Operator MECA_STATIQUE

Code_Aster

Version

8.2

Titrate:

Operator

MECA_STATIQUE

Date:

31/01/06

Author (S):

J. PELLET

Key

U4.51.01-I1

Page

1/6

Instruction manual

U4.5- booklet: Methods of resolution

HT-62/06/004/A

Organization (S):

EDF-R & D/AMA

Instruction manual
U4.5- booklet: Methods of resolution
Document: U4.51.01

Operator

MECA_STATIQUE

1 Goal

To solve a problem of static mechanics linear.

This operator allows to solve is:

a linear static mechanical problem with superposition of various conditions with
limits and of various loadings,

a thermomechanical analysis for a given list of moments.
-

in this case the mechanical characteristics of materials can depend on
temperature: the concept of the type

cham_mater

must then be defined starting from functions

(Cf operator

DEFI_MATERIAU

[U4.43.01] operand

ELAS_FO)

the loading of dilation can be given only if one defined the coefficient of
dilation and the temperature of reference (cf operators

DEFI_MATERIAU

[U4.43.01] and

AFFE_MATERIAU

[U4.43.03]).

The concept produced by this operator is of type

evol_elas

containing one or more fields of

displacements at the various moments of calculation.

In the case of the static mechanical analysis, one assigns the sequence number 0 (moment 0) to the field
solution.

Product a structure of data of the evol_elas type.

When a calculation of sensitivity of the result compared to a parameter is required, there is production
of as many structures of data of the type

evol_elas

that definite parameters of sensitivity.

Code_Aster

Version

8.2

Titrate:

Operator

MECA_STATIQUE

Date:

31/01/06

Author (S):

J. PELLET

Key

U4.51.01-I1

Page

2/6

Instruction manual

U4.5- booklet: Methods of resolution

HT-62/06/004/A

2 Syntax

mestat [evol_elas] = MECA_STATIQUE

, reuse = mestat,

(

MODEL

[model]

CHAM_MATER

chmat

[cham_mater]

CARA_ELEM

carac

[cara_elem]

EXCIT

= (_F (

CHARGE = tank

,/[char_meca]

[char_cine_meca]

FONC_MULT=

fmult

,/[function]

/[formula]

),)

INST

tps

[R]

[DEFECT]

LIST_INST

litps

[listr8]

INST_FIN = tf,

SOLVEUR = (

… to see [U4.50.01]

SENSITIVITY

(

… to see [U4.50.02]

)

OPTION

“SIEF_ELGA_DEPL”, [DEFECT]

“WITHOUT”,

INFORMATION

[DEFECT]

TITRATE

= title,

[l_K80]

);

Code_Aster

Version

8.2

Titrate:

Operator

MECA_STATIQUE

Date:

31/01/06

Author (S):

J. PELLET

Key

U4.51.01-I1

Page

3/6

Instruction manual

U4.5- booklet: Methods of resolution

HT-62/06/004/A

3 Operands

3.1 Operands

MODEL

CHAM_MATER

CARA_ELEM

One provides the arguments allowing to calculate the matrix of rigidity (and the second member):

MODEL = Mo,

Name of the model whose elements are the subject of mechanical calculation.

CHAM_MATER = chmat,

Name of the material field.

CARA_ELEM

= carac,

Name of the characteristics of the structural elements (beam, hull, discrete,…) if they are used
in the model.

3.2 Word

key

EXCIT

and operands

INST

LIST_INST

One defines here the boundary conditions and the loadings.

EXCIT

This key word factor makes it possible to define several concepts of the type

charge

, one by occurrence;

solution is calculated by superimposing the effects of the various loads applied.

3.2.1 Operands

CHARGE

FONC_MULT

CHARGE = tank,

Name of a concept of the type

char_meca

product by

AFFE_CHAR_MECA

AFFE_CHAR_MECA_F

[U4.44.01] starting from the model

. Only one occurrence must make

reference to the temperature

(load with

TEMP_CALCULEE

One can also give the name of a “kinematic load” (standard

char_cine_meca

)

result of the operators

AFFE_CHAR_CINE

and

AFFE_CHAR_CINE_F

[U4.44.03].

FONC_MULT = fmult,

Name of a concept of the type

function

(or formulates) which makes it possible to define for each

moment of calculation a multiplying coefficient applied to the load

tank

For a thermal loading of origin (dilation) defined by

TEMP_CALCULEE

order

AFFE_CHAR_MECA

[U4.44.01] the field of temperature is not multiplied by

fmult

is a function of time: by defect it is a constant function which is worth 1.

3.2.2 Operands

INST

LIST_INST

/INST = tps,

Key word used to carry out calculation at only one moment

tps

with the temperature

agent at this moment.

Code_Aster

Version

8.2

Titrate:

Operator

MECA_STATIQUE

Date:

31/01/06

Author (S):

J. PELLET

Key

U4.51.01-I1

Page

4/6

Instruction manual

U4.5- booklet: Methods of resolution

HT-62/06/004/A

/LIST_INST = litps,

INST_FIN = tf,

The list

litps

produced by

DEFI_LIST_REEL

[U4.34.01] defines the moments for which one

ask for the calculation of a thermomechanical evolution.
Key word INST_FIN makes it possible to calculate only the moments former or equal to tf.

This key word (INST_FIN) compound with the key word “reuse” (control réentrante) allows

to split a long thermomechanical transient.

One will make for example:

resu = MECA_STATIQUE (…

LIST_INST = linst, INST_FIN = 10.,…)

MECA_STATIQUE (reuse = resu, LIST_INST = linst, INST_FIN = 20.,…)
MECA_STATIQUE (reuse = resu, LIST_INST = linst, INST_FIN = 30.,…)

3.3

Key word factor

SOLVEUR

See [U4.50.01].

3.4 Word

key

SENSITIVITY

Activate the calculation of derived from the field of displacement compared to a parameter of the problem.
See [U4.50.02].

3.5 Operand

OPTION

OPTION =/“WITHOUT”

/“SIEF_ELGA_DEPL”

By defect control MECA_STATIQUE calculates the stresses at the points of Gauss (or efforts

generalized for the elements of structure).
The other options of postprocessing will be calculated a posteriori by control CALC_ELEM

[U4.81.01].
If the user indicates OPTION = “WITHOUT”, these stresses will not be calculated and the structure

data produced will be less bulky.

3.6 Operand

INFORMATION

INFORMATION = 1,

Print the main characteristics of the linear systems to solve: a number of unknown factors,
cut matrix.

3.7 Operand

TITRATE

TITRATE = titr,

Titrate that one wants to give to the result [U4.03.01].

Code_Aster

Version

8.2

Titrate:

Operator

MECA_STATIQUE

Date:

31/01/06

Author (S):

J. PELLET

Key

U4.51.01-I1

Page

5/6

Instruction manual

U4.5- booklet: Methods of resolution

HT-62/06/004/A

Examples of calculations

4.1

Static calculation with superposition of 2 loading cases

mest1 = MECA_STATIQUE (

MODEL = Mo, CHAM_MATER = chmat,

CARA_ELEM

carac,

EXCIT = (_F (LOAD = CH1, FONC_MULT = COS),

_F (

CHARGE

ch2

),),

)

4.2

Elastic thermo calculation at various moments

ch_temp = AFFE_CHAR_MECA (

… TEMP_CALCULEE = evoth…) );

mest2 = MECA_STATIQUE (

MODEL = Mo, CHAM_MATER = chmat,

EXCIT

(_F (

CHARGE

ch_temp

_F (LOAD = bloq),),

LIST_INST

litps

)

4.3

Sensitivity to an imposed displacement

psx= DEFI_PARA_SENSI (VALE=7.0)
psy= DEFI_PARA_SENSI (VALE=3.0)

ch=AFFE_CHAR_MECA_F (MODELE=mo,
FACE_IMPO=_F (GROUP_MA=' BORD_SUP', DX=psx, DY=psy))

mest3 = MECA_STATIQUE (

MODEL = Mo, CHAM_MATER = chmat,

EXCIT

_F (

CHARGE

SENSIBILITE= (psx, psychiatrist),)

This calculation will produce the structure of data mest3 of the evol_elas type, containing the field of

displacement penny sle name “DEPL”. It will produce two other structures of data of the type
evol_elas. The first will contain under the name of field “DEPL”, the field of derived from

displacement compared to the parameter psx. The second will contain the derivative compared to
psychological parameter.
The name of these 2 structures is created automatically by the code and remains unknown to the user.
The access to their contents (impression, test, post_releve,…) is done by calling upon the control
corresponding with the name of the main structure, mest3, and the name of the significant parameter
concerned (psx or psychiatrist).

5 Remark

For certain studies in linear elasticity for which characteristics of rigidity of
structure are independent of the thermal history and the boundary conditions kinematics
independent of the other loads, one can determine the deformations for several cases of
loading while using

MACRO_ELAS_MULT

[U4.51.02].