$-----------------------------------------------------------------------
$ 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 the LAMA table (frequencies) and mode shapes
$ out in a choice of formats for later processing. Optionally the user
$ can output a subset of the modes using a 'U2' set.
$
$ Special instructions to use this alter:
$-----------------------------------------------------------------------
$ FILE MANAGEMENT SECTION (FMS)
$
$ If OUTPUT2 or OUTPUT4 formats are chosen these files should be
$ assigned as follows:
$
$ ASSIGN OUTPUT4=fem_modes.op4 UNIT=11 DELETE
$
$ or
$
$ ASSIGN OUTPUT2=fem_modes.op2 UNIT=11 DELETE
$
$ Note that a formatted OUTPUT4 file can be chosen as follows:
$
$ ASSIGN OUTPUT4=fem_modes.op4 UNIT=11 DELETE FORMATTED
$
$-----------------------------------------------------------------------
$ EXECUTIVE CONTROL DECK
$
$ SOL 103
$ Include this alter immediately before the CEND statement
$
$-----------------------------------------------------------------------
$ CASE CONTROL DECK
$
$ No special input is required. The Case Control deck must include
$ standard modal solution requests (SPC, METHOD, etc.). Some output
$ request such as DISP(PLOT)=ALL is required to force data recovery.
$
$-----------------------------------------------------------------------
$ BULK DATA DECK
$
$ Optional parameters:
$
$ PARAM,OMODES,I <0 : Write modes to OUTPUT2 file UNIT = |OMODES|
$ 0 : Write modes to PCH file in DMIG format
$ >0 : Write modes to OUTPUT4 file UNIT = OMODES
$
$ If desired, only a subset of the DOF can be exported using a 'U2'
$ set
$
$-----------------------------------------------------------------------
$ EXAMPLE NASTRAN DECK
$
$ ASSIGN OUTPUT4='gpsc_modes.op4' UNIT=11 DELETE
$ ASSIGN MASTER='gpsc.MASTER'
$ ASSIGN DBALL ='gpsc.DBALL'
$ RESTART
$ $
$ SOL 103
$ INCLUDE write_modes.v2001
$ CEND
$ $
$ TITLE = GENERAL PURPOSE SPACECRAFT
$ SUBTITLE = NORMAL MODES DATA RECOVERY RESTART
$ LABEL = WRITE FEM MODES
$ $
$ SPC = 1
$ METHOD = 50 $ Modes to 50 Hz
$ $
$ DISP(PLOT) = ALL $ Recover but don't print displacements
$ $
$ BEGIN BULK
$ $
$ PARAM,OMODES,11 $ Write modes to OUTPUT4 file on unit 11
$ $
$ USET1,U2,123,1,1000 $ Limit DOF
$ $
$ ENDDATA
$
$-----------------------------------------------------------------------