Applied Sciences,
Год журнала:
2024,
Номер
14(3), С. 1207 - 1207
Опубликована: Янв. 31, 2024
The
paper
compares
and
evaluates
the
influence
of
presence
perforations
on
sound
absorption
coefficient
(SAC)
a
negative
stiffness
metamaterial
based
foamed
ceramic
geopolymer.
Chemical–physical,
microstructural,
dynamic–mechanical,
characterisations
are
presented.
A
rigid,
lightweight
geopolymeric
porous
material
has
been
prepared
using
an
inorganic/organic
monomeric
mixture
containing
oligomeric
sialates
siloxanes
with
aluminium
powder.
This
process
results
in
amorphous
rigid
light
foam
apparent
180
Kg/m3
density
78%
open-pore.
viscoelastic
characterisation
by
dynamic
mechanical
analysis
(DMA)
carried
out
from
10−3
to
103
Hz
indicates
behaviour
enabling
ultrahigh
energy
at
straining
frequencies
300
1000
Hz.
loss
factor
(the
ratio
dissipative/elastic
shear
moduli)
is
about
0.03
(essentially
elastic
behaviour)
for
up
200
suddenly
increase
value
six
(highly
dissipative
behaviour).
corresponding
storage
moduli
were
8.2
MPa
20
MPa,
respectively.
Impedance
tube
acoustic
measurements
perforated
unperforated
specimens
highlighted
role
perforation-resonant
cavities
enhancing
efficiency,
particularly
within
specified
frequency
band
where
mass
geopolymer
matrix
magnifies
dissipation
effect.
In
limits
still
exploratory
comparative
study,
we
aimed
verify
technological
transfer
potentiality
architected
metamaterials
sustainable
building
practices.
Mechanics of Materials,
Год журнала:
2024,
Номер
191, С. 104952 - 104952
Опубликована: Фев. 20, 2024
Lightweight
materials
used
for
impact
mitigation
must
be
able
to
resist
and
absorb
the
maximum
amount
of
energy
from
impactor.
Auxetic
have
potential
achieve
high
resistance
by
drawing
material
into
zone
providing
higher
indentation
shear
resistance.
However,
these
artificially
designed,
large
deformation
dynamic
effects
created
structures
taken
consideration
when
deciding
on
a
protection
concept.
Despite
their
promise,
little
attention
has
been
given
understanding
working
mechanisms
high-rate
finite
architected
auxetic
lattice
structures.
This
study
compares
static
elastic
properties
different
with
honeycomb
structure,
typical
non-auxetic
lattice,
at
equivalent
mass
stiffness
levels.
In
this
study,
we
limit
investigation
behavior
do
not
consider
contact
between
beams
lattices.
It
is
demonstrated
that
individual
lattices
an
undeformed
state
are
insufficient
explain
variations
observed
in
situations.
particular,
initial
Poisson's
ratio
does
determine
ability
structure
impact.
To
gain
thorough
comprehension
overall
during
localized,
rate
compression,
evolution
tangent
under
compression
was
monitored,
leading
more
profound
understanding.
Observations
made
one
configuration
replicated
analyzed
related
configurations.
Materials & Design,
Год журнала:
2024,
Номер
241, С. 112885 - 112885
Опубликована: Март 27, 2024
The
metal-based
2D
auxetic
lattice
structures
hold
the
potential
for
multifunctional
tasks
in
aerospace
applications.
However,
compression
response
of
those
manufactured
by
powder
bed
fusion
process
is
underexplored.
This
study
proposes
a
comprehensive
comparison
in-plane
quasi-static
performance
structures,
utilizing
three
designs
(anti-tetrachiral
(ATC),
double
arrow-headed
(DAH),
and
tree-like
re-entrant
(TLR)),
with
stiff
Ti6Al4V
electron
beam
(PBF-EB)
various
manufacturing
speeds.
results
revealed
unique
failure
patterns
superior
energy
absorptions
among
literature.
TLR
design
enhanced
absorption
overcoming
failures
between
DAH
columns
exhibited
lowest
standard
deviations
specific
(SEA)
values
(9.75
%–12.62
%).
Besides,
Kernel
average
misorientation
(KAM)
followed
order
DAH,
TLR,
ATC,
inversely
correlated
SEA
values.
ATC
KAM
outperformed
47.5
%
6.44
%,
respectively.
Scan
speed
variations
affected
porosity
differently
each
while
exhibiting
similar
microstructure
characteristics.
findings
this
propose
significant
contribution
to
development
sandwich
where
harsh
environments
exist
employment
topologies
are
required.
Engineering Structures,
Год журнала:
2023,
Номер
299, С. 117122 - 117122
Опубликована: Ноя. 14, 2023
In
this
study,
a
novel
approach
is
proposed
to
enhance
the
crushing
efficiency
and
energy-absorbing
performance
of
origami
metastructure
by
incorporating
shear
thickening
fluid
(STF),
which
mimics
existence
viscoelastic
material
found
inside
protective
mechanism
in
nature.
The
dynamic
performances
STF-filled
are
numerically
investigated
using
commercial
software
LS-DYNA.
A
fluid-structure
interaction
(FSI)
technique
employed
simulate
coupling
between
structure
parts
infilled
fluid.
(STF-OM)
compared
with
non-filled
viscous
fluid-filled
counterparts
under
various
velocities.
effects
filled
height
STF,
viscosity
folding
angle
on
STF-OM
also
investigated.
It
that
can
generate
higher
more
steady
force
without
inducing
significantly
high
initial
peak
force.
Its
resistance
capability
increase
velocity,
demonstrating
its
adaptive
for
impact
scenarios.
as
well
angle,
affect
structure.
