calcul Sineon Random

[wba2025]

j'ai un calcul sine on random sur une structure, j'ai mis les matériaux les chargements, les step de calcul (frequency, puis random response et sine tone (steady state dynamic)
des le debut j'ai postratié les premières fréquences propres de psd, j'ai trouvé des valeur pour S11, S22,... environ 10E-4 et les RMSmises ou RS sont de l'ordre de 10E25
j'ai bien vérifié les unités (densité , psd definition amplitude avec g=9810) j'arrive pas à trouvé la cause de cette contrainte trop élevée
cidessous extrait de fichier inp (partie finale)
*End Assembly
*Psd-definition, name=PSD_Endurance, g=9810., type=BASE
0., 0., 10.
0.02, 0., 10.
0.02, 0., 300.
0.002, 0., 2000.
0., 0., 2000.
*Psd-definition, name=PSD_Performance, g=9810., type=BASE
0., 0., 10.
0.01, 0., 10.
0.01, 0., 300.
0.001, 0., 2000.
0., 0., 2000.
*Amplitude, name=Sine_Endurance
0., 0., 21.2, 0., 21.3, 4., 21.4, 0.
42.5, 0., 42.6, 4.3, 42.7, 0., 83.4, 0.
83.5, 8.4, 83.6, 0., 360.9, 0., 361., 20.
361.1, 0.
*Amplitude, name=Sine_Performance
0., 0., 21.2, 0., 21.3, 1.7, 21.4, 0.
42.5, 0., 42.6, 3.4, 42.7, 0., 83.4, 0.
83.5, 6.7, 83.6, 0., 360.9, 0., 361., 16.7
361.1, 0.
**
** MATERIALS
**
*Material, name="AISI 304 s"
*Density
7.9e-09,
*Elastic
200000., 0.27
*Plastic
179.3, 0.
503.3, 0.4
*Material, name="AISI 321"
*Density
7.9e-09,
*Elastic
200000., 0.27
*Plastic
151.69, 0.
468.86, 0.4
*Material, name="Alu 3103 H12"
*Density
2.7e-09,
*Elastic
70000., 0.33
*Plastic
90., 0.
130., 0.097
*Material, name="Alu 5052 H32"
*Density
2.7e-09,
*Elastic
69634., 0.33
*Plastic
158.5, 0.
213.7, 0.07
*Material, name="Alu 6061 T6"
*Density
2.71e-09,
*Elastic
68258., 0.33
*Plastic
241.3, 0.
262., 0.1
*Material, name=Flexible
*Density
1.31e-09,
*Elastic, type=ENGINEERING CONSTANTS
10., 100., 60., 0.05, 0.05, 0.3, 4.76, 4.76
38.5,
** Silicone HT + Tresse de verre
*Material, name=Gaine640
*Density
2.16e-09,
*Elastic
3570., 0.32
*Material, name=Rubber
*Density
1.3e-09,
*Elastic
2.999, 0.4996
*Material, name=ZAT_3103_6061
*Density
2.7e-09,
*Elastic
68000., 0.33
*Plastic
70., 0.
150., 0.15
**
** BOUNDARY CONDITIONS
**
** Name: B_P1 Type: Symmetry/Antisymmetry/Encastre
*Boundary
B_P1, ENCASTRE
** Name: B_P2 Type: Symmetry/Antisymmetry/Encastre
*Boundary
B_P2, ENCASTRE
** Name: Bride_Brasee_1 Type: Symmetry/Antisymmetry/Encastre
*Boundary
B_BrideBrasee_1, ENCASTRE
** Name: Bride_Brasee_2 Type: Symmetry/Antisymmetry/Encastre
*Boundary
B_BrideBrasee_2, ENCASTRE
** Name: Bride_Fix Type: Symmetry/Antisymmetry/Encastre
*Boundary
B_BrideFixe, ENCASTRE
** ----------------------------------------------------------------
**
** STEP: Frequency
**
*Step, name=Frequency, nlgeom=NO, perturbation
*Frequency, eigensolver=Lanczos, normalization=mass
20, , , , ,
**
** OUTPUT REQUESTS
**
*Restart, write, frequency=0
**
** FIELD OUTPUT: F-Output-1
**
*Output, field
*Node Output
U,
*Element Output, directions=YES
MISES,
*End Step
** ----------------------------------------------------------------
**
** STEP: PSD
**
*Step, name=PSD, nlgeom=NO, perturbation
*Random Response
10., 2000., 20, 3.,
*Modal Damping
1, 20, 0.02
**
** BOUNDARY CONDITIONS
**
** Name: PSD Type: Acceleration base motion
*Base Motion, type=ACCELERATION, dof=1, scale=1., load case=6
*Correlation, type=CORRELATED, psd=PSD_Performance, complex=NO
6, 1.
**
** OUTPUT REQUESTS
**
**
** FIELD OUTPUT: F-Output-2
**
*Output, field
*Node Output
A,
*Element Output, directions=YES
RMISES, RS,
*Output, history, frequency=0
*End Step
** ----------------------------------------------------------------
**
** STEP: Sine_Tones
**
*Step, name=Sine_Tones, nlgeom=NO, perturbation
*Steady State Dynamics
20., 400., 20, 3.
*Modal Damping
1, 20, 0.02
**
** BOUNDARY CONDITIONS
**
** Name: Sine_Tones Type: Acceleration base motion
*Base Motion, type=ACCELERATION, dof=1, amplitude=Sine_Performance, scale=9810.
**
** OUTPUT REQUESTS
**
**
** FIELD OUTPUT: F-Output-3
**
*Output, field
*Node Output
A, TA, U
*Element Output, directions=YES
E, MISES, S
*Output, history, frequency=0
*End Step

 

[WKTaylor]

Posted by wba2025 Student

Our attempt to translate this intent would be poor at best, terrible at worst.

I recognize the 'physical materials' in your code-lines... but have no context as to the INTENT of the code.

E-T is not a forum for students and their work/homework.... with exception of the student forum. We are focused professionals, and most of us are working.

 

[rb1957]

to be fair, this is the student forum. But not many French speakers.

 

[GregLocock]

I have a sine-on-random calculation on a structure. I entered the materials, the loads, the calculation steps (frequency, then random response and sine tone (steady state dynamics).
From the beginning, I post-rated (?) the first natural frequencies of the PSD. I found values for S11, S22, etc., around 10E-4, and the RMS values or RS values are around 10E25.
I checked the units (density, PSD definition amplitude with g=9810). I can't find the cause of this excessively high stress.
Below is an extract from the INP file (final part).

First thing to do is run a static analysis and check that it agrees with your estimated stiffness, and that stresses are reasonable. Also check your damping.