Unconstrained error

[barnlogic]

Hey,


I have been using Pro and Mechanica for about 15 years and I have never had this error occur. It says that the model is not constrained, but I know that it is. Is there a bug in the M230 version of WF3.0? This is what mechanica spits out:


The model is insufficiently constrained for the analysis.
Please review the element connections, properties, and
constraints.


You may be able to locate your model's problem area by
using Mechanica database ID numbers. ID numbers can be
queried using the "Entity ID" macro in Pro/MECHANICA
Standalone. The following ID numbers are associated
with this error:


3452
3454


The unconstrained degree of freedom can be seen by running
a constrained Modal Analysis with rigid mode search.
Animating the rigid modes will display the unconstrained
degrees of freedom. If the error still occurs, then the
issue could be caused by material properties or unattached
spring/mass idealizations.


But I KNOW that the model is constrianed, it is a test case that I made to test the error. It is a simple cantilevered beam, with a simple loading. I have run it a million times and I have never gotten this error.


Suggestions?


Thanks!

 

[indigo2]

Check the material properties. Might be missing some data there...

just a thought.
-tsl

 

[Ray Ellender]

I agree with indigo2.


In WF3, Mechanica uses the Pro/E material database, whereas in previous releases it had a separate database. This is basically a good idea, but the problem is that when people set up a material in Pro/E, they are really only interested in density and don't enter the Youngs Modulus and Poissons Ratio. Hence many companies have a Pro/E material library which contains materials with no E and Poissons ratio.


Thus when Pro/E is upgraded to WF3, the analyst comes along and picks up these materials without realising they have not been fully defined, and when they run their model, it gives (rather unhelpfully) this kind of 'unconstrained' error message.


Therefore check the details of the material in this model and in your whole database. (Note the standard materials that are provided by PTC are fine, the comment above applies to materials made by designers in Pro/E in WF2 and earlier)

 

[mneal]

I have gotten that error where I was using tab to jump between fields during creation of a material and skipped over poisions and/or shear mod. I assume you ran the rigid mode search to see what (if anything) the behavior looked like? Maybe something goofy in the mesh creation? (hiccup in automesh, not something you did)