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Typical warning message from LUSAS Solver text output file (*.OUT):
***WARNING*** MATRIX IS VERY ILL-CONDITIONED (BCSLSV PROCESSOR)
***WARNING*** RELATIVE ERROR IN THE ORDER OF .2176E-01 EXCEEDS RECOMMENDED MAXIMUM OF .10E-01 USE RESULTS WITH CAUTION (BCSLSV PROCESSOR)
Most common causes & links to solutions
Common causes for these warning messages include:
- Insufficient supports assigned to the model. It is
necessary to ensure that there exist supports that restrain the
entire model from rigid body movements. The model should not
be free to translate or rotate freely.
- 3D beam is in use and there is no rotational restraint for rotation about the x-axis of the beam
- Break in the mesh. There may be coincident point features between lines which apparently join,
or coincident line feature between surfaces which apparently join,
causing there to be a break in the mesh.
- Elements of zero length. This classically occurs where a line lies between two coincident
points has been assigned a beam element mesh.
-
6 DOF assigned to thick shell element nodes
with excessively thick or thin shell. By default, the option
to "assign 6 DOF to all thick shell element nodes" is
switched on. If there are no rotational supports or loads
you may remove this option using the menu item:
File> Model Properties> Solution tab> (click) Element
Options button> (uncheck) Assign 6 DOF to all thick shell
element nodes
- Shear area or other stiffnesses set to zero. Check your geometric attributes for stiffnesses which are zero. In general, eccentricity is the only stiffness parameter where a zero should be specified.
Continued difficulties? Try
the pivot checklist
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on ill-conditioning
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