Output Mass and Stiffness matrices from NASTRAN? 1

[Onemorechance]

I make a simple beam model in which only stiffness and mass properties are attributed to the beams.
I would like to extract the mass and stiffness matrices for this model. How can I do this?
If possible I would like to have this data available in the F06-file?

 

[pjhype]

It has been a while since I have done this, but I believe you will need to make a "dummy" run to print out the solution rigid format by putting DIAG 14 in your executive control deck. Once you locate the matrices that you want to print out, you will need to place a rigid format ALTER in the executive control, followed by a MATGPR statement (there is a certain format that you need to specify the MATGPR statement that you will need to get from the NASTRAN reference manual). The MATGPR will allow you to print out the global stiffness and mass matrices, KGG and MGG, into your .F06 or .PCH file.

pj

 

[Onemorechance]

Thanks a lot pj,

It is very helpful.

This is how I proceeded to get the desired results. Please comment on it if you think I am not exactly on the right track with what I want to achieve.

From the solution sequence (DIAG 14) I found the first DMAP module that could give me results on MGG and KGG to be SEMODES.



DMAP-DMAP INSTRUCTION
NO.
1 SUBDMAP SEMODES $ SOL 103 - SUPERELEMENT NORMAL MODES
2 $ IFP, PHASE0
2 TYPE DB AXIC,PVT,BULK,GEOM1Q,TIMSIZ,K4JJ,YG,RMG,CASESX,USET0,GEOM1S,
VIEWTB,GPSNTS,BGPDTVU,IBULK,EHT,EHTA,CASERS,PVTBC,EDOM,DRG,
MEDGE,MFACE,GDNTAB,PELSETS,ELEMVOL,PVAL,ERROR,TEMPALL,ERRORG,
$ PHASE 1
KJJ,MJJ,BJJ,USET,GOT,KAA,DYNAMICS,DYNAMIC,KGG,PCDBS,AGG,

… ETC …





Then at line 63 I found an instruction containing the input (GPLS, USET0, SILS) and output data blocks (MGG, KGG) I need:




63 CALL PHASE1DR,
SLIST ,EMAP ,DIT ,MATPOOLS,EDTS ,
DYNAMICS,GEOM4S ,EPTS ,CASECC ,MPTS ,
CASES ,GPLS ,EQEXINS ,CASESX ,CSTMS ,
BGPDTS ,SILS ,ECTS ,MAPS ,PVTS ,
,VGFS ,GDNTAB ,CONTACT ,DEQATN ,
DEQIND ,GPSNTS ,ECTAS ,MEDGE ,EHT ,
RMG ,USET0 ,YG ,SLT ,ETT ,
,EPTA ,EHTA ,SCSTM ,PVTBC ,
, ,EQEXIN , , ,
, ,AG0 , , ,
, , , , ,
DRG , , , /
EST ,GPECT ,VELEM ,KELM ,KDICT ,
MELM ,MDICT ,KJJ ,MJJ ,BJJ ,
K4JJ , , ,KGG ,GM ,
USET ,KSF ,KFS ,KSS , ,
KAA ,MPHVZ ,LOO , ,GOT ,
KLL ,LLL ,ULL ,DAR ,MGG ,
BGG ,K4GG ,MAA , ,MR ,
MLR ,MLL ,MRR ,CMPHA ,CMPHO ,
CMLAMA , ,GOQ , ,MAR ,
MEA , ,BAA ,K4AA , ,
, , , , ,
, ,ESTL ,ESTNL ,AGG ,
BTOPO ,KMG ,MMG ,MSF ,BMG ,
BSF ,K4MG ,K4SF , ,ORSEQ ,
LRSEQ ,VGFD ,DITID , , ,
, , , , ,
,BK4ZZ , , , /
APP /ERROR /LASTSEID/SOLTYP /ALTRED /
CYCLIC /ADPTINDX/NLHEAT /AERO /RSONLY /
LUSETS /SEMG /SEKR /SELG /SELR /
SEMR /FIXEDB /MODACC /INREL /FSCOUP /
NONLNR /K6ROT /AUTOSPC /TRUE /EXTERSE /
PEXIST /FALSE /FALSE /KDIFF /FALSE /
FALSE /' '/FLUIDSE0/0 $


… ETC …




I included the following DMAP alter in the executive control deck:

$
COMPILE SEMODES $
ALTER 63 $
MATGPR GPLS,USET0,SILS,MGG//'G' $
MATGPR GPLS,USET0,SILS,KGG//'G' $
$

This gave me the following results in the .f06 file:



0 MGG
POINT VALUE POINT VALUE POINT VALUE POINT VALUE POINT VALUE


COLUMN 1 ( 1-T1).
1 T1 1.00000E+01

COLUMN 2 ( 1-T2).
1 T2 1.00000E+01

COLUMN 3 ( 1-T3).
1 T3 1.00000E+01

COLUMNS 4 ( 1-R1) THRU 6 ( 1-R3) ARE NULL.

COLUMN 7 ( 2-T1).
2 T1 2.00000E+01

COLUMN 8 ( 2-T2).
2 T2 2.00000E+01

COLUMN 9 ( 2-T3).
2 T3 2.00000E+01

…etc…

0 KGG
POINT VALUE POINT VALUE POINT VALUE POINT VALUE POINT VALUE


COLUMN 1 ( 1-T1).
1 T1 1.05000E+08 1 T3 1.26940E+00 1 R2 -1.05000E+08 2 T1 -1.05000E+08 2 T3 -1.26940E+00
2 R2 -1.05000E+08

COLUMN 2 ( 1-T2).
1 T2 1.05000E+08 1 R1 1.05000E+08 1 R3 1.27365E+00 2 T2 -1.05000E+08 2 R1 1.05000E+08
2 R3 1.27365E+00

COLUMN 3 ( 1-T3).
1 T1 1.26940E+00 1 T3 3.50000E+05 1 R2 -1.27365E+00 2 T1 -1.26940E+00 2 T3 -3.50000E+05
2 R2 -1.27365E+00

COLUMN 4 ( 1-R1).
1 T2 1.05000E+08 1 R1 1.40000E+08 1 R3 1.53899E+00 2 T2 -1.05000E+08 2 R1 7.00000E+07
2 R3 1.00831E+00

COLUMN 5 ( 1-R2).
1 T1 -1.05000E+08 1 T3 -1.27365E+00 1 R2 1.40000E+08 2 T1 1.05000E+08 2 T3 1.27365E+00
2 R2 7.00000E+07

COLUMN 6 ( 1-R3).
1 T2 1.27365E+00 1 R1 1.53899E+00 1 R3 1.31253E+07 2 T2 -1.27365E+00 2 R1 1.00831E+00
2 R3 -1.31253E+07



…etc…




I hope I am doing it right?
Thanks again,
Regards,

Onemorechance