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#1 2017-11-02 00:02:54

xwang
Member
Registered: 2017-05-17
Posts: 11

dynamic linear analysis with excited harmonic sound pressure

Hello,

I would like to simulate my linear model with a sinusoid sounds pressure with frequency equals to 2kHz, I've used the macro named ASSEMBLAGE to define the M, K,C and the DYNE_LINE_HARM to describe the model and the sounds pressure I would like to use. But it seems like having some errors with it. Could you please help me to check the attached *comm file and let me know where I should correct? Thanks for your time and help!

Xuan


Attachments:
dal160211_j_all_15_mir_dyn.comm, Size: 6.57 KiB, Downloads: 9

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#2 2017-11-02 17:16:09

Johannes_ACKVA
Member
From: Ingenieurbüro für Mechanik, DE
Registered: 2009-11-04
Posts: 643
Website

Re: dynamic linear analysis with excited harmonic sound pressure

your .comm file is rather complicated. You should add at least a .mess-file pointing to the problems appearing, this makes it easier to help you

Regards
Johannes_ACKVA

_________________________________________________________
CODE-ASTER-courses at Ingenieurbüro für Mechanik, Germany

*** CODE-ASTER  DYNAMIC ANALYSIS
     30 Nov - 01 Dec 2017

*** CODE-ASTER  INTRODUCTION
     05 Feb - 09 Feb 2018


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#3 2017-11-02 20:20:08

xwang
Member
Registered: 2017-05-17
Posts: 11

Re: dynamic linear analysis with excited harmonic sound pressure

Hello Johannes,

Attached is my *mess file, please let me know what additional information you might need. Thanks for your help.

Xuan


Attachments:
mes.mess, Size: 21.89 KiB, Downloads: 8

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#4 2017-11-03 11:25:57

Johannes_ACKVA
Member
From: Ingenieurbüro für Mechanik, DE
Registered: 2009-11-04
Posts: 643
Website

Re: dynamic linear analysis with excited harmonic sound pressure

xwang,
the error message says:
- or the file with your mesh does not exist
- or it is in a wrong .med-version

Your .export file contains the list of all files engaged as input or output in the Code-Aster run. It must contain such a line:

F med   path-to-your-working-directory/your-mesh-file.med  D  20

Essential is the  "D" which means "input file" and the unity "20", because this is the file number from which the command LIRE_MAILLAGE(...UNITE=20,..) tries to read (see in your .mess-file).

If the file entry exists then the cause is the wrong .med-version of your mesh-file. This can happen if for example you created the mesh with SalomeMeca2017, but used for the analysis a Code-Aster-version of SalomeMeca2016. In your case: from the .mess-file I see that Code-Aster is version 12.6. Which is part of SalomeMeca2016. So use also  SalomeMeca2016 to create the mesh. To check the .med-version afterwards: Open SalomeMeca, activate Mesh Module, File-import-Medfile, highlight the imported mesh-object, right-mouse-click, MED-File-Information

Regards
Johannes_ACKVA

_________________________________________________________
CODE-ASTER-courses at Ingenieurbüro für Mechanik, Germany

*** CODE-ASTER  DYNAMIC ANALYSIS
     30 Nov - 01 Dec 2017

*** CODE-ASTER  INTRODUCTION
     05 Feb - 09 Feb 2018


Ingenieurbüro für Mechanik
D 91717 Wassertrüdingen / Germany

www.code-aster.de                                                Training & Support for NASTRAN and CODE-ASTER

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#5 2017-11-03 20:46:09

xwang
Member
Registered: 2017-05-17
Posts: 11

Re: dynamic linear analysis with excited harmonic sound pressure

Thanks, Johannes,

I've modified my *comm file but still having an error which requires using the keyword PARTIE. I am not exactly sure where went wrong. As I defined the sinusoid sound pressure frequency as 2000Hz using "FREQ=2000". I am thinking of defining the timespan and time step for the simulation as I defined those parameters in the variable "TimeStps" but I am not quite sure how I could properly use this in DYNA_LINE_HARM. One of my guessings is you don't need to specify the timespan and time steps for the simulation. Code-aster will calculate and assign the proper values depending on the different cases. Am I right? Now I get the error message which requires using the keyword "PARTIE" if I understand it correctly. But I do not quite understand where goes wrong and where should I modify my comm file. I've attached my new *comm file and * mess file for your reference. Could you please provide more advice on this? Thanks so much!

Xuan


Attachments:
xuan_model.tar.gz, Size: 11.26 KiB, Downloads: 8

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#6 2017-11-03 21:56:52

konyaro
Member
From: Genève
Registered: 2016-04-02
Posts: 62

Re: dynamic linear analysis with excited harmonic sound pressure

If you read carefully the error message and the doc U7.05.21, you will notice that it's not possible to write complex fields with IMPR_RESU. You need to choose between the real or imaginary part, cf. §5.7.
(PARTIE=’REEL’ or PARTIE=’IMAG’ inside your IMPR_RESU command)


失敗は成功のもと (L'échec est la base de la réussite)

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#7 2017-11-14 00:50:44

xwang
Member
Registered: 2017-05-17
Posts: 11

Re: dynamic linear analysis with excited harmonic sound pressure

Thanks Konyaro,

I've edited my file according to u4.53.03, the operator of DYNA_VIBRA, however, I've run into the issue that the SCHEMA_TEMPS is not recognized. I assume this operator is to define the alpha and beta for my Rayleigh damping right? I've attached my *comm and *mess files for your reference, thanks for your help in advance!

Xuan

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#8 2017-11-14 09:45:27

Johannes_ACKVA
Member
From: Ingenieurbüro für Mechanik, DE
Registered: 2009-11-04
Posts: 643
Website

Re: dynamic linear analysis with excited harmonic sound pressure

xwang

in DYNA_VIBRA(.. SCHEMA_TEMPS( SCHEMA='nameofthemethod',  BETA, GAMMA  ..    you choose the integration method and BETA, GAMMA are parameters to tune certain integration methods. The Rayleigh-damping is done in a different place: with

mat=DEFI_MATERIAU(ELAS=_F(E=2.1e+11, NU=0.3,  RHO=7850.0,
                          AMOR_ALPHA=alfa, AMOR_BETA=beta,),);

then creating the damping matrix

ASSEMBLAGE(MODELE=model,
....
           MATR_ASSE=(_F(MATRICE=CO('Stiffn'),
                         OPTION='RIGI_MECA',),
                      _F(MATRICE=CO('Mass'),
                         OPTION='MASS_MECA',),
                      _F(MATRICE=CO('Damping'),
                         OPTION='AMOR_MECA',),),);


and including it to the  analysis command

Tran=DYNA_VIBRA(MATR_MASS=Mass ,   MATR_RIGI=Stiffn,  MATR_AMOR=Damping

The reason of your confusion might be that some integration methods show also a damping behaviour. This is often called "numerical damping". It is unwished and has nothing to do with the physical damping (rayleigh, modal, hysteretic, .., damping elements, viscous behaviour) which the user tries to model

Regards
Johannes_ACKVA

_________________________________________________________
CODE-ASTER-courses at Ingenieurbüro für Mechanik, Germany

*** CODE-ASTER  DYNAMIC ANALYSIS
     30 Nov - 01 Dec 2017

*** CODE-ASTER  INTRODUCTION
     05 Feb - 09 Feb 2018


Ingenieurbüro für Mechanik
D 91717 Wassertrüdingen / Germany

www.code-aster.de                                                Training & Support for NASTRAN and CODE-ASTER

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