#1 2012-04-04 17:19:39

Johannes_ACKVA

Member

From: Ingenieurbüro für Mechanik, DE

Registered: 2009-11-04

Posts: 763

Website

Defi_list_freq ?

Dear developpers,

a proposal: when doing a harmonic analysis the list of exciting frequencies should also contain the exact eigenfrequencies of the system (which must be calculated before). As far as I know  there is not a command

list=DEFI_LIST_FREQ
    (RESULTAT=modes,
     LOWER_BOUND=1.,
     UPPER_BOUND=1000.,
    N_PER_MODE=7.
    SPREAD = 4.)
    ..

with
RESULTAT   resultat of a modal analysis
LOWER_BOUND lower bound of freq range
UPPER_BOUND upper bound of freq range
N_PER_MODE  number of evenly spaced exciting frequencies per eigenfrequency, the 4th is the eigenfreq.
SPREAD   range of spread of the evenly spaced N_PER_MODE values per eigenfrequency

which creates such a list in an automatic manner from a modal resultat.

Such a command exists for example in Nastran (bulk data keyword FREQ4).
Could it be realized for Code-Aster?

Johannes Ackva
______________________________________________________________________
Ingenieurbüro für Mechanik
Dr.-Ing. Johannes Ackva
Markgrafenstr. 21
D 91717 Wassertrüdingen

______________________________________________________________________
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D 91717 Wassertrüdingen / Germany

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Yvon Goth

Member

Registered: 2007-11-26

Posts: 20

Re: Defi_list_freq ?

Hi,

While some fast and dirty python such as

dico = MODE.LIST_VARI_ACCES()
fmod=dico['FREQ']
frq=list(N.linspace(fmin,fmax,nmbre))
for f in fmod:
     frq.append(f)
frq.sort()
LiF=DEFI_LIST_REEL(VALE=frq )

would help,

I agree with Johannes proposal. This function is needed every time we want to compute the dynamic response of a structure, and it would be helpfull to integrate it in the part of the code under QA. Nice suggestion.

Regards

Yvon Goth

AsterO'dactyle

Administrator

Registered: 2007-11-29

Posts: 465

Re: Defi_list_freq ?

Yes, it's a good idea.
Thank you for your suggestion !

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Code_Asterの開発者

Thomas DE SOZA

Guru

From: EDF

Registered: 2007-11-23

Posts: 3,066

Re: Defi_list_freq ?

Hi,

This feature is now available in Code_Aster starting from version 12.015. See this news for more details.

TdS