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Alter to Perform Rigid Body Checks, Kinetic Energy
Calculation, and Modal Effective Weight Calculation


Alter Name    checka.v707


Purpose

Performs mass and stiffness checks in preparation for analysis. 
Calculates assembly weight when using superelements.  In modal
solutions, calculates modal effective weight and kinetic energy.  If
superelements are used, provides the total fractions of effective
weight and kinetic energy for each superelement and assembly.
Will force Lanczos method to treat a SUPORT entry like the other 
eigenvalue solution methods.


Solution Sequences

SOL 101, 103 (possibly others).


Input
 
Executive Control

Include 'checka.v7075'.
 
Bulk Data

The following parameters affect the operation of this DMAP
Alter:

CKMCHNSM (default=no) NEW IN.v707.5 - checks for mechanisms
in the model. If set to YES and any mechanisms are found, 
the run will indicate them and terminate. 

GRDPNT (Default = -1).  Used by grid point weight generator. 
This DMAP also uses this grid point for assembly grid point
weight generator and as the reference location for rigid-body
checks.

CHKSTIF (Default = 1).  A positive value causes the DMAP
to perform checks on the stiffness as follows:

1 = check KGG, KNN, and KAA.
2 = check KGG and KNN.
3 = check KGG only.

CHKSTIFF (default=-1) A positive value (in addition to 
setting CHKSTIF>0 or CHECKA=YES) causes the DMAP to
perform checks on the F-set stiffness matrix.

The DMAP performs rigid-body checks on the stiffness
matrices by generating geometric rigid-body vectors about
GRDPNT and multiplying the stiffness matrix by the vectors.

CHECKTOL (Default = 1.e-05) - Acceptable tolerance on
stiffness matrix checks.  If the strain energy for all checks of a
stiffness matrix is less than this value, a message is printed
stating so.  If not, then the strain energy and the resulting
(normalized) reactions are printed.

CHKMASS (Default = 1) - Similar to CHKSTIF only for the
mass matrices.  Allows verification that no mass was removed
during processing.

KEPRT (Default = 1) - Applicable only in modal solutions.  A
positive value of this parameter results in the calculation of
kinetic energy fractions for the modes (assuming that modes
are normalized to unit mass).

EFWGT (Default = 2) - Applicable only in modal solutions.  A
positive value results in the calculation of the modal effective
mass for each mode (once again, assuming modes are
normalized to unit mass).

1 = calculates the effective weight and print for each mode.
2 = calculates the effective weight and fraction of the total
for each mode and prints the fraction (requires CHKMASS>0). 

LANSUP (default = 1) - forces Lanczos method to treat a SUPORT
entry in the same manner as the other eigenvalue solution
methods.

1 = Lanczos will treat a SUPORT like the other methods
<>1 => No change from the current way Lanczos handles a SUPORT

PARAM,TOLGN,x - Acceptable strain energy tolerance for check on
KGG and KNN before run will terminate.  Default = -1.0 => do not
terminate due to strain energy tolerance.

PARAM,TOLF,x - Acceptable strain energy tolerance for check on
KFF before the run will terminate. Default = -1.0 => do not
terminate due to strain energy tolerance.

PARAM,CHECKTOL - Acceptable strain energy tolerance before the   
alter will print that a direction has failed the check.  
Default = the program will calculate a value.

PARAM,PRINTOL - Tolerance on printout of normalized reactions when
performing rigid-body tests.  Default = .1 

PARAM,QUIT - Manual exit point during checks evaluation.  Value      
determines if run terminates after (1) G-size (2) N-size or
(3) A-size reduction.  Default = no manual termination.

Output

Various matrices representing the calculated quantities.


Limitations

The alter does what is requested by the user.  That is, if kinetic energy
is requested in a static solution, the DMAP is not smart enough to
realize that the solution is static.  Therefore, it calculates and prints an
incorrect quantity using the static vectors.


Sample Files

check1.dat (SOL 103) - Run to perform stiffness and mass checks
plus effective weight and kinetic energy calculations.


Additional Documentation

JPL, "MSC/NASTRAN Model Checkout," 1986 MSC World Users'
Conference Proceedings, Paper No. 9, March 1986.

T. Rose, "Using Superelements to Identify the Dynamic Properties of a
Structure," 1988 MSC World Users' Conference Proceedings, Vol. 1,
Paper No. 41, March 1988.