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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 | S E P T E M B E R 2 0 1 5
1 2 TESTING | CHARACTERIZATION
BOXFISH INSPIRES NEW
ARMOR DESIGNS
Engineers at the University of Cal-
ifornia, San Diego, discovered that the
unique armor of the boxfish draws its
strength from hexagon-shaped scales
and the connections between them,
which could inspire advanced body
armor and flexible electronics design.
The scales, called scutes, are connected
by sutures similar to the connections
in a baby’s skull, which grow and fuse
together as the baby develops.
Most fish have overlapping scales,
says Steven Naleway, a materials sci-
ence and engineering Ph.D. student.
“We are currently investigating what
mechanical advantage scutes and
sutures might provide. The boxfish has
survived for 35 million years with this
armor, so the design has proved very
successful in nature,” he explains.
Each scute has a raised starlike
structure in the center that distributes
stress across the entire surface. Under
the scutes, an inner layer forms a com-
plex structure in which collagen fibers
interlock. This structure creates a flex-
ible inner layer in the armor, which is
difficult to penetrate due to the inter-
locking collagen fibers. Together, the
The boxfish gets its name from its boxy shape (left). Its shell is composed of several hexagonal scutes that provide body support and
armored protection (center). Scutes are connected by toothlike joints called sutures (right). Courtesy of Jacobs School of Engineering/
UC San Diego.
the latest research and developments
in the field of electronic device failure
analysis on topics such as emerging
failure analysis techniques, fault isola-
tion, sample preparation, counterfeit
electronics, and more. Other special
programs taking place at ISTFA include
mainstays like the annual ISTFA video
and photo contests and the return of
the popular “Tools of the Trade VIP
Expo Tour,” as well as a new student
poster contest. Three educational
workshops will be held on Saturday,
October 31: Fault Isolation, Packag-
ing Failure Analysis, and Beam-Based
Defect Localization. Albert Yu-Min Lin,
National Geographic Explorer, serves as
this year’s keynote speaker and will dis-
cuss his groundbreaking work on using
noninvasive computer techniques to
explore archaeological sites, including
that of Genghis Khan.
ELECTRON SPIN RESONANCE
EXPLORES TINY OBJECTS
Researchers at the National Insti-
tute of Standards and Technology
(NIST), Gaithersburg, Md., devised away
to shrink a research instrument gener-
ally associatedwith largemachines that
make bulk measurements of samples
down to a pinpoint-precision probe.
outer and inner layers of the boxfish ar-
mor provide unique protection. Mean-
while, connections between the scutes,
called sutures, make the armor even
stronger. Upon impact, the sutures’
zigzag patterns essentially lock in and
keep the scutes from breaking apart.
These sutures are different from many
of those found elsewhere in nature,
says Naleway.
Researchers used scanning elec-
tron microscopy to characterize the sur-
face structure of the scutes. They also
took cross sections and used micro-
computer tomography to character-
ize dense regions. Mechanical testing
results left researchers wondering why
the boxfish has a design that excludes
overlapping scales. These structures
are now being studied with support of
the U.S. Air Force for potential use in
advanced armor designs. .
TECHNICAL PROGRAM
ANNOUNCED FOR ISTFA 2015
The International Symposium
for Testing and Failure Analysis (ISTFA
2015), being held November 1-5 in Port-
land, Ore., features more than 22 tech-
nical sessions, 106 presentations, four
user groups, and 18 tutorials. The tech-
nical program is now live and includes