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Huge calculation time with stress output (FEMAP 9.3.1 with NX.Nastran 5.1)

hello,
a linear static  analysis with stress output using FEMAP 9.3.1 bzw NX.Nastran 5.1 is very slow. In  .f04-file I see that Nastran Modul SDR2 has a huge I/O-Transfer, about 130GB (mesh having 81997 Tet4-elm). This module does (if I understand well) Postprocessing  (calc of stress), thus the global matrix is already solved before (about 1 minute solution time). Due to the large I/O-Volume the complete run needs 20 minutes (19 min only for this I/O-Transfer).
 
The computer is Windows XP 64bit with  8GB RAM. I tried sustituted the memory-estimate of Nastran with MEM=4Gb (and tried also other values), but no effect. BUFFSIZE=8193
 

With another installation (Femap11.0 with Nastran8.5 on Win7 64bit) the I/O-Tranfer is much smaller and needs only a few secons, causing a run time of <1min.

 

I would like also to use my older license (FEMAP 9.3.1 bzw NX.Nastran 5.1), so my question is:

 

Is there any means (parameter, configuration, ?) to do the run faster with my old installation?

 

Thank You for Your help, best regards,
Johannes Ackva
3 REPLIES
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Accepted by topic author johannes_
‎08-26-2015 04:32 AM

Re: Huge calculation time with stress output (FEMAP 9.3.1 with NX.Nastran 5.1)

Hi,

 

   Windows XP has poor I/O performance. You can probably add multiple SSD disk drives to alleviate this issue. The disk drives need to be software RAID striped (RAID0).

 

  The only other alternative is to reduce the amount of stress output requested.

 

   Can you update to the recent released version of NX Nastran (version 9.0)?

 

EaswaranV

Solution
Solution
Accepted by topic author johannes_
‎08-26-2015 04:32 AM

Re: Huge calculation time with stress output (FEMAP 9.3.1 with NX.Nastran 5.1)

Dear Johannes,

You are solving a model using a very old NX NASTRAN 5.1 solver on a "modern" Windows XP x64 bits pltaform (well, XP is considered obsolete just now). But please check if your NX NASTRAN 5.1 is for sure running as a 32-bits application in a x64-bit platform, in this case not matter if you have 8 GB RAM because the NX NASTRAN 5.1 solver only will address 2 GB RAM per process.

I have revised my records (see my WEB site at http://www.iberisa.com/productos/nxnastran/nx_nastran_v60.htm) and in NX NASTRAN 6.0 of June 2008 -six years ago!!- a mention exist under Numerical Performance "Improved performance for Windows64 and Linux x86-64 platforms", but with NX Nastran 5.0 of April 2007 not any mention exist, then I don't know if the solver take advanced of x64 platforms with RAM memory above 2 GB RAM.

 

In summary, NX NASTRAN 5.1 is a very old solver, with serious limitations in hardware architecture, I don't know the reason why you try to use such quite old version, but if you are running a 32-bits solver, then the use of MEM=4GB is useless at all. I suggest to update to NX NASTRAN 9.0 modern version.

 

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: Huge calculation time with stress output (FEMAP 9.3.1 with NX.Nastran 5.1)

EaswaranV and Blas Molero,
thank You for Your answers and suggestions which helped me to get more clear. Probably the best solution for me will be to update the software