JEC COMPOSITES MAGAZINE - Issue #137 - November/December 2020 - 55

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

Tab.2: Nomenclature of the Specimens (t - Thickness)
Nomenclature

Rigid adherend

Flexible adherend

A-a

Aluminium (t =1.6 mm)

Aluminium
(t =0.5 mm)

C-a

CFRP ( 0° / 90° / 0° / 90° / 0° )s
(t =2.4 mm)

Aluminium
(t =0.5 mm)

C-c

CFRP ( 0° / 90° / 0° / 90° / 0° )s
(t =2.4 mm)

CFRP ( 0° / 90° )
(t =0.37 mm)

A-c

Aluminium (t =1.6 mm)

CFRP ( 0° / 90° )
(t =0.37 mm)

A special focus was given to the thermal stresses that can derive from bonding two materials with different coefficients
of thermal expansion. Some solutions have been suggested,
such as dual adhesive joints (combination of a high- temperature adhesive with a low-temperature adhesive), to
minimize the possible strength loss due to residual thermal
stresses [10,11].
There is, however, limited research available on the adhesion
properties of composite-to-aluminium joints: are the adherends properly bonded together? And will this bond endure?
These types of questions are extremely important to avoid
in-service interfacial failure of adhesive joints. Lap shear test
coupons give very little information about the adhesion of
the joints. Adhesion tests should be added to the lap shear
test results in order to ensure the integrity of an adhesive
joint.
Some authors combine SLJ with DCB or T-peel tests in order to evaluate the durability of bonded composite-to-aluminium joints, for example, against humidity, or the effect
of different surface pretreatments [12,13]. Nevertheless, both
studies were more focused on evaluating the effects on mechanical properties rather than the adhesion properties of
the joints.
Established standard tests are currently used for testing adhesion in bonded metal joints. Today, floating roller peels
tests or wedge tests are used in industry together with lap
shear tests to ensure the integrity of bonded metal joints.
For adhesively-bonded composite joints and composite-toaluminium joints, the same adhesion requirements need to
be satisfied.
However, no standard tests have been established yet for
testing the adhesion properties to composite adherends.

Figure

Also for bonded composite joints, research has been focused
on DCB and SLJ [14-17]. No simple and straightforward test
coupon revealing the adhesion of composite bonding and
composite-to-aluminium bonding has been established yet
[18,19].
In this research, the adhesion properties of bonded composite-to-aluminium joints are evaluated using floating roller
peel tests. Due to their simplicity of concept and geometry,
these peel tests are widely used in industry to evaluate the
adhesion properties of metal-bonded structures. The aim is
to investigate the viability of using such peel tests in bonded composite-to-aluminium and composite-to-composite
joints and how to assess their adhesion properties from the
peel test results.

Materials and specimens
Floating roller peel test specimens were produced by adhesive bonding a thin-flexible adherend to a thick-rigid adherend. During testing, the flexible adherend was peeled off
from the rigid adherend.
Materials
The peel test specimens were produced using clad aluminium alloy 2024. The aluminium surfaces were pretreated with
chromic acid anodizing and primed with BR 127 (Cytec
Engineered Materials, USA). The flexible aluminium sheets
were 0.5 mm thick, and the rigid aluminium sheets were 1.6
mm thick.
The carbon fibre-reinforced polymer (CFRP) panels
were prepared from unidirectional prepreg consisting of
HexPly 8552 epoxy matrix in combination with AS4 carbon fibre (Hexcel Corporation, USA). A lay-up of 10 plies
(0°/90°/0°/90°/0°) was used to produce the rigid composite

N°137 November - December 2020

/ jec composites magazine

55



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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