Code_Aster
®
Version
7.4
Titrate:
Modeling
2d_DIS_T
and
2d_DIS_TR
Date:
03/06/05
Author (S):
J.M. PROIX, F. LEBOUVIER
Key
:
U3.13.09-C
Page
:
1/4
Instruction manual
U3.13 booklet: Mechanical finite elements 2D
HT-66/05/004/A
Organization (S):
EDF-R & D/AMA, DeltaCAD
Instruction manual
U3.13 booklet: Mechanical finite elements 2D
Document: U3.13.09
Modelings
2D
_
DIS_T
and
2D
_
DIS_TR
Summary:
This document describes for modelings
2d_DIS_T
,
2d_DIS_TR
(cf [R5.03.17]):
·
degrees of freedom carried by the finite elements which support modeling,
·
the related meshs supports,
·
supported loadings,
·
nonlinear possibilities,
·
case-tests implementing modelings.
Modeling
2D
_
DIS_T
the representation of discrete elements of translation one or two nodes allows.
Modeling
2D
_
DIS_TR
the representation of discrete elements of translation and rotation allows one or
two nodes.
They are usable for two-dimensional problems in linear mechanical analysis or not linear.
Code_Aster
®
Version
7.4
Titrate:
Modeling
2d_DIS_T
and
2d_DIS_TR
Date:
03/06/05
Author (S):
J.M. PROIX, F. LEBOUVIER
Key
:
U3.13.09-C
Page
:
2/4
Instruction manual
U3.13 booklet: Mechanical finite elements 2D
HT-66/05/004/A
1 Discretization
1.1
Degrees of freedom
The degrees of freedom of discretization are, in each node of the mesh support, both
components of displacement of translation and rotation.
Finite element
Degrees of freedom (with each node node)
2d_DIS_T
DX
DY
2d_DIS_TR
DX
DY
DRZ
1.2
Net support of the matrices of rigidity
The meshs support of the discrete elements, in displacement formulation, are segments with two
nodes
SEG2
or of the specific meshs
POI1
confused with a node:
Modeling Nets Element
finished
Remarks
2d_DIS_T POI1
MECA_2D_DIS_T_N
SEG2
MECA_2D_DIS_T_L
2d_DIS_TR POI1
MECA_2D_DIS_TR_N
SEG2
MECA_2D_DIS_TR_L
With regard to the meshs
POI1
, the efforts intern are calculated starting from the differences of
degrees of freedom of the mesh with the reference mark fixes (as if this discrete node were attached to a reference mark
fixed).
For the meshs
SEG2
, the efforts are calculated starting from the differences of the degrees of freedom carried by
each of the 2 nodes.
2
Assignment of the characteristics
For these discrete elements, it is necessary to affect geometrical characteristics which are
complementary to the data of mesh. The definition of these data is carried out with
order
AFFE_CARA_ELEM
associated the key words following factors:
·
DISCRETE
Allows to define and affect the values of the matrices of rigidity, mass or damping.
Supported modelings:
2d_DIS_T
,
2d_DIS_TR
·
ORIENTATION
Allows to define and affect a local reference mark.
Supported modelings:
2d_DIS_T
,
2d_DIS_TR
Code_Aster
®
Version
7.4
Titrate:
Modeling
2d_DIS_T
and
2d_DIS_TR
Date:
03/06/05
Author (S):
J.M. PROIX, F. LEBOUVIER
Key
:
U3.13.09-C
Page
:
3/4
Instruction manual
U3.13 booklet: Mechanical finite elements 2D
HT-66/05/004/A
3 Loadings
supported
The supported loading is as follows:
·
“GRAVITY”
Allows to apply a loading of the gravity type.
Supported modelings:
2d_DIS_T
,
2d_DIS_TR
4
Possibilities not - linear
Only modeling
2d_DIS_T
being pressed on a mesh with 2 nodes is usable with
STAT_NON_LINE
and
DYNA_NON_LINE
. It is only in this case that one uses
DEFI_MATERIAU
.
4.1
Law of behavior
Laws of behaviors specific to these modelings, usable under
COMP_INCR
in
STAT_NON_LINE
and
DYNA_NON_LINE
the following ones (cf [U4.51.11]):
/“DIS_GOUJ 2e_ELAS”
Supported modeling:
2d_DIS_T
(Mesh SEG2)
/“DIS_GOUJ 2e_PLAS”
Supported modeling:
2d_DIS_T
(Mesh SEG2)
/“ELAS”
Supported modelings:
2d_DIS_T
,
2d_DIS_TR
In addition to the assignment of the characteristics (
AFFE_CARA_ELEM
) the use of modelings
DIS_T
and
DIS_TR
with
STAT_NON_LINE/DYNA_NON_LINE/DYNA_TRAN_EXPLI
imply to define
characteristics material (
AFFE_MATERIAU
).
4.2 Deformations
Deformations available, used in the relations of behavior under the key word
DEFORMATION
for the operators
STAT_NON_LINE
and
DYNA_NON_LINE
are (cf [U4.51.11]):
/“SMALL”
The deformations used for the relation of behavior are the linearized deformations
calculated on the initial geometry.
Supported modeling:
2d_DIS_TR
(Mesh SEG2)
/“PETIT_REAC”
The deformations used in the incremental relation of behavior are the deformations
linearized calculated on the reactualized geometry.
Supported modeling:
2d_DIS_TR
(Mesh SEG2)
Code_Aster
®
Version
7.4
Titrate:
Modeling
2d_DIS_T
and
2d_DIS_TR
Date:
03/06/05
Author (S):
J.M. PROIX, F. LEBOUVIER
Key
:
U3.13.09-C
Page
:
4/4
Instruction manual
U3.13 booklet: Mechanical finite elements 2D
HT-66/05/004/A
5
Examples of implementation: case-tests
·
2d_DIS_T
Statique
linear
SSLL108A [V3.01.108]: Analyze response of a bar, modelized by 10 elements
discrete (Meshs SEG2) subjected to a loading of traction.
Statique
non-linear
ZZZZ120A: Calcul of an assembly Pin-Attaches without top of flange, with a law of
elastoplastic behavior of Von Mises representing the local behavior of a net of
pin of threaded assembly.
Dynamique
linear
SDLD02E [V2.01.002]: Seek frequencies of vibration and modes associated with one
mechanical structure made up of masses and springs.
Dynamique
non-linear
Rubbing SDNV104A: Dynamic response of a rigid shoe subjected to a pressure and one
force of recall.
·
2d_DIS_TR
Dynamique
linear
SDLD02F [V2.01.002]: Seek frequencies of vibration and modes associated with one
mechanical structure made up of masses and springs.