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
Organization (S): EDF-R & D/AMA, DeltaCAD
Handbook of Utilization
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.
Handbook of Utilization
U3.11 booklet: Mechanical elements of structure 1D
HT-66/05/004/A
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
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 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 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 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 grid. The definition of these data is carried out with
order AFFE_CARA_ELEM associated with the key words following factors:
· DISCRET
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
· “PESANTEUR”
Allows to apply a loading of the gravity type.
Supported modelings: DIS_T, DIS_TR
Handbook of Utilization
U3.11 booklet: Mechanical elements of structure 1D
HT-66/05/004/A
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
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
/“ARME”
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 characteristics (AFFE_CARA_ELEM), the use of modelings DIS_T
and DIS_TR with STAT_NON_LINE/DYNA_NON_LINE/DYNA_TRAN_EXPLI implies 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 operators STAT_NON_LINE, DYNA_NON_LINE and DYNA_TRAN_EXPLI are
(Cf [U4.51.11]):
/“PETIT”
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.
Handbook of Utilization
U3.11 booklet: Mechanical elements of structure 1D
HT-66/05/004/A
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
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 inflection.
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 inflection of which the model is composed of one
mix modeling 3D, Coque and Poutre.
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.
Handbook of Utilization
U3.11 booklet: Mechanical elements of structure 1D
HT-66/05/004/A
Outline document