Inactive DOF error

[zhirayr]

Please can you help

I want carry out a test similar to cantilever bending, where I constraint all dofs on one end of the structure and induce a load on the other end. The structure is meshed using modified tet elements. When I run an analysis after a very long time I get an error saying that "244 nodes have inactive dofs on which BCs have been specified". How do I fix this?

Thanks
Zhirayr

 

[Drej]

Your tets will have 3 DOF/node (translational DOF). My guess is that you've probably specified rotational constraints which the tets do not have (I'm puzzled that the error occurs late on if this is the case though). Hence, to stop this message appearing, remove the rotational DOF constraints. Voila, c'est fini!

Cheers,

-- drej --

 

[zhirayr]

Dear Drej

Thank you very much for your help. Does this mean I can't do any cantilevered tests on a structure with a tet mesh?

Zhirayr

 

[corus]

I think applying rotational restraints would only give a warning, and not an error but I could be wrong. Contact with restraints at the same position would give an error as freedoms would have been removed. If Drej is right then simply remove freedoms 4 to 6 from the boundary condition and it should work. By having tets and restraining a face in the translational freedoms you automatically induce rotational restraints to your solid beam.

corus

 

[andrearrd]

yeah if u just constrain it in the displcement dof then it should be ok and since tet elements dont have rotational dof then its the same thing as having constrained them rotationally also ( i think).

jld
andrearrd

 

[zhirayr]

Dear All

Thank you very much for the help. The analysis works now!

Z