described herein may be performed in
any sequence that is physically possible.
[0051] All definitions, as defined and used herein, should be
understood to control over dictionary definitions, definitions in
documents incorporated by reference, and/or ordinary meanings of
the defined terms. The indefinite articles "a" and "an," as used
herein in the specification and in the claims, unless clearly
indicated to the contrary, should be understood to mean "at least
one." The phrase "and/or," as used herein in the specification and
in the claims, should be understood to mean "either or both" of the
elements so conjoined, i.e., elements that are conjunctively
present in some cases and disjunctively present in other cases.
[0052] It should also be understood that, unless clearly indicated
to the contrary, in any methods claimed herein that include more
than one step or act, the order of the steps or acts of the method
is not necessarily limited to the order in which the steps or acts
of the method are recited.
[0053] In the claims, as well as in the specification above, all
transitional phrases such as "comprising," "including," "carrying,"
"having," "containing," "involving," "holding," "composed of," and
the like are to be understood to be open-ended, i.e., to mean
including but not limited to. Only the transitional phrases
"consisting of" and "consisting essentially of" shall be closed or
semi-closed transitional phrases, respectively, as set forth in the
United States Patent Office Manual of Patent Examining Procedures,
Section 2111.03.
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