Materials,
Journal Year:
2023,
Volume and Issue:
17(1), P. 130 - 130
Published: Dec. 27, 2023
Material
joining
processes
are
a
critical
factor
in
engineering
structures
since
they
influence
such
structures'
structural
integrity,
performance,
and
longevity
[...].
The Journal of Adhesion,
Journal Year:
2023,
Volume and Issue:
100(4), P. 219 - 242
Published: May 25, 2023
The
work
investigates
failure
criteria
and
mean
stress
correction
approaches
for
the
fatigue
lifetime
prediction
of
two
hyperelastic
adhesives
(a
polyurethane,
PU,
a
silicon-modified
polymer,
SMP).
Fatigue
experiments
are
carried
under
constant
amplitude
cyclic
loading
at
RT
40°C/60%
r.h
with
butt-
thick-adherend-shear-test-joints
three
ratios
R
=
−1,
0.1
0.5.
Three
evaluated:
Goodman
(static
strength
based),
Schütz
(mean
sensitivity
based)
Kujawski
&
Ellyin
(parameter
optimisation
based).
considered
are:
Drucker-Prager
(linear-relation
hydrostatic
stress),
Beltrami
(quadratic
relationship
multivariable
nominal
shear
tensile
stresses
criterion
(data-based).
comparison
is
based
on
accuracy
(R-squared
master
SN
curves)
complexity
parameter
determination.
highest
values
R-squared
were
obtained
by
correction,
followed
then
Goodman.
However,
determination
follows
an
opposite
trend
being
lightest
approach.
Failure
yielded
comparable
results
having
advantage
not
dealing
FEA,
but
limited
to
joints
nearly
uniform
distribution.
Finally,
compared
Drucker-Prager,
had
more
robust
Environmental Research Letters,
Journal Year:
2023,
Volume and Issue:
18(12), P. 125001 - 125001
Published: Oct. 23, 2023
Abstract
Positive
feedbacks
between
permafrost
degradation
and
the
release
of
soil
carbon
into
atmosphere
impact
land–atmosphere
interactions,
disrupt
global
cycle,
accelerate
climate
change.
The
widespread
distribution
thawing
is
causing
a
cascade
geophysical
biochemical
disturbances
with
impacts.
Currently,
few
earth
system
models
account
for
feedback
(PCF)
mechanisms.
This
research
study
integrates
artificial
intelligence
(AI)
tools
information
derived
from
field-scale
surveys
across
tundra
boreal
landscapes
in
Alaska.
We
identify
interpret
cycling
links
sensitivities
GeoCryoAI,
hybridized
multimodal
deep
learning
(DL)
architecture
stacked
convolutionally
layered,
memory-encoded
recurrent
neural
networks
(NN).
framework
in-situ
measurements
flux
tower
observations
teacher
forcing
model
training.
Preliminary
experiments
to
quantify,
validate,
forecast
efflux
Alaska
demonstrate
fidelity
this
data-driven
architecture.
More
specifically,
GeoCryoAI
logs
ecological
memory
effectively
learns
covariate
dynamics
while
demonstrating
an
aptitude
simulate
PCF
dynamics—active
layer
thickness
(ALT),
dioxide
(CO
2
),
methane
(CH
4
)—with
high
precision
minimal
loss
(i.e.
ALT
RMSE
:
1.327
cm
[1969–2022];
CO
0.697
µ
molCO
m
−2
s
−1
[2003–2021];
CH
0.715
nmolCH
[2011–2022]).
variability
sensitive
harbinger
change,
unique
signal
characterizing
PCF,
our
first
characterization
these
space
time.
Fatigue & Fracture of Engineering Materials & Structures,
Journal Year:
2024,
Volume and Issue:
47(6), P. 2029 - 2043
Published: March 26, 2024
Abstract
This
study
proposes
a
fatigue
life
prediction
method
for
composite
bolted
joints,
which
combines
algorithm
optimization‐based
hybrid
neural
networks
with
finite
element
modeling.
First,
based
on
the
Hashin
failure
criterion
of
physical
mechanism,
model
joints
is
established,
and
simulation
calculations
have
been
conducted
using
various
initial
conditions.
Then,
by
integrating
experiment
data,
we
established
database
that
serves
machine
learning
training
prediction.
Finally,
data
undergo
comprehensive
process
deep
feature
extraction
through
utilization
convolutional
network
(CNN).
The
resulting
features
are
utilized
as
inputs
backpropagation
(BPNN)
to
predict
life.
results
indicate
this
synergistic
combination
CNN
BPNN
in
substantial
improvement
accuracy
has
remarkable
superiority
predicting
joints.
International Journal of Adhesion and Adhesives,
Journal Year:
2024,
Volume and Issue:
134, P. 103782 - 103782
Published: July 24, 2024
A
comparative
investigation
between
an
invariant-based
approach
using
the
signed
Beltrami-stress
and
critical-plane
Findley-stress
is
carried
out
for
fatigue
lifetime
prediction
of
epoxy
structural
adhesive
under
multiaxial
non-proportional
loading
with
varying
mean
stress.
Fatigue
experiments
uniaxial
(proportional
non-proportional)
are
done
at
stress
ratios
−1
0.1.
Two
joints
evaluated:
a
hollow-cylinder
butt-joint
(HCBJ,
sample
homogeneous
stresses
distribution),
flange-rod-joint
(FRJ,
component-like
specimen
complex
state).
For
both
geometries,
increasing
lead
to
strength
reduction,
whereas
phase-shift
effect
less
pronounced.
systematic
procedure
parameter
determination
implemented
approaches.
predictions
HCBJ-sample,
analytically
obtained.
validation
FRJ-sample,
FEA-based
calculation
used.
joints,
critical
plane
results
in
more
accurate
than
approach.
In
terms,
experimentally
complex,
by
requiring
correction,
but
its
numerically
simpler
lower
time.
The
requires
fewer
provides
loading.
However,
it
demanding
larger
computing
Processes,
Journal Year:
2023,
Volume and Issue:
11(12), P. 3369 - 3369
Published: Dec. 4, 2023
Adhesive
bonded
joints
have
become
vital
to
modern
engineering,
offering
advantages
such
as
weight
reduction,
enhanced
fatigue
performance,
and
improved
stress
distribution
[...]
Eng—Advances in Engineering,
Journal Year:
2023,
Volume and Issue:
4(4), P. 2615 - 2639
Published: Oct. 16, 2023
A
compliance-based
method
for
the
determination
of
fatigue
design
curves
elastomeric
adhesive
joints
is
developed
and
validated.
Fatigue
experiments
are
conducted
on
adhesives
(a
polyurethane
a
silane-modified
polymer)
under
different
stress
ratios
(R
=
0.1/0.5/−1)
conditions
(23
°C/50%
r.h.
40
°C/60%
r.h.).
The
investigation
focused
butt
thick
adherent
shear
test
joints.
tests
recorded
with
cameras
to
identify
stages
crack
initiation
propagation.
For
each
test,
stiffness
compliance
per
cycle
calculated
until
final
failure.
proposed
identifies
transition
point
that
distinguishes
regions
stable
unstable
growth.
then
built
based
number
cycles
reach
degrees
initial
(90%,
80%,
70%
60%).
failure
ratio,
i.e.,
lifetime
reaching
given
approach
divided
by
total
lifetime,
introduced
evaluate
data
in
terms
average
values
standard
deviation.
results
indicate
can
yield
high
coefficient
(accuracy)
ratio
(avoiding
over-conservative
design).
Moreover,
robust,
as
adhesives,
ratios,
geometries
highly
consistent.