U.S. patent application number 14/975829 was filed with the patent office on 2016-04-21 for method of manufacturing a variable-radius laminated radius filler.
This patent application is currently assigned to The Boeing Company. The applicant listed for this patent is The Boeing Company. Invention is credited to Gabriel Z. FORSTON, Christopher G. HARRIS, William T. KLINE, Scott Edward KRAJCA, Joseph L. SWEETIN.
Application Number | 20160107432 14/975829 |
Document ID | / |
Family ID | 55748356 |
Filed Date | 2016-04-21 |
United States Patent
Application |
20160107432 |
Kind Code |
A1 |
KRAJCA; Scott Edward ; et
al. |
April 21, 2016 |
METHOD OF MANUFACTURING A VARIABLE-RADIUS LAMINATED RADIUS
FILLER
Abstract
A method of forming a radius filler may include providing an
upper portion having substantially constant width composite plies,
providing a base portion as a stack of variable width composite
plies, and stacking the upper portion onto the base portion to form
a radius filler stack.
Inventors: |
KRAJCA; Scott Edward;
(Seattle, WA) ; SWEETIN; Joseph L.; (Edmonds,
WA) ; HARRIS; Christopher G.; (Auburn, WA) ;
KLINE; William T.; (Seattle, WA) ; FORSTON; Gabriel
Z.; (Lake Stevens, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Boeing Company |
Chicago |
IL |
US |
|
|
Assignee: |
The Boeing Company
|
Family ID: |
55748356 |
Appl. No.: |
14/975829 |
Filed: |
December 20, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13705800 |
Dec 5, 2012 |
|
|
|
14975829 |
|
|
|
|
Current U.S.
Class: |
156/250 ;
156/60 |
Current CPC
Class: |
B26D 1/04 20130101; B29D
99/0014 20130101; B26D 1/06 20130101; B26D 7/018 20130101; B26D
1/00 20130101; B29C 70/30 20130101; Y10T 428/24074 20150115; Y10T
428/24174 20150115; Y10T 428/24116 20150115; Y10T 428/24289
20150115; B29L 2031/3085 20130101; B29C 70/342 20130101; B32B 37/14
20130101; B26D 1/0006 20130101; B26D 1/045 20130101; B32B 2605/18
20130101; B26D 2001/0033 20130101; B29D 99/0003 20130101; B32B 3/08
20130101; Y10T 428/24124 20150115; B29C 70/545 20130101; Y10T
428/24058 20150115 |
International
Class: |
B32B 37/14 20060101
B32B037/14 |
Claims
1. A method of forming a radius filler, comprising the steps of:
providing an upper portion having substantially constant width
composite plies; providing a base portion as a stack of variable
width composite plies; and stacking the upper portion onto the base
portion to form a radius filler stack.
2. The method of claim 1, wherein the step of providing the base
portion comprises: forming at least one of the upper portion and
the base portion in a stepped pyramidal cross-sectional shape.
3. The method of claim 1, wherein the step of providing the upper
portion comprises at least one of the following: forming a tip
portion with a generally triangular cross-sectional shape; and
forming a keyway portion as a stack of the substantially constant
width composite plies.
4. The method of claim 3, wherein the step of providing the upper
portion comprises: stacking the tip portion on top of the keyway
portion to form the upper portion.
5. The method of claim 3, further including the step of: providing
the tip portion with a constant cross-sectional area and a variable
cross-sectional shape.
6. The method of claim 3, further comprising the step of: forming
at least one of the keyway portion and the tip portion from a stack
of layers; and each one of the layers comprising a laminated charge
containing a plurality of composite plies.
7. The method of claim 6, further including the step of: providing
the laminated charge as a stack of composite plies containing at
least one pair of alternating +45 degree and -45 degree composite
plies sandwiched between a pair of 0 degree composite plies.
8. The method of claim 1, wherein the step of providing the base
portion includes: forming the base portion with at least one
transition zone comprising a change in at least one of a base
portion width and a base portion height.
9. The method of claim 8, further including: forming the base
portion with one or more constant zones comprising regions wherein
the base portion has a relatively constant cross-sectional shape;
and the constant zones being separated by a transition zone.
10. The method of claim 1, wherein the base portion is comprised of
a top layer, a bottom layer, and one or more mid layers located
between the top layer and the bottom layer, the step of providing
the base portion includes: changing a base portion height by
terminating a mid layer of the base portion.
11. The method of claim 10, wherein the step of changing the base
portion height includes: terminating the mid layer at a terminating
end having a non-square shape.
12. The method of claim 1, wherein the base portion is comprised of
a top layer, a bottom layer, and one or more mid layers located
between the top layer and the bottom layer, the step of providing
the base portion includes: extending the top layer continuously
along a length of the base portion.
13. The method of claim 1, wherein: the composite plies are
fiber-reinforced pre-preg plies.
14. A method of forming a radius filler, comprising the steps of:
providing an upper portion having substantially constant width
pre-preg composite plies; providing a base portion as a stack of
variable width composite plies; stacking the upper portion onto the
base portion to form a radius filler stack; and applying heat and
pressure to the radius filler stack to form a final radius filler
having a variable cross-sectional shape.
15. The method of claim 14, wherein the step of providing the base
portion comprises: forming at least one of the upper portion and
the base portion in a stepped pyramidal cross-sectional shape.
16. The method of claim 14, wherein the step of providing the upper
portion comprises at least one of the following: forming a tip
portion with a generally triangular cross-sectional shape; and
forming a keyway portion as a stack of the substantially constant
width composite plies.
17. The method of claim 16, further comprising the step of: forming
at least one of the upper portion and the tip portion from a stack
of layers; and each one of the layers comprising a laminated charge
containing a plurality of composite plies.
18. The method of claim 17, further including the step of:
providing the laminated charge as a stack of composite plies
containing at least one pair of alternating +45 degree and -45
degree composite plies sandwiched between a pair of 0 degree
composite plies.
19. The method of claim 14, wherein: the pre-preg composite plies
are carbon-fiber-reinforced pre-preg plies.
20. A method of forming a radius filler, comprising the steps of:
forming a tip portion with a generally triangular cross-sectional
shape; forming a keyway portion as a stack of substantially
constant width composite plies; stacking the tip portion on the
keyway portion to form an upper portion; providing a base portion
as a stack of variable width composite plies; stacking the upper
portion onto the base portion to form a radius filler stack;
applying heat and pressure to the radius filler stack to form a
final radius filler having a variable cross-sectional shape; and
contouring opposing radius filler sides complementary to opposing
radii of a radius filler region of a composite structure.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional application of and
claims priority to pending U.S. application Ser. No. 13/705,800
filed on Dec. 5, 2012, and entitled VARIABLE-RADIUS LAMINATED
RADIUS FILLER AND SYSTEM AND METHOD FOR MANUFACTURING SAME, the
entire contents of which is expressly incorporated by reference
herein.
FIELD
[0002] The present disclosure relates generally to composite
structures and, more particularly, to composite radius fillers for
composite structures, and methods for manufacturing the same.
BACKGROUND
[0003] Composite structures are used in a wide variety of
applications due to their high strength-to-weight ratio, corrosion
resistance, and other favorable properties. In aircraft
construction, composites are used in increasing quantities to form
the fuselage, wings, horizontal and vertical stabilizer, and other
components. For example, the horizontal stabilizer of an aircraft
may be formed of composite skin panels co-bonded to internal
composite structures such as composite stiffeners or spars. The
composite spars may extend from the root to the tip of the
horizontal stabilizer and may generally taper in thickness along a
spanwise direction to improve the stiffness characteristics of the
horizontal stabilizer and reduce weight. Composite spars may also
include localized increases in the composite thickness such as
where the spar attaches to other structures or components.
[0004] Composite stiffeners or spars may be provided in a variety
of cross-sectional shapes. For example, a composite spar or
stiffener may be formed in an I-beam shape by bonding together the
vertical webs of two "C" composite channels in back-to-back
arrangement. Each one of the "C" channels may have horizontal
flanges extending outwardly from the upper and lower ends of the
web. Each horizontal flange may transition into the web at a
radiused web-flange transition. When the "C" channels are joined
back-to-back to form the I-beam shape, the radiused web-flange
transitions result in a lengthwise notch along the upper and lower
ends of the I-beam. The lengthwise notches may be referred to as
radius filler regions or noodle regions. To improve the strength,
stiffness, and durability of a composite structure, radius filler
regions may be filled with radius fillers or noodles formed of
composite material.
[0005] Unfortunately, existing radius fillers suffer from several
drawbacks that detract from their utility. For example, existing
radius fillers may exhibit cracking due to residual stress that may
occur during the manufacturing process. In addition, certain radius
fillers may result in relatively low pull-off strength at the bond
between the I-beam and the skin panel. Furthermore, radius fillers
formed of unidirectional fibers may prevent non-destructive
inspection (NDI) of the inner radii at the web-flange transitions
in the I-beam. For example, the geometry of the radius fillers may
prevent inspection of the inner radii using conventional acoustic
inspection methods due to adverse effects on acoustic
transmissions. Further in this regard, localized changes in the
composite thickness along the length of the I-beam may result in
variations in the contour of the inner radii of the I-beam which
may complicate acoustic inspection of the inner radii.
[0006] As can be seen, there exists a need in the art for a radius
filler that minimizes cracking during the composite manufacturing
process and which provides favorable pull-off strength.
Furthermore, there exists a need in the art for a radius filler
that improves the inspectability of the inner radius of a composite
structure. Preferably, the radius filler can be manufactured in a
low-cost and relatively rapid manner with a minimal amount of touch
labor.
SUMMARY
[0007] The above-noted needs associated with radius fillers for
composite structures are specifically addressed and alleviated by
the present disclosure which provides a variable-radius laminated
composite radius filler that may include a base portion, a keyway
portion, and a tip portion. The base portion may be formed of a
plurality of variable width composite plies defining a variable
cross-sectional shape of the base portion. The keyway portion may
be stacked on the base portion and may be formed of a plurality of
substantially constant width composite plies defining a
substantially constant cross-sectional shape of the keyway portion.
The tip portion may be stacked on the keyway portion and may be
formed of composite plies.
[0008] Also disclosed is a method of forming a radius filler. The
method may include providing an upper portion having substantially
constant width composite plies. The method may further include
providing a base portion as a stack of variable width composite
plies. In addition, the method may include stacking the upper
portion onto the base portion to form a radius filler stack, and
applying heat and pressure to the radius filler stack to form a
final radius filler having a variable cross-sectional shape.
[0009] In a further embodiment, disclosed is a system for
manufacturing a composite radius filler. The system may include a
cutting head having a plurality of cutters arranged in a
side-by-side configuration. The cutters may be movable along a
lengthwise direction of a laminated stack of composite plies. The
cutters may have blades that may be positionable at different
heights for cutting the laminated stack into a base portion having
a stepped pyramidal cross-sectional shape. The cutters may be
individually movable along a lateral direction for cutting the
composite plies into variable cross-sectional shapes.
[0010] Also disclosed is a method of manufacturing a composite
radius filler including the step of assembling a laminated stack of
composite plies. The method may further include cutting, using a
cutting head, the laminated stack along a lengthwise direction in a
manner forming a base portion having a stepped pyramidal
cross-sectional shape. In addition, the method may include forming
the composite plies in a variable width when cutting the laminated
stack along the lengthwise direction.
[0011] The features, functions and advantages that have been
discussed can be achieved independently in various embodiments of
the present disclosure or may be combined in yet other embodiments,
further details of which can be seen with reference to the
following description and drawings below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] These and other features of the present disclosure will
become more apparent upon reference to the drawings wherein like
numbers refer to like parts throughout and wherein:
[0013] FIG. 1 is a perspective view of an aircraft;
[0014] FIG. 2 is a perspective view of a horizontal stabilizer
taken along line 2 of FIG. 1;
[0015] FIG. 3 is a side view of a composite stiffener bonded to
upper and lower skin panels and taken along line 3 of FIG. 2;
[0016] FIG. 4 is a side view of a final radius filler taken along
line 4 of FIG. 3;
[0017] FIG. 5 is an embodiment of a radius filler stack from which
the final radius filler of FIG. 4 may be formed;
[0018] FIG. 6 is an exploded side view of an embodiment of a radius
filler stack comprised of a tip portion, a keyway portion, and a
base portion;
[0019] FIG. 7 is a schematic illustration of an inverted radius
filler stack prior to installation in a forming die;
[0020] FIG. 8 is a schematic illustration of the application of
heat and pressure to the radius filler stack within the forming
die;
[0021] FIG. 9 is a schematic illustration of the final radius
filler after removal from the forming die;
[0022] FIG. 10 is a perspective illustration of an embodiment of a
tip portion having a substantially constant cross-sectional
shape;
[0023] FIG. 11 is a perspective illustration of an embodiment of a
keyway portion having a substantially constant cross-sectional
shape;
[0024] FIG. 12 is a perspective illustration of the keyway portion
formed from a laminated charge wherein each laminated charge is
comprised of a plurality of composite plies having a predetermined
fiber orientation angle sequence;
[0025] FIG. 13 is a end view of an embodiment of a base
portion;
[0026] FIG. 14 is a perspective view of an embodiment of a base
portion having a variable cross-sectional shape and including a
plurality of mid layers, the mid layers terminating at different
locations along a lengthwise direction of the base portion;
[0027] FIG. 15 is a perspective view of an embodiment of a base
portion having a continuous top layer overlapping the terminating
ends of the mid layers;
[0028] FIG. 16 is a side view of the base portion of FIG. 15
illustrating the continuous top layer overlapping the terminating
mid layers;
[0029] FIG. 17 is a sectional view of the base portion taken along
line 15 of FIG. 14 and illustrating the base portion, the keyway
portion, and the tip portion collectively forming the radius filler
stack having a first radius being formable on opposing sides of the
filler radius;
[0030] FIG. 18 is a sectional view of the base portion taken along
line 16 of FIG. 14 and illustrating a reduced cross-sectional area
base portion resulting in the radius filler stack having a second
radius being formable on opposing sides of the filler radius and
wherein the second radius is smaller than the first radius of FIG.
15;
[0031] FIG. 19 is a perspective view of a part of the base portion
illustrating a termination of a mid layer to achieve a reduction in
the base portion height and in the cross-sectional area;
[0032] FIG. 20 is a perspective view of a portion of an I-beam
composite structure illustrating a radius filler region on a top
side of the I-beam and further illustrating localized ply additions
and ply drops in the I-beam which are accommodated by transition
zones in the cross-sectional area of the base portion as a means to
maintain a substantially constant stiffener inner radius along the
I-beam;
[0033] FIG. 21 is a schematic top view of an embodiment of a layer
profile shape of one or more composite plies of a base portion
having transition zones that are offset from the start of a ply
drop or a ply addition in a composite structure into which the
radius filler is installed;
[0034] FIG. 22 is a flow chart illustrating one or more operations
that may be included in a method of forming a radius filler;
[0035] FIG. 23 is a schematic top view of an embodiment of a system
for manufacturing radius filler;
[0036] FIG. 24 is a schematic top view of an embodiment of a
laminating station and a cutting station for laminating and cutting
a laminated stack of composite plies into a base portion of a
radius filler stack;
[0037] FIG. 25 is schematic top view of an embodiment of a cutting
head for cutting the laminated stack into a stepped pyramidal cross
sectional shape;
[0038] FIG. 26 is a side view of the cutting head cutting through
layers of composite plies in the laminated stack;
[0039] FIG. 27 is an end view of an embodiment of a cutting head
taken along line 24 of FIG. 23 and illustrating the cutting head
cutting through a laminated stack;
[0040] FIG. 28 is a side schematic view of a stacking station;
[0041] FIG. 29 is a top view of the stacking station having a pair
of individual multi-ply layers supported on a vacuum table prior to
translating the multi-ply layers onto a layup table;
[0042] FIG. 30 is a schematic end view of a vacuum rail translating
a base portion from a vacuum table onto a layup table;
[0043] FIG. 31 is a schematic end view of the vacuum rail lifting
the base portion off of a cutting table prior to translating the
base portion onto the layup table;
[0044] FIG. 32 is a schematic end view of the vacuum rail stacking
an upper portion onto the base portion to form a radius filler
stack;
[0045] FIG. 33 is a schematic side view of an embodiment of a
pressing station for forming each one of a pair of radius filler
stacks into a final radius filler;
[0046] FIG. 34 is a schematic side view of the pressing station
illustrating the application of heat and pressure to the pair of
radius filler stacks to form the final radius fillers into a
variable cross-sectional shape that may be contoured complementary
to the corresponding radius filler regions of a composite
structure;
[0047] FIG. 35 is a flow diagram illustrating one or more
operations that may be included in a method for automated
manufacturing of one or more radius fillers;
[0048] FIG. 36 is a flow diagram of an aircraft manufacturing and
service methodology; and
[0049] FIG. 37 is a block diagram of an aircraft.
DETAILED DESCRIPTION
[0050] Referring now to the drawings wherein the showings are for
purposes of illustrating preferred and various embodiments of the
disclosure, shown in FIG. 1 is a perspective view of an aircraft
100 having a fuselage 102 extending from a forward end of the
aircraft 100 to an aft end of the aircraft 100. The aft end may
include an empennage 112 having one or more tail surfaces for
directional control of the aircraft 100 such as a vertical
stabilizer 114 and a pair of horizontal stabilizers 116. The
aircraft 100 may further include a pair of wings 110 extending
outwardly from the fuselage 102 and one or more propulsion units
104 that may be mounted to the wings 110. The fuselage 102, the
wings 110, the vertical stabilizer 114, the horizontal stabilizers
116, and other aircraft components may be formed as composite
structures 106.
[0051] Referring to FIG. 2 shown is a perspective cutaway view of a
portion of a horizontal stabilizer 116 of the aircraft 100 of FIG.
1. The horizontal stabilizer 116 may have a stabilizer leading edge
124 and a stabilizer trailing edge 126 (FIG. 1) and may extend
along an outboard direction 122 from a stabilizer root 118 to a
stabilizer tip 120. As indicated above, the horizontal stabilizer
116 may be formed of composite skin panels 130 that may be
co-bonded to one or more composite stiffeners or spars 132. The
composite stiffeners or spars 132 may have a generally tapered or
reduced thickness along a spanwise direction 128 of the horizontal
stabilizer 116. In addition, the composite spars 132 or stiffeners
134 may include localized changes in the composite thickness (FIG.
20) along the length of the spars 132 or stiffeners.
[0052] In FIG. 2, the composite spar 132 or stiffener 134 is
provided in an I-beam 142 shape although the composite stiffener
134 may be provided in a variety of cross-sectional shapes. The
composite stiffener 134 may include horizontal flanges 148 that
transition from the web 146 at a radiused web-flange transition 150
as indicated above. Each one of the web-flange transition 150
defines a stiffener outer radius 138 and a stiffener inner radius
136. Each composite stiffener 134 may further include a base
laminate 152 that may enclose a radius filler region 140 on upper
and lower ends of the composite stiffener. The radius filler region
140 may extend along a lengthwise direction of the composite
stiffener 134.
[0053] Advantageously, the present disclosure provides a laminated
composite radius filler 200 having a variable cross-sectional shape
322 (e.g., a generally reducing cross-sectional area) along an
outboard direction 122 of a composite stiffener 134 to accommodate
a tapering or reducing thickness of the composite stiffener 134. In
addition, the variable cross-sectional shape 322 radius filler 200
disclosed herein has opposing sides that are contoured to
accommodate localized increases and decreases 218 in the thickness
of the composites stiffener 134 along a spanwise direction 128, as
described in greater detail below. By forming the radius filler 200
in a variable cross-sectional shape 322, the stiffener inner radius
136 may be generally constant along a length thereof which may
significantly improve the inspectability of the stiffener inner
radius 136 relative to the significant amount of time and
complexity required for inspecting a stiffener inner radius that
varies (not shown) along a lengthwise direction.
[0054] Advantageously, a substantially constant stiffener inner
radius 136 may allow for forming the stiffener tooling with a
constant radius which may significantly reduce tooling costs
relative to the cost of tooling having variable radii. Furthermore,
the variable cross-sectional shape laminated composite radius
filler 200 disclosed herein may advantageously reduce cracking
during the manufacturing process relative to existing radius
fillers such as unidirectional radius fillers. In addition, the
variable cross-sectional shape 322 laminated composite radius
filler 200 disclosed herein may result in improved pull-off
strength at the bond between the composite stiffener 134 and a skin
panel 130.
[0055] Referring to FIG. 3, shown is I-beam 142 composite stiffener
134 prior to co-bonding to upper and lower skin panels 130. The
composite stiffener 134 is comprised of a pair of channels 144
positioned in back-to-back relationship to form the I-beam 142
shape. Each channel 144 includes a web 146 having horizontal
flanges 148 at the upper and lower ends of the channel 144. As
indicated above, the radiused web-flange transitions in each
channel 144 result in a lengthwise notch or radius filler region
140 at the upper and lower ends of the I-beam 142. The radius
filler regions 140 are filled with the variable cross-sectional
shape 322 laminated upper radius filler 202 and lower radius filler
204. Advantageously, each radius filler 202, 204 is formed with a
variable cross-sectional shape 322 that matches the changing
contour of the outer stiffener 134 radii in the radius filler
region 140 along a length of the stiffener. In this manner, the
composite structure 106 advantageously has a substantially constant
stiffener inner radius 136 along a lengthwise direction.
[0056] Referring to FIG. 4, shown is an end view of a final radius
filler 206 after co-bonding or co-curing with the composite
stiffener 134. The final radius filler 206 has opposing radius
filler sides 208. Each one of the radius filler sides 208 may have
a variable radius along a lengthwise direction. In the final
profile shape, the radius filler sides 208 are preferably contoured
complementary to the radius filler region 140 of a composite
structure 106 such as a composite stiffener 134. The final profile
shape may be applied to the radius filler sides 208 using a forming
die 230 as described below.
[0057] Referring to FIG. 5, each radius filler 200 may be formed of
a laminated stack 422 of composite plies 276. The composite plies
276 may comprise pre-preg composite plies 276 such as carbon fiber
reinforced plastic (CFRP) plies. The base portion 320 may be formed
as a plurality of variable width composite plies 346 defining a
variable cross-sectional shape 322 of the base portion 320. As
described below, the variable cross-sectional shape 322 of the base
portion 320 may extend along a lengthwise direction 324 or along at
least a portion of the length of the base portion 320. The radius
filler 200 may also include an upper portion 212 stacked on top of
the base portion 320. The upper portion 212 may comprise a tip
portion 250 and a keyway portion 300. The upper portion 212 may
advantageously have a substantially constant cross-sectional shape
along a lengthwise direction which may simplify manufacturing of
the radius filler 200.
[0058] Referring to FIG. 6, shown is an exploded view of a radius
filler 200 wherein the upper portion 212 is shown comprised of a
separate tip portion 250 and a separate keyway portion 300.
However, as indicated above, the tip portion 250 and the keyway
portion 300 may be formed as a unitary upper portion 212 to
simplify manufacturing. The tip portion 250 may be comprised of a
plurality of substantially constant width composite plies 310
defined by a tip portion width 254. The tip portion 250 may have a
triangular cross-sectional shape 264 with tip portion sides 260
terminating at a tip portion apex 262. The tip portion 250 may have
a substantially constant cross-sectional area along a lengthwise
direction. However, although not shown, the tip portion may have a
variable cross-sectional shape. For example, the triangular
cross-sectional shape 264 may vary along the lengthwise direction.
In an embodiment, the tip portion width 254 may vary in
correspondence with the changing radii of the radius filler region
140 (FIG. 2) of a composite structure 106.
[0059] Although not shown, the tip portion 250 may be configured
such that at a location of a relatively large radius in the radius
filler region 140 (e.g., at the root 118 of the horizontal
stabilizer 116--FIG. 1), the tip portion 250 may have a narrower
tip portion width 254 and a taller tip portion height 256 relative
to a location of a smaller radius in the radius filler region 140
(e.g., at the tip 120 of the horizontal stabilizer 116--FIG. 1)
where the tip portion 250 may have a wider tip portion width 254
and a shorter tip portion height 256. However, the tip portion 250
may also be configured with a substantially constant tip portion
height 256 and/or a substantially constant tip portion width 254
along a lengthwise direction 252 of the tip portion 250.
Furthermore, in an embodiment not shown, the tip portion 250 may be
eliminated from the upper portion 212 where the volume of the
radius filler region 140 filled by the tip portion 250 is
relatively small, such that the upper portion may be comprised
solely of the keyway portion 300.
[0060] In FIG. 6, the keyway portion 300 may have a substantially
constant cross-sectional shape along the lengthwise direction 302.
The keyway portion 300 may also be formed of a plurality of
substantially constant width composite plies 310 defined by a
keyway portion width 304. In an embodiment, the keyway portion 300
may have a stepped pyramidal cross-sectional shape 312 along the
lengthwise direction 302. However, the keyway portion 300 may have
angled sides and (not shown) such that the keyway portion 300 may
have a trapezoidal shape (not shown). The keyway portion height 306
may be a constant height 308 along a lengthwise direction 302. The
upper portion 212 may be stacked onto the base portion 320 to form
a radius filler stack 210.
[0061] By configuring the upper portion with a substantially
constant cross-sectional area and/or a substantially constant
cross-sectional shape along the lengthwise direction, the cost of
manufacturing radius fillers 200 may be significantly reduced by
eliminating the need to build a relatively narrow,
uniquely-tailored, upper portion 212 (e.g., a uniquely-tailored tip
portion 250 and a uniquely-tailored keyway portion 300) for each
radius filler region in a composite structure 106. In this regard,
a common upper portion 212 may be paired with different base
portion 320 configurations for use in different composite
stiffeners such as the different composite stiffener 134 I-beams
142 of the horizontal stabilizer 116 of FIG. 2. In an embodiment,
the upper portion 212 (e.g., a tip portion 250 and a keyway portion
300) may be built in batches at relatively low cost for pre-kitting
with base portions 320. Costs may further be reduced by purchasing
pre-manufactured upper portions 212 from an outside supplier.
[0062] FIG. 7 is a schematic illustration of an inverted radius
filler stack 210 prior to installation in a forming die 230. The
forming die 230 may have a die cavity 232 that may substantially
duplicate the radius filler region 140 of a composite structure
106. In this regard, the die cavity 232 may be contoured
complementary to the changing stiffener outer radii 138 of the
radius filler region 140 of a composite structure 106. In FIG. 6,
the radius filler stack 210 may be sized and configured to provide
a design overfill volume (not shown) that is a larger than the
volume of the die cavity 232 (FIGS. 7-9) and/or the volume of a
corresponding radius filler region 140 of a composite structure
106. In this regard, the cross-sectional area of the radius filler
200 may be larger than the cross-sectional area of the radius
filler region 140. In a further embodiment, the die cavity 232 may
be sized and configured to provide a tooling overfill volume (not
shown) that may be larger than the volume of the corresponding
radius filler region 140. By sizing and configuring the radius
filler 200 and the die cavity 232 in an overfill condition,
pull-off strength may be improved relative to a radius filler
having a volume that is substantially equivalent to the volume of
the radius filler region or the die cavity.
[0063] FIG. 8 shows the application of heat 238 and pressure 236 to
the radius filler stack 210 within the forming die 230. A pressure
plate 234 may be applied over the base portion 320. Heat 238 and
pressure 236 may be applied to the radius filler stack 210 in a
predetermined heat-pressure cycle to debulk and/or consolidate the
radius filler 200. The heat 238 may reduce the viscosity of the
resin in the pre-preg composite plies 276 allowing the resin to
soften so that the radius filler 200 can conform to the
cross-sectional shape of the die cavity 232.
[0064] FIG. 9 illustrates the removal of a final radius filler 206
from the forming die 230. The final radius filler 206 may be in a
green state wherein the resin in the composite plies 276 is
uncured. The final radius filler 206 may be installed into a radius
filler region 140 of a composite structure 106 for final co-curing
and/or co-bonding with the composite structure 106 and/or skin
panels 130.
[0065] FIG. 10 is a perspective view of an embodiment of a tip
portion 250 having a generally constant cross-sectional shape 268
along the lengthwise direction 252. The tip portion 250 is shown
having a generally constant triangular cross-sectional shape 264
along the lengthwise direction 252. However, the tip portion 250
may be provided in any cross-sectional shape and is not limited to
the triangular cross-sectional shape 264 shown in FIG. 10. In an
embodiment, the tip portion 250 may be formed of a relatively small
quantity of composite plies 276. For example, the tip portion 250
may be formed of three (3) composite plies 276 each comprising
approximately 0.25 inch wide CFRP tape each having a thickness of
approx me 0.0075 inch. In this regard, the tip portion 250 may have
a maximum tip portion width 254 of approximately 0.25 inch and a
tip portion height 256 of approximately 0.023 inch. However, the
tip portion 250 may be formed in any tip portion width 254 or tip
portion height 256 and may be comprised of any type of composite
material 108 and is not limited to CFRP tape.
[0066] FIG. 11 is a perspective view of an embodiment of a keyway
portion 300 having a generally constant cross-sectional shape along
a lengthwise direction 302. The keyway portion 300 is shown having
a stepped pyramidal cross-sectional shape 312 formed of
substantially constant width composite plies 310. In an embodiment,
the keyway portion 300 may have a maximum width of less than
approximately 0.25 inch although the keyway portion 300 may be
provided in any keyway portion width 304. The quantity of composite
plies 276 of the keyway portion 300 may be substantially constant
such that the keyway portion 300 has a substantially constant
height 308 along a lengthwise direction 302. In an embodiment, the
keyway portion 300 may contain in the range of approximately eight
(8) to 20 composite plies 276 or more. However, the keyway portion
300 may contain less than eight (8) composite plies 276.
[0067] FIG. 12 is a perspective illustration of an embodiment of
the keyway portion 300 formed from a plurality of layers 272. Each
one of the layers 272 may comprise a pre-manufactured laminated
charge 270 containing a predetermined quantity of composite plies
276. Each one of the layers 272 in the keyway portion 300 may be
manufactured from the same laminated charge 270 or from a laminated
charge 270 having the same composite material 108 as the remaining
layers 272 of the keyway portion 300. Further in this regard, as
described below, the base portion 320 may also be formed from one
or more laminated charges 270 and which may be substantially
similar to the laminated charges 270 used in forming the keyway
portion 300.
[0068] In FIG. 12, the composite plies 276 in a laminated charge
270 may have a predetermined fiber orientation stacking sequence.
For example, FIG. 12 illustrates each layer 272 being formed as a
4-ply charge 274 containing a pair of +45 degree and -45 degree
composite plies 282, 284 sandwiched between a pair of 0 degree
composite plies 276 with one 0-degree composite ply 280 on each
side of the +/-45 degree composite plies 282, 284. However, a
laminated charge 270 may be formed of any quantity of composite
plies 276 and in any fiber orientation stacking sequence in any
range from a 0 degree fiber orientation angle to a 90 degree fiber
orientation angle. In an embodiment, the fiber orientation angle
278 stacking sequence may be selected to provide the radius filler
200 with a stiffness that is compatible with the stiffness of the
composite structure 106 into which the radius filler 200 is
installed. In this regard, the fiber orientation stacking sequence
in the tip portion 250, the keyway portion 300, and/or the base
portion 320 may be selected to be compatible with the stiffness
characteristics of the composite structure 106. In addition, the
composite material 108 in the tip portion, the keyway portion 300,
and/or the base portion 320 may be selected to be thermally
compatible with the composite material 108 of the composite
structure 106.
[0069] Referring to FIG. 13, shown is an end view of an embodiment
of the base portion 320. The base portion 320 may be provided in a
stepped pyramidal cross-sectional shape 312 along the lengthwise
direction 324. As indicated above, the base portion 320 may have a
variable height 334 along the lengthwise direction 324 and may be
formed of variable width composite plies 346. The base portion 320
may be formed of a plurality or stack of layers 272 including a
base portion top layer 340, a base portion bottom layer 342, and
one or more base portion mid layers 344. In an embodiment, each
layer 272 may comprise a laminated charge 270 containing a
predetermined quantity of composite plies 276 arranged in a
predetermined fiber orientation stacking sequence. In FIG. 13, the
base portion 320 is comprised of eight (8) layers 272 wherein each
layer 272 comprises a 4-ply charge 274 containing +/-45 degree
composite plies 282, 284 sandwiched between 0 degree composite
plies 276 for a total of 32 composite plies 276 in the base portion
320 of FIG. 13. However, the base portion 320 may be provided with
any quantity of composite plies 276. For example, the base portion
320 may contain up to 52 composite plies 276 (e.g. 13 layers of
4-ply charge 274), although the base portion 320 may contain more
than 52 composite plies 276.
[0070] FIG. 14 is a perspective view of an embodiment of the base
portion 320 having a variable cross sectional shape along a
lengthwise direction 324. The base portion 320 has a stepped
pyramidal cross-sectional shape 312 which has a variable height 334
and which includes variable width composite plies 346 in each one
of the layers 272. Each one of the composite plies 276 may have a
layer profile shape 348 that varies along the lengthwise direction
324. The layer profile shape 348 may include transition zones 356
that correspond to ply drops 154 or ply additions 160 in the
composite structure 106 as described in greater detail below. The
left hand side of the base portion 320 in FIG. 14 has an increased
cross-sectional area as may be located at a stabilizer root 118 of
the horizontal stabilizer 116 of FIG. 2. The right hand side of the
base portion 320 in FIG. 14 has a reduced cross sectional area as
may be located at a stabilizer tip 120 of the horizontal stabilizer
116. The base portion shown in FIG. 14 may be comprised of a bottom
layer 342, one or more mid layers 344, and a top layer (not shown).
The mid layers 345 may periodically terminate along a lengthwise
direction and may be covered by a substantially continuous top
layer 340 as shown in FIG. 15. However, the base portion 320 may be
provided in an embodiment where the top layer is omitted as shown
in FIG. 14.
[0071] FIG. 15 is a perspective view of an embodiment of a base
portion 320 having a substantially continuous top layer 340
extending along a length of the base portion 320. The top layer 340
is shown in FIG. 15 in a planar condition prior to conforming the
top layer 340 to the stair-step shape of the terminating mid layers
345 as shown in FIG. 16. By forming the top layer 340 as a
continuous layer covering the mid layers 345, the cured radius
filler 200 may have reduced porosity. The top layer 340 may be
provided in a top layer width 341 that may vary with ply drops 154
(FIG. 20) and/or ply additions 160 (FIG. 20) in the composite
structure 106. In addition, the top layer width 341 may be sized to
provide the radius filler 200 with a desired amount of design
overfill along the length of the radius filler 200 and which may
improve the strength properties of the cured composite structure
106 as mentioned above.
[0072] FIG. 16 is a side view of a part of the base portion 320 of
FIG. 15 and illustrating the overlapping of the top layer 340 over
the mid layers 345. The top layer 340 may generally follow the
stair-step shape formed by the termination of the mid layers 345.
In this manner, the top layer 340 may generally cover or
encapsulate the mid layers 345 which may improve processing and
resulting in improved properties of the cured radius filler
200.
[0073] FIG. 17 is a sectional view taken along the left hand side
of the base portion 320 of FIG. 14 and illustrating the keyway
portion 300 and the tip portion 250 (shown in phantom lines)
stacked on top of the base portion 320. The tip portion 250 and the
keyway portion 300 have a constant height 258, 308 and may have
substantially constant width composite plies 310 along their
lengthwise directions 252, 302. The base portion 320 may have a
relatively large quantity of layers 272 or composite plies 276
(e.g., 8 layers or 32 composite plies or more) defining a first
height 336 and a first width 328. The relatively large cross
sectional area of the base portion 320 in FIG. 17 facilitates a
relatively large first radius 214 on opposing sides of the radius
filler 200.
[0074] FIG. 18 is a sectional view taken along the right hand side
of the base portion 320 of FIG. 14. The tip portion 250 and the
keyway portion 300 in FIG. 18 maintain the substantially constant
width composite plies 310 and the same height as the tip portion
250 and the keyway portion 300 in FIG. 17. However, the base
portion 320 in FIG. 18 has a reduced quantity of layers 272 or
composite plies 276 (e.g., 4 layers or 16 composite pies) which
results in a second height 338 of the base portion 320 in FIG. 18
that is reduced relative to the first height 336 of the base
portion 320 in FIG. 17. Additionally, the variable width composite
plies 346 of the base portion 320 in FIG. 18 have a second width
330 which is reduced relative to the first width 328 of the
variable width composite plies 346 in FIG. 17. The reduced cross
sectional area of the base portion 320 in FIG. 18 facilitates the
formation of a second radius 216 on opposing sides in FIG. 18 that
is smaller than the first radius 214 in FIG. 17. In this manner,
changes in the cross-sectional shape of the radius filler 200 may
be facilitated by changing the width of the variable width
composite plies 346 along a lengthwise direction 324 of the base
portion 320, and/or by reducing the quantity of composite plies 276
or layers 272 by terminating one or more top layers 340 of the base
portion 320 along a lengthwise direction 324.
[0075] FIG. 19 illustrates the termination of a mid layer 345 of
the base portion 320 to achieve a reduction in the base portion
height 332 and resulting in a reduction in the cross-sectional area
of the radius filler 200. In an embodiment, the terminating end 350
of the mid layer 345 may have a non-square shape 352 which may
improve the ability of the radius filler 200 to fill the volume of
the radius filler region 140 and which may increase the strength
and stiffness characteristics of the final composite structure 106.
For example, the terminating end 350 of a mid layer 345 may have a
generally pointed shape or the terminating end 350 may have a
generally rounded shape (not shown). As indicated above, the
composite structure 106 may have a generally tapered or reducing
thickness facilitated by one or more ply drops 154 along a
lengthwise direction of the composite structure 106. In addition,
the composite structure 106 may have localized increases in
thickness due to one or more ply additions 160 in the composite
structure 106. In this regard, the base portion 320 may include one
or more constant zones 354 comprising regions wherein the base
portion 320 has a relatively constant cross-sectional shape and
which may be separated by transition zones 356 comprising regions
of change in the cross sectional shape of the base portion 320. The
transition zones 356 may be positioned adjacent to ply drops 154
and/or ply additions 160 in the composite structure 106. Each
transition zone 356 may comprise a change in the base portion width
326 and/or a change in the base portion height 332 in
correspondence with the ply drop(s) 154 and/or the ply addition(s)
160 in the composite structure 106.
[0076] FIG. 20 shows a composite structure 106 having a changing
thickness along a lengthwise direction. The changing thickness may
include a stiffener ply drop 154 wherein one or more composite
plies 276 of the composite structure 106 may be terminated. The
changing thickness of a composite structure 106 may also include a
stiffener ply addition 160 wherein one or more composite plies 276
of the composite structure 106 may be added. The stiffener ply
drops 154 and stiffener ply additions 160 may result in variation
in the stiffener outer radii 138 (FIG. 3) along the length of the
flanges 148. Advantageously, the variable cross-sectional shape 322
of the radius filler 200 disclosed herein may be contoured
complementary to the variation in stiffener outer radii 138. In
this manner, the stiffener inner radii 136 of the composite
structure 106 may be substantially constant along a lengthwise
direction and which may improve the inspectability of the composite
structure 106 and may additionally reduce tooling costs associated
with manufacturing the composite stiffener 134.
[0077] FIG. 21 is a plan view of a layer profile shape 348 of one
or more composite plies 276 of the base portion 320. As indicated
above, the base portion 320 may be configured with transition zones
356 corresponding to ply drops 154 and ply additions 160 in the
composite structure 106. Each transition zone 356 may be offset 358
from the start 156 of a ply drop 154 or the start 162 of a ply
addition 160. A ply drop 154 may comprise a region along which one
or more composite plies 276 may be terminated from the composite
structure 106. A ply addition 160 may comprise a region along which
one or more composite plies 276 may be added to the composite
structure 106.
[0078] In FIG. 21, the base portion 320 may be configured such that
for ply drops 154 in the composite structure, the start of a
transition zone 356 in the base portion 320 may be positioned after
the start 156 of a stiffener ply drop 154. The end of a transition
zone 356 in the base portion 320 may be positioned after the end
158 of a stiffener ply drop 154. Conversely, for ply additions 160
in the composite structure, the start of the transition zone 356 in
the base portion 320 may be positioned before the start 162 of a
stiffener ply addition 160, and the end of the transition zone 356
in the base portion 320 may be positioned before the end 164 of the
stiffener ply addition 160 in the composite structure 106. In an
embodiment, transition zones 356 may be offset 358 from the start
156 and of the stiffener ply drops 154 and ply additions 160 by a
distance of approximately 0.10 inch 0.50 inch or larger. In a
further embodiment, the offset 358 distance may be approximately
0.25 inch. It has been determined that offsetting the transition
zones 356 from the start 156 and end 158 of ply drops 154 and ply
additions 160 improves the filling of the radius filler region 140
with the radius filler disclosed herein which improves the
strength, stiffness, and inspectability of the composite structure
106.
[0079] Referring to FIG. 22, shown is a flow chart illustrating an
embodiment of a method 500 of forming a radius filler 200. The
method may include Step 502 comprising providing an upper portion
212 of the radius filler 200 as a stack of substantially constant
width composite plies 310 as shown in FIG. 6. As indicated above,
the upper portion 212 may comprise a tip portion 250 and a keyway
portion 300. The tip portion 250 and the keyway portion 300 may
each have a substantially constant cross-sectional shape along a
lengthwise direction 252, 302. The method may include forming the
upper portion 212 in a stepped pyramidal variable cross-sectional
shape 322 as shown in FIG. 6.
[0080] Step 502 of the method 500 of FIG. 22 may further include
forming the tip portion 250 as a stack of less than five (5)
composite plies 276 (e.g., three composite plies). In an
embodiment, the tip portion 250 may be formed with in a generally
triangular cross-sectional shape 264. The tip portion 250 may have
a substantially constant cross-sectional area 266 (FIG. 10) along
the lengthwise direction 252 even though the cross-sectional shape
of the tip portion 250 may change along the lengthwise direction
252. The method may further include forming the keyway portion 300
as a stack of substantially constant width composite plies 310
(FIG. 11) from a pre-manufactured laminated charge 270 wherein the
composite plies have a pre-determined fiber orientation angle 278
(e.g., FIG. 12). The keyway portion 300 may have a substantially
constant stepped pyramidal cross-sectional shape 312 (FIG. 11)
along the lengthwise direction 302. The upper portion 212 may be
formed by stacking the tip portion 250 onto the keyway portion 300
(FIG. 5).
[0081] Step 504 of the method 500 of FIG. 22 may include providing
the base portion 320 (FIG. 13) as a stack of variable width
composite plies 346 defining a variable cross-sectional shape 322
of the base portion 320 along the lengthwise direction 324 as
illustrated in FIGS. 14 and 17. In an embodiment, the method may
include forming the base portion 320 in a stepped pyramidal
variable cross-sectional shape 322 by providing the layers 272 in
successively narrower widths from the bottom layer 342 (FIG. 13) of
the base portion 320 toward the top layer 340 of the base portion
320.
[0082] Step 506 of the method 500 of FIG. 22 may include stacking
the upper portion 212 onto the base portion 320 to form a radius
filler stack 210 as shown in FIGS. 15-16. Step 506 may include
forming one or more transition zones 356 in the base portion 320
wherein the transition zone 356 comprises the location of a change
in the base portion width 326 and/or a change in the base portion
height 332 as shown in FIGS. 14 and 17. The method may further
include locating each transition zone 356 in correspondence with a
ply drop 154 of a composite structure 106 or a ply addition 160 of
the composite structure 106 as shown in FIG. 21. In this regard,
Step 506 may include positioning the transition zone 356 before a
ply drop 154 and after a ply addition 160. Changing the base
portion width 326 may include terminating one or more mid layers
345 of the base portion 320 at the location of a ply drop 154 in
the composite structure 106 and providing the terminating end 350
in a non-square shape 352 such as in a generally rounded shape or
in pointed shape as shown in FIG. 19.
[0083] Step 508 of the method 500 of FIG. 22 may include applying
heat 238 and pressure 236 to the radius filler stack 210 in a
forming die 230 to form a final radius filler 206 having a variable
cross-sectional shape 322. In this regard, Step 508 may include
providing the forming die 230 with a die cavity 232 that may be
configured complementary to the changing contour of the stiffener
outer radii 138 of a radius filler region 140 of a composite
structure 106. In this manner, the stiffener inner radii 136 may be
generally constant along a lengthwise direction which may improve
inspectability and reduce tooling costs associated with the
composite stiffener.
[0084] Referring to FIG. 23, shown is top schematic view of an
embodiment of a system 400 that may be implemented for automated
manufacturing of a composite laminated radius filler 200 having a
variable cross-sectional shape 322. The system 400 may include a
laminating station 402, a cutting station 404, a stacking station
446, and a pressing station 466. In an embodiment, the laminating
station 402 and the cutting station 404 may be combined into a
single location. Likewise, the stacking station 446 and the
pressing station 466 may be combined into a single location. It is
also contemplated that any one of the stations disclosed herein may
be combined with any one of the other stations into a single
location in order to simplify manufacturing and minimize the
requirement for translating or moving the radius filler from
station to station. The system 400 advantageously provides a means
for automated or semi-automated laminating, cutting, stacking, and
pressing of radius fillers 200 such as for use in radius filler
regions 140 of structural composite components such as the I-beam
composite stiffener 134 shown in FIGS. 2-3. The system 400 may
minimize or eliminate the need for hand layup of radius fillers and
may result in a significant improvement in the consistency and
quality of radius fillers 200.
[0085] In FIG. 23, the laminating station 402 may include a
laminating head 406 that may be coupled to a laminating head drive
system 408. In this regard, the laminating head 406 may be
configured as a tape laying machine for applying tape or composite
plies 276 onto a lamination/cutting table 416. The
lamination/cutting table 416 may be configured as a vacuum table
418 having a vacuum pump 420 (FIG. 29) for applying a suction force
on the laminated composite plies 276 to prevent movement thereof
during the laminating and cutting process. In an embodiment, the
laminating head 406 may be configured to apply single composite
plies 276 of any fiber angle orientation, or the laminating head
406 may be configured to apply individual multi-ply layers onto the
cutting table 416. Each individual multi-ply layer 272 may comprise
a laminating charge 270 (e.g., a 4-ply charge 274--FIG. 12)
comprising a pre-manufactured stack of composite plies 276 having a
predetermined fiber orientation angle 278 sequence as described
above. The laminating head 406 may be configured to lay-up a
laminated stack 422 in any thickness such as in a thickness of up
to 0.75 inch or more, and in any width such as in widths of up to
18 inches or more. In the present disclosure, a laminated stack 422
is comprised of a stack of composite plies 276 of any quantity and
may include an individual composite ply 276, an individual
multi-ply layer 272 (e.g., a laminated charge 270), or a stack of
multi-ply layers 272. FIG. 22 illustrates a direction of movement
410 of the laminating head 406 along a laminating direction 442 to
apply composite plies 276 or layers 272 of a laminated charge 270
onto the lamination/cutting table 416 to form a laminated stack
422.
[0086] Referring to FIG. 24, shown is a cutting head 424 having a
plurality of blades 432 for cutting the laminated stack 422
positioned on the lamination/cutting table 416. The cutting head
424 may be operatively coupled to a cutting head drive system 426
for moving the cutting head 424 lengthwise along the length of the
laminated stack 422. In an embodiment, the lamination/cutting table
416 may have a cutting surface such as self-healing surface to
allow cutting into the surface without damaging the blades 432 of
the cutting head 424. The laminating head 406 may be moved to a
home position 412 when the cutting head 424 is an in active
position 414 cutting the laminated stack 422 along a cutting
direction 440. After cutting an individual multiply layer 272 or
cutting a laminated stack 422 into a base portion 320, the
lamination/cutting table 416 may be translated into a stacking
station 446 where a lifting mechanism 454 may lift each individual
multi-ply layer 272 (e.g., laminated charge 270) onto a layup table
for stacking with other multi-ply layers 272 to form a base portion
320 and/or a radius filler stack 210. The cutting head 424 may also
cut a laminated stack 422 into a stepped pyramidal base portion 320
which may then be moved into the stacking station 446. At the
stacking station 446, the lifting mechanism may lift and translate
the base portion 320 onto the layup table 450 for stacking with the
remaining components of the radius filler 200. The radius filler
stack 210 may then be transferred into a pressing station 466 for
forming into a final radius filler 206 as described below.
[0087] Referring to FIG. 25, shown is a top view of a cutting head
424 which may include one or more cutters 428. Although the cutting
head 424 is shown having twelve (12) cutters 428, any number of
cutters 428 may be provided. The cutters 428 may be arranged in
staggered, side-by-side configuration 430, although the cutters 428
may be arranged in other configurations not shown. The cutters 428
may be movable along a lengthwise direction of the laminated stack
422 supported on the lamination/cutting table 416. The cutting head
424 may be configured to cut individual multi-ply layers 272 in on
or more passes. The cutting head 424 may be configured to cut a
laminated stack 422 of multi-ply layers 272 in a single pass or in
multiple passes. Advantageously, the one or more cutters 428 may be
individually movable along a lateral 438 direction during movement
of the cutting head 424 along the lengthwise direction. In this
manner, the cutters 428 may cut the laminated stack 422 into a
variable cross-sectional shape 322 of the base portion 320. More
specifically, each one of the cutters 428 may be configured to cut
one or more composite plies 276 into a predetermined layer profile
shape 348 such as the layer profile shapes 348 of the base portion
320 shown in FIG. 14.
[0088] In FIG. 26, shown is a side view of a cutting head 424
having cutters 428 arranged in a staggered formation and moving
along a cutting direction 440. Each one of the cutters 428 may have
a cutting means for cutting one or more composite plies 276 or
multi-ply layers 272, or a laminated stack 422 comprising a
plurality of multi-ply layers 272. The cutting means may comprise
an excited cutting means or the cutting means may comprise a
non-excited cutting means. An excited cutting means may comprise an
ultrasonic 434 knife or blade for cutting one or more composite
plies 276 (e.g., approximately 0.0075 inch thick) at a relatively
small depth tolerance (e.g., approximately 0.0005 inch).
Advantageously, ultrasonic 434 blades may be easily plunged into
the composite plies 276 without significant downward force.
Non-excited cutting means (not shown) may comprise a rotary cutter
such as a disk cutter, a rolling cutter, or other cutter
configurations.
[0089] FIG. 26 illustrates traces in dashed lines illustrating the
cutting path of each blade 432 passing through a laminated stack
422. The blades 432 may be arranged in a staggered formation as
shown in FIGS. 23-25 wherein the uppermost blades 432 may be
located furthest forward along the cutting direction 440 and
furthest inboard (e.g., nearest a center of the laminated stack 422
or nearest a centerline of a base portion 320). The lowermost
blades 432 may be located furthest aft and furthest outboard. Each
one of the blades 432 may be individually adjustable along a
vertical direction 436 to correspond to a ply depth of the
composite ply to be cut by a blade 432. As was indicated above, the
cutting head 424 may also comprise a single (not shown) blade 432
that may be movable along a lengthwise direction and along a
vertical direction 436 and a lateral direction 438. The cutting
head 424 may include any number of blades 432 to cut an individual
multi-ply layer 272 into a desired layer profile shape of a base
portion 320, or to cut a stack of multi-ply layers 272. Individual
multi-ply layers 272 may be moved into the stacking station 446
after cutting. The individual multi-ply layers 272 may then be
stacked on top of one another at the stacking station to form a
base portion 320 of the radius filler 200 as described below.
[0090] FIG. 27 shows an end view of an embodiment of a cutting head
424 cutting through a laminated stack 422 of multi-ply layers 272
such as to form a base portion 320 of a radius filler 200. The
blades 432 may be positionable in a vertical orientation at
different ply depths corresponding to one of the composite plies
276 to be cut. Depending on a thickness of the laminated stack 422
and the depth of each cut, the cutting head 424 may make 1 to 3 or
more cutting passes along the laminated stack 422. The blades 432
may be configured to form vertical cuts in the laminated stack 422
to produce a base portion 320 having the stepped pyramidal
cross-sectional shape 312. Scrap (shown in cross-hatch) may be
removed during or following the cutting of the laminated stack
422.
[0091] In an embodiment not shown, one or more of the blades 432
may be positionable in an angled orientation (not shown) to form
angled cuts (not shown) in the laminated stack 422 such as to form
a base portion 320 having a trapezoidal cross-sectional shape (not
shown). As indicated above, the blades 432 may be individually
movable along a lateral 438 direction during movement of the
cutting head 424 along the lengthwise direction so that the
composite plies 276 are cut into a predetermined layer profile
shape 348 to provide a variable cross-sectional shape 322 to the
base portion 320. The cutters 428 may also be configured to
terminate one or more mid layers 340 of the base portion 320 in a
manner described above and illustrated in FIGS. 14, 15, and 17.
Although not shown, the cutting head 424 may also be implemented
for cutting the keyway portion 300 and/or the tip portion 250 of
the radius filler 200.
[0092] FIG. 28 a side view of an embodiment of a stacking station
446. Individual multi-ply layers 272 or a stepped pyramidal base
portion 320 that was cut from the laminated stack 422 at the
cutting station 404 may be moved into the stacking station 446 such
as by rolling the lamination/cutting table 416 into position at the
stacking station 446. Alternatively, the stacking station 446 may
include a stacking table 448 such as a vacuum table 418 for
receiving individual multi-ply layers 272 or for receiving the
stepped pyramidal base portion 320 and/or other components of the
radius filler 200. One or more layup tables 450 may also be
positioned on one or both sides of the vacuum table 418 at the
stacking station 446. The layup tables 450 may have a table surface
452 upon which the radius filler components may be stacked in an
automated manner or by manual stacking. The cutting table 416 may
include supports for supporting the layup table 450.
[0093] In FIG. 28, a lifting mechanism 454 may be included at the
stacking station 446 to assist in translating 444 individual
multi-ply layers 272 or a base portion 320 from the stacking table
448 onto a layup table 450. The layup table 450 may be positionable
adjacent to the stacking table 448. In an embodiment, the lifting
mechanism 454 may be vertically 462 movable for picking up an
individual multi-ply layer 272 or a base portion 320 and placing
the individual multi-ply layers 272 or the base portion 320 onto
the layup table 450. In an embodiment, the lifting mechanism 454
may comprise a pick-and-place mechanism having a vacuum rail 456
with a plurality of spaced-apart vacuum pads 458 connected to a
vacuum source (not shown). The vacuum pads 458 may apply a suction
force to a top surface of an individual multi-ply layer 272 or base
portion 320 for lifting the individual multi-ply layers 272 or base
portion 320 off of the cutting table 416 or stacking table 448 and
placing an individual multi-ply layer 272 or base portion 320 onto
the layup table 450 or into a stacking fixture (not shown).
[0094] FIG. 29 is a top view of an embodiment of a stacking station
446 having a vacuum table 418. The vacuum table is shown supporting
an individual multi-ply layer 272 for an upper radius filler 202
(FIG. 3) and an individual multi-ply layer 272 for a lower radius
filler 204 (FIG. 3) of a composite structure 106. The stacking
station 446 may include one or more vacuum rails 456 that may be
aligned to the centerline of the top ply of one of the base
portions 320 such as by using a laser alignment system (not shown)
or other alignment device. An individual multi-ply layer 272 or a
base portion 320 may be lifted by the vacuum rail 456 and laterally
464 moved or translated over to an adjacently-positioned layup
table 450.
[0095] FIG. 30 shows a vacuum rail 456 aligned over the center of a
top layer 340 of a base portion 320. The vacuum rail 456 may be
lowered into the vacuum pads 458 into contact with the top layer
340. A suction force may be applied to the vacuum pads 458 so that
the vacuum pad may be secured to the upper surface of the base
portion 320.
[0096] FIG. 31 illustrates the base portion 320 of FIG. 30 lifted
by the vacuum rail 456 and translated over to the layup table 450.
The stacking station 446 may include an indexing device 460 to
control the positioning of the vacuum rail 456. The indexing device
460 may comprise a mechanical stop, a machine vision system, a
laser system, or any other indexing device 460 for controlling the
position of the vacuum rail 456. The base portion 320 may be
lowered onto the layup table 450 and suction force may be removed
from the vacuum pads 458 to release the base portion 320.
Individual multi-ply layers 272 may be stacked onto the layup table
450 in the same manner.
[0097] FIG. 32 illustrates a vacuum rail 456 being used to stack an
upper portion 212 of composite plies 276 (e.g., a keyway portion
300 and/or tip portion 250) onto a base portion 320 to form a
radius filler stack 210. A radius filler stack 210 may also be
formed by staking up a plurality of multi-ply layers 272 that may
be individually cut by the cutting head 424. At the completion of
the stacking of a radius filler stack 210, the radius filler stack
210 may be moved to the pressing station 466. The vacuum rail 456
and the indexing device 460 may be employed for stacking any number
of composite plies 276 or layers 272 onto layup table 450 until all
composite plies 276 are stacked. For example, FIG. 32.
[0098] FIG. 33 is a side view of a pressing station 466 for forming
a pair of radius filler stacks 210 into final radius fillers 206.
The pressing station 466 may include one or more presses 468 having
at least one forming die 230. Each forming die 230 may be
configured to receive a radius filler stack 210 comprising an upper
portion 212 stacked onto the base portion 320. Although shown in an
inverted configuration, the forming die cavity 232 may be
configured to receive the radius filler stack 210 in an upright
configuration (not shown). Each press 468 may include a heating
device (not shown) for heating the radius filler stack 210. For
example, the heating device may comprise a resistance heating heat
plate 470 and/or a heating die, or the press 468 may be positioned
within an autoclave or a convection oven for heating the press 468
and the radius filler stack(s) 210.
[0099] FIG. 34 illustrates the press 468 in an activated state for
applying heat and pressure to the pair of radius filler stacks 210
mounted within the dye cavities 476. The press 468 may include one
or more actuators 472 configured to apply pressure to the radius
filler stacks 210 during heating thereof. The forming dies 474 may
be sized and configured complementary to the radius filler regions
140 of a composite structure 106. In this regard, each forming die
474 may have a die cavity 476 that may be contoured complementary
to the radius filler region 140 of a composite structure 106 for
forming each radius filler stack 210 into a final radius filler 206
having a variable cross-sectional shape 322 that substantially
matches a radius filler region 140 (FIG. 20).
[0100] FIG. 35 is a flowchart of a method 600 that may be
implemented for automated manufacturing of one or more radius
fillers 200 such as by using the system 400 illustrated in FIGS.
23-34 and described above. Step 602 of the method 600 may include
assembling a laminated stack 422 onto a cutting table 416 such as
the cutting table 416 illustrated in FIG. 23. As indicated above, a
laminated stack 422 may comprise an individual multi-ply layer 272
(e.g., a laminated charge 270) or a stack of multi-ply layers 272.
A laminated stack 422 may be formed by laminating a plurality of
composite plies 276 or layers 272 onto the cutting table 416 using
a laminating head 406 (FIG. 23).
[0101] Step 604 of the method 600 of FIG. 35 may include cutting
the laminated stack 422 along a lengthwise direction using a
cutting head 424. The cutting head 424 may cut individual multi-ply
layers 272 or a stack of multi-ply layers 272. The individual
multi-ply layers 272 may be used to form a base portion 320 having
a stepped pyramidal cross-sectional shape 312 as illustrated in
FIGS. 22-25. In this regard, the method may include passing a
plurality of blades 432 (e.g., ultrasonic blades 434) of the
cutting head 424 through a laminated stack 422 to ultrasonically
cut the composite plies 276. The blades 432 may be arranged in a
side-by-side configuration 430 and positioned at different heights
and different lateral 438 positions relative to one another. The
method may further include varying the lateral position of the
blades 432 while passing the blades 432 through the laminated stack
422 along the lengthwise direction as shown in FIG. 27.
[0102] Step 606 of the method 600 of FIG. 35 may include removing
scrap from the laminated stack 422. For example, the scrap (e.g.,
shown in cross-hath in FIG. 27) may be removed to expose the
stepped pyramidal cross-sectional shape 312 of a base portion 320.
The scrap may be removed during the cutting of the laminated stack
422. Alternately, the cutting head 424 may make several passes
along the laminated stack 422 and the scrap may be removed
following each pass.
[0103] Step 608 of the method 600 of FIG. 35 may be performed in
the stacking station 446 and may include stacking individual
multi-ply layers 272 to form a base portion 320 having a stepped
pyramidal shape. An upper portion 212 of composite plies 276 may be
stacked onto the base portion 320 to form the radius filler stack
210. As indicated above, after cutting the laminated stack 422 into
individual multi-ply layers 272 or cutting the laminated stack 422
into a base portion 320, the cutting table 416 may be translated
(e.g., rolled) into the stacking station 446 as shown in FIG. 23. A
lifting mechanism 454 may be activated for stacking the individual
multi-ply layers 272 to form a radius filler stack 210. The method
may include picking up the base portion 320 using a vacuum-type
lifting mechanism 454 such as a vacuum rail 456 having vacuum pads
458 as shown in FIGS. 30-32.
[0104] As shown in FIG. 29, the vacuum rail 456 may be laterally
moved 464 or translated from the cutting table 416 over to a layup
table 450. One or more layup tables 450 may be positioned alongside
the cutting table 416 at the stacking station 446. The vacuum rail
456 may be indexed using an indexing device 460 for placement of
the individual multi-ply layers 272 or placement of a cut base
portion 320 into a desired location onto the layup table 450. The
indexing device 460 may also facilitate the aligning of the upper
portion 212 with the individual multi-ply layers 272 or the base
portion 320. The method may further include stacking the upper
portion 212 onto the base portion 320 using the vacuum rail 456 to
form the radius filler stack 210 as shown in FIGS. 28-30. Although
not shown, the method may include stacking the radius filler stack
210 in an inverted position such as in a fixture having a V-shape
along a lengthwise direction.
[0105] Step 610 of the method 600 of FIG. 35 may include
positioning the radius filler stack 210 within a forming die 474
located within a pressing station 466 as shown in FIGS. 30-31. In
this regard, the radius filler stack 210 may be transferred from
the stacking station 446 to the pressing station 466 by using a
transporting fixture (not shown) for supporting the length of the
radius filler stack 210. Alternatively, in an embodiment not shown,
the pressing station 466 may be located adjacent to the stacking
station 446 such that the lifting mechanism 454 may stack the base
portion 320 and the upper portion 212 directly into the forming die
474.
[0106] Step 612 of the method 600 of FIG. 35 may include applying
heat and pressure to the radius filler stack 210 to form a final
radius filler 206 having a variable cross-sectional shape 322.
FIGS. 33-34 illustrate a press 468 having a pair of forming dies
474 with die cavities 476 that may be shaped complementary to the
filler radius regions of a composite structure 106. The press 468
may have a heat plate 470 for heating and softening the resin in
the pre-preg composite plies 276 of the radius filler stacks 210.
The press 468 may include actuators 472 in FIG. 33 to apply
pressure to the heated and softened composite plies 276 such that
the stepped pyramidal cross-sectional shape 312 of the radius
filler stacks 210 is formed into a relatively smooth radius of the
final radius filler 206.
[0107] Step 614 of the method 600 of FIG. 35 may include removing
the final radius filler 206 from the forming die 474. It should be
noted that in the present disclosure, the radius filler 200 may
have radius filler sides 208 that are formed into a non-radial
shape (e.g., a parabolic shape, an elliptical shape, rounded
flats--not shown) on the opposing radius filler sides 208 (FIG. 4).
In this regard, the radius filler 200 may be formed in any shape
that substantially matches the shape or contour of a radius filler
region of a composite structure 106.
[0108] Referring to FIGS. 36-37, embodiments of the disclosure may
be described in the context of an aircraft manufacturing and
service method 700 as shown in FIG. 36 and an aircraft 702 as shown
in FIG. 37. During pre-production, exemplary method 700 may include
specification and design 704 of the aircraft 702 and material
procurement 706. During production, component and subassembly
manufacturing 708 and system integration 710 of the aircraft 702
takes place. Thereafter, the aircraft 702 may go through
certification and delivery 712 in order to be placed in service
714. While in service by a customer, the aircraft 702 is scheduled
for routine maintenance and service 716 (which may also include
modification, reconfiguration, refurbishment, and so on).
[0109] Each of the processes of method 700 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 vendors,
subcontractors, and suppliers; and an operator may be an airline,
leasing company, military entity, service organization, and so
on.
[0110] As shown in FIG. 37 the aircraft 702 produced by exemplary
method 700 may include an airframe 718 with a plurality of systems
720 and an interior 722. Examples of high-level systems 720 include
one or more of a propulsion system 724, an electrical system 726, a
hydraulic system 728, and an environmental system 730. Any number
of other systems may be included. Although an aerospace example is
shown, the principles of the disclosed embodiments may be applied
to other industries, such as the automotive industry.
[0111] The radius filler 200 and system and methods embodied herein
may be employed during any one or more of the stages of the
production and service method 700. For example, components or
subassemblies corresponding to production process 708 may be
fabricated or manufactured in a manner similar to components or
subassemblies produced while the aircraft 702 is in service. Also,
one or more radius filler 200 embodiments, system embodiment,
method embodiments, or combinations thereof may be utilized during
the production stages 708 and 710, for example, by substantially
expediting assembly of or reducing the cost of an aircraft 702.
Similarly, one or more of apparatus embodiments, method
embodiments, or a combination thereof may be utilized while the
aircraft 702 is in service, for example and without limitation, to
maintenance and service 716.
[0112] Many modifications and other configurations of the
disclosure will come to mind to one skilled in the art, to which
this disclosure pertains, having the benefit of the teachings
presented in the foregoing descriptions and the associated
drawings. The configurations described herein are meant to be
illustrative and are not intended to be limiting or exhaustive.
Although specific terms are employed herein, they are used in a
generic and descriptive sense only and not for purposes of
limitation.
* * * * *