1st year graduate student(M1)
Yusuke
Sawamura
- RESERCH
TOPIC:Numerical simulation of
dynamic failure behavior for
CFRP
- In this study, dynamic and
static failure tests for
cylindrical CFRP are conducted,
and their numerical simulations
are performed using commercial
finite element method software,
ABAQUS. Multi-scale analysis is
carried out for the numerical
simulation to account for
inhomogeneity of the CFRP. In
the micro scale numerical
simulation, a 2D periodic unit
cell (PUC) analysis is
conducted. The model simulates
matrix failure and fiber/matrix
interface debonding by continuum
damage mechanics (CDM)
considering rate dependence and
cohesive zone modeling (CZM),
respectively. Rate-dependent
failure criteria under
multi-axial loadings for macro
scale simulation are determined
based on the micro scale
simulation.
Norie Itano
- RESERCH TOPIC:Evaluation
of interfacial strength by
experiment and numerical
simulation
- This study simulates
interfacial strength using
molecular dynamics simulation
(MD) to investigate the
relationship between interfacial
strength and molecular
structure. Interfacial strength
between carbon fiber and epoxy
resin is evaluated by
microdroplet experiment and the
finite element method (FEM). In
the microdroplet experiment,
when a resin droplet is debonded
from the fiber, the load on the
fiber is measured. The
interfacial strength is
calculated using the FEM, and
the interaction energy is
calculated using molecular
dynamics simulation. The results
of the MD simulation agree with
those of the experiment and the
FEM.
Satoshi Tomita
- RESERCH TOPIC:
Time-dependent mechanical
properties of carbon
fiber-resin composite
containing CNT layer
- Finite element analysis
modeling for the analysis of
differences in time-dependent
apparent modulus between carbon
fiber-resin composite material
models with and without a CNT
layer was conducted. A
computational simulation was
performed with the ABAQUS
software package using a beam
finite element model. Stress
relaxation test data was used to
create a curve representing the
relationship between elastic
modulus and time, in order to
define the viscoelasticity in
the time domain. It was found
that the apparent elastic
modulus of the CNT layer must be
smaller than the resin when the
speed is high, in order to
reproduce the time dependency of
the apparent modulus of
elasticity obtained from the
experiment.
Sakie Shirai
- RESERCH TOPIC:
Numerical Simulation for
strain rate and temperature
dependence of Transverse
Tensile Failure of UD-CFRP
- In the present study,
strain-rate dependence and
temperature dependence of
failure mode are numerically
simulated by finite element
analyses. In the analyses,
interface failure and matrix
failure are expressed by
cohesive zone modeling and
continuum damage mechanics,
respectively. It is assumed that
the damage initiates dependently
of strain rate and temperature,
and cohesive zone modeling is
assumed to be temperature- and
time-independent.
- When temperature is high
and/or strain rate is low,
matrix crack occurs very often
and the failure mode is
matrix-failure-dominant mode. On
the other hand, when temperature
is low and/or strain rate is
high, interface crack
significant, i.e. failure mode
becomes interface-crack-dominant
mode.
Mao Hososhima
- RESERCH TOPIC:Fatigue
life prediction based on
thermodynamic entropy
- In recent years, attempts have
been made to treat irreversible
thermodynamic entropy, a source
of fatigue failure. Irreversible
entropy in a system
monotonically increases until
the final fracture of a metallic
material. The damage progresses,
and the material ruptures when
the entropy production reaches a
certain value. In this study,
fatigue tests on aluminum alloy
Al2024-T4 and polyimide were
carried out to calculate the
entropy generation during the
fatigue process. Entropy use for
fatigue life prediction based on
the calculated entropy
generation value is also
examined.
Tomoya Kazama
- RESERCH TOPIC:The
Evalutaion of membarane
material of inflatable
aeroshell for atmospheric
entry
- The inflatable aeroshell is
new key technology supporting
atmospheric entry missions.
- A Martin penetrator is
promising application using an
inflatable ring is critical
because the inflatable aeroshell
is deployed and supported by the
gas pressure. The aerothermal
environment during atmospheric
entry differs depending on the
atmosphere of the planet and the
planetary entry conditions. The
aerodynamic heating condition is
estimated by a numerical
simulation based on, the Martin
penetrator mission. The
durability of the membrane
material for the inflatable ring
is evaluated experimentally by
CO2 laser heating and ICP
heating according to the
estimated results of the
aerodynamic heating condition
during Martin entry
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