$-----------------------------------------------------------------------
$ 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)
$
$-----------------------------------------------------------------------
$ 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
$
$-----------------------------------------------------------------------