$-----------------------------------------------------------------------
$ 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 performs a Hybrid TAM reduction
$
$ Kammer, D.C., "A Hybrid Approach to Test Analysis Model
$ Development for Large Space Structures," Journal of Vibration
$ and Acoustics, Vol. 113, No. 3, July 1991, pp. 325-332.
$
$ A Hybrid TAM reduction combines a static and modal TAM.
$
$ The equations for the Hybrid TAM shapes are as follows:
$
$
$ | IAA | | IAA | | IAA | | IAA |
$ | | = | | + (| | - | |) * P
$ | GOTH | | GOTS |+ | GOTM | - | GOTS |
$
$ WHERE:
$
$ GOTS - Static Reduction
$ GOTM - Modal Reduction
$
$ T
$ P = [PHIA]*[PHIA] *MAAM
$
$ MAAM - Modally reduced mass matrix
$ PHIA - A-set partition of FEM mode shapes
$
$ No special processing is required to use this alter. Simply include the
$ alter with standard ASET cards defining the reduced DOF. If the reduced
$ mass matrix is desired it can be requested with a PARAM,EXTOUT,DMIGPCH.
$
$
$ Special instructions to use this alter:
$-----------------------------------------------------------------------
$ FILE MANAGEMENT SECTION (FMS)
$
$ The FEM mode shapes must be made available. If these are stored in
$ OUTPUT2 or OUTPUT4 forma using the write_modes alter they must be
$ assigned using INPUTT2 or INPUTT4 cards as follows:
$
$ ASSIGN INPUTT4=fem_modes.op4 UNIT=11
$
$ or
$
$ ASSIGN INPUTT2=fem_modes.op2 UNIT=11
$
$ Note that a formatted OUTPUT4 file can be used as follows
$
$ ASSIGN INPUTT4=fem_modes.op4 UNIT=11 FORMATTED
$
$-----------------------------------------------------------------------
$ EXECUTIVE CONTROL DECK
$
$ SOL 103
$ Include this alter immediately before the CEND statement.
$
$-----------------------------------------------------------------------
$ CASE CONTROL DECK
$
$ No special input is required.
$
$-----------------------------------------------------------------------
$ BULK DATA DECK
$
$ Optional parameters:
$
$ PARAM,OMODES,I <0 : Read FEM modes from OUTPUT2 file UNIT = |OMODES|
$ 0 : Read FEM modes from DMIG cards in bulk data
$ >0 : Read FEM modes from OUTPUT4 file UNIT = OMODES
$
$ PARAM,N1,I : 1st FEM mode to use for hybrid TAM (default = 1)
$
$ PARAM,N2,I : Last FEM mode to use for hybrid TAM (default = all)
$
$ If the FEM modes are defined on DMIG cards, these must be included
$ in the bulk data
$
$-----------------------------------------------------------------------
$ EXAMPLE NASTRAN DECK
$
$
$ ASSIGN INPUTT4='gpsc_modes.op4', UNIT=13
$ ASSIGN MASTER='gpsc_aset.MASTER'
$ ASSIGN DBALL ='gpsc_aset.DBALL'
$ $
$ SOL 103
$ INCLUDE hybrid_tam.v2001
$ CEND
$ $
$ TITLE = GENERAL PURPOSE SPACECRAFT
$ SUBTITLE = HYBRID TAM REDUCED MODES
$ LABEL = MY ASET DOF
$ $
$ SPC = 1
$ METHOD = 50 $ Modes to 50 Hz
$ $
$ DISP(PLOT) = ALL $ Recover but don't print displacements
$ $
$ BEGIN BULK
$ $
$ PARAM,OMODES,13
$ $
$ ... Standard Bulk data including ASET cards ...
$ $
$ ENDDATA
$
$-----------------------------------------------------------------------