Slides that accompanied my conference presentation at the 11th International Conference on Composite Science and Technology (ICCST) on April 5th, 2017. Full manuscript can be found in at https://www.researchgate.net/publication/316472276_Enhancing_the_Self-Sensing_Capability_of_Carbon_Fiber_Reinforced_Polymer Program: BSc in Mechanical Engineering Affiliation: American University of Sharjah, Department of Mechanical Engineering

1. Enhancing the Self-Sensing Capability of
Carbon Fiber Reinforced
Polymer
11TH INTERNATIONAL CONFERENCE ON COMPOSITE
SCIENCE AND TECHNOLOGY
ARWA ABOUGHAREEB, WAEL ABUZAID, MAEN ALKHADER

2. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Motivation
CFRP are used in many advanced
applications.
 Aircraft structures
Marine applications
Concrete structures reinforcement
Traditional inspection techniques
are being challenged in these critical
applications.
There is a need for improved
structural health monitoring
systems.
Arwa Aboughareeb
American University of Sharjah
2
Composites in Airbus @ Global Investor Forum by Dr Roland Thévenin
CFRP for externally
bonded
reinforcement
By Michelle Meltzer @ Buildera

3. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Motivation
Polymer matrix is insulative
Carbon Fiber is highly conductive
Composite is slightly conductive
Resistance changes as load is applied
Exploit feature for SHM applications
Can we enhance the electrical response
of CFRP (linearity/sensitivity)?
Can we predict damage (fiber/matrix
breakage)?
Arwa Aboughareeb
American University of Sharjah
3
CFRP for externally
bonded
reinforcement

4. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Objectives
Exploit feature for SHM applications
Can we enhance the sensitivity of
CFRP?
Can we predict damage (fiber/matrix
breakage)
Enhance the load sensitivity of
CFRPs to measure deformation and
predict damage by introducing into
the polymer matrix:
Graphene Nanoplatelets (GNPs)
Milled Carbon Fiber (MCF)
Arwa Aboughareeb
American University of Sharjah
4
CFRP for externally
bonded
reinforcement
SEM by Nanoshell ®

5. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Methods - Dispersion of Nanoparticles
Proper dispersion is critical for conductivity
enhancement
Different methods uses:
Sonication
Three-roll milling
Manual stirring
Re-aggregation is a major issue
Adequate sonication time can be selected
based on resistance measurements
Achieve minimum resistance
Arwa Aboughareeb
American University of Sharjah
5
CFRP for externally
bonded
reinforcement
Probe Sonicator

6. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Methods - Dispersion of Nanoparticles
Arwa Aboughareeb
American University of Sharjah
6
0.0001
0.001
0.01
0.1
1
10
100
1000
0 1 2 3 4 5 6 7 8 9 10
Resistance(MegaOhms)
Sonication time (min)
Suspension resistance during sonication at 50% Amplitude
1 wt% GNP 5 wt% GNP
6 wt% GNP 2 wt% GNP + 2 wt% MCF (i) (incremental*)
4 wt% MCF (i) (incremental*) 4 wt% GNP(i) (incremental**)

7. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Methods – CFRP
Conductive particles incorporated in resin
Low viscosity infusion resin
The following composition considered:
As-is resin (control)
4 wt% GNP (15 µm from XG Sciences)
4 wt% MCF (100 µm milled carbon fiber)
2 wt% GNP+ 2 wt% MCF
Samples created using:
Wet layup
Vacuum bagging
Room temperature cure for 24 hrs
Post cure at 60 °C for 5 hrs
Arwa Aboughareeb
American University of Sharjah
7
CFRP for externally
bonded
reinforcement
Carbon Fiber 2/2 Twill 3k 200g

8. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Methods – Deformation & Resistance measurements
Electrical contacts with
copper tape, stranded
copper wire and silver
paint
Load in tension @
1mm/min up to 3.5 mm
extension
Resistance measurement
during tension with
voltage divider circuit and
LabVIEW DAQ
Arwa Aboughareeb
American University of Sharjah
8
CFRP Tension Sample
Clamp
Region
Wire
Contact
Measurement Circuit

9. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Results – Control Sample (As-Is Resin)
Sample resistance
changes during loading
Monitor the change as a
function of time (in-situ)
Also capture stress and
sample extension
(deformation)
A good correlation is not
observed under these
conditions (As Is Resin).
Arwa Aboughareeb
American University of Sharjah
9

10. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Results – Modified with Conductive Particles
Arwa Aboughareeb
American University of Sharjah
10
As-Is 4wt% GNP
4wt% MCF 2wt% GNP
2wt% MCF

11. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Results – Describe deformation based on resistance
Arwa Aboughareeb
American University of Sharjah
11
OK
OK

12. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Results – Damage Detection
Arwa Aboughareeb
American University of Sharjah
12
As-Is 4wt% GNP
4wt% MCF 2wt% GNP
2wt% MCF
What induces
this change ?

13. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Results – Damage Detection
Arwa Aboughareeb
American University of Sharjah
13
Stress drops
Stress drops

14. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Results – Damage Detection
Arwa Aboughareeb
American University of Sharjah
14
Damage in the CFRP sample causes
sudden drop in stress
Fiber breakage
Matrix cracking
The introduction of damage can be
picked up by resistance
measurements
Large increment in resistance
Slope changes
Fatigue of Composite Materials: Damage Mechanisms and Fatigue-Life Diagrams
R. Talreja. Proc. R. Soc. Lond. A 1981 378 461-
75; DOI: 10.1098/rspa.1981.0163. Published 17 November 1981

15. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Conclusions
Arwa Aboughareeb
American University of Sharjah
15
The self-sensing capability of CFRPs can be
enhanced by the addition of MCF or GNP.
The as-is resin control case showed an
inferior correlation between resistance
change and extension compared to the
modified samples.
Early stages of damage accumulation in the
form of fiber breakage or matrix cracking can
be detected through :
 large and sudden resistance change
 or less pronounced slope change in the ΔR/Ro signal.

16. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Future Work
Wael Abuzaid
American University of Sharjah
16
1
Test more samples
under each condition
for improved
confidence
2
Use of slow vs. fast
hardener
3
Other particle
dispersion methods
e.g. rolling
4
Fatigue life

17. A m e r i c a n U n i v e r s i t y o f S h a r j a h
D e pa rt me nt of Me c ha nic a l Engine e ring
Thank You
Questions ?
Wael Abuzaid
American University of Sharjah
17