JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 59

Adhesion properties of bonded composite-to-aluminium joints using peel tests

Fig. 8: Close up of the fracture surfaces at the rigid adherend of EA 9695 specimens
when peeling off (a) the aluminium from the aluminium (A-a) and (b) the aluminium
from the composite (C-a): 1-CF, 3a-AF at the aluminium interface, 3b-AF at the
composite interface

Fig. 7: Load-displacement graphs of EA 9695 peel specimens and corresponding
failure surfaces of the rigid adherends (a) when peeling off the aluminium and (b)
when peeling off the composite

icant decrease of the peel load from C-c to A-a is not caused
by the type of failure mechanism but mainly by the type of
flexible adherend.
Looking at the peel load between 20 mm displacement and
70 mm displacement in Figure 4(b), the peel load of C-c is
higher than A-c. When looking at the fracture surface between that area, the C-c fracture surface has relatively more
% CF than % ILFC and the other way around for the A-c.
On the contrary, after 150 mm displacement, the peel load
of C-c is lower than the A-c, since the % CF decreased in
the C-c and increased in the A-c. This might indicate that
the adhesive's peel strength (CF) is higher than the CFRP's
intralaminar strength.
Figure 7 shows examples of load-displacement curves and
corresponding fracture surfaces of EA 9695 specimens.

As described in the results, the EA 9695 A-a specimens had a
lower peel performance than the C-a specimens. Looking at
the fracture surface of the A-a specimens, two types of failure surfaces can be identified: CF and AF. A close-up view
of the two types of failure is shown in Figure 8(a). Indeed,
the AF has a smooth fracture surface in contrast with the CF.
In the A-a load-displacement curve, the peel load is around
50 N/25 mm up to 60-70 mm displacement.
At around 100 mm displacement, the peel load shows a peak
of approximately 70-75 N/25 mm.
This peak corresponds to an increase of % CF around 90 mm
of debonding length. This increase of CF percentage is the
reason for the increase of the peel load. This comparison indicates that the CF leads to higher peel loads than the AF, as
expected. However, in this case, there are no adhesive stripes
as described before, nor sudden drops. The adhesive areas
are in combination with the CF in the same cross sections.
For the C-a specimen, the peel load is more constant along
the displacement. The major failure mechanism is cohesive
with some small AF areas (approximately 10%). A closeup view of the fracture surface in this specimen is shown in
Figure 8(b). In contrast with the previous examples where
the AF was always at the interface with the flexible adherend, in this case AF also occurs at the interface with the rigid
adherend (CFRP).
The peel load of the C-a specimens is always higher than
on the A-a specimens, because the CF percentage is always
higher in the former than in the latter. The peel loads of
both specimens get closer when the CF percentage in the
A-a specimens increases. Both peel loads are below what was
expected because none of them had 100% CF.
Figure 7(b) shows the results of EA 9695 when peeling off a
flexible CFRP. Similar to what was observed in FM 73, the
peel loads are considerably lower than when peeling off an
aluminium sheet. This indicates that this decrease is not related to the type of adhesive.
The AF ''stripes'' also correspond to sudden drops in the
peel load, as shown in the C-c specimen. There is also a direct correspondence between the load-displacement measured and the failure-debonding length observed. Even in the

N°137 November - December 2020

/ jec composites magazine

59



JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020

Cover
Edito
“We can change the way we envision global shipping overall”
Contents
NEWS
In brief
Agenda
BUSINESS
Human ressources - Skills requirements in the composite materials sector – the French example
Startup - Make lightness and performance affordable without compromising the environment
Offshore - GWEC: Asia Pacific to become the largest offshore wind market by 2030
MANUFACTURING
Additive manufacturing - The METHOD platform expands to support more materials,applications, and markets
Automation - One-shot manufacturing of cylindrical lattice structures for satellite applications
Recycling - World’s first fully-recycled thermoplastic composite application in aerospace
Additive molding - From large-scale continuous thermoplastic composites to mass production
FEATURE AUTOMOTIVE - Is it possible to do better?
FRP - Fully coupled processstructure analysis for automotive center floor panel
Honeycomb - Composite materials for lighter vehicles
Additive manufacturing - Transforming composite production processes with FDM additive manufacturing
EV - All-composite EV wheel moves to next development phase with pilot production
Security - The world’s fastest armoured car
Natural fibre - Sustainable composite solution for new Toyota LQ concept car
SOLUTIONS
Defence - Drones as wingmen
City - Composites for tomorrow’s cities
Maintenance - Degradation mechanism and maintenance of GFRP hydrochloric acid storage tanks
TECHNOLOGY
Bonding - Adhesion properties of bonded composite-to-aluminium joints using peel tests
Inside the lab - The University of Southern Queensland - Centre for Future Materials
Method - Weight and cost reduction with double-double laminates
Index
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JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Cover
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 2
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Edito
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - “We can change the way we envision global shipping overall”
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 5
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Contents
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 7
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - In brief
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 9
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Agenda
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Human ressources - Skills requirements in the composite materials sector – the French example
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 12
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 13
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Startup - Make lightness and performance affordable without compromising the environment
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 15
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 16
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Offshore - GWEC: Asia Pacific to become the largest offshore wind market by 2030
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 18
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Additive manufacturing - The METHOD platform expands to support more materials,applications, and markets
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 20
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Automation - One-shot manufacturing of cylindrical lattice structures for satellite applications
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 22
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 23
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Recycling - World’s first fully-recycled thermoplastic composite application in aerospace
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 25
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 26
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Additive molding - From large-scale continuous thermoplastic composites to mass production
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 28
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 29
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - FRP - Fully coupled processstructure analysis for automotive center floor panel
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 31
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 32
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 33
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Honeycomb - Composite materials for lighter vehicles
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 35
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 36
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Additive manufacturing - Transforming composite production processes with FDM additive manufacturing
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 38
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - EV - All-composite EV wheel moves to next development phase with pilot production
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 40
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Security - The world’s fastest armoured car
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 42
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 43
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Natural fibre - Sustainable composite solution for new Toyota LQ concept car
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 45
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 46
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Defence - Drones as wingmen
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 48
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 49
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - City - Composites for tomorrow’s cities
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 51
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Maintenance - Degradation mechanism and maintenance of GFRP hydrochloric acid storage tanks
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 53
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Bonding - Adhesion properties of bonded composite-to-aluminium joints using peel tests
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 55
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 56
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 57
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 58
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 59
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 60
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 61
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Inside the lab - The University of Southern Queensland - Centre for Future Materials
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 63
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Method - Weight and cost reduction with double-double laminates
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 65
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - Advertisers
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 67
JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 68
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