Page Menu
Home
c4science
Search
Configure Global Search
Log In
Files
F92269533
fragmentation.py
No One
Temporary
Actions
Download File
Edit File
Delete File
View Transforms
Subscribe
Mute Notifications
Award Token
Subscribers
None
File Metadata
Details
File Info
Storage
Attached
Created
Mon, Nov 18, 23:16
Size
5 KB
Mime Type
text/x-python
Expires
Wed, Nov 20, 23:16 (1 d, 23 h)
Engine
blob
Format
Raw Data
Handle
22378103
Attached To
rAKA akantu
fragmentation.py
View Options
#!/usr/bin/env python
# coding: utf-8
""" fragmentation.py: Fragmentation example"""
__author__
=
"Guillaume Anciaux"
__credits__
=
[
"Guillaume Anciaux <guillaume.anciaux@epfl.ch>"
,
]
__copyright__
=
"Copyright (©) 2018-2021 EPFL (Ecole Polytechnique Fédérale"
\
" de Lausanne) Laboratory (LSMS - Laboratoire de Simulation"
\
" en Mécanique des Solides)"
__license__
=
"LGPLv3"
# import akantu
import
akantu
as
aka
# import numpy for vector manipulation
import
numpy
as
np
# ### Setting up the *SolidMechanicsModelCohesive*
# We need to read again the material file and the mesh
# Create the Solid Mechanics Cohesive Model in Akantu
# reading material file
aka
.
parseInput
(
'material.dat'
)
# creating mesh
spatial_dimension
=
2
mesh
=
aka
.
Mesh
(
spatial_dimension
)
# geometry (as defined in geo file)
L
=
10
length
=
L
/
100
mesh
.
read
(
'fragmentation_mesh.msh'
)
# creates the model
model
=
aka
.
SolidMechanicsModelCohesive
(
mesh
)
model
.
initFull
(
_analysis_method
=
aka
.
_static
,
_is_extrinsic
=
True
)
# Initialize the solver
# configures the static solver
solver
=
model
.
getNonLinearSolver
(
'static'
)
solver
.
set
(
'max_iterations'
,
100
)
solver
.
set
(
'threshold'
,
1e-10
)
solver
.
set
(
"convergence_type"
,
aka
.
SolveConvergenceCriteria
.
residual
)
# Initilize a new solver (explicit Newmark with lumped mass)
model
.
initNewSolver
(
aka
.
_explicit_lumped_mass
)
# Dynamic insertion of cohesive elements
model
.
updateAutomaticInsertion
()
# Implement Boundary and initial conditions
# Dirichlet Boundary condition
# model.applyBC(aka.FixedValue(0., aka._x), 'left')
model
.
applyBC
(
aka
.
FixedValue
(
0.
,
aka
.
_y
),
'bottom'
)
model
.
getExternalForce
()[:]
=
0
# ### Generate paraview files
# Initialization for bulk vizualisation
model
.
setBaseName
(
'plate'
)
model
.
addDumpFieldVector
(
'displacement'
)
model
.
addDumpFieldVector
(
'velocity'
)
model
.
addDumpFieldVector
(
'external_force'
)
model
.
addDumpField
(
'strain'
)
model
.
addDumpField
(
'stress'
)
model
.
addDumpField
(
'blocked_dofs'
)
# Initialization of vizualisation for Cohesive model
model
.
setBaseNameToDumper
(
'cohesive elements'
,
'cohesive'
)
model
.
addDumpFieldVectorToDumper
(
'cohesive elements'
,
'displacement'
)
model
.
addDumpFieldToDumper
(
'cohesive elements'
,
'damage'
)
model
.
addDumpFieldVectorToDumper
(
'cohesive elements'
,
'tractions'
)
model
.
addDumpFieldVectorToDumper
(
'cohesive elements'
,
'opening'
)
# Custom Dirichlet Boundary Condition to impose constant velocity
# Boundary functor fixing the displacement as it is
class
FixedDisplacement
(
aka
.
DirichletFunctor
):
'''
Fix the displacement at its current value
'''
def
__init__
(
self
,
axis
,
vel
):
super
()
.
__init__
(
axis
)
self
.
axis
=
axis
self
.
time
=
0
self
.
vel
=
vel
def
set_time
(
self
,
t
):
self
.
time
=
t
def
__call__
(
self
,
node
,
flags
,
disp
,
coord
):
# sets the blocked dofs vector to true in the desired axis
flags
[
int
(
self
.
axis
)]
=
True
disp
[
int
(
self
.
axis
)]
=
self
.
vel
*
self
.
time
functor_r
=
FixedDisplacement
(
aka
.
_x
,
1e-1
)
model
.
applyBC
(
functor_r
,
'right'
)
functor_l
=
FixedDisplacement
(
aka
.
_x
,
-
1e-1
)
model
.
applyBC
(
functor_l
,
'left'
)
# Initial condition : velocity gradient:
# in x = 0 we have -v and in x = L we have +v
nodes
=
model
.
getMesh
()
.
getNodes
()
vel_field
=
np
.
zeros
(
nodes
.
shape
)
vel_field
[:,
0
]
=
(
2
*
nodes
[:,
0
]
-
L
)
/
L
*
1e-1
model
.
getVelocity
()[:]
=
vel_field
# ### Run the dynamical simulation
# Initialize data arrays
# Energies :
E_pot
=
[]
E_kin
=
[]
E_dis
=
[]
E_rev
=
[]
E_con
=
[]
# Stress :
Stress
=
[]
dt
=
model
.
getStableTimeStep
()
*
0.1
# choose the timestep
model
.
setTimeStep
(
dt
)
# set maximum number of iteration
maxsteps
=
5000
# solve
for
i
in
range
(
0
,
maxsteps
):
time
=
dt
*
i
functor_r
.
set_time
(
time
)
# fix displacements of the right boundary
model
.
applyBC
(
functor_r
,
'right'
)
functor_l
.
set_time
(
time
)
# fix displacements of the left boundary
model
.
applyBC
(
functor_l
,
'left'
)
if
i
%
10
==
0
:
model
.
dump
()
model
.
dump
(
'cohesive elements'
)
pass
if
i
%
50
==
0
:
print
(
'step {0}/{1}'
.
format
(
i
,
maxsteps
))
model
.
checkCohesiveStress
()
model
.
solveStep
(
'explicit_lumped'
)
Ep
=
model
.
getEnergy
(
"potential"
)
Ek
=
model
.
getEnergy
(
"kinetic"
)
Ed
=
model
.
getEnergy
(
"dissipated"
)
Er
=
model
.
getEnergy
(
"reversible"
)
Ec
=
model
.
getEnergy
(
"contact"
)
E_pot
.
append
(
Ep
)
E_kin
.
append
(
Ek
)
E_dis
.
append
(
Ed
)
E_rev
.
append
(
Er
)
E_con
.
append
(
Ec
)
Stress_field
=
model
.
getMaterial
(
0
)
.
getStress
(
aka
.
_triangle_3
)
Stress_mean
=
np
.
mean
(
Stress_field
)
Stress
.
append
(
Stress_mean
)
# Use the fragment Manager
fragment_manager
=
aka
.
FragmentManager
(
model
)
fragment_manager
.
computeAllData
()
Nb_elem_per_frag
=
fragment_manager
.
getNbElementsPerFragment
()
Nb_frag
=
fragment_manager
.
getNbFragment
()
print
(
'Nb_frag:'
,
Nb_frag
)
# Average number of elements per fragment
Nb_elem_mean
=
np
.
mean
(
Nb_elem_per_frag
)
print
(
'average Nb elem / fragment:'
,
Nb_elem_mean
)
# knowing the element size we can get the average fragment size
s_mean
=
Nb_elem_mean
*
length
print
(
'average fragment size:'
,
s_mean
)
# ## Plots
# Plot stress as a function of time
Time
=
[
i
*
dt
for
i
in
range
(
0
,
maxsteps
)]
Stress_MPa
=
[
x
/
10
**
6
for
x
in
Stress
]
Event Timeline
Log In to Comment