International Journal of Mechanical Sciences,
Год журнала:
2023,
Номер
248, С. 108195 - 108195
Опубликована: Фев. 11, 2023
In
this
paper,
an
advanced
computational
method
is
proposed,
whose
aim
to
obtain
approximately
optimal
design
of
a
particular
class
acoustic
metamaterials,
by
means
novel
combination
multi-objective
optimization
and
dimensionality
reduction.
Metamaterials
are
modeled
as
beam
lattices
with
internal
local
resonators
coupled
the
microstructure
through
viscoelastic
phase.
The
dynamics
governed
set
integro-differential
equations,
that
transformed
into
Z-Laplace
space
in
order
derive
eigenproblem
solution
provides
dispersion
relation
free
in-plane
propagating
Bloch
waves.
A
problem
stated,
achieve
largest
multiplicative
trade-off
between
bandwidth
first
stop
band
one
successive
pass
metamaterial
frequency
spectrum.
Motivated
multi-dimensionality
parameters
space,
goal
above
achieved
integrating
numerical
machine
learning.
Specifically,
solved
combining
sequential
linear
programming
algorithm
principal
component
analysis,
exploited
data
reduction
technique
applied
properly
sampled
field
gradient
directions,
perform
optimized
sensitivity
analysis.
This
represents
original
way
applying
analysis
connection
optimization.
Successful
performances
proposed
its
savings
demonstrated.
International Journal of Mechanical Sciences,
Год журнала:
2022,
Номер
241, С. 107915 - 107915
Опубликована: Ноя. 17, 2022
Hierarchy
provides
unique
opportunities
for
the
design
of
advanced
materials
with
superior
properties
that
arise
from
architecture,
rather
than
constitutive
material
response.
Contrary
to
quasi-static
regime,
where
potential
hierarchy
has
been
largely
explored,
its
role
in
vibration
mitigation
and
wave
manipulation
remains
elusive.
So
far,
majority
studies
concerning
hierarchical
elastic
metamaterials
have
proposed
a
self-similar
repetition
specific
unit
cell
at
multiple
scale
levels,
leading
activation
same
bandgap
mechanism
different
frequencies.
On
contrary,
here,
we
show
by
designing
non
geometries
allows
us
create
periodic
structures
supporting
multiple,
highly
attenuative
broadband
bandgaps
involving
(independently
or
simultaneously)
scattering
mechanisms,
namely,
Bragg
scattering,
local
resonance
and/or
inertial
amplification,
The
type
band
gap
is
identified
discussed
examining
vibrational
mode
shapes
imaginary
component
wavenumber
dispersion
diagram
cell.
We
also
experimentally
confirm
this
performing
measurements
lowest
frequency
regime
on
3D
printed
structure.
Hierarchical
strategies
may
find
application
civil,
aerospace
mechanical
engineering.
Mechanics of Advanced Materials and Structures,
Год журнала:
2024,
Номер
31(30), С. 12885 - 12897
Опубликована: Март 18, 2024
Sandwich
plates
are
extensively
utilized
across
various
fields,
encompassing
building
engineering,
mechanical
and
aerospace
owing
to
their
exceptional
stiffness-to-weight
ratio.
However,
effectively
attenuating
the
low-frequency
broadband
vibrations
of
these
poses
a
significant
challenge.
This
paper
proposes
new
type
metamaterial
sandwich
plate
that
incorporates
two-degree
freedom
inertial
amplified
resonators
(IA-MSPDF2),
attain
two
band
gaps
(BGs)
achieve
vibration
attenuation.
The
dispersion
relation
IA-MSPDF2
is
calculated
based
on
Bloch-Floquet
theorem,
generation
mechanism
BGs
analyzed
through
eigenmodes.
Both
numerical
experimental
studies
conducted
substantiate
advantages
associated
with
presence
in
design.
results
show
enhanced
coupling
effect
between
primary
secondary
leads
local
resonance
shifts
lower
frequencies,
resulting
Bragg
scattering
BG
arises
above
locally
resonant
BG.
Compared
one-degree
(IA-MSPDF1)
equal
mass,
exhibits
an
increased
relative
bandwidth
by
15%.
Increasing
damping
resonator
causes
attenuation
zones
widen
merge
into
wider
zone.
proposed
can
robustly
attenuate
small
mass
cost,
contributing
further
exploration
utilization
engineering
applications.
International Journal of Mechanical Sciences,
Год журнала:
2024,
Номер
268, С. 109035 - 109035
Опубликована: Янв. 11, 2024
Bandgaps
are
endowed
to
elastic
metamaterials
(EMMs)
attributed
the
rationally
designed
unit
cells
and
extensive
works
devoted
bandgap
enlargement
for
improving
applicability
of
EMMs
in
multi-disciplinary
applications.
Nonetheless,
most
existing
optimization
frameworks
neglect
manufacturing
imperfections,
such
as
microscale
heterogeneity
system
uncertainties,
which
can
significantly
affect
behaviours.
Without
properly
accounting
these
effects,
design
may
fail
achieve
optimal
goal,
exhibiting
consistently
ultra-wide
wave
attenuation
bands
practical
EMMs.
Herein,
this
paper,
a
stochastic
framework
is
developed
involving
aiming
at
optimizing
first
two
statistical
moments
normalized
bandwidth
(NB)
simultaneously.
To
alleviate
large
computational
costs
approximating
moments,
surrogate
model
employed
reveal
constitutive
relationship
between
parameters
NB
multiscale
EMM.
Moreover,
solve
problem
effectively
efficiently,
high-order
mutation
strategy
proposed
develop
an
improved
particle
swarm
(PSO)
variant,
namely
adaptively
mutation-based
PSO
(AHMPSO).
demonstrate
viability
efficiency
framework,
numerical
investigation
implemented
on
3D
EMM,
highlights
enlarged
bandwidths
coupling
with
improvement
robustness
optimum.
