Modelings DKT - DST

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7.4

Titrate:

Modelings

DKT

DST

Q4G

Date:

01/06/05

Author (S):

X. DESROCHES, F. LEBOUVIER

Key

U3.12.01-D

Page

1/6

Instruction manual

U3.12 booklet: Mechanical elements of structure 2D

HT-66/05/004/A

Organization (S):

EDF-R & D/AMA, DeltaCAD

Instruction manual
U3.12 booklet: Mechanical elements of structure 2D
Document: U3.12.01

Modelings

DKT

DST

Q4G

Summary:

This document describes for modelings

DKT

DST

Q4G

degrees of freedom carried by the finite elements which support modeling,

the related meshs supports,

supported loadings,

nonlinear possibilities,

case-tests implementing modelings.

They are usable for problems of plate into three-dimensional [R3.07.03] in mechanical analysis
linear for all modelings and in nonlinear material for modeling

DKT

only. Their

use for problems of hull is usually allowed by considering that the plan of the element is
comparable to a tangent breakage with the average layer of the hull (attention, only the plane breakages are
allowed).

Thermomechanical calculations are chained starting from the finite elements of thermal hulls (see [U3.22.01]).

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Version

7.4

Titrate:

Modelings

DKT

DST

Q4G

Date:

01/06/05

Author (S):

X. DESROCHES, F. LEBOUVIER

Key

U3.12.01-D

Page

2/6

Instruction manual

U3.12 booklet: Mechanical elements of structure 2D

HT-66/05/004/A

1 Discretization

1.1

Degrees of freedom

For three modelings of plate into three-dimensional the degrees of freedom of discretization are,
in each node of the mesh support six components of displacement (three translations and three
rotations) with the nodes nodes of the mesh support. These nodes are supposed to describe a breakage
tangent with the average layer of the hull.

Finite element

Degrees of freedom (with each node node)

DKT/DKQ

DRX

DRY

DRZ

DST/DSQ

DRX

DRY

DRZ

Q4G (Q4

)

DRX

DRY

DRZ

1.2

Net support of the matrices of rigidity

The meshs support of the finite elements, in displacement formulation, can be triangles or
quadrangles. In this last case, the meshs are supposed to be plane (4 nodes nodes
coplanar):

Modeling Nets Element

finished

Remarks

DKT TRIA3

QUAD4

MEDKTR3
MEDKQU4

DST TRIA3

QUAD4

MEDSTR3
MEDSQU4

Q4G (Q4

)

QUAD4 MEQ4QU4

1.3

Net support of the loadings

All the loadings applicable to the breakages of the elements of plate are treated by discretization
direct on the mesh support of the element in displacement formulation.

No mesh support of loading is thus necessary for the faces of the elements of plates.

For the applicable loadings on the edges of the elements of plate, a mesh support of the type

SEG2

is usable:

Modeling Nets Element

finished

Remarks

DKT SEG2

MEBODKT

DST SEG2

MEBODST

Q4G (Q4

)

SEG2 MEBOQ4G

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Version

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Titrate:

Modelings

DKT

DST

Q4G

Date:

01/06/05

Author (S):

X. DESROCHES, F. LEBOUVIER

Key

U3.12.01-D

Page

3/6

Instruction manual

U3.12 booklet: Mechanical elements of structure 2D

HT-66/05/004/A

Assignment of the characteristics

For these elements of plate or hulls, it is necessary to affect characteristics
geometrical which is complementary to the data of mesh. The definition of these data is
carried out with the control

AFFE_CARA_ELEM

associated the key word following factor:

HULL

Allows to define and affect on the meshs, the thickness, the coefficient of shearing,
offsetting,…

For the study of structures comprising of multi-layer materials it is necessary to affect them
characteristics of each layer (thickness, type of material) and their stacking
(orientation of fibers). The definition of these data is carried out with the control

DEFI_COQU_MULT

3 Loadings

supported

The loadings available are as follows:

FORCE_ARETE

Allows to apply linear forces.

Supported modelings:

DKT

DST

Q4G

FORCE_COQUE

Allows to apply surface efforts.

Supported modelings:

DKT

DST

Q4G

GRAVITY

Allows to define the acceleration and the direction of gravity.

Supported modelings:

DKT

DST

Q4G

PRES_REP

Allows to apply surface efforts.

Supported modelings:

DKT

DST

Q4G

TEMP_CALCULEE

Allows to apply a thermal loading of origin.

Supported modelings:

DKT

DST

Q4G

EPSI_INIT

Allows to apply a loading of initial deformation.

Supported modelings:

DKT

DST

Q4G

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Version

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Titrate:

Modelings

DKT

DST

Q4G

Date:

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Author (S):

X. DESROCHES, F. LEBOUVIER

Key

U3.12.01-D

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Instruction manual

U3.12 booklet: Mechanical elements of structure 2D

HT-66/05/004/A

4 Possibilities

non-linear

For modeling

DKT

only.

4.1

Law of behaviors

Only modeling

“DKT”

have non-linear possibilities. Laws of behaviors

specific to this modeling, usable under

COMP_INCR

STAT_NON_LINE

and

DYNA_NON_LINE

are the relations of behavior in plane stresses available with

modelings

“AXIS”

and

“C_PLAN”

. These relations are to be used with the key word

ALGO_C_PLAN = ' DEBORST'

'(Cf [U4.51.11]).

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 deformations
linearized.

/“PETIT_REAC”

The increments of deformations used in the incremental relation of behavior are
linearized deformations of the increment of displacement in the reactualized geometry.

Note:

Attention, the calculation of the deformations using

PETIT_REAC

is only one approximation of

assumptions of great displacements. It requires to carry out very small increments of
loading. To correctly take into account great displacements, and especially them
great rotations, it is recommended to use modeling

COQUE_3D

, with

DEFORMATION=' GREEN_GR'

List cases tests available

DKT

 Statique

linear

FORMA01B [V7.15.100]: Analyze of a piping comprising an elbow subjected to one
specific force and with an internal pressure.
SSLS100A [V3.03.100]: Plate circular embedded on its contour, subjected to one
uniform pressure, with a normal force and its actual weight.

 Statique

non-linear

SSNL501C [V6.02.501]: Quasi-static analysis of a beam fixed to both
ends, subjected to a uniform pressure, with an elastic material perfectly
plastic.

 Dynamique

linear

SDLS03C: Seek Eigen frequencies and modes associated with a plate
rectangular thin in simple support on its edges.

 Dynamique

non-linear

ELSA01D: Non-linear dynamic response of a piping in the shape of quadrant (elsa)
subjected to a seismic loading.

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Version

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Titrate:

Modelings

DKT

DST

Q4G

Date:

01/06/05

Author (S):

X. DESROCHES, F. LEBOUVIER

Key

U3.12.01-D

Page

5/6

Instruction manual

U3.12 booklet: Mechanical elements of structure 2D

HT-66/05/004/A

DST

 Statique

linear

SSLS101F [V3.03.101]: Plate circular posed on the edge, subjected 3 loadings:
actual weight, pressure and effort distributed constant.

HSLS01A [V7.11.001]: Analyze of a thin square plate embedded on its contour
subjected to a heat gradient in the thickness.

 Dynamique

linear

SDLS03A: Seeks Eigen frequencies and modes associated with a plate
rectangular thin in simple support on its edges.

Q4G

 Statique

linear

SSLS101H [V3.03.101]: Plate circular posed on the edge under 3 loadings: weight
clean, pressure and effort distributed constant.
HSLS01B [V7.11.001]: Analyze of a thin square plate embedded on its contour
subjected to a heat gradient in the thickness.

 Dynamique

linear

SDLS03B: Seeks Eigen frequencies and modes associated with a plate
rectangular thin in simple support on its edges.