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

JohLut
I'd like to export mass and stiffness matrices of a constrained model (e.g. MPC applied) and retain information on the ASET, i.e. the independent degrees of freedom. Is that possible somehow?
 
Up to now I've used to obtain the relevant matrices only under free-free conditon by using PARAM,EXTOUT,DMIGPCH
 
Best regards,
Johannes
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  • 0
    You can also do this using an Alter (if you have DMAP in your licensing)… the alter below will print and punch the MAA and KAA matrices (if you do not want it to print, just remove the MATGPR lines). Insert this alter just before the CEND line of the Nastran input file:
     
    MALTER 'MALTER.*KAA.*MAA.*' $
    MATGPR GPLS,USET0,SILS,MAA//'A' $
    MATGPR GPLS,USET0,SILS,KAA//'A' $
    MATMOD KAA,EQEXINS,USET,,,/,/16/1/1/s,n,dum1/////////'KAAEXT'/'A' $
    MATMOD MAA,EQEXINS,USET,,,/,/16/1/1/s,n,dum2/////////'MAAEXT'/'A' $
     
    Test it out with the attached sample.
    Attached Files (1)
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  • 0
    You can also do this using an Alter (if you have DMAP in your licensing)… the alter below will print and punch the MAA and KAA matrices (if you do not want it to print, just remove the MATGPR lines). Insert this alter just before the CEND line of the Nastran input file:
     
    MALTER 'MALTER.*KAA.*MAA.*' $
    MATGPR GPLS,USET0,SILS,MAA//'A' $
    MATGPR GPLS,USET0,SILS,KAA//'A' $
    MATMOD KAA,EQEXINS,USET,,,/,/16/1/1/s,n,dum1/////////'KAAEXT'/'A' $
    MATMOD MAA,EQEXINS,USET,,,/,/16/1/1/s,n,dum2/////////'MAAEXT'/'A' $
     
    Test it out with the attached sample.
    Attached Files (1)
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