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material_damage_iterative.cc
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rAKA akantu
material_damage_iterative.cc
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/**
* @file material_damage_iterative.cc
*
* @author Aurelia Isabel Cuba Ramos <aurelia.cubaramos@epfl.ch>
*
*
* @brief Specialization of the class material damage to damage only one gauss
* point at a time and propagate damage in a linear way. Max principal stress
* criterion is used as a failure criterion.
*
*
* Copyright (©) 2010-2012, 2014 EPFL (Ecole Polytechnique Fédérale de Lausanne)
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
*/
/* -------------------------------------------------------------------------- */
#include "material_damage_iterative.hh"
#include "communicator.hh"
#include "data_accessor.hh"
#include "solid_mechanics_model_RVE.hh"
/* -------------------------------------------------------------------------- */
namespace
akantu
{
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
MaterialDamageIterative
<
spatial_dimension
>::
MaterialDamageIterative
(
SolidMechanicsModel
&
model
,
const
ID
&
id
)
:
MaterialDamage
<
spatial_dimension
>
(
model
,
id
),
Sc
(
"Sc"
,
*
this
),
reduction_step
(
"damage_step"
,
*
this
),
equivalent_stress
(
"equivalent_stress"
,
*
this
),
max_reductions
(
0
),
norm_max_equivalent_stress
(
0
)
{
AKANTU_DEBUG_IN
();
this
->
registerParam
(
"Sc"
,
Sc
,
_pat_parsable
,
"critical stress threshold"
);
this
->
registerParam
(
"prescribed_dam"
,
prescribed_dam
,
0.1
,
_pat_parsable
|
_pat_modifiable
,
"prescribed damage"
);
this
->
registerParam
(
"dam_threshold"
,
dam_threshold
,
0.8
,
_pat_parsable
|
_pat_modifiable
,
"damage threshold at which damage damage will be set to 1"
);
this
->
registerParam
(
"dam_tolerance"
,
dam_tolerance
,
0.01
,
_pat_parsable
|
_pat_modifiable
,
"damage tolerance to decide if quadrature point will be damageed"
);
this
->
registerParam
(
"max_damage"
,
max_damage
,
0.99999
,
_pat_parsable
|
_pat_modifiable
,
"maximum damage value"
);
this
->
registerParam
(
"max_reductions"
,
max_reductions
,
UInt
(
10
),
_pat_parsable
|
_pat_modifiable
,
"max reductions"
);
this
->
use_previous_stress
=
true
;
this
->
use_previous_gradu
=
true
;
this
->
Sc
.
initialize
(
1
);
this
->
equivalent_stress
.
initialize
(
1
);
this
->
reduction_step
.
initialize
(
1
);
AKANTU_DEBUG_OUT
();
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
void
MaterialDamageIterative
<
spatial_dimension
>::
computeNormalizedEquivalentStress
(
const
Array
<
Real
>
&
grad_u
,
ElementType
el_type
,
GhostType
ghost_type
)
{
AKANTU_DEBUG_IN
();
/// Vector to store eigenvalues of current stress tensor
Vector
<
Real
>
eigenvalues
(
spatial_dimension
);
auto
Sc_it
=
Sc
(
el_type
,
ghost_type
).
begin
();
auto
equivalent_stress_it
=
equivalent_stress
(
el_type
,
ghost_type
).
begin
();
Array
<
Real
>::
const_matrix_iterator
grad_u_it
=
grad_u
.
begin
(
spatial_dimension
,
spatial_dimension
);
Array
<
Real
>::
const_matrix_iterator
grad_u_end
=
grad_u
.
end
(
spatial_dimension
,
spatial_dimension
);
Real
*
dam
=
this
->
damage
(
el_type
,
ghost_type
).
storage
();
Matrix
<
Real
>
sigma
(
spatial_dimension
,
spatial_dimension
);
for
(;
grad_u_it
!=
grad_u_end
;
++
grad_u_it
)
{
sigma
.
zero
();
MaterialElastic
<
spatial_dimension
>::
computeStressOnQuad
(
*
grad_u_it
,
sigma
,
0.
);
computeDamageAndStressOnQuad
(
sigma
,
*
dam
);
/// compute eigenvalues
sigma
.
eig
(
eigenvalues
);
/// find max eigenvalue and normalize by tensile strength
*
equivalent_stress_it
=
*
(
std
::
max_element
(
eigenvalues
.
storage
(),
eigenvalues
.
storage
()
+
spatial_dimension
))
/
*
(
Sc_it
);
++
Sc_it
;
++
equivalent_stress_it
;
++
dam
;
}
AKANTU_DEBUG_OUT
();
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
void
MaterialDamageIterative
<
spatial_dimension
>::
computeAllStresses
(
GhostType
ghost_type
)
{
AKANTU_DEBUG_IN
();
/// reset normalized maximum equivalent stress
if
(
ghost_type
==
_not_ghost
)
norm_max_equivalent_stress
=
0
;
MaterialDamage
<
spatial_dimension
>::
computeAllStresses
(
ghost_type
);
/// find global Gauss point with highest stress
auto
rve_model
=
dynamic_cast
<
SolidMechanicsModelRVE
*>
(
&
this
->
model
);
if
(
rve_model
==
NULL
)
{
/// is no RVE model
const
auto
&
comm
=
this
->
model
.
getMesh
().
getCommunicator
();
comm
.
allReduce
(
norm_max_equivalent_stress
,
SynchronizerOperation
::
_max
);
}
AKANTU_DEBUG_OUT
();
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
void
MaterialDamageIterative
<
spatial_dimension
>::
findMaxNormalizedEquivalentStress
(
ElementType
el_type
,
GhostType
ghost_type
)
{
AKANTU_DEBUG_IN
();
if
(
ghost_type
==
_not_ghost
)
{
// const Array<Real> & e_stress = equivalent_stress(el_type);
// if (e_stress.begin() != e_stress.end() ) {
// auto equivalent_stress_it_max =
// std::max_element(e_stress.begin(),e_stress.end());
// /// check if max equivalent stress for this element type is greater
// than the current norm_max_eq_stress
// if (*equivalent_stress_it_max > norm_max_equivalent_stress)
// norm_max_equivalent_stress = *equivalent_stress_it_max;
// }
const
Array
<
Real
>
&
e_stress
=
equivalent_stress
(
el_type
);
auto
equivalent_stress_it
=
e_stress
.
begin
();
auto
equivalent_stress_end
=
e_stress
.
end
();
Array
<
Real
>
&
dam
=
this
->
damage
(
el_type
);
auto
dam_it
=
dam
.
begin
();
for
(;
equivalent_stress_it
!=
equivalent_stress_end
;
++
equivalent_stress_it
,
++
dam_it
)
{
/// check if max equivalent stress for this element type is greater than
/// the current norm_max_eq_stress and if the element is not already fully
/// damaged
if
(
*
equivalent_stress_it
>
norm_max_equivalent_stress
&&
*
dam_it
<
max_damage
)
{
norm_max_equivalent_stress
=
*
equivalent_stress_it
;
}
}
}
AKANTU_DEBUG_OUT
();
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
void
MaterialDamageIterative
<
spatial_dimension
>::
computeStress
(
ElementType
el_type
,
GhostType
ghost_type
)
{
AKANTU_DEBUG_IN
();
MaterialDamage
<
spatial_dimension
>::
computeStress
(
el_type
,
ghost_type
);
Real
*
dam
=
this
->
damage
(
el_type
,
ghost_type
).
storage
();
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_BEGIN
(
el_type
,
ghost_type
);
computeDamageAndStressOnQuad
(
sigma
,
*
dam
);
++
dam
;
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_END
;
computeNormalizedEquivalentStress
(
this
->
gradu
(
el_type
,
ghost_type
),
el_type
,
ghost_type
);
norm_max_equivalent_stress
=
0
;
findMaxNormalizedEquivalentStress
(
el_type
,
ghost_type
);
AKANTU_DEBUG_OUT
();
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
UInt
MaterialDamageIterative
<
spatial_dimension
>::
updateDamage
()
{
UInt
nb_damaged_elements
=
0
;
AKANTU_DEBUG_ASSERT
(
prescribed_dam
>
0.
,
"Your prescribed damage must be greater than zero"
);
if
(
norm_max_equivalent_stress
>=
1.
)
{
AKANTU_DEBUG_IN
();
/// update the damage only on non-ghosts elements! Doesn't make sense to
/// update on ghost.
GhostType
ghost_type
=
_not_ghost
;
for
(
auto
&&
el_type
:
this
->
model
.
getFEEngine
().
getMesh
().
elementTypes
(
spatial_dimension
,
ghost_type
))
{
const
Array
<
Real
>
&
e_stress
=
equivalent_stress
(
el_type
);
auto
equivalent_stress_it
=
e_stress
.
begin
();
auto
equivalent_stress_end
=
e_stress
.
end
();
Array
<
Real
>
&
dam
=
this
->
damage
(
el_type
);
auto
dam_it
=
dam
.
begin
();
auto
reduction_it
=
this
->
reduction_step
(
el_type
,
ghost_type
).
begin
();
for
(;
equivalent_stress_it
!=
equivalent_stress_end
;
++
equivalent_stress_it
,
++
dam_it
,
++
reduction_it
)
{
/// check if damage occurs
if
(
*
equivalent_stress_it
>=
(
1
-
dam_tolerance
)
*
norm_max_equivalent_stress
)
{
/// check if this element can still be damaged
if
(
*
reduction_it
==
this
->
max_reductions
)
continue
;
*
reduction_it
+=
1
;
if
(
*
reduction_it
==
this
->
max_reductions
)
{
*
dam_it
=
max_damage
;
}
else
{
*
dam_it
+=
prescribed_dam
;
}
nb_damaged_elements
+=
1
;
}
}
}
}
auto
*
rve_model
=
dynamic_cast
<
SolidMechanicsModelRVE
*>
(
&
this
->
model
);
if
(
rve_model
==
NULL
)
{
const
auto
&
comm
=
this
->
model
.
getMesh
().
getCommunicator
();
comm
.
allReduce
(
nb_damaged_elements
,
SynchronizerOperation
::
_sum
);
}
AKANTU_DEBUG_OUT
();
return
nb_damaged_elements
;
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
void
MaterialDamageIterative
<
spatial_dimension
>::
updateEnergiesAfterDamage
(
ElementType
el_type
)
{
MaterialDamage
<
spatial_dimension
>::
updateEnergies
(
el_type
);
}
/* -------------------------------------------------------------------------- */
INSTANTIATE_MATERIAL
(
damage_iterative
,
MaterialDamageIterative
);
}
// namespace akantu
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