Materials Sciences and Applica tio ns, 2011, 2, 458-464
doi:10.4236/msa.2011.25061 Published Online May 2011 (http://www.SciRP.org/journal/msa)
Copyright © 2011 SciRes. MSA
Optimization in Autoclave Process to Produce
Durable Aluminium Composite
Handoko Subawi
Indonesian Aerospace Ltd, Bandung, Indonesia.
Email: handoko@indonesian-aerospace.com
Received September 22nd, 2010; revised May 1st, 2011; accepted May 11th, 2011.
ABSTRACT
The purpose of this paper is to characterize adhesive bonding performance through the fracture evaluation. Failure
modes correlate to the bond strength, in which the weak bond of adhesion will be considered unacceptable in the air-
craft manufacture certifica tion, whereas the cohesion bond as strong as adhesive itself is preferably accepted. The final
quality of adhesive bonding process depends on several key variables during manufacturing. A good anodizing treat-
ment is properly maintained in order to eliminate possible bond failures in the long term bond durability in service.
This paper described the method to improve an adhesive joining for durable bonds through optimizing the process va-
riable during autoclave curing. The process simulation utilized the drum peel test to describe the cohesive fracture
phenomenon in which applicable on a daily load basis in commercial application.
Keywords: Aluminium Composite, Adhesive B onding, Failure Mode, Cohesive Failure
1. Introduction
Adhesive b onded panel is formed by an adhesive joining
process between skins, its doublers and honeycomb core
using a film adhesive which undergoes a physical or
chemical hardening reaction. This reaction causes the
parts to join together through adherence and cohesion
strength. The final quality of adhesive bonding process
depends on the several key variables during manufactu-
ring. The honeycomb core must sufficiently compact
with adhesive layer to join its cover skins and doublers.
The application of metal bonding technology using a
film adhesive in any case has some advantages compare
to others metal joining concept. The main advantage of
the adhesive joining compared to the welding, riveting,
brazing and screw fastening is that the adhesive bonded
load is distributed u niformly to the loading direction [1].
However, employing primer and film adhesive requires a
proper handling and storage of these materials. Handling
system of sensitive materials include the packaging in
sealed bag, the supporting tool to maintain roll condition,
its transportation to customer shop, and how to manage
the time life of these materials.
Adhesive bonded panel is widely used for primary
composite structure in commercial aircrafts. The effect of
surface preparation procedures and material systems on
the aluminium surface chemistry subsequently correlates
to the bond performance. A good anodizing process en-
sures a high adherence grade between the aluminium
skin surface and the cured primer coat. A number of
characterization techniques to evaluate adhesive bonding
quality include the surface appearance, the surface che-
mistry, the surface energy, and the fracture evaluation.
In the fracture evaluation, the only way to measure
bond quality empowers the standard specimens for lap
shear [2] and drum peel tests [3]. Most of bonding shops
utilize these strength tests to qualify the bonding pro-
cesses, meanwhile some researchers [4-9] focused on the
efforts to improve quality of the adhesive materials.
However, there is not an effective solution to provide a
method to differentiate between the bond strength and
the bond durability practically in commercial application.
Failure mode correlates to the bond strength in which
the weak bond of adhesion will be considered unaccept-
able in the aircraft manuf acture certification, whereas the
cohesion bond as strong as adhesive itself and also the
inter laminar (structure) bond as strong as laminate itself
are preferably accepted. For practical purposes, some
researchers proposed a modification of metal to metal
peel test called as a “rapid adhesion test” method that is a
quick to assess the adhesion in which the backing adhe-
rent clamped to while the peeling adherent is removed.
Optimization in Autoclave Process to Produce Durable Aluminium Composite
Copyright © 2011 SciRes. MSA
459
The failure mode represents poor bond of adhesion fail-
ure and strong bond of cohesive failure [10].
A good anodizing treatment as the main process vari-
able mostly eliminates bond failures in a long term bond
durability in service. The aluminium surface does not
only require clean, but also chemically active surface that
is resistant to hydration. The possible bond failure modes
are classified in the form of the adherents outside the
joint, the cohesion failure of the adhesive, or the adhe-
sion failure of the interface. Failure of the adherents out-
side the joint may be achieved while using moderately
thin adherent materials. The cohesion failure may be
caused by an inadequate overlap length, or the presence
of thermal stresses or void defects. While, the adhesion
failure of the interface can be caused by an inadequate or
ineffective surface preparation process.
One important factor to improve adhesive bonds per-
formance is a comprehensively effort to develop both the
bond strength and the bond durability. The bond durabi-
lity depends on the resistance of the adhesive to adherent
interface against to water ingress. The resistance to hy-
dration is established by the process used to prepare the
surface of the adherents for bonding. The adhesive bond
durability becomes an important topic since the publica-
tion of the recommendation of Amendment FAR Section
25.605 proposed by Directorate General Technical Air-
worthiness of Royal Australian Air Force [11]. The regu-
lation is:
1) The methods of fabrication used must produce a
consistently sound and durable structure. If a fabrication
process (such as gluing, spot welding, or heat treating)
requires close control to reach this objective, the process
must be performed under an approved process specifica-
tion that has been demonstrated to produce a structure
that is strong and durable.
2) Each new aircraft fabrication method must be sub-
stantiated by a test program that demonstrates that the
process used is capable of producing a structure that is
strong and durable.
Some researchers argue that lap shear specimen is not
capable to validate long term bond durability. The ser-
vice history statistically describes that lap shear testing
can not distinguish between a good and a bad processes.
The metal bond durability can be validated through the
wedge test that tolerates the specimen crack growth of an
average of 0.50 inch and a maximum of 0.75 inch in one
hour exposure to 60˚C and 95% RH [12]. However, a
further recommendation offered an acceptance criteria
requires more stringent than broad consensus where a
crack growth length should be less 0.20 inch/24 hrs and
0.25 inc h/ 48 hrs, and also <5% adhesion failure [13].
Although it is confirmed that durable bonds of adhe-
sive joining meet a wedge test criteria, however the
wedge test is still considered less practical to be applied
in daily load commercially to accompany the speed of
the production rate. Actually, the wedge test is being
applied when producing the first article or if any major
chemical replenishment or solution dumping for revali-
dation of the surface preparation process. In a commer-
cial application, it is not easy to anticipate crack propa-
gation less 0.15 inch/1.25 hour consistently in a climatic
chamber at 95% RH.
The wedge specimen does not only require long se-
quential steps and enough processing period, but also
requires a high care especially during specimen cutting to
eliminate any vibration impact to the subsequent result
anomalies indicated by an improper crack propagation
length in this specimen. In daily load basis, practically,
the preferably commercial test to validate the failure
mode analysis is the drum peel specimen to configure the
durability characteristics of the actual aluminium com-
posite panels. This paper describes one of tactically im-
provement for durable bonds of adhesive joining through
optimizing the process variable during autoclave curing.
2. Key Variables in the Adhesive Bonding
Process
2.1. Setting Single Parts Prior to Integration
Setting or pre-fitting activity integrates precisely b etween
honeycomb core and all required aluminium skins prior
to surface treatment of the skins and all related single
parts. The work of this sequent refers to the detail draw-
ing and depends on the operator hands. The operators
should ensure that all single parts have been completely
pre-fitted. Commonly it requires the additional thickness
allowance in the range of 0.30 mm until 0.50 mm during
this pre-integration step.
This additional thickness allowance is sufficiently re-
quired to anticipate pressurization impact through the
vacuum bagging of an aluminium composite panel. The
utilization of the cover on the stopper contributes to
maintain the final thickness and the surface uniformity or
the smoothness of the aluminium composite panels. The
required thermocouples are positioned at the leading and
lagging point on the surface of the tool is to ease the con-
trol during autoclave curing. The key indicator of the
success of this pre-fitting is when the honeycomb core is
capable to adhere to the film adhesive perfectly.
2.2. Environmental Factor to Materials
The film adhesive and other related adhesives in the form
of foam and primer are classified as materials that sensi-
tive to time and temperature. These materials require a
proper handling and storage system to provide the phy-
sical mechanical properties for manufacturing the adhe-
Optimization in Autoclave Process to Produce Durable Aluminium Composite
Copyright © 2011 SciRes. MSA
460
sive bonded structure. The sensitive materials are stored
in a cold storage to eliminate potentially polymerization
before lay up process. Prior to cut and applied through
dry lamination process, these materials should be condi-
tioned to reach the lay up room condition between 18˚C
until 24˚C and required relative humidity in the range of
55% to 75%.
The adhesion failure is indicated by the absence of
adhesive on one of the bonding surfaces. It may occur
due to hydration of the chemical bonds which form in the
molecular link between the film adhesive and the bond-
ing surface. The adhesive bond between aluminiums will
fail only if the anodized layer converts to the hydrated
and causes the aluminium surface-to-adhesive chemical
bonds to dissociate leading to non bond. The oven heat-
ing after primer application ensures the adherence of
primer on to anodized aluminium surface and enhances
the adhesive adherence. Adhesive joining which is formed
on surfaces which are chemically active and resistant to
hydration will be durable in service.
2.3. Anodizing to Activate the Aluminium
Surface
In the view of human aspect, the causes of adhesion fail-
ure should be anticipated through the well understanding
of an appropriate surface preparation technique which is
able to produce a chemically active surface resistant to
hydration. The first preparation of aluminium skin before
anodizing is manually cleaned to remove any anti corro-
sion coating oil. Basically, aluminium surface treatment
provides good bond durability involves a number of steps,
namely: to degrease the whole surface through emulsion
or alkaline cleaning, to remove the existing surface layer
through deoxidizing and to establish an active surface in
the anodizing bath which will form hydration resistant
bonds with the adhesive or primer.
The key indicator of the successful of this surface
treatment and the primer application is that the primer
will adhere perfectly on to the surface of the anodized
aluminium skin. In contrary words, the inappropriate
anodizing process will not provide a strong bond be-
tween the primer layer to the anodized skin surface. The
anodizing process is essential and must be performed
sequentially to establish a durable bond. Many process
specifications, reference books and rep air manuals d o not
contain completely procedures to conform complete se-
quence and consequently do not produce durable bond
[14].
2.4. Adhesive Bonding Technique
Adhesive bond does not tolerate any contamination on
aluminium surfaces prior to bonding. Any adhesion fail-
ure which occurs in service is a direct result of the manu-
facturing process. Certain types of gloves (such as nitrile
gloves) reduce the surface energy after contact on alu-
minium surfaces and subsequently reduce bond strength.
In some cases the low surface energy is reflected in the
reduced average fracture toughness and the change of the
mode of failure. Both without gloves and contaminated
gloves change the failure mode of the drum peel speci-
mens [10].
In case of bonding on tight surfaces, the super thin fa-
bric reduces tacky problem to ease adhesive bonding.
Actually, this super thin fabric reinforces the film adhe-
sive with a typical thickness of 0.010 inch (0.250 mm)
such as FM-73M.OST.06 Cytec or thicker. The super
thin fabric usually does not require a thinner film adhe-
sive for metal-to-metal bonding. The contaminated super
thin fabric will remain spots or specific smell and these
are easily detected. The super thin fabric should be stored
in dry sealed bag and free from any contamination.
2.5. Process Control during Autoclave Curing
The autoclave facility is operated referred to a number of
process parameters such as heat up rate, holding time and
temperature, cooling down rate and the end temperature.
The vacuum bagging is checked from any vacuum leak-
age and maintained in a partial vacuum just before an
application of the autoclave pressure. Partial vacuum is
vacuum condition in which less to the maximum value of
vacuum capacity. Meanwhile, vacuum indicator will drop
if there is a leakage in the sealed bag. The lagging ther-
mocouple that controls the slowest heating location of
the bagging system should be placed in the proper place.
The historical process control is recorded on the auto-
clave recorder. The controlled parameters include the
vacuum and pressure values. If any vacuum leakage is
detected during the process, it will be indicated through
the vacuum graph that moves abruptly to the edge side of
rolling recorder and move to roll direction consistently at
zero scale. The perfectly sealed fully or partially vacuum
should be maintained at a constant value during curing
cycle.
The manufacturing adhesive bonded panel requires
different pressure parameters for metal to metal bonding
and sandwich panels. The metal to metal configuration
requires a cure pressure of 3.0 bars, whereas the sand-
wich metals needs a lower pressure around 1.7 to 2.0
bars. The drum peel at this range of results a consistently
high strength for adhesive bond, but the historical data do
not show consistently a perfect cohesive bonding espe-
cially for sandwich structure.
3. Experimental Procedures
3.1. Methodology
The experiment evaluated the performance of a crack
Optimization in Autoclave Process to Produce Durable Aluminium Composite
Copyright © 2011 SciRes. MSA
461
wedge compared to non crack wedge tests. The evalua-
tion of non crack wedge test involved sequentially work
steps by varying the process variables to examine its
possible impact against to the cohesive failure pheno-
menon. The sequentially experiment were performed to
determine different types of roots dominantly cause the
cohesive failure phenomenon in the aluminium compo -
site panels. A number of steps involved in the experi-
mental procedure as followed:
1) Evaluate the test specimen types to validate the
most critical the bonding adherence variables among the
peel, shear and drum peel specimens. The first step of
this study utilized the expired and new film adhesive to
select the most representative test to examine the alu-
minium composite panels.
2) Identify how far the process parameter variation
would induce the mechanical properties through destruct-
tive test specimen by using the new film adhesive. The
process variables include: a) incomplete cleaning in alk a-
line bath and drying at room temperature, b) application
of multi layer adhesive, and c) application of interlayer
of aramid.
3) Identify the impact of slightly higher autoclave
pressure against to the mechanical properties of the sand-
wich panels. The process variables included: a) single
film adhesive, b) interlayer of super thin fabric, c) used
primed skin, and 4) interlayer of super thin fabric.
3.2. Cohesive Failure Criteria
This study employed destructive specimens to explain
the adhesive bonding phenomenon in the aluminium
composite panels. The drum peeling specimens was cho-
sen to measure the confidence level of the quality of this
adhesive bonding strength. The specimens were firstly
treated in an anodizing line and the primer adhesive of
BR-127 Cytec was applied within 4-8 µm thickness.
Further, this primed skin was fully dried in an oven at
120˚C during one hour, prior to bonding lay up using the
film adhesive FM-73M.OST.06 Cytec at 0.010 inch
(0.250 mm) thickness [15].
The drum peeling specimens were prepared using the
cladded aluminium alloy LP-3140-T3. The upper skin
(300 mm × 75 mm) and lower skin (240 mm × 75 mm)
of specimen was approximately 0.5 mm thickness. The
thickness of metal core 7.9-1/4-4ON was 12 mm [13].
The laboratory testing was conducted by Instron ma-
chine.
The bonding surface was also observed visually to
check cohesively grade of film adhesive. The possibility
of any cohesive failure area was checked with refer of
the bonding surface profile of the destructive specimens
using drum peel testing. The best adhesive bonding
should be 100% cohesively b on ded.
4. Results and Discussion
4.1. Crack Wedge Test
The validation of metal bond durability based on the
wedge test ASTM D3762-03 that tolerated the crack
wedge propagation length until 0.50 inch in one hour ex-
posure to 60˚C and 95% RH. This validation was dif- fi-
cult to be fulfilled consistently. Even, a further recom-
mendation called out an acceptance criterion more strin-
gent less 0.15 inch/hour. In Figure 1 the bare aluminium
tended to show inconsistency result compare to clad alu-
minium (Figu re 2 ). However, the root cause of this failure
might be depend- ing on the specimen cutting prior to la-
boratory test, rather than the surface treatment procedure.
This crack wedge specimen applied stringent process
variable of internal pressure at 6 bars during autoclave
curing to obtain the adherence quality of the metal bond.
The basic handicap executed this test type in the produc-
tion line, if applied in daily load. The difficulty is h ow to
maintain production speed when requires re-test proce-
dure to pass the criteria tolerance. The possible re-test
Figure 1. Crack wedge length of bare Al.
Figure 2. Crack wedge length of clad Al.
Optimization in Autoclave Process to Produce Durable Aluminium Composite
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462
may frequently be performed due to the result inconsis-
tency. However, the application of this method either for
processing the first article and revalidation after totally
chemical replenishment was acceptable to ensure the whole
control of a surface treatm ent prior to metal bonding.
4.2. Non Crack Wedge Test
The tactically stratification intended to identify the most
critical test to determine the adhesive bonding perfor-
mance. By utilizing the expired and new film adhesive
FM-73M OST.06 Cytec, the critical test type was subse-
quently selected. Table 1 herein shows the values of
three standard test specimens in which the drum peel test
method became the most critical performance among the
others.
This table also shows that the peel and shear speci-
mens still provide exciting values than the drum peel
specimens although using the expired adhesive film. The
utilization of new film adhesive results a higher strength
value through the drum peel test compared to the peel
test. It shows that the expired film adhesive ind icates out
tolerance in performance based on the drum peel test
rather than peel and shear test. The configuration of the
peel and shear specimens represent metal to metal bond-
ing in which the upper skin will press uniformly over
bond surface. The utilization of the film adhesive
FM-73M.OST.06 with the initial thickness of 0.25 mm
tends to reach a bonding thickness between 0.050 mm to
0.200 mm in adhesive bonded panels after an autoclave
curing process. However, the metal to metal bonding
sufficiently utilizes the film adhesive FM-73M.OST.03
with an initial thickness of 0.125 mm.
In this matter, the study focused on the drum peel test
to examine a relationship between the process parameter
and its failure mode characteristic of aluminium sand-
wich panels. The experiment utilized the new adhesive
film and in the same time with the surface preparation
was simulated to do an improper cleaning in the a lkaline
bath at lower temperature around 25˚C. The standard
process in alkaline cleaning should be conducted at 65˚C
in ‘Turco’ solution, and the anodized aluminium required
an air drying at 60˚C. The ‘Turco’ solution used in this
experiment actually was removed and replaced by a new
non-chlorofluorocarbon and at a low temperature, NCLT
solution operating in room temperature condition. The
curing process utilized the autoclave internal pressure
between 1.7 to 2.0 bars to cure these specimens. All
sandwich specimens fulfilled minimum value of drum
peeling strength of 400 N minimum.
The double layers of film adhesive FM-73M OST.06
Cytec drastically proved higher value of mechanical
strength in sandwich panels. In practical application,
double layer of film adhesive was intended for rework
purposes to fill a gap between core and cover skins. Un-
fortunately, by accommodating the interlayer such as
aramid pre-impregnated between two film adhesive lay-
ers dropped its mechanical properties until 238 N, far
less than the practical requirement of 400 N minimum
(Table 2).
Set of operating parameters were completely fulfilled
during surface preparation to ensure the higher bond
characteristic between the film adhesive and the primed
aluminium skins. The autoclave operated with an internal
pressure of 1.7 to 2.0 bars, and the drum peel specimen
consistently passed the practical requirement, however
the fracture characteristic after peeling test did not gua-
rantee absolutely free of cohesive failure.
The trial experiment was conducted applying higher
pressure to the specimen by mean of the table press at
around 3.0 bars and showed excellent adhesive bond
without crash on the honeycomb core 7.9-1/4-4ON of 12
mm thickness. With refer to this parameter, then auto-
clave operation was prepared to higher pressure than the
common practice at 1.7 to 2.0 bars to gain higher adhe-
sive bond to avoid adhesive failure.
Further step was prepared the drum peel specimen us-
ing the new film adhesive to be subsequently polymer-
rized in the autoclave at the higher internal pressure be-
tween 2.5 to 3.0 bars. Other variable was simulated for
example an additional super thin fabric and trial used
primed skin to evaluate each of adhesive bond perfor-
mance. The applied pressure at 2.5 bars to 3.0 bars re-
sulted clearly characteristic of peeling fracture. These
peel specimen showed consistently 100% cohesive than
Table 1. Identification of test specimens performance.
Specimen ID No. 1102A 2502A 2303A
Film adhesive configuration and specification 1 layer FM-73M.OST.06 1 layer FM-73M.OST.06 1 layer FM-73M.OST.06
Film adhesive life time expired expired new
Peel strength, (>170 N) 247 330 342
Shear strength, (>27 MPa) 42 40 39
Drum peel strength, (>400 N) 299 66 520
Optimization in Autoclave Process to Produce Durable Aluminium Composite
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Table 2. Test specimens comparison at standard autoclave internal pressure.
Specimen ID No. 1103A 1103B 1103C
Film adhesive configuration and
specification 1 layer FM-73M.OST.06 2 layers FM-73M.OST.06 1 layer FM-73M.OST.06 + aramid
Film adhesive life time new new new
Process variables in preparation
before bonding Incomplete cleaning in alkaline and
drying at room temperature multi layer adhesive fully interlayer of aramid
Cut section photograph
Drum peel strength, (> 400 N) 446 1722 238 (not comply)
Autoclave internal pressure, bars 1.7 to 2.0 1.7 to 2.0 1.7 to 2.0
A-scan ultrasonic test Completely bonded Completely bonded Completely bonded
Cohesive failure determination Not consistent Nearly 100% cohesive Nearly 100% cohesive
Table 3. Test specimens comparison at higher autoclave pressure.
Specimen ID No. 0604A 0604B 0604C
Film adhesive configuration and
specification FM-73M.OST.06/original skin FM-73M.OST.06 +Cerec +original skin
FM-73M.OST.06 / used skin
Film adhesive life time new new new
Process variables in bonding lay up
Standard Interlayer of super thin fabric Used primed skin
Cut section photograph
Drum peel strength, (> 400 N) 471 520 495
Autoclave internal pressure, bars 2.5 to 3.0 2.5 to 3.0 2.5 to 3.0
A-scan ultrasonic test Completely bonded Completely bonded Completely bonded
Failure mode determination 100% cohesive/inter laminar bond 100% cohesive/inter lamina r bond 100% cohesive/i nter laminar bond
the common practice less than 2.0 bars (Table 3).
Additionally, the super thin fabric that was manually
laid on film adhesive improved its mechanical properties
up to 10% compared to the standard adhesive film. The
super thin layer should be placed on the tacky side of the
adhesive layer FM-73M.OST.06 Cytec at 0.010 inch
(0.250 mm) thickness to ease the bonding application
during manual lay up.
In the other case, the used primed skin with the suffi-
ciently peel strength at 495 N provided higher confidence
to ensure the rework process. In this case, the rework
configured one side skin removal and partially core re-
placement. In this experiment, the used primed skin was
treated in the similar anodizing process prior to bonding
Optimization in Autoclave Process to Produce Durable Aluminium Composite
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464
application utilizing film adhesive FM-73M.OST.06.
5. Conclusions
The first important step to provide excellent bond dura-
bility involves the surface cleaning, the deoxidizing sur-
face layer and the activating surface to form hydration
resistant bonds with the primer and film adhesive. In
fracture evaluation recently, the optimal measurement of
adhesive bond still depends on lap shear and drum peel.
Failure mode of the accepted adhesive bond preferably
indicates cohesion bond as strong as adhesive itself or
inter laminar bond as strong as laminate itself.
The crack wedge extension to validate adhesive bond
durability is considered less practical commercially if
conducted on a daily load basis, and usually being ap-
plied to produce the first article or to revalidate the sur-
face preparation process. Practically, drum peel specimen
configures bond durability characteristics. The applied
slightly higher autoclave pressure between 2.5 bars until
3.0 bars proves clearly characteristic of 100% cohesive
peeling fracture than the common practice less than 2.0
bars.
REFERENCES
[1] L. Dorn, “Adhesive BondingTerms and Definitions,”
Training in Aluminium Application Technologies, Tuto-
rial, Lecture 4701, Technische Universitat, Berlin, 2010.
Internet Available:
http://www.eaa.net/eaa/education/talat/lectures/4701.pdf
[2] ASTM D 1002-01, “Standard Test Method for Apparent
Shear Strength of Single-Lap-Joint Adhesively Bonded
Metal Specimens by Tension Loading (Metal-to-Metal),”
ASTM International, 2001.
[3] ASTM D 1781-98, “Standard Test Method for Climbing
Drum Peel for Adhesives,” ASTM International, 1998.
[4] S. Hojabr and S. R. Tanny, “Low Activation Tem-
perature Adhesive Composition with High Peel Strength
and Cohesive Failure,” United States Patent No. 6855432,
E. I. du Pont de Nemours and Company, Wilmington, DE,
15 February 2005.
[5] T. Takano, “Method to Improve High Temperature Co-
hesive Strength with Adhesive Having Multi-Phase
System,” United States Patent No. 7160946, National
Starch and Chemical Investment Holding Corporation,
New Castle, DE, 9 January, 2007.
[6] J. C. Engelaere, “Bonding Composition with Cohesive
Failure,” United States Patent Application No. 200702
12504, Soplaril, 1 rue de l’Union, Rueil Malmaison,
France, 13 September 2007.
[7] S. Kozakai, N. Ichiroku, A. Suzuki and T. Shiobara,
“Adhesive Composition and Adhesive Film,” United
States Patent No. 7364797, Shin-Etsu Chemical Co., Ltd.,
Tokyo, Japan, 29 April 2008.
[8] S. Hamano, “Adhesive Film,” United States Patent Appli-
cation No. 20090286073, Kyodo Giken Chemical Co.,
Ltd, Saitama, Japan, 19 November 2009.
[9] A. Nishiura, H. Sugihara and K. Abe, “Adhesive Prepara-
tion,” United States Patent Application No. 20100041758,
Ono Pharmaceutical Co., Ltd., Osaka-shi, Japan, 18 Febru-
ary 2010.
[10] B. D. Flinn, F. Ohuchi, M. Phariss, J. Satterwhite, J. Au-
bin and C. Keenen, Improving Adhesive Bonding of
Composites through Surface Characterization,” The Joint
Advanced Materials and Structures Center of Excellence,
CECAM, and AMTAS, University of Washington, 2010.
http://depts.washington.edu/amtas/ev-ents/jams_08/21.Fli
nn.pdf
[11] M. J. Davis, “FAA Workshop on Best Practice in Adhe-
sive Bonding, Principal Research Scientist,” Directorate
General Technical Airworthiness, Royal Australian Air
Force, 2010.
http://www.niar.wichita.edu/NIARWorkshops/LinkClick.
aspx?fileticket=iGBXdAGtWEk%3D&tabid=104&mid=
569
[12] ASTM D 3762-03, “Standard Test Method for Adhe-
sive-Bonded Surface Durability of Aluminum (Wedge
Test),” ASTM International, 2003.
[13] M. J. Davis and D. A. Bond, “The Importance of Failure
Mode Identification in Adhesive Bonded Aircraft Struc-
tures and Repairs,” Aircraft Structural Integrity Section,
Directorate General of Technical Airworthiness, Royal
Australian Air Force, Amberley Detachment, 501 Wing,
RAAF Amberley 4306, Australia, RAAF Williams, Mel-
bourne 3027, Australia, 2010.
http://www.adhesionassociates.com/papers/46%20Import
ance%20of%20Failure%20Mode%20Indentification%20I
CCM%2012%20Paris.pdf.
[14] D. R. Arnott, A. R. Wilson, A. N. Ride r, C. L. J. Olsson,
L. T. Lambrianidis, P. J. Pearce, M. J. Davis and G. Swan,
“Research Underpinning the Adherent Surface Prepara-
tion Aspects of the RAAF Engineering Standard C5033,”
International Aerospace Congress, Sydney, 25-28 Febru-
ary 1997.
[15] Cytec Engineered Material Ltd., “Primer Adhesive and
Film Adhesive,” Technical Data Sheet, Arizona, 2008.
http://www.cytec.com/