February/March_AMP_Digital

12 / 82

A D V A N C E D M A T E R I A L S & P R O C E S S E S | F E B R U A R Y / M A R C H 2 0 1 7
1 2
SMART TISSUES, SMART
TEXTILES
Researchers at the University of
New South Wales, Australia, produced
an advanced functional fabric that mim-
ics the adaptive stress-strain properties
of a soft tissue from the human body,
reportedly for the first time. The team
used high fidelity 3D imaging to map
the complex architecture of periosteum,
a soft tissue sleeve that envelops most
bony surfaces in the body and provides
resilience and strength under high im-
pact loads. After applying CAD modeling
to scale up periosteum’s pattern of struc-
tural proteins, researchers produced
prototype multidimensional fabrics on
a computer-controlled jacquard loom.
In a first test of the concept, a series of
textile swatches were woven in a twill
pattern using elastic and silk instead of
periosteum’s collagen and elastin fibers,
which are too small to fit into the loom.
Mechanical testing showed the novel
fabric possessed properties similar to
those exhibited by the natural tissue.
The next step is to produce fab-
ric prototypes for a range of advanced
functional materials, from protective
suits for skiers that stiffen under high
impact to smart compression bandages
for deep-vein thrombosis that respond
to the wearer’s movement. Eventually,
the team hopes to weave tissues in the
lab that can be used to replace failing
joints, bringing the material full circle.
.
SAND STRONGER THAN STEEL
FOR ENERGY ABSORPTION
Researchers fromtheNational Uni-
versity of Singapore (NUS) demonstrat-
ed that the energy absorption capability
of sand is significantly higher than that
of steel, suggesting it could serve as a
cheaper, lighter, greener alternative to
Periosteum is a tissue fabric layer on the
outside of bone (upper left). The natural
weave of elastin (green) and collagen
(yellow) are evident under the micro-
scope. Courtesy of Melissa Knothe Tate.
the metal in armor systems and critical
infrastructure protection. After firing
projectiles of various shapes and mass-
es at a silica sand block using a wide
range of velocities, the team discovered
that the sand absorbs more than 85%
of the energy exerted against it—an
ability that increases with the projec-
tile’s speed, even at high velocities.
Additionally, because the sand grains
dilate on impact and resist continual
penetration, an extreme frictional force
is created that could potentially break
the projectile into pieces. In contrast,
the energy absorption capability of an
equivalent steel plate reduces dramati-
cally as projectile velocity increases due
to the hydrodynamic effect: As projec-
tile velocity surpasses the ballistic lim-
it—the minimum velocity required to
penetrate the target—steel behaves as
a fluid without material strength. The
team plans to explore the integration of
sand with other compliant materials as
well as investigate the energy absorp-
tion capabilities of other geomaterials,
such as rock rubble. .
A teamof researchers fromNUS found that when a projectile is fired at a sand block
at high speed, it absorbs more than 85%of the energy exerted against it.
BRIEF
Lawrence Livermore National Laboratory and National Nuclear Security Administra-
tion officials recently broke ground on the Advanced Manufacturing Lab, a collaborative
hub for developing next-generation materials and manufacturing technologies. Construc-
tion is underway at the Livermore Valley Open Campus, Calif., with completion expected lat-
er this year. The $9.4 million, 13,000-sq-ft facility will feature a reconfigurable wet chemistry
lab, dry instrument lab, and collaboration and conference space. llnl.gov.
EMERGING TECHNOLOGY
Schematic of the new Advanced
Manufacturing Lab at Lawrence Livermore.