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rAKA akantu
geometry_utils.cc
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/**
* @file geometry_utils.cc
*
* @author Mohit Pundir <mohit.pundir@epfl.ch>
*
* @date creation: Mon Mmay 20 2019
* @date last modification: Mon May 20 2019
*
* @brief Implementation of various utilities needed for contact geometry
*
* @section LICENSE
*
* Copyright (©) 2010-2018 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 "geometry_utils.hh"
/* -------------------------------------------------------------------------- */
namespace
akantu
{
/* -------------------------------------------------------------------------- */
void
GeometryUtils
::
normal
(
const
Mesh
&
mesh
,
const
Array
<
Real
>
&
positions
,
const
Element
&
element
,
Vector
<
Real
>
&
normal
,
bool
outward
)
{
UInt
spatial_dimension
=
mesh
.
getSpatialDimension
();
UInt
surface_dimension
=
spatial_dimension
-
1
;
UInt
nb_nodes_per_element
=
Mesh
::
getNbNodesPerElement
(
element
.
type
);
Matrix
<
Real
>
coords
(
spatial_dimension
,
nb_nodes_per_element
);
UInt
*
elem_val
=
mesh
.
getConnectivity
(
element
.
type
,
_not_ghost
).
storage
();
mesh
.
extractNodalValuesFromElement
(
positions
,
coords
.
storage
(),
elem_val
+
element
.
element
*
nb_nodes_per_element
,
nb_nodes_per_element
,
spatial_dimension
);
Matrix
<
Real
>
vectors
(
spatial_dimension
,
surface_dimension
);
switch
(
spatial_dimension
)
{
case
2
:
{
vectors
(
0
)
=
Vector
<
Real
>
(
coords
(
1
))
-
Vector
<
Real
>
(
coords
(
0
));
Math
::
normal2
(
vectors
.
storage
(),
normal
.
storage
());
break
;
}
case
3
:
{
vectors
(
0
)
=
Vector
<
Real
>
(
coords
(
1
))
-
Vector
<
Real
>
(
coords
(
0
));
vectors
(
1
)
=
Vector
<
Real
>
(
coords
(
2
))
-
Vector
<
Real
>
(
coords
(
0
));
Math
::
normal3
(
vectors
(
0
).
storage
(),
vectors
(
1
).
storage
(),
normal
.
storage
());
break
;
}
default
:
{
AKANTU_ERROR
(
"Unknown dimension : "
<<
spatial_dimension
);
}
}
// to ensure that normal is always outwards from master surface
if
(
outward
)
{
const
auto
&
element_to_subelement
=
mesh
.
getElementToSubelement
(
element
.
type
)(
element
.
element
);
Vector
<
Real
>
outside
(
spatial_dimension
);
mesh
.
getBarycenter
(
element
,
outside
);
// check if mesh facets exists for cohesive elements contact
Vector
<
Real
>
inside
(
spatial_dimension
);
if
(
mesh
.
isMeshFacets
())
{
mesh
.
getMeshParent
().
getBarycenter
(
element_to_subelement
[
0
],
inside
);
}
else
{
mesh
.
getBarycenter
(
element_to_subelement
[
0
],
inside
);
}
Vector
<
Real
>
inside_to_outside
=
outside
-
inside
;
auto
projection
=
inside_to_outside
.
dot
(
normal
);
if
(
projection
<
0
)
{
normal
*=
-
1.0
;
}
}
}
/* -------------------------------------------------------------------------- */
void
GeometryUtils
::
covariantBasis
(
const
Mesh
&
mesh
,
const
Array
<
Real
>
&
positions
,
const
Element
&
element
,
const
Vector
<
Real
>
&
normal
,
Vector
<
Real
>
&
natural_coord
,
Matrix
<
Real
>
&
tangents
)
{
UInt
spatial_dimension
=
mesh
.
getSpatialDimension
();
const
ElementType
&
type
=
element
.
type
;
UInt
nb_nodes_per_element
=
mesh
.
getNbNodesPerElement
(
type
);
UInt
*
elem_val
=
mesh
.
getConnectivity
(
type
,
_not_ghost
).
storage
();
Matrix
<
Real
>
nodes_coord
(
spatial_dimension
,
nb_nodes_per_element
);
mesh
.
extractNodalValuesFromElement
(
positions
,
nodes_coord
.
storage
(),
elem_val
+
element
.
element
*
nb_nodes_per_element
,
nb_nodes_per_element
,
spatial_dimension
);
UInt
surface_dimension
=
spatial_dimension
-
1
;
Matrix
<
Real
>
dnds
(
surface_dimension
,
nb_nodes_per_element
);
#define GET_SHAPE_DERIVATIVES_NATURAL(type) \
ElementClass<type>::computeDNDS(natural_coord, dnds)
AKANTU_BOOST_ALL_ELEMENT_SWITCH
(
GET_SHAPE_DERIVATIVES_NATURAL
);
#undef GET_SHAPE_DERIVATIVES_NATURAL
tangents
.
mul
<
false
,
true
>
(
dnds
,
nodes_coord
);
auto
temp_tangents
=
tangents
.
transpose
();
for
(
UInt
i
=
0
;
i
<
spatial_dimension
-
1
;
++
i
)
{
auto
temp
=
Vector
<
Real
>
(
temp_tangents
(
i
));
temp_tangents
(
i
)
=
temp
.
normalize
();
}
tangents
=
temp_tangents
.
transpose
();
// to ensure that direction of tangents are correct, cross product
// of tangents should give the normal vector computed earlier
switch
(
spatial_dimension
)
{
case
2
:
{
Vector
<
Real
>
e_z
(
3
);
e_z
[
0
]
=
0.
;
e_z
[
1
]
=
0.
;
e_z
[
2
]
=
1.
;
Vector
<
Real
>
tangent
(
3
);
tangent
[
0
]
=
tangents
(
0
,
0
);
tangent
[
1
]
=
tangents
(
0
,
1
);
tangent
[
2
]
=
0.
;
auto
exp_normal
=
e_z
.
crossProduct
(
tangent
);
auto
ddot
=
normal
.
dot
(
exp_normal
);
if
(
ddot
<
0
)
{
tangents
*=
-
1.0
;
}
break
;
}
case
3
:
{
auto
tang_trans
=
tangents
.
transpose
();
auto
tang1
=
Vector
<
Real
>
(
tang_trans
(
0
));
auto
tang2
=
Vector
<
Real
>
(
tang_trans
(
1
));
auto
tang1_cross_tang2
=
tang1
.
crossProduct
(
tang2
);
auto
exp_normal
=
tang1_cross_tang2
/
tang1_cross_tang2
.
norm
();
auto
ddot
=
normal
.
dot
(
exp_normal
);
if
(
ddot
<
0
)
{
tang_trans
(
1
)
*=
-
1.0
;
}
tangents
=
tang_trans
.
transpose
();
break
;
}
default
:
break
;
}
}
/* -------------------------------------------------------------------------- */
void
GeometryUtils
::
curvature
(
const
Mesh
&
mesh
,
const
Array
<
Real
>
&
positions
,
const
Element
&
element
,
const
Vector
<
Real
>
&
natural_coord
,
Matrix
<
Real
>
&
curvature
)
{
UInt
spatial_dimension
=
mesh
.
getSpatialDimension
();
auto
surface_dimension
=
spatial_dimension
-
1
;
const
ElementType
&
type
=
element
.
type
;
UInt
nb_nodes_per_element
=
mesh
.
getNbNodesPerElement
(
type
);
UInt
*
elem_val
=
mesh
.
getConnectivity
(
type
,
_not_ghost
).
storage
();
Matrix
<
Real
>
dn2ds2
(
surface_dimension
*
surface_dimension
,
Mesh
::
getNbNodesPerElement
(
type
));
#define GET_SHAPE_SECOND_DERIVATIVES_NATURAL(type) \
ElementClass<type>::computeDN2DS2(natural_coord, dn2ds2)
AKANTU_BOOST_ALL_ELEMENT_SWITCH
(
GET_SHAPE_SECOND_DERIVATIVES_NATURAL
);
#undef GET_SHAPE_SECOND_DERIVATIVES_NATURAL
Matrix
<
Real
>
coords
(
spatial_dimension
,
nb_nodes_per_element
);
mesh
.
extractNodalValuesFromElement
(
positions
,
coords
.
storage
(),
elem_val
+
element
.
element
*
nb_nodes_per_element
,
nb_nodes_per_element
,
spatial_dimension
);
curvature
.
mul
<
false
,
true
>
(
coords
,
dn2ds2
);
}
/* -------------------------------------------------------------------------- */
UInt
GeometryUtils
::
orthogonalProjection
(
const
Mesh
&
mesh
,
const
Array
<
Real
>
&
positions
,
const
Vector
<
Real
>
&
slave
,
const
Array
<
Element
>
&
elements
,
Real
&
gap
,
Vector
<
Real
>
&
natural_projection
,
Vector
<
Real
>
&
normal
,
Real
alpha
)
{
UInt
index
=
UInt
(
-
1
);
Real
min_gap
=
std
::
numeric_limits
<
Real
>::
max
();
UInt
spatial_dimension
=
mesh
.
getSpatialDimension
();
UInt
counter
=
0
;
for
(
auto
&
element
:
elements
)
{
if
(
!
GeometryUtils
::
isBoundaryElement
(
mesh
,
element
))
continue
;
Vector
<
Real
>
normal_ele
(
spatial_dimension
);
GeometryUtils
::
normal
(
mesh
,
positions
,
element
,
normal_ele
);
Vector
<
Real
>
master
(
spatial_dimension
);
GeometryUtils
::
realProjection
(
mesh
,
positions
,
slave
,
element
,
normal_ele
,
master
);
Vector
<
Real
>
xi
(
natural_projection
.
size
());
GeometryUtils
::
naturalProjection
(
mesh
,
positions
,
element
,
master
,
xi
);
auto
master_to_slave
=
slave
-
master
;
Real
temp_gap
=
master_to_slave
.
norm
();
if
(
temp_gap
!=
0
)
master_to_slave
/=
temp_gap
;
Real
tolerance
=
1e-8
;
auto
product
=
master_to_slave
.
dot
(
normal_ele
);
auto
variation
=
std
::
abs
(
product
+
alpha
);
if
(
variation
<=
tolerance
and
temp_gap
<=
min_gap
and
GeometryUtils
::
isValidProjection
(
xi
))
{
gap
=
-
temp_gap
;
min_gap
=
temp_gap
;
index
=
counter
;
natural_projection
=
xi
;
normal
=
normal_ele
;
}
counter
++
;
}
return
index
;
}
/* -------------------------------------------------------------------------- */
void
GeometryUtils
::
realProjection
(
const
Mesh
&
mesh
,
const
Array
<
Real
>
&
positions
,
const
Vector
<
Real
>
&
slave
,
const
Element
&
element
,
const
Vector
<
Real
>
&
normal
,
Vector
<
Real
>
&
projection
)
{
UInt
spatial_dimension
=
mesh
.
getSpatialDimension
();
const
ElementType
&
type
=
element
.
type
;
UInt
nb_nodes_per_element
=
Mesh
::
getNbNodesPerElement
(
element
.
type
);
UInt
*
elem_val
=
mesh
.
getConnectivity
(
type
,
_not_ghost
).
storage
();
Matrix
<
Real
>
nodes_coord
(
spatial_dimension
,
nb_nodes_per_element
);
mesh
.
extractNodalValuesFromElement
(
positions
,
nodes_coord
.
storage
(),
elem_val
+
element
.
element
*
nb_nodes_per_element
,
nb_nodes_per_element
,
spatial_dimension
);
Vector
<
Real
>
point
(
nodes_coord
(
0
));
Real
alpha
=
(
slave
-
point
).
dot
(
normal
);
projection
=
slave
-
alpha
*
normal
;
}
/* -------------------------------------------------------------------------- */
void
GeometryUtils
::
naturalProjection
(
const
Mesh
&
mesh
,
const
Array
<
Real
>
&
positions
,
const
Element
&
element
,
Vector
<
Real
>
&
real_projection
,
Vector
<
Real
>
&
natural_projection
)
{
UInt
spatial_dimension
=
mesh
.
getSpatialDimension
();
const
ElementType
&
type
=
element
.
type
;
UInt
nb_nodes_per_element
=
mesh
.
getNbNodesPerElement
(
type
);
UInt
*
elem_val
=
mesh
.
getConnectivity
(
type
,
_not_ghost
).
storage
();
Matrix
<
Real
>
nodes_coord
(
spatial_dimension
,
nb_nodes_per_element
);
mesh
.
extractNodalValuesFromElement
(
positions
,
nodes_coord
.
storage
(),
elem_val
+
element
.
element
*
nb_nodes_per_element
,
nb_nodes_per_element
,
spatial_dimension
);
#define GET_NATURAL_COORDINATE(type) \
ElementClass<type>::inverseMap(real_projection, nodes_coord, \
natural_projection)
AKANTU_BOOST_ALL_ELEMENT_SWITCH
(
GET_NATURAL_COORDINATE
);
#undef GET_NATURAL_COORDINATE
}
/* -------------------------------------------------------------------------- */
void
GeometryUtils
::
contravariantBasis
(
const
Matrix
<
Real
>
&
covariant
,
Matrix
<
Real
>
&
contravariant
)
{
Matrix
<
Real
>
A
(
covariant
.
rows
(),
covariant
.
rows
());
A
.
mul
<
false
,
true
>
(
covariant
,
covariant
);
auto
inv_A
=
A
.
inverse
();
contravariant
.
mul
<
false
,
false
>
(
inv_A
,
covariant
);
}
}
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