Tech Briefs Magazine - November 2023 - 12

Q & A
New Lightweight Energy-Dissipating
Material for Industry
Professor Pablo Zavattieri
and his team
from Purdue University
have developed an
architected material
that can dissipate energy
caused by bending,
compression, torque,
and tensile stresses,
avoiding permanent plastic deformation
or damage.
Tech Briefs: What got you started
on this project?
Professor Pablo Zavattieri: In 2011, we
had the idea of connecting some bistable
and metastable mechanisms together. As
an exploratory project, we built a material
using those mechanisms as unit cells and
found that the materials could be used to
absorb energy without damage. We call
these materials architected materials. The
idea is that we are using geometry and local
properties to control their emerging behavior.
Their behavior doesn't come from
their chemistry or processing - it comes
from designing them to bend and twist in
a way that is well controlled. A key aspect
of these materials is that they can change
from one stable state to another and back
again. We decided to use our idea to make
a mat that would be super light and could
be put on the ground, where it would absorb
energy due to impacts. For example,
we were thinking about airplanes hitting
the ground very hard. Instead of causing
damage, the energy would be absorbed by
the panel in an elastic way - it would just
cause an elastic deformation and then go
back to its original shape.
Tech Briefs: What do you mean by
architected material?
Zavattieri: Architected materials are designed
with geometry. We can design them
as building blocks, like rooms in a big
building. We call it architected because we
use architectural concepts. The big difference
is that, although our materials could
be thought of as rooms in a building, each
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of our rooms is very tiny - they might be
micron scale or millimeter scale. And it can
be done with 3D printing. These materials
experience minimal internal deformation,
preserving their structural integrity without
any damage or inelastic behavior.
Tech Briefs: Is there a limit to the
size of the panel you could make?
Zavattieri: There are two things that limit
the size. One is the manufacturing process.
If you want to build something on the
scale of meters, then you have to use a lot
of material, so 3D printing would not be
the best way to go. If you want to do something
on the micron scale, you could print
using lithography and other techniques
that are typically used for electronics. The
other limitation is the plastic deformation
for a given material. For example, if you
use polymer, it will deform plastically before
it fails. But you can calculate those limits,
using equations from material science.
Tech Briefs: Besides the mat, what
are other potential applications?
Zavattieri: We are currently evaluating
our material for earthquake-resistant
structures. In tall buildings, the capability
of the material to absorb energy
might be just enough to prevent failure
and damage. There could also be applications
for cars and airplanes because
they are lightweight. Also seats that can
accommodate the human body and absorb
energy as well as protective helmets.
Tech Briefs: What's the time frame for
when it might be practically usable?
Zavattieri: If an industry is interested,
we can start developing structures for
particular applications - we have all the
tools. We just need an application and
then maybe a couple of years. But for the
mats, we are ready to go. So, our goal, is
to start working with industry.
To read the full interview, visit www.
techbriefs.com.
Tech Briefs, November 2023
http://info.hotims.com/84485-719 http://www.techbriefs.com http://www.techbriefs.com
Tech Briefs Magazine - November 2023

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