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  Re-Distributed by http://www.tpub.com
PARAM
BAILOUT
-1
$ --------------------------------------------------------------
$ Data for Applying Enforced Displacements
$
$ SPC SET
DEFINITION
$ -------
----------
$
1
SYMMETRIC BC
-- (CARDS LOCATED AT END OF BULK DATA)
$
2
ANTISYMMETRIC BC --
"
"
$
3
CONSTRAIN GRID POINT 5754 (NEAR CG) IN ALL SIX DOF
$
13
COMBINE SET 1 AND SET 3
$
23
COMBINE SET 2 AND SET 3
$
SPC1
3
123456 5754
SPCADD 13
1
3
SPCADD 23
2
3
$
$ ENFORCED DISPLACEMENTS AT GRID POINT 5754 (CHOSEN
$ BECAUSE IT IS NEAR THE CG)
$
SPCD
100
5754
1
1.0
SPCD
200
5754
2
1.0
SPCD
300
5754
3
1.0
SPCD
400
5754
4
1.0
SPCD
500
5754
5
1.0
SPCD
600
5754
6
1.0
$
$ --------------------------------------------------------------
.
.
.
ENDDATA
Check the output for the following:
NOTE: NASTRAN will issue a series of warning messages (UWM 3204). Ignore these.
They are left over from the older versions of MSC/NASTRAN which required a dummy load
card with enforced displacements (e.g., SPCDs).
1. OLOAD RESULTANT: All terms should be zero since no loads were applied.
2. Inspect the messages output by the DCMP module (sparse decomposition). User
Information Message 4158 provides statistics which inform the user of the numerical quality
of the stiffness matrix, KLL.
3. User Information Message 5293, output by the forward/backward substitution (FBS)
module provides more information about the numerical quality of KLL. The error measure,
epsilon, and the external work are printed.
4. Check the spc force resultant, the maximum spc forces, maximum displacements and
maximum applied loads. Note that the spc forces will not be exactly zero, especially for the
rotational DOF.
5. Finally, a good visual confirmation of the results can be obtained by plotting the
deformed shapes. The plots should not show any visible deformation other than rigid-body
motion.
16
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