ANSYS APDL, unconstrained model error.
ANSYS APDL, unconstrained model error.
(OP)
Hello
I am trying to model a concrete beam with BFRP supports and I have been having this error everytime I solve it.
"The value of UY at node 14 is 2.84937889E+11. It is greater than the current limit of 1000000. This generally indicates rigid body motion as a result of an unconstrained model. Verify that your model is properly constrained."
So I de-constructed the whole thing and built it up one by one structural element. And the error re appears even when its just a plain concrete beam (No links, No rbars) on supports (rigid and roller) and 2 loads.
I am wondering if someone can point out what I am doing wrong (any fundamentals I am forgetting), whether there is a way to fix this issue or change the setting on convergence or a tolerance limits or any other suggestion you might think is useful.
Many thanks.
I am trying to model a concrete beam with BFRP supports and I have been having this error everytime I solve it.
"The value of UY at node 14 is 2.84937889E+11. It is greater than the current limit of 1000000. This generally indicates rigid body motion as a result of an unconstrained model. Verify that your model is properly constrained."
So I de-constructed the whole thing and built it up one by one structural element. And the error re appears even when its just a plain concrete beam (No links, No rbars) on supports (rigid and roller) and 2 loads.
I am wondering if someone can point out what I am doing wrong (any fundamentals I am forgetting), whether there is a way to fix this issue or change the setting on convergence or a tolerance limits or any other suggestion you might think is useful.
Many thanks.





RE: ANSYS APDL, unconstrained model error.
RE: ANSYS APDL, unconstrained model error.
can you post the code of the model (if available)?
Regards
Alex
MESHPARTS
Tuning Your Simulation
http://www.meshparts.de
RE: ANSYS APDL, unconstrained model error.
RE: ANSYS APDL, unconstrained model error.
If the model is created in Workbench, then the batch file created.
MESHPARTS
Tuning Your Simulation
http://www.meshparts.de
RE: ANSYS APDL, unconstrained model error.
RE: ANSYS APDL, unconstrained model error.
RE: ANSYS APDL, unconstrained model error.
RE: ANSYS APDL, unconstrained model error.
the solution is nonlinear due to the concrete material and nonlinear stress/strain curve.
I added some lines of code at the end of the file, before solving (time stepping, output control).
See:
http://files.engineering.com/getfile.aspx?folder=648f5f44-d616-49ad-9230-8d6ed3d774d4&file=Sample_Beam.ans
Now if you run the file, you still get non convergence, but you can take a look at the last converged deformation. Choose the next-to-last result set and plot the stress, strain and deformation. You also have plastic deformation. I'm not a concrete specialist, so I cannot say what the problem is, but I suppose it's you material definition. Try to increase the number of stress/strain points. See if the results are still in the described interval.
Regards
Alex
MESHPARTS
Tuning Your Simulation
http://www.meshparts.de
RE: ANSYS APDL, unconstrained model error.
Thank you, I will try this right now and let you know if its any better.
As I have mentioned above this is the basic foundation of the compact beam. I have been remodelling it to create the log file for that as well. If you don't mind taking a look at that too, I will post that afterwards.
Thanks again!
RE: ANSYS APDL, unconstrained model error.
The code you sent does produce a solution which is great to start with considering it used to not even go past that earlier so thanks so much for that.
Attached herewith is the real problem; much more elements added. I have tried filtering out code for zooming etc. So when you do have a minute please take a look at it.
Many thanks.
RE: ANSYS APDL, unconstrained model error.
I'm having a similar error with my code. I'm trying to run a probabilistic analysis on a 3D Truss system. The FE analysis is fine but a similar error as the one Tachie was having comes up when i try to run a probabilistic analysis. Is it okay if I upload my code on here so you can have a look at it for me pls
RE: ANSYS APDL, unconstrained model error.
according to what i know this error message means that the beam fail i am now working on a concrete beam with ansys and i depend on this message to know that my beam fail
try this code
/SOLUTION
ANTYPE,STATIC,new
!solcontrol,on
OUTRES,all,all
RESCONTROL,DEFINE,ALL,1,1
NROPT,FULL, ,ON
CNVTOL,F, ,0.05,2, ,
DELTIM,0.001,0.0001,0.05
AUTOTS,1
LNSRCH,0
NLGEOM,0
NCNV,2,0,0,0,0
EQSLV,SPAR
NEQIT,100
TIME,1
but change this numbers "DELTIM,0.001,0.0001,0.05",because i do change them from model to another to get the convergence .
good luck