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Alter to Remove Selected Modes


Alter Name     delmodea.v707


Purpose

To allow the user to remove individual modes from the set of system
(residual) level modes prior to subsequent modal response analysis.


Solution Sequences

Any modal response Structured Solution Sequence (111,112,145...).


Input
 
Executive Control

Include 'delmodea.v705'.


Case Control:

No additional cards required

Bulk Data

User must input a DMI matrix named SKPMODE into the Bulk Data 
Section to identify which modes are to be removed.  A DMI 
entry is required for each mode to be deleted, plus the 
"header" line for the DMI matrix as well.  

To delete mode number "i" from the system modes, enter a
"-1.0" into the "i-th" column (first row) of  matrix SKPMODE.  
The DMI header record (DMI, SKPMODE, 0,... entry) must have the
mode number of the highest mode to be deleted in field 9.

The following example shows the DMI, SKPMODE entries
required to delete the third and fifth system modes.

 FIELD:  -1-     -2-   -3-   -4-   -5-   -6-   -7-  -8-   -9-
         DMI   SKPMODE  0     2     1     0          1     5
         DMI   SKPMODE  3     1    -1.                     ^
         DMI   SKPMODE  5     1    -1.                     |
                        ^                                  |
                        |                                  |
                        |   HIGHEST MODE TO BE DELETED ----+
                        |
                        +------- MODE NUMBER OF MODE TO BE DELETED
                                 ONE ENTRY CARD PER MODE


Output

The Eigenvalue Summary table for the truncated system modes is
printed AFTER the Summary table for the full set of modes.  The user
is informed as to what modes are being deleted and urged to review
the analysis results carefully.


Other items of note: 

 -Alter package has undergone limited testing with coldstart, regular
  restart, and read-only restart runs.  
 -Use of the PARAM,SERST,RSMDS, which was required for restarts in 
  the earlier versions of this alter, SHOULD NOT BE USED.  There are
  no extra cards required to use this alter in a restart run.  
 -Part-SuperELements have also been tested. 


Limitations

Extreme caution is advised when deleting system modes as this
obviously will change the results of the analysis being performed.

The TRUNCATED set of modes, NOT THE FULL SET of modes, is subseqently
stored on the database.  THERE WILL BE NO WARNING THAT A TRUNCATED 
SET OF MODES IS BEING USED ON ANY SUBSEQUENT RESTART FROM THIS 
DATABASE!!!!  The only way to restore the full set of modes to the
current VERSION of the primary database is to recalculate them all 
over again.


Sample Files

delmode1.dat - A modal transient response run with 4 selected modes
               removed
delmode2.dat - Normal modes SOL 103 run
delmode3.dat - Modal transient SOL 112 read-only restart (no alter, 
               no modes removed, provided for baseline comparisons)
delmode4.dat - Modal transient SOL 112 read-only restart with 
               4 selected modes removed


Additional Documentation

None.