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material_cohesive_exponential.cc
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rAKA akantu
material_cohesive_exponential.cc
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/**
* @file material_cohesive_exponential.cc
*
* @author Seyedeh Mohadeseh Taheri Mousavi <mohadeseh.taherimousavi@epfl.ch>
* @author Marco Vocialta <marco.vocialta@epfl.ch>
*
* @date creation: Mon Jul 09 2012
* @date last modification: Fri Mar 21 2014
*
* @brief Exponential irreversible cohesive law of mixed mode loading
*
* @section LICENSE
*
* Copyright (©) 2014 EPFL (Ecole Polytechnique Fédérale de Lausanne)
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
* Akantu is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* Akantu is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
* A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Akantu. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* -------------------------------------------------------------------------- */
#include "material_cohesive_exponential.hh"
#include "solid_mechanics_model.hh"
#include "sparse_matrix.hh"
#include "dof_synchronizer.hh"
__BEGIN_AKANTU__
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
MaterialCohesiveExponential
<
spatial_dimension
>::
MaterialCohesiveExponential
(
SolidMechanicsModel
&
model
,
const
ID
&
id
)
:
MaterialCohesive
(
model
,
id
)
{
AKANTU_DEBUG_IN
();
this
->
registerParam
(
"beta"
,
beta
,
0.
,
_pat_parsable
,
"Beta parameter"
);
this
->
registerParam
(
"delta_c"
,
delta_c
,
0.
,
_pat_parsable
,
"Critical displacement"
);
this
->
registerParam
(
"exponential_penalty"
,
exp_penalty
,
true
,
_pat_parsable
,
"Is contact penalty following the exponential law?"
);
this
->
registerParam
(
"contact_tangent"
,
contact_tangent
,
1.0
,
_pat_parsable
,
"Ratio of contact tangent over the initial exponential tangent"
);
// this->initInternalArray(delta_max, 1, _ek_cohesive);
use_previous_delta_max
=
true
;
AKANTU_DEBUG_OUT
();
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
void
MaterialCohesiveExponential
<
spatial_dimension
>::
initMaterial
()
{
AKANTU_DEBUG_IN
();
MaterialCohesive
::
initMaterial
();
if
((
exp_penalty
)
&&
(
contact_tangent
!=
1
)){
contact_tangent
=
1
;
AKANTU_DEBUG_WARNING
(
"The parsed paramter <contact_tangent> is forced to 1.0 when the contact penalty follows the exponential law"
);
}
AKANTU_DEBUG_OUT
();
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
void
MaterialCohesiveExponential
<
spatial_dimension
>::
computeTraction
(
const
Array
<
Real
>
&
normal
,
ElementType
el_type
,
GhostType
ghost_type
)
{
AKANTU_DEBUG_IN
();
/// define iterators
Array
<
Real
>::
vector_iterator
traction_it
=
tractions
(
el_type
,
ghost_type
).
begin
(
spatial_dimension
);
Array
<
Real
>::
vector_iterator
opening_it
=
opening
(
el_type
,
ghost_type
).
begin
(
spatial_dimension
);
Array
<
Real
>::
const_vector_iterator
normal_it
=
normal
.
begin
(
spatial_dimension
);
Array
<
Real
>::
vector_iterator
traction_end
=
tractions
(
el_type
,
ghost_type
).
end
(
spatial_dimension
);
Array
<
Real
>::
iterator
<
Real
>
delta_max_it
=
delta_max
(
el_type
,
ghost_type
).
begin
();
Array
<
Real
>::
iterator
<
Real
>
delta_max_prev_it
=
delta_max
.
previous
(
el_type
,
ghost_type
).
begin
();
/// compute scalars
Real
beta2
=
beta
*
beta
;
/// loop on each quadrature point
for
(;
traction_it
!=
traction_end
;
++
traction_it
,
++
opening_it
,
++
normal_it
,
++
delta_max_it
,
++
delta_max_prev_it
)
{
/// compute normal and tangential opening vectors
Real
normal_opening_norm
=
opening_it
->
dot
(
*
normal_it
);
Vector
<
Real
>
normal_opening
(
spatial_dimension
);
normal_opening
=
(
*
normal_it
);
normal_opening
*=
normal_opening_norm
;
Vector
<
Real
>
tangential_opening
(
spatial_dimension
);
tangential_opening
=
*
opening_it
;
tangential_opening
-=
normal_opening
;
Real
tangential_opening_norm
=
tangential_opening
.
norm
();
/**
* compute effective opening displacement
* @f$ \delta = \sqrt{
* \beta^2 \Delta_t^2 + \Delta_n^2 } @f$
*/
Real
delta
=
tangential_opening_norm
;
delta
*=
delta
*
beta2
;
delta
+=
normal_opening_norm
*
normal_opening_norm
;
delta
=
sqrt
(
delta
);
if
((
normal_opening_norm
<
0
)
&&
(
std
::
abs
(
normal_opening_norm
)
>
Math
::
getTolerance
()))
{
Vector
<
Real
>
op_n
(
*
opening_it
);
op_n
*=
*
normal_it
;
Vector
<
Real
>
delta_s
(
*
opening_it
);
delta_s
-=
op_n
;
delta
=
tangential_opening_norm
*
beta
;
computeCoupledTraction
(
*
traction_it
,
*
normal_it
,
delta
,
delta_s
,
*
delta_max_it
,
*
delta_max_prev_it
);
computeCompressiveTraction
(
*
traction_it
,
*
normal_it
,
normal_opening_norm
,
*
opening_it
);
}
else
computeCoupledTraction
(
*
traction_it
,
*
normal_it
,
delta
,
*
opening_it
,
*
delta_max_it
,
*
delta_max_prev_it
);
}
AKANTU_DEBUG_OUT
();
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
void
MaterialCohesiveExponential
<
spatial_dimension
>::
computeCoupledTraction
(
Vector
<
Real
>
&
tract
,
const
Vector
<
Real
>
&
normal
,
Real
delta
,
const
Vector
<
Real
>
&
opening
,
Real
&
delta_max_new
,
Real
delta_max
)
{
AKANTU_DEBUG_IN
();
/// full damage case
if
(
std
::
abs
(
delta
)
<
Math
::
getTolerance
())
{
/// set traction to zero
tract
.
clear
();
}
else
{
/// element not fully damaged
/**
* Compute traction loading @f$ \mathbf{T} =
* e \sigma_c \frac{\delta}{\delta_c} e^{-\delta/ \delta_c}@f$
*/
/**
* Compute traction unloading @f$ \mathbf{T} =
* \frac{t_{max}}{\delta_{max}} \delta @f$
*/
Real
beta2
=
beta
*
beta
;
Vector
<
Real
>
op_n_n
(
opening
);
op_n_n
*=
normal
;
op_n_n
*=
(
1
-
beta2
);
op_n_n
*=
normal
;
tract
=
beta2
*
opening
;
tract
+=
op_n_n
;
delta_max_new
=
std
::
max
(
delta_max
,
delta
);
tract
*=
exp
(
1
)
*
sigma_c
*
exp
(
-
delta_max_new
/
delta_c
)
/
delta_c
;
}
AKANTU_DEBUG_OUT
();
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
void
MaterialCohesiveExponential
<
spatial_dimension
>::
computeCompressiveTraction
(
Vector
<
Real
>
&
tract
,
const
Vector
<
Real
>
&
normal
,
Real
delta_n
,
const
Vector
<
Real
>
&
opening
)
{
Vector
<
Real
>
temp_tract
(
normal
);
if
(
exp_penalty
)
{
temp_tract
*=
delta_n
*
exp
(
1
)
*
sigma_c
*
exp
(
-
delta_n
/
delta_c
)
/
delta_c
;
}
else
{
Real
initial_tg
=
contact_tangent
*
exp
(
1
)
*
sigma_c
*
delta_n
/
delta_c
;
temp_tract
*=
initial_tg
;
}
tract
+=
temp_tract
;
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
void
MaterialCohesiveExponential
<
spatial_dimension
>::
computeTangentTraction
(
const
ElementType
&
el_type
,
Array
<
Real
>
&
tangent_matrix
,
const
Array
<
Real
>
&
normal
,
GhostType
ghost_type
)
{
AKANTU_DEBUG_IN
();
Array
<
Real
>::
matrix_iterator
tangent_it
=
tangent_matrix
.
begin
(
spatial_dimension
,
spatial_dimension
);
Array
<
Real
>::
matrix_iterator
tangent_end
=
tangent_matrix
.
end
(
spatial_dimension
,
spatial_dimension
);
Array
<
Real
>::
const_vector_iterator
normal_it
=
normal
.
begin
(
spatial_dimension
);
Array
<
Real
>::
vector_iterator
opening_it
=
opening
(
el_type
,
ghost_type
).
begin
(
spatial_dimension
);
Array
<
Real
>::
vector_iterator
traction_it
=
tractions
(
el_type
,
ghost_type
).
begin
(
spatial_dimension
);
Array
<
Real
>::
iterator
<
Real
>
delta_max_it
=
delta_max
.
previous
(
el_type
,
ghost_type
).
begin
();
Real
beta2
=
beta
*
beta
;
/**
* compute tangent matrix @f$ \frac{\partial \mathbf{t}}
* {\partial \delta} = \hat{\mathbf{t}} \otimes
* \frac{\partial (t/\delta)}{\partial \delta}
* \frac{\hat{\mathbf{t}}}{\delta}+ \frac{t}{\delta} [ \beta^2 \mathbf{I} +
* (1-\beta^2) (\mathbf{n} \otimes \mathbf{n})] @f$
**/
/**
* In which @f$
* \frac{\partial(t/ \delta)}{\partial \delta} =
* \left\{\begin{array} {l l}
* -e \frac{\sigma_c}{\delta_c^2 }e^{-\delta / \delta_c} & \quad if
* \delta \geq \delta_{max} \\
* 0 & \quad if \delta < \delta_{max}, \delta_n > 0
* \end{array}\right. @f$
**/
for
(;
tangent_it
!=
tangent_end
;
++
tangent_it
,
++
normal_it
,
++
opening_it
,
++
traction_it
,
++
delta_max_it
)
{
Real
normal_opening_norm
=
opening_it
->
dot
(
*
normal_it
);
Vector
<
Real
>
normal_opening
(
spatial_dimension
);
normal_opening
=
(
*
normal_it
);
normal_opening
*=
normal_opening_norm
;
Vector
<
Real
>
tangential_opening
(
spatial_dimension
);
tangential_opening
=
*
opening_it
;
tangential_opening
-=
normal_opening
;
Real
tangential_opening_norm
=
tangential_opening
.
norm
();
Real
delta
=
tangential_opening_norm
;
delta
*=
delta
*
beta2
;
delta
+=
normal_opening_norm
*
normal_opening_norm
;
delta
=
sqrt
(
delta
);
if
((
normal_opening_norm
<
0
)
&&
(
std
::
abs
(
normal_opening_norm
)
>
Math
::
getTolerance
()))
{
Vector
<
Real
>
op_n
(
*
opening_it
);
op_n
*=
*
normal_it
;
Vector
<
Real
>
delta_s
(
*
opening_it
);
delta_s
-=
op_n
;
delta
=
tangential_opening_norm
*
beta
;
computeCoupledTangent
(
*
tangent_it
,
*
traction_it
,
*
normal_it
,
delta
,
delta_s
,
*
delta_max_it
);
computeCompressivePenalty
(
*
tangent_it
,
*
normal_it
,
normal_opening_norm
);
}
else
computeCoupledTangent
(
*
tangent_it
,
*
traction_it
,
*
normal_it
,
delta
,
*
opening_it
,
*
delta_max_it
);
}
AKANTU_DEBUG_OUT
();
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
void
MaterialCohesiveExponential
<
spatial_dimension
>::
computeCoupledTangent
(
Matrix
<
Real
>
&
tangent
,
Vector
<
Real
>
tract
,
const
Vector
<
Real
>
&
normal
,
Real
delta
,
const
Vector
<
Real
>
&
opening
,
Real
delta_max_new
)
{
AKANTU_DEBUG_IN
();
Real
beta2
=
beta
*
beta
;
Matrix
<
Real
>
I
(
spatial_dimension
,
spatial_dimension
);
I
.
eye
(
beta2
);
Matrix
<
Real
>
nn
(
spatial_dimension
,
spatial_dimension
);
nn
.
outerProduct
(
normal
,
normal
);
nn
*=
(
1
-
beta2
);
I
+=
nn
;
if
(
std
::
abs
(
delta
)
<
Math
::
getTolerance
()){
I
*=
exp
(
1
)
*
sigma_c
/
delta_c
;
tangent
+=
I
;
}
else
{
Real
traction_norm
=
tract
.
norm
();
Vector
<
Real
>
t_hat
(
opening
);
Vector
<
Real
>
beta2delta
(
opening
);
beta2delta
*=
beta2
;
t_hat
*=
normal
;
t_hat
*=
(
beta2
-
1
);
t_hat
*=
normal
;
t_hat
+=
beta2delta
;
Vector
<
Real
>
deriv_t_hat
(
t_hat
);
deriv_t_hat
/=
delta
;
Real
derivatives
=
0
;
if
((
delta
>
delta_max_new
)
||
(
std
::
abs
(
delta
-
delta_max_new
)
<
1e-12
))
{
derivatives
=
-
exp
(
1
-
delta
/
delta_c
)
*
sigma_c
/
(
delta_c
*
delta_c
);
}
deriv_t_hat
*=
derivatives
;
Matrix
<
Real
>
t_var_t
(
spatial_dimension
,
spatial_dimension
);
t_var_t
.
outerProduct
(
t_hat
,
deriv_t_hat
);
I
*=
traction_norm
/
delta
;
tangent
+=
t_var_t
;
tangent
+=
I
;
}
AKANTU_DEBUG_OUT
();
}
/* -------------------------------------------------------------------------- */
template
<
UInt
spatial_dimension
>
void
MaterialCohesiveExponential
<
spatial_dimension
>::
computeCompressivePenalty
(
Matrix
<
Real
>
&
tangent
,
const
Vector
<
Real
>
&
normal
,
Real
delta_n
)
{
if
(
!
exp_penalty
)
delta_n
=
0
;
Matrix
<
Real
>
n_outer_n
(
spatial_dimension
,
spatial_dimension
);
n_outer_n
.
outerProduct
(
normal
,
normal
);
Real
normal_tg
=
contact_tangent
*
exp
(
1
)
*
sigma_c
*
exp
(
-
delta_n
/
delta_c
)
*
(
1
-
delta_n
/
delta_c
)
/
delta_c
;
n_outer_n
*=
normal_tg
;
tangent
+=
n_outer_n
;
}
INSTANSIATE_MATERIAL
(
MaterialCohesiveExponential
);
__END_AKANTU__
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