No Results, EXCESSIVE PIVOT RATIOS

Published 2013-06-12
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Question

After I ran the model, and attach the results, nothing is available.

I found the following message in the .F06 file:

"USER FATAL MESSAGE 9050 (SEKRRS)

^^^ RUN TERMINATED DUE TO EXCESSIVE PIVOT RATIOS IN MATRIX KLL.
^^^ USER ACTION: CONSTRAIN MECHANISMS WITH SPCI OR SUPORTI ENTRIES OR SPECIFY PARAM,BAILOUT,-1 TO CONTINUE THE RUN WITH MECHANISMS. "

What does this mean?

Answer

EXCESSIVE PIVOT RATIOS means that something in the model is not connected or loose.

A number of things could be the reason:

  1. Not all nodes have been equivalenced (merged) which could result in a loose section
  2. The structure as a whole can move in one or more of the 6 degrees of freedom (rigid body movement directions), i.e. freely float in a direction or freely rotate about a point/line
  3. If you can not find any of the above problems, run a modal analysis instead (just make sure you have density specified for your materials). A model analysis don't need constraints and animating the results (for modes with frequencies near Zero) will clearly show where the model is free to move.

I think this is...