7.14.       WRITE_GPKE Alter

 

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$  Rigid Format 103 - Normal modes analysis

$  MSC/NASTRAN Version 2001 or NX Nastran Version 1.0

$

$

$     ******************************************************

$     *****            COPYRIGHT  (C)  2003            *****

$     *****          BY ATA ENGINEERING INC.           *****

$     *****             ALL RIGHTS RESERVED            *****

$     ******************************************************

$

$     09-03- ATA/Paul Blelloch

$

$  Description:

$

$  This alter writes Grid Point Kinetic Energy (GPKE) results in DMIG format

$  to the .pch file.  It also optionally calculates GPKE on A-set rather than

$  G-set matrices as follows:

$

$  GPKE = (MAA*UA).*UA

$

$  WHERE:

$

$  MAA     - Mass matrix reduced to A-set (F-set if no ASET cards in model)

$  UA      - Mode shapes partitioned to A-set

$

$  GPKE results are merged back to the G-set for output processing, but will

$  only be non-zero on A-set DOF.  They will still have the property that the

$  sum of GPKE for any mode will be 100.  The THRESH qualifier on the GPKE card

$  still applies.

$

$  Note that MAA is not usually a diagonal matrix, even in the case of a lumped

$  mass formulation.  This may result in unusual GPKE results in some cases.

$

$  The major difference in using this alter is that only DOF with non-zero GPKE,

$  or with GPKE above the threshhold value set by the user are written to the

$  .pch file.  This can result in a significantly shorter and easier to interpret

$  .pch file.

$

$  The GPASET option in this alter is designed to facilitate selection of

$  important DOF using GPKE.   The difference is that the default calculation

$  will include all DOF in the model, so DOF in the M-set  may have large GPKE.

$  The user can either modify the model to move these DOF into the A-set or use

$  this alter to find equivalent DOF that are already in the A-set.

$

$  If the user includes a PRINT (default) or PUNCH option on the GPKE card, the

$  results will be written in the standard format to either the .f06 or .pch

$  files as well as the DMIG results written by this alter.  The NOPRINT option

$  should therefore be selected.

$

$  Special instructions to use this alter:

$-----------------------------------------------------------------------

$  FILE MANAGEMENT SECTION (FMS)

$

$    None

$

$-----------------------------------------------------------------------

$  EXECUTIVE CONTROL DECK

$

$    SOL 103

$    Include this alter immediately before the CEND statement

$

$-----------------------------------------------------------------------

$  CASE CONTROL DECK

$

$    GPKE output must be requested with the NOPRINT option

$

$-----------------------------------------------------------------------

$  BULK DATA DECK

$

$    Optional parameters:

$

$    PARAM,GPASET,CHAR8  'YES' : Calculate GPKE on the A-set

$                        'NO'  : Calcluate GPKE on the G-set (default)

$

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$  EXAMPLE NASTRAN DECKS

$

$    ASSIGN  MASTER='gpsc_fem.MASTER'

$    ASSIGN  DBALL ='gpsc_fem.DBALL'

$    RESTART

$    $

$    SOL     103

$    INCLUDE gpke_aset.v2001

$    CEND

$    $

$    TITLE    = GENERAL PURPOSE SPACECRAFT

$    SUBTITLE = NORMAL MODES DATA RECOVERY RESTART

$    LABEL    = CALCULATE AND WRITE GPKE ON A-SET MATRICES

$    $

$    SPC = 1

$    METHOD = 50                 $ Modes to 50 Hz

$    $

$    GPKE(NOPRINT) = ALL         $ Recover and punch GPKE

$    $

$    BEGIN BULK

$    $

$    PARAM,GPASET,YES

$    $

$    ENDDATA

$

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