A static TAM is the easiest type of TAM to create. A static TAM requires no special input beyond the generic items described in Section 3.2. The matrix operations used to perform the static (Guyan) reduction are a standard feature of SOL 103 and are activated by the presence of ASET and/or ASET1 cards in the Bulk Data deck.
No special differences are needed for superelement or non-superelement models beyond those listed in Section 1.5.
A sample input file to create a static TAM is shown in Figure 3-2. This includes the ortho alter to calculate pseudo- and cross-orthogonality. This alter is better described in Section 3.3.
gpsc_stam.dat
ASSIGN INPUTT4='gpsc_fem.op4', UNIT=13
ASSIGN MASTER ='gpsc_stam.MASTER', DELETE
ASSIGN DBALL ='gpsc_stam.DBALL', DELETE
$
SOL 103 $ Normal modes
INCLUDE 'ortho.v2001'
CEND
TITLE =GENERAL PURPOSE SPACECRAFT (GPSC)
SUBTITLE =TAM - STATIC REDUCTION AND ORTHOGONALITY
$
SPC = 10 $ Constrain booster interface points
METHOD = 70 $ Modes to 70 Hz
$
DISP(PLOT) = ALL $ Recover but do not print mode shapes
$
BEGIN BULK
$
$ PARAMeter cards
$ ---------------
$
PARAM GRDPNT 0
PARAM USETPRT 0
PARAM WTMASS .00259
PARAM OMODES 13
$
$ Compute eigenvalues using the Lanczos method
$ --------------------------------------------
$
EIGRL 70 70.
$
$ Spacecraft bulk data
$ --------------------
$
INCLUDE 'gpsc.blk'
INCLUDE 'gpsc.prp'
$
$ Static reduction data
$ ---------------------
$
INCLUDE 'gpsc_rke1.aset'
$
ENDDATA
Figure 3-2. No special input requirements are needed to create a Static TAM.
For this example, the pseudo-orthogonality of the FEM mode shapes with respect to the statically reduced mass matrix is presented in Table 3-1. The cross-orthogonality between the TAM and FEM mode shapes is presented in Table 3-2. The interpretation of the pseudo- and cross-orthogonality matrices is further discussed in Section 2.4 but the static TAM does a fairly good job of representing these seventeen modes.
Table 3-1. Pseudo-orthogonality of FEM modes w.r.t. statically reduced mass matrix.
Table 3-2. Cross-orthogonality of TAM/FEM modes w.r.t. statically reduced mass matrix.