IntechOpen eBooks,
Год журнала:
2024,
Номер
unknown
Опубликована: Июль 3, 2024
Nowadays,
acoustic
black
holes
(ABHs)
are
very
popular
for
producing
efficient
vibration
reduction
at
high
frequencies
in
combination
with
some
damping
mechanisms.
However,
its
low-frequency
performance
is
hard
to
improve
since
the
ABH
effect
principally
occurs
beyond
cut-on
frequency.
Fortunately,
periodic
configuration
offers
bandgaps
below
that
frequency
wave
attenuation.
In
this
chapter,
a
topological
structure
suggested
produce
new
bandgap
low
frequencies,
by
taking
supercell
and
decreasing
distance.
The
Rayleigh-Ritz
method
(WRRM)
adopted
compute
complex
dispersion
curves.
Examinations
of
curves
transmissibilities
confirm
efficiency
capability
proposed
ABHs.
Mechanics of Advanced Materials and Structures,
Год журнала:
2024,
Номер
unknown, С. 1 - 18
Опубликована: Дек. 31, 2024
In
this
paper,
based
on
the
local
resonance
mechanism,
four
thin
elastic
plate
structures
with
low-frequency
bandgap
are
proposed
through
structural
design
and
optimization.
The
first
onset
frequency
of
optimized
structure
is
lower
than
100
Hz,
which
realizes
vibration
damping
provides
an
effective
method
for
subsequent
research.
It
analyzed
that
caused
by
offset
form,
opening
due
to
scatterer
substrate,
forms
include
rotational
resonance.
Group
velocity
phase
images
show
variations
have
a
significant
effect
energy
transfer,
wave
speed
direction
in
structure.
response
spectra
obtained
from
transfer
experiments
well
verify
accuracy
band
gap.
Displacement
clouds
finite
period
cross-checked
modes
modeled
single
cell.
minimum
value
transmission
coefficient
T
range
0–300
Hz
−91.8,
corresponds
frequencies
strong
attenuation.
characteristics
vary
material
parameters
clear
regularity.
These
great
potential
application
practical
engineering
involving
noise
suppression.
European Journal of Mechanics - A/Solids,
Год журнала:
2024,
Номер
106, С. 105344 - 105344
Опубликована: Май 14, 2024
This
paper
presents
an
efficient
bandgap
analysis
method
for
metamaterial
structures
based
on
variational
principle
and
linear
expression
technique.
is
in
view
of
the
challenges
constructing
a
displacement
function
that
satisfies
Bloch
boundary
when
applying
traditional
energy
to
analyze
dispersion
relations
structures.
Also,
inclusion
wave
numbers
leads
inefficient
computation.
While
there
have
been
methods,
such
as
virtual
springs,
proposed
deal
with
problems,
issues
remain
be
resolved.
The
main
idea
current
solution
uncorrelated
coefficients
by
processing
constraints.
In
this
way,
unknown
equations
motion
can
linearly
expressed,
thereby
allowing
become
variational.
Both
Gaussian
elimination
null-space
techniques
are
used
implement
method.
procedures
two
methods
detailed
demonstrated
using
one-dimensional
two-dimensional
accuracy
verified
comparing
results
those
from
finite
element
calculation
efficiency
compared
terms
both
matrix
dimension
number
points
numbers.
show
has
much
higher
than
free
convergence
problems
dealing
problems.
Furthermore,
discussion
combined
periodic
structures,
it
shown
still
good
geometrical
applicability
containing
multiple
conditions,
showing
great
potential
solving
complex
engineering
The Journal of the Acoustical Society of America,
Год журнала:
2024,
Номер
155(5), С. 3051 - 3059
Опубликована: Май 1, 2024
Acoustic
black
holes
(ABHs)
are
known
as
efficient
structural
dampers.
Periodic
lattices
identified
an
way
to
forbidden
wave
propagation
in
targeted
frequency
bandgaps
(BGs).
The
paper
demonstrates
the
possibility
merge
ABH
effect
with
Bragg
BGs.
geometrical
layout
leading
this
double
consists
of
a
plate
periodically
modulated
thickness
by
combination
cosine
functions
spatial
coordinates
constituting
ABH-like
cell,
coated
thin
damping
layer.
resulting
metamaterial
allows
realization
solid,
stiff,
and
nonresonant
panels
over
wide
range,
including
low
frequencies,
without
increasing
mass.
First,
band
structure
is
analyzed
conservative
case
(without
layer)
using
plane
expansion
model
following
Kirchhoff's
assumptions.
results
show
existence
low-frequency
BGs
that
can
be
controlled
only
three
geometric
parameters,
which
defined
on
type
lattice
chosen
(square
or
hexagonal).
Next,
finite
size
panel
designed
for
hexagonal
lattice.
Experimental
characterization
demonstrator
viscoelastic
coating
shows
very
attractive
broadband
vibration
mitigation
performances
due
fact
dissipation
produced
does
not
deter
filtering
effects
BG.
Journal of Vibration and Control,
Год журнала:
2024,
Номер
unknown
Опубликована: Май 10, 2024
Vibrations
generated
from
machinery
in
various
industries,
such
as
the
automotive,
aerospace,
and
shipbuilding
must
be
suppressed
for
developing
low-vibration
low-noise
systems.
High-frequency
vibrations
can
easily
controlled
via
damping
treatments;
however,
controlling
low-frequency
range
large
is
a
major
challenge.
In
general,
substantial
amount
of
material
required
suppressing
vibrations.
This
unsuitable
when
low-cost,
lightweight,
eco-friendly
To
overcome
limitations,
effective
methods
are
these
this
study,
an
method
was
proposed
using
multiple
acoustic
black
holes
(multi-ABHs)
considering
suitability
values
attachment
positions,
which
were
determined
by
flexural
wave
propagation
interactions
between
multi-ABHs
structures.
The
positions
non-dimensional
parameters
that
calculated
structural
intensity
mode
superposition
methods.
For
validating
method,
vibration
suppression
characteristics
analyzed
steel
plate.
cases
categorized
into
six
groups
according
to
multi-ABHs.
largest
reduction
observed
attached
location
with
highest
cases.
Finally,
applied
2-pole
motor
dominant
at
60,
120,
180
Hz
frequencies
suppressed.
