SAMPE Journal - March/April 2023 - 16

FEATURE / HELICOID FIBER ARCHITECTURES
the damage morphology. Figure 4 respectively
shows the perforation energy for each one of the
configuration tested in this work (A), representative
load vs displacement curves for the Helicoid hybrid
laminates and Helicoid monolithic GFRP and NFRP
laminates (B), representative load vs displacement
curves for the conventional QI hybrid laminates
and conventional QI monolithic GFRP and NFRP
laminates (C), and the load vs. displacement curves
of representative monolithic NCF conventional QI
GFRP, conventional QI NFRP and Helicoid NFRP.
Note that the representative curves are reported for
samples that achieved full perforation to provide a
comprehensive view of the load vs displacement
behavior of each sample including, elastic region,
peak-load and post perforation.
For similar total laminate weight, Table 2 and
Figure 4b-4c show that Helicoid laminates overall
outperformed conventional QI laminates both
in monolithic as well as hybrid configurations.
The performance improvement increases with
the amount of GFRP added to the composite.
Specifically, compared to the monolithic NFRP
conventional QI, Helicoid monolithic NFRP
achieved up to 21% higher peak load, 69% delay
(a)
in occurrence of catastrophic failure and 104%
higher energy dissipation before the occurrence of
catastrophic failure (peak load).
While FH underperformed GQI and GH, by
adding 21% by mass of GFRP to the Helicoid NFRP
(i.e. HY21%) the performance achieved were
similar to GQI. Furthermore, Figure 4A shows that
by adding 30% by mass of GFRP to the Helicoid
NFRP it was possible to achieve an increase in
perforation energy of about 17% compared to GQI.
Figure 4A shows that Helicoid technology applied
to
monolithic NFRP (FH) and to
monolithic
GFRP (GH) leads to a 43% and a 48% increase in
perforation energy compared to the respective
conventional QI configurations (FQI and GQI),
hence highlighting the versatility of Helicoid
technology to be applied to different material
systems.
While the majority of the results are related
to the prepreg/autoclave processed materials,
initial results on NCF/VA-RTM samples reported
in Figure 4a and Figure 4d show that, compared
to conventional QI NFRP laminates (NCF-FQI),
Helicoid NFRP achieves a 14% higher peak load,
a 38% delayed catastrophic failure, a 74% higher
(b)
(c)
(d)
Figure 4. (a) Perforation energy; (b) Load vs displacement curves of
representative hybrid GFRP/NFRP, GFRP and NFRP Helicoid samples
tested up to full perforation (prepreg and autoclave); (c) Load vs
displacement curves of representative hybrid GFRP/NFRP, GFRP and
NFRP conventional QI samples tested up to full perforation (prepreg
and autoclave); (d) Load vs displacement curves of representative GFRP
conventional QI, NFRP conventional QI and NFRP Helicoid samples tested
up to full perforation (NCF and VA-RTM).
16 | SAMPE JOURNAL | MARCH APRIL 2023
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SAMPE Journal - March/April 2023

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