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Code_Aster
®
Version
7.4
Titrate:
Modelings
DIS_T
and
DIS_TR
Date:
03/06/05
Author (S):
J.M. PROIX, F. LEBOUVIER
Key
:
U3.11.02-E
Page
:
1/4
Instruction manual
U3.11 booklet: Mechanical elements of structure 1D
HT-66/05/004/A
Organization (S):
EDF-R & D/AMA, DeltaCAD















Instruction manual
U3.11 booklet: Mechanical elements of structure 1D
Document: U3.11.02



Modelings
DIS_T
and
DIS_TR



Summary:

This document describes for modelings
DIS_T
and
DIS_TR
:
·
degrees of freedom carried by the finite elements which support modeling,
·
the related meshs supports,
·
supported loadings,
·
nonlinear possibilities,
·
case-tests implementing modelings.

Two modelings
DIS_T
and
DIS_TR
allow the representation of discrete elements of translation and of
translation-rotation.

They are usable for three-dimensional problems in linear and nonlinear mechanical analysis.
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Code_Aster
®
Version
7.4
Titrate:
Modelings
DIS_T
and
DIS_TR
Date:
03/06/05
Author (S):
J.M. PROIX, F. LEBOUVIER
Key
:
U3.11.02-E
Page
:
2/4
Instruction manual
U3.11 booklet: Mechanical elements of structure 1D
HT-66/05/004/A
1 Discretization
1.1
Degrees of freedom
For two modelings into three-dimensional the degrees of freedom of discretization are, in each
node of the mesh support, three components of displacement of translation or six
components (three translations and three rotations).
Finite element
Degrees of freedom (with each node node)
DIS_T
DX
DY
DZ
DIS_TR
DX
DY
DZ
DRX
DRY
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
DIS_T POI1
MECA_DIS_T_N
SEG2
MECA_DIS_T_L
DIS_TR POI1
MECA_DIS_TR_N
SEG2
MECA_DIS_TR_L
For the meshs
POI1
, the efforts are calculated starting from the differences of the degrees of freedom of the node
mesh with the fixed reference mark, while for the meshs
SEG2
, they are calculated from
differences of ddl between the two 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:
DIS_T
,
DIS_TR
·
ORIENTATION
Allows to define and affect a local reference mark.
Supported modelings:
DIS_T
,
DIS_TR

3 Loadings
supported
·
“GRAVITY”
Allows to apply a loading of the gravity type.
Supported modelings:
DIS_T
,
DIS_TR
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Code_Aster
®
Version
7.4
Titrate:
Modelings
DIS_T
and
DIS_TR
Date:
03/06/05
Author (S):
J.M. PROIX, F. LEBOUVIER
Key
:
U3.11.02-E
Page
:
3/4
Instruction manual
U3.11 booklet: Mechanical elements of structure 1D
HT-66/05/004/A
4 Possibilities
non-linear
4.1
Law of behaviors
Laws of behaviors specific to these modelings, usable under
COMP_INCR
in
STAT_NON_LINE
,
DYNA_NON_LINE
and
DYNA_TRAN_EXPLI
are as follows (cf [U4.51.11]):
/“ASSE_CORN”
Supported modeling:
DIS_TR
/“WEAPON”
Supported modeling:
DIS_TR
/“DIS_CHOC”
Supported modelings:
DIS_T
,
DIS_TR
/“DIS_CONTACT”
Supported modelings:
DIS_T
,
DIS_TR
/“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 (via
DEFI_MATERIAU
and
AFFE_MATERIAU
).
With
DIS_CONTACT
and
DIS_CHOC
, the elastic matrix is calculated with the characteristic of stiffness
defined in
AFFE_CARA_ELEM
, while the tangent matrix is calculated via the behavior
DIS_CONTACT
or
DIS_CHOC
.

4.2 Deformations
Deformations available, used in the relations of behavior under the key word
DEFORMATION
for the operators
STAT_NON_LINE
,
DYNA_NON_LINE
and
DYNA_TRAN_EXPLI
are
(Cf [U4.51.11]):
/“SMALL”
The deformations used for the relation of behavior are the linearized deformations
calculated on the initial geometry.
/“PETIT_REAC”
The deformations used in the incremental relation of behavior are the deformations
linearized calculated on the reactualized geometry.
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Code_Aster
®
Version
7.4
Titrate:
Modelings
DIS_T
and
DIS_TR
Date:
03/06/05
Author (S):
J.M. PROIX, F. LEBOUVIER
Key
:
U3.11.02-E
Page
:
4/4
Instruction manual
U3.11 booklet: Mechanical elements of structure 1D
HT-66/05/004/A
5
Examples of implementation: case-test
·
DIS_T
­ Statique
linear
SSLL100B [V3.01.100]: Analyze static linear of a formed structure of right beams and
curves subjected to a loading of bending.
­ Statique
non-linear
SSNL118A [V6.02.118]: Analyze static non-linear of a bar subjected to a field of
speed of wind.
­ Dynamique
linear
SDLD02A [V2.01.002]: Seek frequencies and modes of vibration of a structure
mechanics made up of masses and springs.
­ Dynamique
non-linear
SDND102B [V5.01.102]: Seismic response of a system masses non-linear spring multi
supported.
·
DIS_TR
­ Statique
linear
SSLX100D [V3.05.100]: Analyze of a beam in bending of which the model is composed of one
mix modeling 3D, Coque and Beam.
­ Statique
non-linear
SSNL102A [V6.02.102]: Analyze non-linear behavior of an assembly of
angles subjected to a two-dimensional loading of traction and moment.
­ Dynamique
linear
SDLD02C [V2.01.002]: Seek frequencies and modes of vibration of a structure
mechanics made up of masses and springs.
­ Dynamique
non-linear
SDND102B [V5.01.102]: Seismic response of a system masses non-linear spring multi
supported.