U.S. patent application number 13/469349 was filed with the patent office on 2013-11-14 for rotor disk and rotor assembly.
This patent application is currently assigned to E. I. DU PONT DE NEMOURS AND COMPANY. The applicant listed for this patent is J. David Booze, Clifford K. Deakyne, Frederic Pailler, James E. Weishampel. Invention is credited to J. David Booze, Clifford K. Deakyne, Frederic Pailler, James E. Weishampel.
Application Number | 20130302170 13/469349 |
Document ID | / |
Family ID | 49548740 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130302170 |
Kind Code |
A1 |
Booze; J. David ; et
al. |
November 14, 2013 |
ROTOR DISK AND ROTOR ASSEMBLY
Abstract
The disclosure generally relates to rotor disks and rotor
assemblies having a composite lubricated sheet adhered thereon and
having improved tribological properties at high temperatures.
Inventors: |
Booze; J. David;
(Wilmington, DE) ; Deakyne; Clifford K.;
(Wilmington, DE) ; Pailler; Frederic; (Forest,
BE) ; Weishampel; James E.; (Amherst, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Booze; J. David
Deakyne; Clifford K.
Pailler; Frederic
Weishampel; James E. |
Wilmington
Wilmington
Forest
Amherst |
DE
DE
OH |
US
US
BE
US |
|
|
Assignee: |
E. I. DU PONT DE NEMOURS AND
COMPANY
Wilmington
DE
|
Family ID: |
49548740 |
Appl. No.: |
13/469349 |
Filed: |
May 11, 2012 |
Current U.S.
Class: |
416/219R |
Current CPC
Class: |
F01D 5/3092
20130101 |
Class at
Publication: |
416/219.R |
International
Class: |
F01D 5/02 20060101
F01D005/02; F01D 25/18 20060101 F01D025/18 |
Claims
1. A rotor disk comprising a composite lubricating sheet adhered to
at least one rotor disk fan blade slot, wherein the composite
lubricating sheet comprises: a fabric at least partially embedded
with a resin, the fabric including an aromatic polyamide yarn, and
a mixed yarn having the aromatic polyamide yarn and a low-friction
yarn; and a metallic layer adhered to one side of the fabric.
2. The rotor disk according to claim 1, wherein the resin is
phenol-formaldehyde resin.
3. The rotor disk according to claim 1, wherein the aromatic
polyamide yarn is selected from the group consisting of
poly(para-phenylene terephthalamide), poly(meta-phenylene
terephthalamide), poly(meta-phenylene isophthalamide),
poly(para-phenylene isophthalamide), combinations thereof, and
copolymers thereof.
4. The rotor disk according to claim 1, wherein the low-friction
yarn comprises graphite fiber or a fluoropolymer fiber.
5. The rotor disk according to claim 8, wherein the fluoropolymer
fiber comprises a polytetrafluoroethylene.
6. The rotor disk according to claim 1, wherein the metallic layer
is a metal selected from the group consisting of titanium,
aluminum, steel, and nickel.
7. The rotor disk according to claim 6, wherein the metallic layer
is titanium.
8. The rotor disk according to claim 1, wherein the metallic layer
has a Vickers Hardness of approximately 30 HV or greater at a load
of approximately 100 grams applied for approximately 20 seconds
according to ASTM E-384.
9. The rotor disk according to claim 1, wherein the composite
lubricating sheet has a Compression Fraction in a range of 0.1% to
approximately 20% with a pressure applied by compressing at
approximately 127 microns/minute up to approximately 450 MPa and
then released.
10. The rotor disk according to claim 1, wherein the composite
lubricating sheet additionally comprises an attaching layer between
the fabric and the metallic layer, attaching layer comprising an
adhesive selected from the group consisting of a thermoplastic
adhesive or a thermoset adhesive.
11. A rotor assembly comprising: a rotor disk having fan blade
slots; fan blades secured in the fan blade slots by fan blade
roots; and a composite lubricating sheet adhered to at least one
rotor disk fan blade slot, wherein the composite lubricating sheet
comprises: a fabric at least partially embedded with a resin, the
fabric including an aromatic polyamide yarn, and a mixed yarn
having the aromatic polyamide yarn and a low-friction yarn; and a
metallic layer adhered to one side of the fabric.
12. The rotor assembly according to claim 11, wherein the resin is
phenol-formaldehyde resin.
13. The rotor assembly according to claim 11, wherein the aromatic
polyamide yarn is selected from the group consisting of
poly(para-phenylene terephthalamide), poly(meta-phenylene
terephthalamide), poly(meta-phenylene isophthalamide),
poly(para-phenylene isophthalamide), combinations thereof, and
copolymers thereof.
14. The rotor assembly according to claim 11, wherein the
low-friction yarn comprises graphite fiber or a fluoropolymer
fiber.
15. The rotor assembly according to claim 14, wherein the
fluoropolymer fiber comprises a polytetrafluoroethylene.
16. The rotor assembly according to claim 11, wherein the metallic
layer is a metal selected from the group consisting of titanium,
aluminum, steel, and nickel.
17. The rotor assembly according to claim 16, wherein the metallic
layer is titanium.
18. The rotor assembly according to claim 11, wherein the metallic
layer has a Vickers Hardness of approximately 30 HV or greater at a
load of approximately 100 grams applied for approximately 20
seconds according to ASTM E-384.
19. The rotor assembly according to claim 11, wherein the composite
lubricating sheet has a Compression Fraction in a range of 0.1% to
approximately 20% with a pressure applied by compressing at
approximately 127 microns/minute up to approximately 450 MPa and
then released.
20. The rotor assembly according to claim 11, wherein the composite
lubricating sheet additionally comprises an attaching layer between
the fabric and the metallic layer, attaching layer comprising an
adhesive selected from the group consisting of a thermoplastic
adhesive or a thermoset adhesive.
Description
FIELD OF THE INVENTION
[0001] The disclosure generally relates to rotor disks and rotor
assemblies; more particularly to rotor disks and rotor assemblies
having adhered thereon a composite lubricating sheet.
BACKGROUND OF THE INVENTION
[0002] Typically, wear resistant articles are used to prevent or to
reduce friction and wear when in sustained contact with other
objects due to relative motion of both under high load and/or
frictional forces.
SUMMARY OF THE INVENTION
[0003] A first aspect of the present invention relates to a rotor
disk comprising a composite lubricating sheet adhered to at least
one rotor disk fan blade slot, wherein the composite lubricating
sheet comprises: a fabric at least partially embedded with a resin,
the fabric including an aromatic polyamide yarn, and a mixed yarn
having the aromatic polyamide yarn and a low-friction yarn; and a
metallic layer adhered to one side of the fabric.
[0004] A second aspect of the present invention relates to a rotor
assembly comprising: a rotor disk having fan blade slots; fan
blades secured in the fan blade slots by fan blade roots; and a
composite lubricating sheet adhered to at least one rotor disk fan
blade slot, wherein the composite lubricating sheet comprises: a
fabric at least partially embedded with a resin, the fabric
including an aromatic polyamide yarn, and a mixed yarn having the
aromatic polyamide yarn and a low-friction yarn; and a metallic
layer adhered to one side of the fabric.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] These and other features of this invention will be more
readily understood from the following detailed description of the
various aspects of the invention taken in conjunction with the
accompanying drawings that depict various embodiments of the
invention, in which:
[0006] FIG. 1 depicts an embodiment of a rotor disk, in accordance
with the present disclosure.
[0007] FIG. 2 depicts an embodiment of a rotor assembly, in
accordance with the present disclosure.
[0008] It is noted that the drawings of the invention are not to
scale. The drawings are intended to depict only typical aspects of
the invention, and therefore should not be considered as limiting
the scope of the invention. In the drawings, like numbering
represents like elements between drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0009] Rotor disks and rotor disk assemblies used in the aerospace
industry, and in particular, in turbine engines often subject
objects in contact with the rotor disks and rotor disk assemblies
to high pressure loads and high frictional forces resulting in
surface wear and crack formation due to fatigue stress of the
objects in contact with the rotor disks and/or rotor disk
assemblies. An example of an object includes, but is not limited
to, a turbine fan blade. Improvements in the wear resistance of
turbine fan blades is sought so as to improve their lifespan; to
reduce the maintenance time of turbine engines; and to increase the
operational time of a device, assembly, airplane, etc. that
incorporate turbine fan blades.
[0010] Wear means the deterioration of any properties of a solid
surface by the action of another surface. The deteriorated
properties may include, but are not limited to, thickness,
smoothness, hardness, strength, and/or integrity. It has been
discovered that the wear and stress imparted on a turbine fan blade
may be decreased by having a composite lubricating sheet adhered to
an area of a rotor disk and/or the rotor disk assembly that makes
contact with the turbine fan blade.
[0011] An embodiment of a rotor disk is shown in FIG. 1 and an
embodiment of a rotor assembly is shown in FIG. 2, in accordance
with the present disclosure. Referring to FIGS. 1 and 2, a rotor
disk 10 is shown having composite lubricating sheets (CLS) 8
adhered thereon. Rotor disk 10 may be an integrated component in a
turbine engine. In another embodiment, rotor disk 10 may be an
integrated component in rotor assembly 18. Rotor disks used in
turbine engines and/or rotor assemblies are known in the art. Rotor
disk 10 may comprise a metal selected from titanium, aluminum,
steel, nickel, and alloys of the aforementioned. In an embodiment,
rotor disk 10 may comprise titanium. In another embodiment, rotor
disk 10 may comprise steel. In another embodiment, rotor disk 10
may comprise aluminum.
[0012] Rotor assembly 18 may comprise: rotor disk 10 having a fan
blade slot 12; a fan blade 14 therein; and CLSs 8 adhered to rotor
disk 10. Fan blade 14 may comprise a fan blade root 16. Fan blade
root 16 may secure fan blade 14 in fan blade slot 12 during
operation of rotor assembly 18. Reference l connotes that fan blade
14 may continue beyond reference 5 to form a larger, complete fan
blade. Fan blade 14 may comprise a metal selected from titanium,
aluminum, steel, nickel, and alloys thereof. In an embodiment, fan
blade 14 may comprise titanium. In another embodiment, fan blade 14
may comprise steel. In another embodiment, fan blade 14 may
comprise aluminum. Rotor assemblies are known in the art. FIG. 2
shows one section of rotor assembly 18 and one having ordinary
skill in the art will recognize that rotor assembly 18 comprises a
plurality of sections each section having the components and
properties described herein.
[0013] CLS 8 may comprise a fabric 6 and a metallic layer 7 adhered
to one side of fabric 6. Fabric 6 may be at least partially
embedded with a resin, and may include an aromatic polyamide yarn
and a mixed yarn having the aromatic polyamide yarn and a
low-friction yarn. The aromatic polyamide yarn may be a plurality
of fibers in a bundle, including fiber comprising an aromatic
polyamide, used for weaving. The aromatic polyamide yarn may
include yarns made from but not limited to poly(para-phenylene
terephthalamide), poly(meta-phenylene terephthalamide),
poly(meta-phenylene isophthalamide), poly(para-phenylene
isophthalamide), combinations thereof, and copolymers thereof.
[0014] The low-friction yarn may be a yarn having a coefficient of
friction (COF) against itself which is lower than the COF of the
aromatic polyamide yarn against itself. The low-friction yarn may
comprise graphite or a fluoropolymer. In an embodiment, the
low-friction yarn may comprise graphite fiber or a fluoropolymer
fiber. In an embodiment, the fluoropolymer fiber may be
polytetrafluoroethylene fiber. Resin embedded fabric 6 may be at
least partially embedded with a resin selected from, but not
limited to, a phenolic resin, epoxy resin, or a polyimide resin. In
an embodiment, the phenolic resin may comprise
phenol-formaldehyde.
[0015] Metallic layer 7 may comprise a metal selected from
titanium, aluminum, steel, and nickel. In an embodiment, metallic
layer 7 may be titanium. In another embodiment, metallic layer 7
may be steel. Metallic layer 7 may have a thickness in a range from
approximately 20 microns to approximately 1,000 microns. In an
embodiment, metallic layer 7 may have a thickness in a range from
approximately 50 microns to approximately 250 microns. In another
embodiment, metallic layer 7 may have a thickness in a range from
approximately 70 microns to approximately 100 microns. In another
embodiment, metallic layer 7 may have a thickness of approximately
90 microns.
[0016] Metallic layer 7 may be in the form a metallic foil. In an
embodiment, the metallic foil may be a thin, flexible sheet of
titanium, aluminum, steel, or nickel. In an embodiment, metallic
layer 7 may be a titanium foil. In another embodiment, the metallic
foil may have a thickness in a range from approximately 20 microns
to approximately 1,000 microns. In another embodiment, the metallic
foil may have a thickness in a range from approximately 50 microns
to approximately 250 microns. In another embodiment, the metallic
foil may have a thickness in a range from approximately 70 microns
to approximately 100 microns. In another embodiment, the metallic
foil may have a thickness of approximately 90 microns. Metallic
layer 7 may be adhered to one side of resin embedded fabric 6.
[0017] In an embodiment, metallic layer 7 may be a pure metal
comprising a single metallic element. In another embodiment,
metallic layer 7 may be a metal alloy comprising two or more
metallic elements. When two or more metallic elements are a part of
metallic layer 7, any element may be a major or predominant element
by weight percent. Embodiments of elements present in metallic
layer 7 include, but are not limited, to titanium, iron, aluminum,
copper, nickel, zinc, tungsten, molybdenum, tin, and cobalt. Any of
the aforementioned elements may be the major or predominant element
by weight percent.
[0018] Metallic layer 7 may have a Vickers hardness value HV of
approximately 30 or greater at a load of 100 g applied for 20
seconds according to ASTM E-384. In an embodiment, metallic layer 7
may have a Vickers HV of approximately 100 or greater. In another
embodiment, metallic layer 7 may have a Vickers HV of approximately
200 or greater. In another embodiment, metallic layer 7 may have a
Vickers HV of approximately 300 or greater.
[0019] An example of composite lubricating sheet 8 having a
titanium metallic layer 7 is Vespel.RTM. ASB-0670 product grade
available from E.I. du Pont de Nemours and Company. Other
Vespel.RTM. composite lubricating sheet 8 product grades may
include metallic layer 7 being steel, aluminum, or nickel.
[0020] Composite lubricating sheet (CLS) 8 may have a thickness in
a range from 30 microns to 3 mm. In embodiment, CLS 8 may have a
thickness in a range from 50 microns to 1 mm. In another
embodiment, the thickness may be in a range from 100 microns to 750
microns.
[0021] CLS 8 may have a Compression Fraction value in a range from
0.1% (0.001) to approximately 20% (0.20) with a pressure applied by
compressing at approximately 127 microns/minute up to approximately
450 MPa and then released. Compression Fraction means the fraction
of thickness lost due to compression under specific conditions. In
an embodiment, composite lubricating sheet 8 may have a Compression
Fraction value in a range from 1% (0.010) to approximately 5.7%
(0.057). In another embodiment, the Compression Fraction value may
be in a range from 1.3% (0.013) to approximately 3% (0.030). The
aforementioned Compression Fraction value embodiments may be
determined with a pressure applied by compressing at approximately
127 microns/minute up to approximately 450 MPa and then
released.
[0022] CLSs 8 may be adhered to any area of rotor disk 10 that
forms rotor disk fan blade slot 12. The adherence of CLS 8 may be
achieved through physical or chemical bonding. One may also use an
adhesive such as thermoplastic adhesive, a thermoset adhesive, and
other bonding adhesives known in the art. In particular, metallic
layer 7 may be adhered to rotor disk 10. In an embodiment, the
thermoset adhesive may be an epoxy adhesive. The bonding adhesive
layer may have a thickness in range from approximately 2 microns to
2,000 microns. In an embodiment, the thickness may be in a range
from approximately 10 microns to 100 microns. In another
embodiment, the thickness may be in a range from approximately 20
microns to 80 microns.
[0023] Prior to adhering CLS 8 to rotor disk 10, the surface of
metallic layer 7 to be adhered to rotor disk 10 and/or the surface
of rotor disk 10 may be surfaced treated. Surface treatment may be
performed by any known process in the art to treat a metallic
surface. In an embodiment, surface treatment may be performed by a
peening process. Typical peening processes involve the impacting a
surface with numerous, small particles. An example of a peening
process is shot peening. The shot-peened, roughened surface may
have a characteristic roughness identifiable by the appearance of
small craters in the surface. In another embodiment, surface
treatment may include sandblasting the surface of metallic layer 7
to be adhered to rotor disk 10 and/or sand blasting the surface of
rotor disk 10. In another embodiment, surface treatment may include
chemical etching of the surface of metallic layer 7 to be adhered
to rotor disk 10 and/or chemical etching the surface of rotor disk
10. In another embodiment, surface treatment may include belt
sanding of the surface of metallic layer 7 to be adhered to rotor
disk 10 and/or belt sanding the surface of rotor disk 10.
[0024] The aforementioned surface treatments may be performed in
combination to treat the surface of metallic layer 7 and/or the
surface of rotor disk 10. For example, the surface of metallic
layer 7 to be adhered to rotor disk 10 may be first shot-peened and
then the shot-peened surface may be treated by sandblasting prior
to adhesion to rotor disk 10. Rotor disk 10 is typically is shown
having composite lubricating sheets (CLS) 8 adhered thereon.
[0025] During normal use, rotor disk 10 may typically come in
sustained contact and movement, through resin embedded fabric 6 of
composite lubricating sheet 8, with fan blade root 16 under a high
pressure load and under vibratory, reciprocating, and/or circular
motions via. The high pressure load may be in a range from
approximately 100 MPa to approximately 600 MPa. CLSs 8 in sustained
contact with fan blade root 12 may have a Coefficient of Friction
(COF) value in a range from 0.01 to 0.1. In an embodiment, the COF
value may be less than approximately 0.05. In another embodiment,
the COF value may be less than 0.04.
[0026] The utility of rotor disk 10 having CLSs 8 adhered thereon
to reduce wear and friction of fan blade 14, and in particular fan
blade root 12, may be demonstrated by measuring the durability of
CLS 8 under controlled pressure and wear conditions. Wear under
pressure may be demonstrated, for example, by: providing a body
having a surface subject to wear, such as a titanium block with a
known roughness; adhering to the surface subject to wear composite
lubricating sheet 8 wherein the adhering occurs between the
metallic layer 7 and the titanium surface subject to wear;
providing an object having a wear surface such as another titanium
block; aligning resin embedded fabric 6 of CLS 8 with the wear
surface of the other object with a pressure in a range from
approximately 210 MPa to approximately 500 MPa; and causing resin
embedded fabric 6 of CLS 8 to be in sustained contact with the
surface of the other object.
EXAMPLES
[0027] The present disclosure may be further defined by the
following examples. It should be understood that the following
examples, while indicating embodiments of the present disclosure,
are given by way of illustration only. From the above discussion
and the following examples, one having ordinary skill in the art
can ascertain the essential characteristics of the present
disclosure, and without departing from the spirit and scope
thereof, may make various changes and modifications of the present
disclosure to adapt it to various uses and conditions. Table 1
lists Vickers Hardness values (HV) for metallic layer 7 of
composite lubricating sheet (CLS) 8. Values listed in Table 1 are
for metallic layer 7 in the form of a metallic foil. Vickers
Hardness values are described in ASTM E-384 which is incorporated
herein by reference in its entirety. Unless otherwise specified, HV
in Table 1. means HV 0.1/20 as determined with 100 gram force
applied for 20 seconds.
TABLE-US-00001 TABLE 1 Designation Foil-1 Foil-2 Foil-3 Foil-4 Foil
5 Foil-6 Material Fe Ti Ti Ti Al Al Foil Stainless ASTM ASTM
Descrip- Steel, B265, B265, tion Type 304 Grade = Grade = 4 9
Thickness 75 70 90 460 125 125 (microns) Meltallic layer Hardness,
407 252 224 176 39.1 23* HV 0.1/20 HV Std Dev 13 10 2.5 6.4 0.3 0.8
*Foil-6 Hardness HV is determined with 50 g for 20 seconds (HV
0.05/20)
[0028] CLS 8 of the present disclosure may be resistant to crushing
by compressive forces. In one embodiment, a suitable test for
resistance to compressible forces is to determine the fraction of
compression that a strong compressive force produces. Table 2 lists
Compression Fraction percentage values for CLS 8 having various
metallic layers 7 and an entry (10) for CLS 8 without a metallic
layer for comparison.
TABLE-US-00002 TABLE 2 CLS 1 2 3 4 5 6 C1 Metallic Fe Ti Ti Ti Al
Al None Layer Thickness, 370 370 400 800 460 435 280 microns
Compression 2.6 1.6 2.8 1.42 5.83 6.55 8.63 Fraction, %
[0029] In Table 2, CLS test samples 2, 3, and 4 are representative
samples of Vespel.RTM. ASB-0670 product grade available from E.I.
du Pont de Nemours and Company in which the metallic layer is
titanium. CLS test samples 1, 5, and 6 are representative samples
of other Vespel.RTM. composite lubricating sheet 8 product grades
in which the metallic layer 7 is steel (Fe) and aluminum. CLS test
sample C1 is a comparative sample in which it does not have a
metallic layer 7.
[0030] Compression fraction percentage values of CLSs 8 were
determined using a Mitutoyo IP 54 micrometer and an Instron 1332
fatigue system with n 8800 controller. The Mitutoyo IP 54
micrometer was used to measure thickness of CLS by first measuring
the initial thickness of a CLS square of approximately 25 mm by
approximately 25 mm. The Instron 1332 fatigue system was used to
apply compressive loads to the CLS square. The measured CLS square
was then compressed with a 10 mm by 10 mm shot-peened surfaced Ti
block to 450 MPa applied at 0.05 inch/min (1270 microns/min) using
the Instron 1332 fatigue system. When 450 MPa pressure was
achieved, the pressure was released and measurement of the final
thickness of the CLS square was made within one minute using the
Mitutoyo IP 54 micrometer.
[0031] CLS 8 of the present disclosure may be resistant to crushing
by compressive forces and wear through rubbing/frictional forces.
In one embodiment, a suitable test for resistance to compressible
forces and simultaneous frictional force is to determine the
Minimum Strokes number CLS 8 may sustain before succumbing to
failure. Table 3 lists Minimum Strokes values for CLS 8 having a
titanium metallic layer 7 and for CLS 8 without a metallic layer
for comparison.
TABLE-US-00003 TABLE 3 CLS 1* 2* 3 Metallic Layer Ti Ti None
Pressure, MPa 400 400 400 Minimum Strokes 43,527 44,244 362 *Two
sets of test specimens used.
[0032] In Table 3, CLS test samples 1 and 2 are representative
samples of Vespel ASB-0670 product grade available from E.I. du
Pont de Nemours and Company in which the metallic layer is
titanium. CLS test sample Cl is a comparative sample in which it
does not have a metallic layer 7.
[0033] Minimum Strokes values of CLSs 8 in use with a metal
substrate were determined using an Instron 1321 fatigue system with
an 8800 controller. The Minimum Strokes values were reported as the
number of reciprocating test strokes of 1.2 mm in length applied at
10 Hz accomplished by the relative motion of the article with
respect to resin embedded fabric layer 6 of CLS 8.
[0034] Prior to evaluating wear under pressure, the resin embedded
fabric layer 6 of CLS 8 was lightly coated with a lubricant
containing a fluorochemical by spraying or painting the lubricant
on the surface of the resin embedded fabric layer 6. The spraying
or coating provides a thin translucent to an opaque coating of
lubricant.
[0035] CLS 8 was adhered to a stationary metal substrate by an
epoxy adhesive such as for example, NB 101 available from Newport
Adhesives and Composites, Inc; Irvine, Calif. The stationary metal
substrate was a sandblasted, 20 mm by 20 mm titanium block with a
peen-hardened surface having a Rockwell C33 hardness. The metallic
layer of CLS 8 was adhered to the titanium block with resin
embedded fabric layer 6 of CLS 8 facing away from the titanium
block. The adhesive was oven cured under low pressure
(approximately 5 psi) comprising a first heating step to
approximately 79.degree. C. for 90 min and then a second heating
step to approximately 149.degree. C. for an hour. The titanium
block was then mounted in the lower carrier of the Instron 1321
with CLS 8 facing up.
[0036] A second titanium block with a peen-hardened surface (Rc of
33) measuring approximately 10 mm by 10 mm was mounted in an upper
carrier of the Instron 1321 and brought into parallel reversible
contact with CLS 8 aligned in the center of the titanium block in
the lower carrier. The pressure between the blocks was raised to
400 MPa, and reciprocating strokes were applied at a rate of 10
forward and 10 backward strokes per second with a stroke length of
1.2 mm. Testing was run until the onset of failure, i.e., a corner
of the 10 mm by 10 mm titanium block penetrated resin embedded
fabric layer 6 of CLS 8. The Minimum Strokes value represents the
number of strokes to reach test specimen failure. The larger the
Minimum Strokes value, the better the performance of CLS 8.
[0037] Comparing CLS examples 1 and 2 having a titanium metallic
layer to example 3 not having a metallic layer, an approximate 100
fold improvement in test samples 1 and 2 was achieved. Under test
conditions, a value greater than 10,000 Minimum Strokes represents
durability to last through, for example, an engine maintenance
cycle.
[0038] The terms "first", "second", and the like, herein do not
denote any order, quantity, or importance, but rather are used to
distinguish one element from another, and the terms "a" and "an"
herein do not denote a limitation of quantity, but rather denotes
the presence of at least one of the referenced items. The modifier
"about" used in connection with a quantity is inclusive of the
state value and has the meaning dictated by the context, (e.g.,
includes the degree of error associated with measurement of the
particular quantity). The suffix "(s)" as used herein is intended
to include both the singular and the plural of the term that it
modifies, thereby including one or more of that term (e.g., the
metal(s) includes one or more metals). Ranges disclosed herein are
inclusive and independently combinable (e.g., ranges of "to
approximately 25 wt %, or, more specifically, approximately 5 wt %
to approximately 20 wt %", is inclusive of the endpoints and all
intermediate values of ranges of "approximately 5 wt % to
approximately 25 wt %", etc.)
[0039] While various embodiments are described herein, it will be
appreciated from the specification that various embodiments of
elements, variations or improvements therein may be made by those
skilled in the art, and are within the scope of the invention. In
addition, many modifications may be made to adapt a particular
situation or material to the teachings of the invention without
departing from essential scope thereof. Therefore, it is intended
that the invention not be limited to the particular embodiment
disclosed as the best mode contemplated for carrying out this
invention, but that the invention will include all embodiments
falling within the scope of the appended claims.
* * * * *