7.15.       WRITE_MODES Alter

 

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

$  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

$

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