Momentum - The Magazine for Virginia Tech Mechanical Engineering Vol. 4 No. 4 Winter 2019 | Page 11

The way the scale armor works is that when in con-
tact with a force, the scales converge inward upon one
another to form a solid barrier. When not under force,
they can ‘move’ on top of one another to provide vary-
ing amounts of flexibility dependent upon their shape
and placement.
“The strength comes from how the scales are orga-
nized, from their geometry,” Li said. “Reza’s team has
done an amazing job by using computational modeling
to further reveal how the scale armor becomes inter-
locked and rigid when the external load reaches a critical
value.”
The design of place-specific armor takes into account
the size of scales used. Smaller scales, such as those
around the girdle of the chiton, are more useful for re-
gions requiring maximum flexibility, while larger scales
are used for areas requiring more protection. “Working
with Reza, our next step is to expand the space so we
can design tailored armor for different body locations.
The flexibility vs. protection needs of the chest, for
example, will be different than for the elbow or knee, so
we would need to design the scale assembly accordingly
in terms of scale geometry, size, orientation, etc.”
The work being featured began with Department
of Defense funding when Li was a graduate research
assistant at the Massachusetts Institute of Technology.
Since he arrived at Virginia Tech in 2017, the work has
continued without sponsorship as part of his start-up
funding.
“We started with a pretty pure motivation – looking
for multifunctional biological materials,” Li said. “We
wanted to integrate flexibility and protection and that’s
very hard to achieve with synthetic systems. We will
continue with our research to explore the design space
beyond the original biological model system and con-
duct testing under different load conditions.”
Li admits the process, which has taken multiple
years, is long, but the work is unique in how they’ve
approached it from the start as a two-step process in
conducting the fundamental biological materials re-
search followed by the bio-inspired research.
“Having that level of familiarity with the subject has
been very useful to the design and modeling of the
armor,” Li said. “I think this type of bio-inspired armor
will represent a significant improvement to what is
currently available.”