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How to export mass and stiffness matrices of a large model?

JohLut
Hi,
 
up to now, I've applied the command EXTSEOUT (STIFFNESS MASS ASMBULK EXTID = 10 DMIGPCH) to get the matrices as a byproduct of the superelement reduction process.
This is ok for models of moderate size.
 
However, this approach seems not reasonable for rather large models (~1.000.000 nodes) as the intermediate files like *.DBALL are blown up to more than 16 GB and the computations take ages.
 
Since I'm not interested in the external superelement itself I'm wondering if there might be a simpler way to export the system matrices without extensive reduction computations.
 
Best regards,
Johannes
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  • 0
    That is correct- I think the best option is to use the USET print to the f06 and read that output with a python script or some other tool. Check out the following two parameters and play around with the options.
     
    PARAM,USETPRT,2
    PARAM,USETSTR1,A
     
    You will see a couple different formats printed to the f06, but here is one that is 'compact' and lists the grid id/DOF in ASET order.
     
                   U S E T  D E F I N I T I O N  T A B L E  ( I N T E R N A L  S E Q U E N C E ,  R O W  S O R T )
                                                          A       DISPLACEMENT SET
    0              -1-       -2-       -3-       -4-       -5-       -6-       -7-       -8-       -9-      -10-
     
         1=       2-1       2-2       2-3       2-4       2-5       2-6       3-1       3-2       3-3       3-4   =   10
        11=       3-5       3-6       4-1       4-2       4-3       4-4       4-5       4-6       5-1       5-2   =   20
        21=       5-3       5-4       5-5       5-6       6-1       6-2       6-3       6-4       6-5       6-6   =   30
        31=       7-1       7-2       7-3       7-4       7-5       7-6       8-1       8-2       8-3       8-4   =   40
        41=       8-5       8-6       9-1       9-2       9-3       9-4       9-5       9-6      10-1      10-2   =   50
        51=      10-3      10-4      10-5      10-6    9001-0    9002-0    9003-0    9004-0    9005-0
     
Reply
  • 0
    That is correct- I think the best option is to use the USET print to the f06 and read that output with a python script or some other tool. Check out the following two parameters and play around with the options.
     
    PARAM,USETPRT,2
    PARAM,USETSTR1,A
     
    You will see a couple different formats printed to the f06, but here is one that is 'compact' and lists the grid id/DOF in ASET order.
     
                   U S E T  D E F I N I T I O N  T A B L E  ( I N T E R N A L  S E Q U E N C E ,  R O W  S O R T )
                                                          A       DISPLACEMENT SET
    0              -1-       -2-       -3-       -4-       -5-       -6-       -7-       -8-       -9-      -10-
     
         1=       2-1       2-2       2-3       2-4       2-5       2-6       3-1       3-2       3-3       3-4   =   10
        11=       3-5       3-6       4-1       4-2       4-3       4-4       4-5       4-6       5-1       5-2   =   20
        21=       5-3       5-4       5-5       5-6       6-1       6-2       6-3       6-4       6-5       6-6   =   30
        31=       7-1       7-2       7-3       7-4       7-5       7-6       8-1       8-2       8-3       8-4   =   40
        41=       8-5       8-6       9-1       9-2       9-3       9-4       9-5       9-6      10-1      10-2   =   50
        51=      10-3      10-4      10-5      10-6    9001-0    9002-0    9003-0    9004-0    9005-0
     
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