Code_Aster ®
Version
5.0
Titrate:
SDLX03 Assemblage of braced thin rectangular plates
Date:
23/01/00
Author (S):
B. QUINNEZ Key
:
V2.05.003-D Page:
1/8

Organization (S): EDF/IMA/MN

Handbook of Validation
V2.05 booklet: Linear dynamics of the assembled structures
Document: V2.05.003

SDLX03 - Assemblage of rectangular plates
thin braced

Summary:

This three-dimensional problem consists in seeking the frequencies of vibration of a mechanical structure
composed of an assembly of plates where one simulated an effect of stiffening. This test of Mécanique of
Structures corresponds to a dynamic analysis of an assembled structure having a linear behavior. It
includes/understands two modelings.

Via this problem, one tests the element of plate DKT as well as the calculation of the frequencies of
vibration by the method of Lanczos with detection of the modes of rigid body.

In the second modeling, one tests in more the connection between hulls (key word LIAISON_COQUE of
order AFFE_CHAR_MECA).

The results obtained are in concord with the results given in guide VPCS (average of results
obtained by various computer codes). The six modes of rigid body were indeed detected.
A comparison with experimental results is also satisfactory.

Handbook of Validation
V2.05 booklet: Linear dynamics of the assembled structures
HI-75/01/010/A

Code_Aster ®
Version
5.0
Titrate:
SDLX03 Assemblage of braced thin rectangular plates
Date:
23/01/00
Author (S):
B. QUINNEZ Key
:
V2.05.003-D Page:
2/8

1
Problem of reference

1.1 Geometry

0.005
0.2
0.05
0.05
(lengths
0.375
0.025
0.075
in meters)
1/2 cross section


Thickness of all the plates:
T = 0.005 m

Plates higher and lower:
length has = 0.375 m
dispatcher B = 0.2 m

Vertical plates:
length has = 0.375 m
width B = 0.05 m

1.2
Properties of materials

E = 2.1 1011 Pa

= 0.3

= 7.800. kg/m3

1.3
Boundary conditions and loadings

Free structure in any point.

1.4 Conditions
initial

Without object for the modal analysis.
Handbook of Validation
V2.05 booklet: Linear dynamics of the assembled structures
HI-75/01/010/A

Code_Aster ®
Version
5.0
Titrate:
SDLX03 Assemblage of braced thin rectangular plates
Date:
23/01/00
Author (S):
B. QUINNEZ Key
:
V2.05.003-D Page:
3/8

2
Reference solution

2.1
Method of calculation used for the reference solution

The reference solution is that given in card SDLX03/89 of guide VPCS.

The reference solution was obtained by experimental study of the frequencies and clean modes
free structure on a model produced with welded sheets.
The structure suspended by flexible connections is put in vibration by a discharger
electrodynamics. The statement of the Eigen frequencies is obtained starting from an accelerometer.

In addition, of the digital simulations, carried out by various computer codes, allowed to establish
“results of reference” for the models finite elements.

2.2
Results of reference

the first 6 nonnull Eigen frequencies.

2.3
Uncertainty on the solution

Lower than 4%.

2.4 References
bibliographical

[1]
Tests carried out by Société METRAVIB (64 Chemin of Mouilles - LP 182 - 69132 Ecully
Cedex - France). Report/ratio METRAVIB R.D.S. n° 1.604.50 (1987).

Handbook of Validation
V2.05 booklet: Linear dynamics of the assembled structures
HI-75/01/010/A

Code_Aster ®
Version
5.0
Titrate:
SDLX03 Assemblage of braced thin rectangular plates
Date:
23/01/00
Author (S):
B. QUINNEZ Key
:
V2.05.003-D Page:
4/8

3 Modeling
With

3.1
Characteristics of modeling

Elements of hull DKT
Z
509 508
X
y
502
419
409
501
491
408
201
109
191
108
402401
102 101
origins of the axes = center of the structure


Cutting:

Plates higher and lower
10 in length
==> 160 meshs TRIA3
8 in width



Vertical plates
10 in length
==> 20 meshs TRIA3
1 in width
Names of the nodes:

Lower plate:
N101,…, N109
N111,…, N119
...........................
N201,…, N209

Higher plate:
N401,…, N409
N411,…, N419
...........................
N501,…, N509

Vertical plates:
N102, N112,…, N202
N402, N412,…, N502

N108, N118,…, N208
N408, N418,…, N508

3.2
Characteristics of the grid

A number of nodes:
198
A number of meshs and types:
360 TRIA3

3.3 Functionalities
tested

Commands



Keys
AFFE_CARA_ELEM HULL

TOUT [U4.24.01]
AFFE_MATERIAU ALL


[U4.23.02]
“MECHANICAL” AFFE_MODELE
“DKT”
TOUT
[U4.22.01]
DEFI_MATERIAU ELAS


[U4.23.01]
MODE_ITER_SIMULT METHOD
“TRI_DIAG”

[U4.52.01]
CALC_FREQ
OPTION
“BANDE”


FREQ



NMAX_FREQ


Handbook of Validation
V2.05 booklet: Linear dynamics of the assembled structures
HI-75/01/010/A

Code_Aster ®
Version
5.0
Titrate:
SDLX03 Assemblage of braced thin rectangular plates
Date:
23/01/00
Author (S):
B. QUINNEZ Key
:
V2.05.003-D Page:
5/8

4
Results of modeling A

4.1 Values
tested

Command of
Reference
Model reference
Aster
% difference/
experimental clean mode
finite elements *
model elements
finished
7
606.
584. ± 1%
590.0310
1.03
8
760.
826. ± 1.5%
829.4009
0.41
9
865.
855. ± 1.7%
848.1548
­ 0.80
10
944.
911. ± 2%
908.8566
­ 0.23
11
1113.
1113. ± 3.6%
1097.6578
­ 1.38
12
1144.
1136. ± 4%
1164.0088
2.46

* average of 5 computer codes

4.2 Remarks

Calculations carried out by:

MODE_ITER_SIMULT
METHODE: “TRI_DIAG”

OPTION
“BANDE”
LIST_FREQ:
(1., 1200.)

DIM_SOUS_ESPACE:
12

4.3
Contents of the file results

The first 6 nonnull Eigen frequencies (clean vectors and modal parameters).

4.4 Parameters
of execution

Version: 5.02



Machine: SGI Origin 2000



Obstruction memory:
64 Mo
Time CPU To use: 2.42 seconds

Handbook of Validation
V2.05 booklet: Linear dynamics of the assembled structures
HI-75/01/010/A

Code_Aster ®
Version
5.0
Titrate:
SDLX03 Assemblage of braced thin rectangular plates
Date:
23/01/00
Author (S):
B. QUINNEZ Key
:
V2.05.003-D Page:
6/8

5 Modeling
B

5.1
Characteristics of modeling

One uses elements of plate DKT

P16
P15
Z
P
y
P
23
8
P22
P14
P
P
7
24
P
P
X
21
13
P
P10
P
P
P
9
11
P12
6
9
P
P
5
X
X
2.5 10-3
P
P
10
20
19
P1
P20
P17
P
P11
2.5 10-3
P18
P
17
P
P
2
12
19
P
P2
P
P
1
4
P
18
0.025
0.15
0.025
3
P4
front view


Cutting is done in the following way:

There is 1
element between P1 and P2

6
elements between P2 and P3

1
element between P3 and P4

1
element between P17 and P20

10 elements according to sides' parallel with y (P4 P5 for example)

2 calculations are passed:

·
in the first calculation, one establishes connections of solid body between the lines:

- P2 P7 and P17 P22
- P3 P6 and P18 P21
- P10 P15 and P20 P23
- P11 P14 and P19 P24

via the key word factor “LIAISON_COQUE” of command AFFE_CHAR_MECA.

·
in the second calculation, one establishes connections of solid body between the nodes in with respect to
above mentioned line couples via the key word factor “LIAISON_SOLIDE” of the command
AFFE_CHAR_MECA.

5.2
Characteristics of the grid

A number of nodes:
242
A number of elements TRIA3:
360

5.3 Functionalities
tested

Commands



Keys
AFFE_CHAR_MECA
LIAISON_SOLIDE LIAISON_COQUE [U4.25.01]
AFFE_CARA_ELEM HULL
²
TOUT
[U4.24.01]
AFFE_MATERIAU ALL


[U4.23.02]
“MECHANICAL” AFFE_MODELE
“DKT”
TOUT
[U4.22.01]
DEFI_MATERIAU ELAS


[U4.23.01]
MODE_ITER_SIMULT METHOD
“TRI_DIAG”

[U4.52.01]
CALC_FREQ
OPTION
“BANDE”


FREQ



NMAX_FREQ


Handbook of Validation
V2.05 booklet: Linear dynamics of the assembled structures
HI-75/01/010/A

Code_Aster ®
Version
5.0
Titrate:
SDLX03 Assemblage of braced thin rectangular plates
Date:
23/01/00
Author (S):
B. QUINNEZ Key
:
V2.05.003-D Page:
7/8

6
Results of modeling B

The results of 2 calculations (one with LIAISON_COQUE, the other with LIAISON_SOLIDE) are
identical. One will mention only calculation with LIAISON_COQUE.

6.1 Values
tested

Command of
Reference
Model reference
Aster
% difference/
experimental clean mode
finite elements *
model elements
finished
7
606.
584. ± 1%
610.2
4.5
8
760.
826. ± 1.5%
852.4
3.2
9
865.
855. ± 1.7%
864.8
1.1
10
944.
911. ± 2%
923.9
1.4
11
1113.
1113. ± 3.6%
1110.8
­ 0.2
12
1144.
1136. ± 4%
1179.5
3.8

* average of 5 computer codes

6.2 Remarks

Calculations carried out by:

MODE_ITER_SIMULT
METHODE: “TRI_DIAG”

OPTION
“BANDE”
LIST_FREQ:
(1., 1200.)

DIM_SOUS_ESPACE:
12

6.3
Contents of the file results

The first 6 nonnull Eigen frequencies (clean vectors and modal parameters).

6.4 Parameters
of execution

Version: 5.02



Machine: SGI Origin 2000



Obstruction memory:
28 Mo
Time CPU To use: 8.7 seconds

Handbook of Validation
V2.05 booklet: Linear dynamics of the assembled structures
HI-75/01/010/A

Code_Aster ®
Version
5.0
Titrate:
SDLX03 Assemblage of braced thin rectangular plates
Date:
23/01/00
Author (S):
B. QUINNEZ Key
:
V2.05.003-D Page:
8/8

7
Summary of the results

For the modeling A, the results provided by Code_Aster are in the interval of dispersion of
codes which made it possible to establish the reference solution VPCS.

For modeling B, the two ways of writing the connection between the hulls give the same ones
results.
Handbook of Validation
V2.05 booklet: Linear dynamics of the assembled structures
HI-75/01/010/A

Outline document