Learning Forum

[Zainaba98]

Hello all,

If I apply a remote displacement on a face with translational and rotational displacements, and then measure the translational displacements of the face (UX, UY, UZ), I don't get the same values as those I applied as boundary conditions.

Any explanation?

[Zainaba98]

Boundary Condition by Remote Displacement:
Results measuring X on very same face:

[peteroznewman]

Was the Remote Displacement Behavior set to Rigid or Deformable? Try setting it to Rigid.
In a nonlinear solution, there are convergence tolerances on Force, Moment, Displacement and Rotation. The default convergence tolerance is 0.5%, which is acceptable for most solutions. If you need tighter tolerances, just type in a smaller value for the displacement tolerance, such as 0.01% under the Nonlinear Controls category of the Analysis Settings. You might find that more iterations are required to solve the model when you use tighter tolerances.

[Zainaba98]

Actually I tried setting it to rigid, and applied a certain rotational angle, the body didn't even rotate.
On the other hand, I don't think it's something related to the tolerance, here's why:
as you see, the applied displacement along y is -0.14mm at step 70 for example. When measuring UY on this face, here's what I get: (0.53 mm!!)

[Zainaba98]

In fact, my problem is that on this very face I need to apply a translational displacement of (x = 7e-2, y= -0.14, z=0.28) and a rotational one too. For this I used a remote displacement, however am not sure anymore that am really applying these boundary conditions (regarding the values am getting when measuring UX, UY,UZ) on this face

[JJ_Thompson]

Have you tried applying the translational boundary conditions only and checking if you get the results you want?
I suspect the rotations you are applying have been decomposed into translational deformation; solid elements do not have rotational DOFs.

[Zainaba98]

with translational BCs the results are logical however I need to apply also a rotational displacement. For that, the only way I know is to apply it using a remote point -> we're back to the same problem