U.S. patent application number 15/396170 was filed with the patent office on 2017-11-09 for methods and tools for forming contoured composite structures with shape memory alloy.
The applicant listed for this patent is The Boeing Company. Invention is credited to Paul E. Nelson, Daniel M. Rotter.
Application Number | 20170320274 15/396170 |
Document ID | / |
Family ID | 51844619 |
Filed Date | 2017-11-09 |
United States Patent
Application |
20170320274 |
Kind Code |
A1 |
Rotter; Daniel M. ; et
al. |
November 9, 2017 |
METHODS AND TOOLS FOR FORMING CONTOURED COMPOSITE STRUCTURES WITH
SHAPE MEMORY ALLOY
Abstract
Methods and tools for forming contoured composite structures are
disclosed. Methods include positioning a sheet of composite
material relative to a structure of shape memory alloy, heating the
structure of shape memory alloy to deform the structure of shape
memory alloy to a deformed conformation and thereby conform the
sheet of composite material to a desired contour corresponding to
the deformed conformation of the structure of shape memory alloy.
Tools include a structure of shape memory alloy and a heat source
for heating the structure of shape memory alloy to conform a sheet
of composite material to a desired contour corresponding to the
deformed conformation of the structure of shape memory alloy.
Inventors: |
Rotter; Daniel M.; (Lake
Forest Park, WA) ; Nelson; Paul E.; (University
Place, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Boeing Company |
Chicago |
IL |
US |
|
|
Family ID: |
51844619 |
Appl. No.: |
15/396170 |
Filed: |
December 30, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14188252 |
Feb 24, 2014 |
9566746 |
|
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15396170 |
|
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61900480 |
Nov 6, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 53/04 20130101;
Y02T 50/40 20130101; C22F 1/006 20130101; B29C 70/46 20130101; B29K
2105/0872 20130101; B29C 70/44 20130101; Y02T 50/43 20130101 |
International
Class: |
B29C 70/44 20060101
B29C070/44; B29C 70/46 20060101 B29C070/46; B29C 53/04 20060101
B29C053/04 |
Claims
1. A tool for forming a contoured composite structure, the tool
comprising: a structure of shape memory alloy configured to deform
from a first conformation to a second conformation when heated to
within an activated temperature range, wherein the second
conformation corresponds to a desired contour of a sheet of
composite material, and wherein the structure of shape memory alloy
is configured to operatively receive the sheet of composite
material; a heat source configured to heat the structure of shape
memory alloy to within the activated temperature range to actively
deform the structure of shape memory alloy from the first
conformation to the second conformation and thus to actively
conform the sheet of composite material to the desired contour at
least partially corresponding to the second conformation of the
shape memory alloy; and a retention structure configured to
selectively retain the sheet of composite material relative to the
structure of shape memory alloy when the heat source heats the
structure of shape memory alloy to within the activated temperature
range.
2. The tool of claim 1, in combination with the sheet of composite
material in operative relation to the structure of shape memory
alloy.
3. The combination of claim 2, wherein the sheet of composite
material includes one or more pre-preg composite plies.
4. The tool of claim 1, wherein the structure of shape memory alloy
includes a first body and a second body positioned relative to the
first body, wherein the first body and the second body are
configured to cooperatively and actively conform the sheet of
composite material to the desired contour when the structure of
shape memory alloy is heated to within the activated temperature
range and thus when the structure of shape memory alloy is deformed
to the second conformation.
5. The tool of claim 1, wherein the structure of shape memory alloy
includes a plurality of bodies, wherein the plurality of bodies
defines a die configuration when the structure of shape memory
alloy is deformed to the second conformation.
6. The tool of claim 5, wherein the bodies of the plurality of
bodies are configured to be translated relative to each other to
conform the sheet of composite material to the desired contour when
the structure of shape memory alloy is heated to within the
activated temperature range.
7. The tool of claim 1, further comprising: a substrate, wherein
the structure of shape memory alloy is operatively positioned
within the substrate, and wherein the substrate is not constructed
of shape memory alloy.
8. The tool of claim 1, wherein the heat source includes one or
more heating plates in operative engagement with the structure of
shape memory alloy.
9. The tool of claim 1, wherein the heat source includes one or
more resistive heating elements that are integral with the
structure of shape memory alloy.
10. The tool of claim 1, wherein the heat source includes an
autoclave or an oven.
11. The tool of claim 1, wherein the structure of shape memory
alloy includes a plurality of sub-regions, and wherein the heat
source is configured to operatively heat fewer than all of the
plurality of sub-regions.
12. The tool of claim 1, wherein the structure of shape memory
alloy includes a plurality of sub-regions, and wherein the heat
source is configured to heat a first subset of the plurality of
sub-regions to within the activated temperature range and to not
heat a second subset of the plurality of sub-regions to within the
activated temperature range.
13. The tool of claim 1, wherein the heat source is configured to
sequentially heat predetermined sub-regions of the structure of
shape memory alloy in a predetermined sequence.
14. The tool of claim 1, further comprising: a controller
configured to operatively control the heat source to sequentially
heat predetermined sub-regions of the structure of shape memory
alloy in a predetermined sequence.
15. The tool of claim 1, wherein the retention structure includes a
vacuum bagging assembly.
16. The tool of claim 1, further comprising: a mechanical impeder
operatively coupled to the structure of shape memory alloy, wherein
the mechanical impeder is configured to operatively resist
deformation of the structure of shape memory alloy from the first
conformation to the second conformation.
17. The tool of claim 1, wherein the second conformation defines a
complex contour.
18. The tool of claim 17, wherein the first conformation is
planar.
19. A tool for forming a contoured composite structure, the tool
comprising: a structure of shape memory alloy configured to deform
from a first conformation to a second conformation when heated to
within an activated temperature range, wherein the second
conformation corresponds to a desired contour of a sheet of
composite material, and wherein the structure of shape memory alloy
is configured to operatively receive the sheet of composite
material; a heat source configured to heat the structure of shape
memory alloy to within the activated temperature range to actively
deform the structure of shape memory alloy from the first
conformation to the second conformation and thus to actively
conform the sheet of composite material to the desired contour at
least partially corresponding to the second conformation of the
shape memory alloy; and a controller configured to operatively
control the heat source to sequentially heat predetermined
sub-regions of the structure of shape memory alloy in a
predetermined sequence.
20. A tool for forming a contoured composite structure, the tool
comprising: a structure of shape memory alloy configured to deform
from a first conformation to a second conformation when heated to
within an activated temperature range, wherein the second
conformation corresponds to a desired contour of a sheet of
composite material, and wherein the structure of shape memory alloy
is configured to operatively receive the sheet of composite
material; and a heat source configured to heat the structure of
shape memory alloy to within the activated temperature range to
actively deform the structure of shape memory alloy from the first
conformation to the second conformation and thus to actively
conform the sheet of composite material to the desired contour at
least partially corresponding to the second conformation of the
shape memory alloy; wherein the structure of shape memory alloy
includes a plurality of sub-regions, and wherein the heat source is
configured to operatively heat fewer than all of the plurality of
sub-regions.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of and claims priority
under 35 U.S.C. .sctn.120 to U.S. patent application Ser. No.
14/188,252, which is entitled "METHODS AND TOOLS FOR FORMING
CONTOURED COMPOSITE STRUCTURES WITH SHAPE MEMORY ALLOY," which was
filed on Feb. 24, 2014 and issued as U.S. patent Ser. No. ______ on
______, and which claims priority under 35 U.S.C. .sctn.119(e) to
U.S. Provisional Patent Application No. 61/900,480, which is
entitled "METHODS AND TOOLS FOR FORMING CONTOURED COMPOSITE
STRUCTURES WITH SHAPE MEMORY ALLOY," which was filed on Nov. 6,
2013, and the disclosures of which are hereby incorporated by
reference.
FIELD
[0002] The present disclosure relates to forming contoured
composite structures.
BACKGROUND
[0003] Composite structures, such as those that are constructed of
fiber reinforced composite materials, typically are formed by
conforming pre-cured or partially cured flexible sheets of
composite material to a rigid mold. Depending on the ultimate
structure being formed, the mold may be required to have very
precise tolerances relative to a desired ultimate shape of the
structure being formed. Such molds, especially when very large, are
very expensive to construct and maintain. Moreover, due to the
nature of conforming a generally planar sheet of material to a mold
having contours, including complex contours, it often is difficult
to avoid imparting undesired wrinkles to the composite material.
Such wrinkling or other anomalies created during forming may not be
acceptable to meet the performance requirements of the final
composite structure.
SUMMARY
[0004] Methods and tools for forming contoured composite structures
with shape memory alloy, as well as apparatuses, including
aerospace structures, that are constructed of contoured composite
structures, are disclosed herein. Methods include positioning a
sheet of composite material in operative relation to a structure of
shape memory alloy, heating the structure of shape memory alloy to
within its activated temperature range, thereby conforming the
sheet of composite material to a desired contour, and then cooling
the structure of shape memory alloy to below its activated
temperature range. Tools include a structure of shape memory alloy
and a heat source configured to heat the structure of shape memory
alloy to within its activated temperature range to conform a sheet
of composite material to a desired contour.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a perspective view of an illustrative,
non-exclusive example of an aircraft.
[0006] FIG. 2 is a flowchart representing illustrative,
non-exclusive examples of methods of forming contoured composite
structures.
[0007] FIG. 3 is a schematic diagram representing illustrative,
non-exclusive examples of tools for forming contoured composite
structures, together with a sheet of composite material to be
formed into a contoured composite structure.
[0008] FIG. 4 is a schematic diagram representing the structure of
shape memory alloy of the tool of FIG. 3 together with the sheet of
composite material, with the structure of shape memory alloy having
been heated from a non-deformed conformation to a deformed
conformation and with the sheet of composite material conformed to
the structure of shape memory alloy.
[0009] FIG. 5 is a schematic diagram representing the structure of
shape memory alloy of the tool of FIG. 3 together with the sheet of
composite material, with the structure of shape memory alloy having
been cooled from the deformed conformation to the non-deformed
conformation and with the sheet of composite material having been
set into a desired contour by the structure of shape memory
alloy.
[0010] FIG. 6 is a schematic diagram representing additional
illustrative, non-exclusive examples of tools for forming contoured
composite structures, together with a sheet of composite material
to be formed into a contoured composite structure.
[0011] FIG. 7 is a schematic diagram representing the structure of
shape memory alloy of the tool of FIG. 6 together with the sheet of
composite material, with the structure of shape memory alloy having
been heated from a non-deformed conformation to a deformed
conformation and with the sheet of composite material conformed to
the structure of shape memory alloy.
[0012] FIG. 8 is a schematic diagram representing the structure of
shape memory alloy of the tool of FIG. 6 together with the sheet of
composite material, with the structure of shape memory alloy having
been cooled from the deformed conformation to the non-deformed
conformation and with the sheet of composite material having been
set into a desired contour by the structure of shape memory
alloy.
[0013] FIG. 9 is a schematic diagram representing additional
illustrative, non-exclusive examples of tools for forming contoured
composite structures, together with a flexible sheet of composite
material to be formed into a contoured composite structure.
[0014] FIG. 10 is a schematic diagram representing the structure of
shape memory alloy of the tool of FIG. 9 together with the sheet of
composite material, with the structure of shape memory alloy having
been heated from a non-deformed conformation to a deformed
conformation and with the sheet of composite material conformed to
the structure of shape memory alloy.
[0015] FIG. 11 is a schematic diagram representing the structure of
shape memory alloy of the tool of FIG. 9 together with the sheet of
composite material, with the structure of shape memory alloy having
been cooled from the deformed conformation to the non-deformed
conformation and with the sheet of composite material having been
set into a desired contour by the structure of shape memory
alloy.
[0016] FIG. 12 is a schematic isometric view representing
illustrative, non-exclusive examples of structures of shape memory
alloy positioned within a substrate and in a non-deformed
conformation.
[0017] FIG. 13 is a schematic isometric view representing the
examples of FIG. 12 with the structures of shape memory alloy
having been heated from the non-deformed conformation to a deformed
conformation.
[0018] FIG. 14 is a schematic plan view of a structure of shape
memory alloy with sub-regions configured to be selectively
heated.
[0019] FIG. 15 is a flowchart representing aircraft production and
service methodology.
[0020] FIG. 16 is a schematic block diagram representing an
aircraft.
DESCRIPTION
[0021] Methods and tools for forming contoured composite
structures, as well as apparatuses constructed of contoured
composite structures, are disclosed herein. In general, in the
drawings, elements that are likely to be included in a given
example are illustrated in solid lines, while elements that are
optional to a given example are illustrated in broken lines.
However, elements that are illustrated in solid lines are not
essential to all examples of the present disclosure, and an element
shown in solid lines may be omitted from a particular example
without departing from the scope of the present disclosure.
[0022] In FIG. 1, an example aircraft 10, which may include various
contoured composite structures 12, is provided; however,
apparatuses other than aircraft are within the scope of the present
disclosure and may include contoured composite structures. For
example, as illustrative, non-exclusive examples, other apparatuses
that may include contoured composite structures include (but are
not limited to) spacecraft, watercraft, land vehicles, wind
turbines, structural towers and masts, etc. Moreover, aircraft 10
may take any suitable form, including commercial aircraft, military
aircraft, private aircraft, or any other suitable aircraft. While
FIG. 1 illustrates aircraft 10 in the form of a fixed wing
commercial aircraft, other types and configurations of aircraft are
within the scope of aircraft 10 according to the present
disclosure, including (but not limited to) helicopters.
[0023] As used herein, a composite structure refers to a structure
that is constructed of composite materials, such as (but not
limited to) fiber reinforced composite materials. Illustrative,
non-exclusive examples of fiber reinforced composite materials
include at least an epoxy or other polymer or binding material
together with fibers, such as constructed of (but not limited to)
glass fibers, carbon fibers, boron fibers, para-aramid (e.g.,
Kevlar.RTM.) fibers, and/or other fibers. In some examples,
composite structures may be constructed of multiple layers, or
plies, of fiber reinforced composite material, and may be described
as a composite laminate or lamination. In some such examples, the
plies may be pre-preg plies, which are layers, or sheets, of fibers
that are pre-impregnated with the associated binding material.
Accordingly, multiple pre-preg plies may be layered to collectively
define a segment of fiber reinforced composite material having
desired properties and characteristics. The binding material of
pre-preg plies may be partially cured, or pre-cured, so as to
permit handling of the plies and selective assembly of the plies.
Typically, partially cured pre-preg plies are flexible and tacky to
the touch and therefore easily stick together when layered, but not
necessarily in a permanent fashion. That is, when layered, two
adjacent plies may be permitted to translate laterally relative to
each other and/or may be able to be separated, if so desired. To
more permanently affix adjacent layers of plies together, the
layered plies may be compacted, or compressed, together, utilizing
any suitable method and at any suitable and various times during
the construction of a fiber reinforced composite structure. This
compression of two or more layers is referred to as compaction, or
as compacting, of the plies. Prior to being cured, composite
materials may be somewhat flexible, or at least flexible relative
to a cured state of the composite material. Accordingly, prior to
being cured, the composite material, which may be in the form of a
sheet, or charge, may be molded or otherwise formed into a desired
contour. Some composite materials may require heating prior to or
during the forming or molding process, with such heat making the
composite material more malleable and easier to conform to a
desired shape, yet with such heat being lower than the temperature
required to cure, and stiffen, the composite material. The
temperature of the composite laminate may influence the rate of
forming or the amount of bending that is permissible to define a
desired contour due to the viscous properties of the uncured resin.
Upon being cured, composite materials become rigid and hold their
shape, yet may have a desired resilience depending on a particular
application for the composite structure.
[0024] With continued reference to FIG. 1, aircraft 10 typically
may be described as including a fuselage 14, which generally
corresponds to the main body of an aircraft for holding passengers,
crew, cargo, and/or equipment, for example, depending on the
particular configuration and/or function of an aircraft. Typically,
although not required, the fuselage of an aircraft is elongate and
somewhat cylindrical or tubular. In some examples, a fuselage may
be constructed of multiple sections 16 that are longitudinally
spaced along the fuselage and operatively coupled together to
define the fuselage. In FIG. 1, five fuselage sections are
indicated schematically; however, any number or size and shape of
sections 16 may be used to construct a fuselage.
[0025] Aircraft 10 also may include wings 18, horizontal
stabilizers 20, and a vertical stabilizer 22. One or more of a
fuselage, wings, horizontal stabilizers, and vertical stabilizers
may be constructed of composite materials. In some examples, such
structures may be described as stiffened composite structures, such
as being defined by a skin supported by a structural frame, or
stiffeners. Any one or more of the aforementioned various
structures of an aircraft, as well as other structures of an
aircraft, may be described as contoured composite structures. By
contoured, it is meant that such structures define non-planar
surfaces. Some examples of contoured composite structures according
to the present disclosure may have non-planar surfaces with a
complex contour, meaning that within a given region of the surface,
the intersection with any orientation of a plane is not linear.
[0026] FIG. 2 schematically provides a flowchart that represents
illustrative, non-exclusive examples of methods 50 of forming
contoured composite structures. FIGS. 3-13 schematically illustrate
illustrative, non-examples of tools 100, and component parts
thereof, for forming contoured composite structures, with such
tools optionally being configured to perform one or more methods
50. Methods 50 and tools 100 utilize a structure of shape memory
alloy. Shape memory alloys, which sometimes are referred to as
smart metals, memory metals, memory alloys, and/or smart alloys,
are a classification of materials that are configured to deform
from a first non-deformed conformation (or shape) to a second
deformed, and different, conformation (or shape) when heated within
an activated temperature range. Additionally or alternatively, some
shape memory alloys may include more than two conformations, such
as an intermediate conformation (or shape) when heated within a
temperature range that is less than the activated temperature
range. Additionally or alternatively, some shape memory alloys may
be described as including more than one activated temperature
range, with respective temperature ranges being operative to deform
the shape memory alloy into a respective conformation. Typical
shape memory alloys include alloys of copper, aluminum, and nickel
and alloys of nickel and titanium; however, other examples of shape
memory alloys are within the scope of the present disclosure and
may be utilized by methods 50 and tools 100. Some shape memory
alloys may be described as existing in a martensite phase at a
relative lower temperature and in an austenite phase at a
relatively higher temperature. In such an alloy, the austensite
phase may be described as occurring when the alloy is heated to
within its activated temperature range.
[0027] With reference initially to the flowchart of FIG. 2 and the
schematic representation of tools 100 of FIGS. 3-5, a method 50 may
include positioning a sheet of composite material 102 in operative
relation to a structure of shape memory alloy 104, as schematically
indicated at 52. Then, following the positioning 52, a method 50
may include heating the structure of shape memory alloy to within
its activated temperature range, as schematically indicated at 54.
The heating 54 results in deforming the structure of shape memory
alloy from its first, or non-deformed, conformation 106 to its
second, or deformed, conformation 108, as schematically indicated
at 56 in FIG. 2, and conforming the sheet of composite material 102
to a desired contour 110 that at least partially corresponds to the
second conformation 108 of the structure of shape memory alloy, as
schematically indicated at 58 in FIG. 2. In some examples, the
second conformation of the structure of shape memory alloy may
have, or define, a complex contour. The conformed configuration of
the sheet of composite material having its desired contour may be
described as a conformed sheet of composite material 112, and
optionally in some examples, the desired contour may be a complex
contour. Then, as schematically indicated 60, following the heating
54, a method 50 may include cooling the structure of shape memory
alloy to below its activated temperature range, thereby deforming
the structure of shape memory alloy from its second conformation
back to its first conformation, as schematically indicated at 62.
Despite the shape memory alloy returning to its first conformation
as a result of the cooling 62, the sheet of composite material
maintains its desired contour 110.
[0028] In FIGS. 3-5, the first conformation of the structure of
shape memory alloy 104 and the initial configuration of the sheet
of composite material 102 are illustrated as being generally
planar, and the second conformation of the structure of shape
memory alloy 104 and the desired contour of the sheet of composite
material 102 are illustrated as having generally sinusoidal
contours. However, while such configurations are within the scope
of the present disclosure, such configurations are not required,
and the representations of the structure of shape memory alloy and
the sheet of composite material in the Figures are schematic in
nature and do not limit the possible configurations and contours of
the structure of shape memory alloy and the sheet of composite
material, including before the deforming, during the deforming, and
after the deforming of the structure of shape memory alloy and thus
before the conforming, during the conforming, and after the
conforming of the sheet of composite material to the second
conformation of the structure of shape memory alloy. For example,
as mentioned, although not required, the second conformation of the
structure of shape memory alloy and the desired contour of the
composite material may have, or define, complex contours.
[0029] In some methods 50, the heating 54 may at least partially
set, or at least partially cure, the conformed sheet of composite
material 112 in the desired contour 110. Accordingly, upon cooling
60, the conformed sheet of composite material will remain in its
desired contour and not revert, or relax, back to its pre-conformed
state.
[0030] The heating 54 may be performed in any suitable manner. A
tool 100 therefore may include a heat source 114 that is configured
to heat the structure of shape memory alloy 104 to within its
activated temperature range to deform the structure of shape memory
alloy from its first conformation to its second conformation and
thus to conform the sheet of composite material 102 to the desired
contour 110. Any suitable heat source may be incorporated into a
tool 100 and utilized by a method 50. For example, as schematically
and optionally illustrated in FIG. 3, a heat source may include one
or more heating plates 116 that are in operative engagement with
the structure of shape memory alloy 104. Additionally or
alternatively, a heat source may include one or more resistive
heating elements 118 that are integral with, or at least partially
embedded within, the structure of shape memory alloy. In some
examples of tools 100, the structure of shape memory alloy 104 may
be described as including a plurality of sub-regions, and the heat
source 114 may be configured to operatively heat fewer than all of
the plurality of sub-regions. Stated differently, the heat source
may be configured to heat a first subset of sub-regions of the
structure of shape memory alloy to within the activated temperature
range and to not heat a second subset of sub-regions of the
structure of shape memory alloy to within the activated temperature
range. This example is schematically illustrated in FIG. 3, in
which a subset of sub-regions 120 are optionally illustrated in
connection with the heat source by dashed lines. In some such
embodiments of tools 100, the sub-regions 120 may include embedded
resistive heating elements 118; however, other mechanisms for
selectively heating only a subset of sub-regions of the structure
of shape memory alloy also may be used.
[0031] In some methods 50, the heating 54 may include sequentially
heating sub-regions of the structure of shape memory alloy 104 in a
predetermined sequence. Accordingly, a heat source 114 of a tool
100, in some embodiments, may be configured to sequentially heat
predetermined sub-regions of the structure of shape memory alloy in
a predetermined sequence. In some such embodiments, a tool 100
additionally may include a controller 122 that is configured to
operatively control the heat source for sequentially heating the
sub-regions in a predetermined sequence. Such methods and tools may
be useful to form contoured composite structures 12 with complex
contours, or non-complex contours, without the sheet of composite
material 102 wrinkling during the conforming 58. The controller
122, when present, may take any suitable form and may include one
or more of a computer and software. For example, a computer may
utilize non-transitory computer readable storage media including
computer-executable instructions that, when executed, direct the
computer to control the heat source to sequentially heat
predetermined sub-regions of the structure of shape memory alloy in
a predetermined sequence.
[0032] In connection with some methods 50 and some tools 100, the
heat source 114 may include an autoclave or oven 124, as
schematically illustrated in FIG. 3. Accordingly, a method 50
additionally may include positioning the sheet of composite
material 102 and the structure of shape memory alloy 104 in the
optional autoclave or oven, with the heating 54 being performed by
the autoclave or oven.
[0033] In some methods 50, the heating 54 may include curing the
conformed sheet of composite material 112, thereby resulting in a
cured composite structure. Accordingly, in some tools 100, the heat
source 114 not only may be configured to heat the structure of
shape memory alloy to within its activated temperature range, but
it also may be configured to heat the composite material to within
its cure temperature range. As illustrative, non-exclusive
examples, a typical activated temperature range of a shape memory
alloy may be in the range of approximately 140 degrees Fahrenheit,
whereas, a typical cure temperature range of a composite material
may be in the range of approximately 350 degrees Fahrenheit;
however, other examples of shape memory alloy and composite
materials are within the scope of the present disclosure.
[0034] Additionally or alternatively, a method 50 further may
include, following the cooling 60, curing the conformed sheet of
composite material 112 to result in a cured composite structure, as
schematically and optionally indicated at 64 in FIG. 2. In some
such methods, the curing 64 may be performed within an autoclave or
oven 124. In some methods, the structure of shape memory alloy may
be located within the autoclave or oven with the conformed sheet of
composite material, while in other methods, the structure of shape
memory alloy first may be separated from the conformed sheet of
composite material and the conformed sheet of composite material
may be located within the autoclave or oven without the structure
of shape memory alloy.
[0035] As schematically and optionally indicated in FIG. 2 at 66,
some methods 50 further may include, following the positioning 52
and prior to the heating 54, retaining the sheet of composite
material 102 relative to the structure of shape memory alloy 104.
Accordingly a tool 100 optionally may include a retention structure
126 that is configured to selectively retain the sheet of composite
material relative to the structure of shape memory alloy when the
heat source heats the structure of shape memory alloy to within the
activated temperature range, as schematically illustrated in FIG.
3. As an illustrative, non-exclusive example, the retention
structure 126 may include a vacuum bagging assembly 128, and thus
the retaining 66 of a method 50 may include vacuum bagging the
sheet of composite material to the structure of shape memory alloy.
For example, the vacuum bagging assembly may include a
gas-impermeable sheet of flexible material 130 for operative
placement over the sheet of composite material, with the
gas-impermeable sheet of flexible material being sealed against the
structure of shape memory alloy or other structure relative to the
sheet of composite material and the structure of shape memory
alloy. The vacuum bagging assembly also may include a vacuum source
132 that is configured to evacuate air from between the
gas-impermeable sheet of flexible material and the structure of
shape memory alloy, and thus from between the sheet of composite
material and the structure of shape memory alloy, thereby retaining
via suction the sheet of composite material to the structure of
shape memory alloy. In some methods, the retaining 66 additionally
may be described as compacting the sheet of composite material to
the structure of shape memory alloy.
[0036] As schematically illustrated in FIG. 3, some tools 100
optionally may include a mechanical impeder 134 that is operatively
coupled between the structure of shape memory alloy 104 and ground.
When present, the mechanical impeder may resist, or retard, the
deformation of the structure of shape memory alloy from its first
conformation 106 to its second, deformed conformation 108. Such a
configuration of tool 100 may facilitate the second conformation
corresponding to a desired contour. For example, as an illustrative
non-exclusive example, when heated to within its activated
temperature range, the structure of shape memory alloy may behave
similar to a spring and contract a first, longer dimension, to a
second, shorter dimension. Absent a mechanical impeder, the second,
shorter dimension may be smaller than desired. Accordingly, a
mechanical impeder may be selected, or adjusted, to result in a
desired second conformation of the structure of shape memory alloy.
Additionally or alternatively, the mechanical impeder may
facilitate a controlled rate of deformation of the structure of
shape memory alloy from its first conformation to its second
conformation. For example, depending on the characteristics of the
composite material being conformed, the viscosity of the resin may
prevent the laminate from appropriately conforming to the structure
of shape memory alloy, unless the deforming is controlled to a
suitable rate. An illustrative, non-exclusive example of a
mechanical impeder that may be utilized with a tool 100 includes an
air cylinder with flow control valves.
[0037] In connection with tools 100 that include an optional
mechanical impeder 134, a method 50 may be described as optionally
including, concurrently with the heating 54, impeding the deforming
56 of the structure of shape memory alloy 104 to control the
deformation of the structure of shape memory alloy to the second
conformation 108, such as to correspond to the desired contour 110
of the sheet of composite material 102.
[0038] Turning now to FIGS. 6-8, additional illustrative
non-exclusive examples of tools 100 are schematically represented
and indicated at 150. Tools 150 may include a structure of shape
memory alloy 104 that includes a first body 152 and a second body
154 that are configured to cooperatively conform a sheet of
composite material 102 to a desired contour when the structure of
shape memory alloy is heated to within its activated temperature
range and thus when the structure of shape memory alloy is deformed
to its second conformation 108. In the schematic example
illustrated, the first body and the second body of the structure of
shape memory alloy are positioned on opposing sides of the sheet of
composite material; however, such a configuration is not required
to all embodiments of tools 150, and any suitable configuration of
the first body and the second body may be used depending on the
desired contour of the sheet of composite material.
[0039] Referring back to FIG. 2 with respect to optional tools 150,
the positioning 52 of a method 50 therefore may include positioning
the sheet of composite material between the first body and the
second body, with the first body and the second body being
positioned relative to each other to cooperatively conform the
sheet of composite material to the desired contour during the
heating 54.
[0040] Turning now to FIGS. 9-11, additional illustrative,
non-exclusive examples of tools 100 are schematically represented
and indicated generally at 160. Tools 160 may include a structure
of shape memory alloy 104 that includes a plurality of bodies 162
that define a die configuration when the structure of shape memory
alloy is deformed to its second conformation 108. Accordingly, a
tool 160 may define a press 164 with support structures 166 that
carry the structure of shape memory alloy for operative translation
of the bodies 162 relative to each other to conform a sheet of
composite material 102 to a desired contour 110 when the structure
of shape memory alloy is heated to within its activated temperature
range.
[0041] Accordingly, with respect to optional tools 160, a method 50
may include operatively translating the plurality of bodies 162,
and collectively with the heating 54, conforming the sheet of
composite material 102 to a desired contour and resulting in a
conformed sheet of composite material 112. In some such methods 50,
the operatively translating may be performed concurrently with the
heating. In other methods 50, the operatively translating may be
performed following the heating and prior to the cooling. In other
methods 50, the operatively translating may be performed prior to
the heating.
[0042] In some tools 100, a structure of shape memory alloy 104 may
be operatively positioned within a substrate 170, such as a
substrate that is not constructed of shape memory alloy. In the
illustrative, non-exclusive example of FIGS. 12-13, four distinct
bodies of a structure of shape memory alloy 104 are schematically
presented, with two bodies generally spanning a width of the
substrate and two bodies being spaced-apart within the substrate.
However, these optional configurations are provided for
illustrative purposes only, and any desired and suitable
configuration may be embodied in a tool 100. Operatively
positioning a structure of shape memory alloy within a substrate
may be useful depending on the desired contour of a contoured
composite structure being formed. For example, various contours,
including complex and even highly complex contours, may be imparted
to a sheet of composite material based on the selective
positioning, size, shape, and selection of shape memory alloy
within a substrate 170. When heated to within the activated
temperature range of the shape memory alloy, the shape memory alloy
will deform to its deformed, second conformation 108, as
illustrated in FIG. 13, while the substrate 170 does not
deform.
[0043] Additionally or alternatively, a structure of shape memory
alloy 104 may be coated, on one or more sides, with a material that
is not constructed of shape memory alloy, such as a polymeric
material. For example, a material may be selected for its surface
characteristics, such as to ensure that the sheet of composite
material appropriately adheres, does not adhere, slips, or does not
slip relative to the structure of shape memory alloy, as may be
desired, during the conforming 58. Additionally or alternatively, a
structure of shape memory alloy 104 may be defined by a structure
of fibers that are embedded in a polymer matrix and thereby
defining a fiber reinforced composite material itself.
[0044] As mentioned, in some tools 100 and methods 50, a heat
source 114 may be configured to selectively heat sub-regions of a
structure of shape memory alloy 104 to within its activated
temperature range. In some such tools and methods, the sub-regions
may be selectively heated in a desired sequence. In some such tools
and methods, fewer than all of the sub-regions may be selectively
heated. Any suitable mechanism may be used to accomplish this
functionality. FIG. 14 schematically illustrates a heat source 114
in connection with a structure of shape memory alloy, with the heat
source defining a matrix, or grid, of possible heating locations on
the structure of shape memory alloy. In some embodiments, a grid of
resistive heating elements may be embedded, or at least partially
embedded within the structure of shape memory alloy. Additional or
alternatively, a heat plate or heat pad may be operatively
positioned relative to the structure of shape memory alloy, with
the heat plate or heat pad being configured to selectively heat the
structure of shape memory alloy according to a predetermined
pattern and/or sequence. Other configurations also are within the
scope of the present disclosure.
[0045] Turning now to FIGS. 15-16, embodiments of the present
disclosure may be described in the context of an aircraft
manufacturing and service method 300 as shown in FIG. 15 and an
aircraft 10 as shown in FIG. 16. During pre-production, exemplary
method 300 may include specification and design 304 of the aircraft
10 and material procurement 306. During production, component and
subassembly manufacturing 308 and system integration 310 of the
aircraft 10 takes place. Thereafter, the aircraft 10 may go through
certification and delivery 312 in order to be placed in service
314. While in service by a customer, the aircraft 10 is scheduled
for routine maintenance and service 316 (which may also include
modification, reconfiguration, refurbishment, and so on).
[0046] Each of the processes of method 300 may be performed or
carried out by a system integrator, a third party, and/or an
operator (e.g., a customer). For the purposes of this description,
a system integrator may include without limitation any number of
aircraft manufacturers and major-system subcontractors; a third
party may include without limitation any number of venders,
subcontractors, and suppliers; and an operator may be an airline,
leasing company, military entity, service organization, and so
on.
[0047] As shown in FIG. 16, the aircraft 10 produced by exemplary
method 300 may include an airframe 318 with a plurality of systems
320 and an interior 322. Examples of high-level systems 320 include
one or more of a propulsion system 324, an electrical system 326, a
hydraulic system 328, and an environmental system 330. Any number
of other systems also may be included. Although an aerospace
example is shown, the principles of the inventions disclosed herein
may be applied to other industries, such as the automotive
industry.
[0048] Apparatus and methods disclosed herein may be employed
during any one or more of the stages of the production and service
method 300. For example, components or subassemblies corresponding
to production process 308 may be fabricated or manufactured in a
manner similar to components or subassemblies produced while the
aircraft 10 is in service. Also, one or more apparatus embodiments,
method embodiments, or a combination thereof may be utilized during
the production stages 308 and 310, for example, by substantially
expediting assembly of or reducing the cost of an aircraft 10.
Similarly, one or more of apparatus embodiments, method
embodiments, or a combination thereof may be utilized while the
aircraft 10 is in service, for example and without limitation,
during maintenance and service 316.
[0049] Illustrative, non-exclusive examples of inventive subject
matter according to the present disclosure are described in the
following enumerated paragraphs:
[0050] A. A method of forming a contoured composite structure, the
method comprising:
[0051] positioning a sheet of composite material in operative
relation to a structure of shape memory alloy, wherein the
structure of shape memory alloy is configured to deform between a
first conformation and a second conformation when heated to within
an activated temperature range;
[0052] following the positioning, heating the structure of shape
memory alloy to within the activated temperature range, thereby
deforming the structure of shape memory alloy from the first
conformation to the second conformation, and thereby conforming the
sheet of composite material to a desired contour at least partially
corresponding to the second conformation and resulting in a
conformed sheet of composite material; and
[0053] following the heating, cooling the structure of shape memory
alloy to below the activated temperature range, thereby deforming
the structure of shape memory alloy from the second conformation to
the first conformation, while maintaining the sheet of composite
material in the desired contour.
[0054] A1. The method of paragraph A,
[0055] wherein the structure of shape memory alloy includes a first
body and a second body;
[0056] wherein the positioning includes positioning the sheet of
composite material between the first body and the second body;
and
[0057] wherein the first body and the second body are positioned
relative to each other to cooperatively conform the sheet of
composite material to the desired contour during the heating.
[0058] A1.1. The method of paragraph A1, wherein the heating is
performed outside of an autoclave or oven.
[0059] A2. The method of any of paragraphs A-A1.1, wherein the
structure of shape memory alloy includes a plurality of bodies,
wherein the plurality of bodies defines a die configuration when
the structure of shape memory alloy is deformed to the second
conformation.
[0060] A2.1. The method of paragraph A2, further comprising:
[0061] operatively translating the plurality of bodies, and
collectively with the heating, conforming the sheet of sheet of
composite material to the desired contour and resulting in the
conformed sheet of composite material.
[0062] A2.1.1. The method of paragraph A2.1, wherein the
operatively translating is performed concurrently with the
heating.
[0063] A2.1.2. The method of paragraph A2.1, wherein the
operatively translating is performed following the heating and
prior to the cooling.
[0064] A2.1.3. The method of paragraph A2.1, wherein the
operatively translating is performed prior to the heating.
[0065] A3. The method of any of paragraphs A-A2.1.3, wherein the
structure of shape memory alloy is operatively positioned within a
substrate, optionally wherein the substrate is not constructed of
shape memory alloy.
[0066] A4. The method of any of paragraphs A-A3, wherein the
heating at least partially sets the conformed sheet of composite
material in the desired contour.
[0067] A5. The method of any of paragraphs A-A4, wherein the
heating includes heating the structure of shape memory alloy with
one or more heating plates in operative engagement with the
structure of shape memory alloy.
[0068] A6. The method of any of paragraphs A-A5, wherein the
structure of shape memory alloy includes one or more integral
resistive heating elements, and wherein the heating is performed by
the one or more integral resistive heating elements.
[0069] A7. The method of any of paragraphs A-A6, further
comprising:
[0070] positioning the sheet of composite material and the
structure of shape memory alloy in an autoclave or an oven, wherein
the heating is performed by the autoclave or the oven.
[0071] A8. The method of any of paragraphs A-A7, wherein the
structure of shape memory alloy includes a plurality of
sub-regions, and wherein the heating includes operatively heating
fewer than all of the plurality of sub-regions.
[0072] A9. The method of any of paragraphs A-A8, wherein the
structure of shape memory alloy includes a plurality of
sub-regions, and wherein the heating results in a first subset of
the plurality of sub-regions being heated to within the activated
temperature range and a second subset of the plurality of
sub-regions not being heated to within the activated temperature
range.
[0073] A10. The method of any of paragraphs A-A9, wherein the
heating includes sequentially heating sub-regions of the structure
of shape memory alloy in a predetermined sequence.
[0074] A11. The method of any of paragraphs A-A10, wherein the
heating includes curing the conformed sheet of composite material,
thereby resulting in a cured composite structure.
[0075] A12. The method of any of paragraphs A-A11, further
comprising:
[0076] following the cooling, curing the conformed sheet of
composite material, thereby resulting in a cured composite
structure.
[0077] A12.1. The method of paragraph A12, wherein the curing is
performed within an autoclave or oven configured to heat the
conformed sheet of composite material to within a cure temperature
range, wherein the composite material is configured to cure within
the cure temperature range.
[0078] A12.1.1. The method of paragraph A12.1, wherein the
structure of shape memory alloy is not within the autoclave or oven
during the curing.
[0079] A12.1.1.1. The method of paragraph A12.1.1, further
comprising:
[0080] following the cooling and prior to the curing, separating
the conformed sheet of composite material from the structure of
shape memory alloy.
[0081] A12.1.2 The method of paragraph A12.1, further
comprising:
[0082] locating the structure of shape memory alloy within the
autoclave or oven with the conformed sheet of composite material
during the curing.
[0083] A13. The method of any of paragraphs A-A12.1.2, further
comprising:
[0084] following the positioning and prior to the heating,
retaining the sheet of composite material relative to the structure
of shape memory alloy.
[0085] A13.1. The method of paragraph A13, wherein the retaining
includes vacuum bagging the sheet of composite material to the
structure of shape memory alloy.
[0086] A13.2. The method of any of paragraphs A13-A13.1, wherein
the retaining includes applying a vacuum between the sheet of
composite material and the structure of shape memory alloy.
[0087] A14. The method of any of paragraphs A-A13.2, further
comprising:
[0088] concurrently with the heating, impeding the deforming so
that the second conformation corresponds to the desired
contour.
[0089] A15. The method of any of paragraphs A-A14, wherein the
second conformation defines a complex contour.
[0090] A16. The method of any of paragraphs A-A15, wherein the
first conformation is generally planar, and optionally planar.
[0091] A17. The method of any of paragraphs A-A16, wherein the
conformed sheet of composite material defines a complex
contour.
[0092] A18. The method of any of paragraphs A-A17, wherein the
sheet of composite material includes one or more pre-preg composite
plies.
[0093] A19. The method of any of paragraphs A-A18, wherein the
composite structure is an aerospace structure.
[0094] A20. An aerospace structure including a contoured composite
structure formed according to the method of any of paragraphs
A-A19.
[0095] B. A tool for forming a contoured composite structure, the
tool comprising:
[0096] a structure of shape memory alloy configured to deform from
a first conformation to a second conformation when heated to within
an activated temperature range, wherein the second conformation
corresponds to a desired contour of a sheet of composite material,
and wherein the structure of shape memory alloy is configured to
operatively receive the sheet of composite material; and
[0097] a heat source configured to heat the structure of shape
memory alloy to within the activated temperature range to deform
the structure of shape memory alloy from the first conformation to
the second conformation and thus to conform the sheet of composite
material to a desired contour at least partially corresponding to
the second conformation of the shape memory alloy.
[0098] B1. The tool of paragraph B, in combination with the sheet
of composite material in operative relation to the structure of
shape memory alloy.
[0099] B2. The tool of any of paragraphs B-B1, wherein the
structure of shape memory alloy includes a first body and a second
body positioned relative to the first body, wherein the first body
and the second body are configured to cooperatively conform the
sheet of composite material to a desired contour when the structure
of shape memory alloy is heated to within the activated temperature
range and thus when the structure of shape memory alloy is deformed
to the second conformation.
[0100] B3. The tool of any of paragraphs B-B2, wherein the
structure of shape memory alloy includes a plurality of bodies,
wherein the plurality of bodies defines a die configuration when
the structure of shape memory alloy is deformed to the second
conformation.
[0101] B3.1. The tool of paragraph B3, wherein the bodies of the
plurality of bodies are configured to be translated relative to
each other to conform the sheet of composite material to the
desired contour when the structure of shape memory alloy is heated
to within the activated temperature range.
[0102] B4. The tool of any of paragraphs B-B3.1, further
comprising:
[0103] a substrate, wherein the structure of shape memory alloy is
operatively positioned within the substrate, optionally wherein the
substrate is not constructed of shape memory alloy.
[0104] B5. The tool of any of paragraphs B-B4, wherein the heat
source includes one or more heating plates in operative engagement
with the structure of shape memory alloy.
[0105] B6. The tool of any of paragraphs B-B5, wherein the heat
source includes one or more resistive heating elements that are
integral with, or at least partially embedded within, the structure
of shape memory alloy.
[0106] B7. The tool of any of paragraphs B-B6, wherein the heat
source includes an autoclave or an oven.
[0107] B8. The tool of any of paragraphs B-B7, wherein the
structure of shape memory alloy includes a plurality of
sub-regions, and wherein the heat source is configured to
operatively heat fewer than all of the plurality of
sub-regions.
[0108] B9. The tool of any of paragraphs B-B8, wherein the
structure of shape memory alloy includes a plurality of
sub-regions, and wherein the heat source is configured to heat a
first subset of the plurality of sub-regions to within the
activated temperature range and to not heat a second subset of the
plurality of sub-regions to within the activated temperature
range.
[0109] B10. The tool of any of paragraphs B-B9, wherein the heat
source is configured to sequentially heat predetermined sub-regions
of the structure of shape memory alloy in a predetermined
sequence.
[0110] B11. The tool of any of paragraphs B-B10, further
comprising:
[0111] a controller configured to operatively control the heat
source to sequentially heat predetermined sub-regions of the
structure of shape memory alloy in a predetermined sequence.
[0112] B12. The tool of any of paragraphs B-B11, further
comprising:
[0113] a retention structure configured to selectively retain the
sheet of composite material relative to the structure of shape
memory alloy when the heat source heats the structure of shape
memory alloy to within the activated temperature range.
[0114] B12.1. The tool of paragraph B12, wherein the retention
structure includes a vacuum bagging assembly.
[0115] B13. The tool of any of paragraphs B-B12.1, further
comprising:
[0116] a mechanical impeder operatively coupled to the structure of
shape memory alloy, wherein the mechanical impeder is configured to
operatively resist deformation of the structure of shape memory
alloy from the first conformation to the second conformation.
[0117] B14. The tool of any of paragraphs B-B13, wherein the second
conformation defines a complex contour.
[0118] B15. The tool of any of paragraphs B-B14, wherein the first
conformation is generally planar, and optionally planar.
[0119] B16. The tool of any of paragraphs B-B15, wherein the sheet
of composite material includes one or more pre-preg composite
plies.
[0120] B17. The tool of any of paragraphs B-B16, wherein the
contoured composite structure is an aerospace structure.
[0121] B18. The tool of any of paragraphs B-B17 configured to
perform the method of any of paragraphs A-A19.
[0122] As used herein, the terms "selective" and "selectively,"
when modifying an action, movement, configuration, or other
activity of one or more components or characteristics of an
apparatus, mean that the specific action, movement, configuration,
or other activity is a direct or indirect result of user
manipulation of an aspect of, or one or more components of, the
apparatus.
[0123] As used herein, the terms "adapted" and "configured" mean
that the element, component, or other subject matter is designed
and/or intended to perform a given function. Thus, the use of the
terms "adapted" and "configured" should not be construed to mean
that a given element, component, or other subject matter is simply
"capable of" performing a given function but that the element,
component, and/or other subject matter is specifically selected,
created, implemented, utilized, programmed, and/or designed for the
purpose of performing the function. It is also within the scope of
the present disclosure that elements, components, and/or other
recited subject matter that is recited as being adapted to perform
a particular function may additionally or alternatively be
described as being configured to perform that function, and vice
versa. Similarly, subject matter that is recited as being
configured to perform a particular function may additionally or
alternatively be described as being operative to perform that
function.
[0124] In the event that any of the patent documents that are
incorporated by reference herein define a term in a manner that is
inconsistent with either the non-incorporated disclosure of the
present application or with any of the other incorporated patent
documents, the non-incorporated disclosure of the present
application shall control with respect to the present application,
and the term or terms as used in an incorporated patent document
shall only control with respect to the document in which the term
or terms are defined.
[0125] The various disclosed elements of apparatuses and steps of
methods disclosed herein are not required to all apparatuses and
methods according to the present disclosure, and the present
disclosure includes all novel and non-obvious combinations and
subcombinations of the various elements and steps disclosed herein.
Moreover, one or more of the various elements and steps disclosed
herein may define independent inventive subject matter that is
separate and apart from the whole of a disclosed apparatus or
method. Accordingly, such inventive subject matter is not required
to be associated with the specific apparatuses and methods that are
expressly disclosed herein, and such inventive subject matter may
find utility in apparatuses and/or methods that are not expressly
disclosed herein.
* * * * *