Strange behavior of RBE2
Hi,
I am enforcing an elongation to a simple cube using a RBE2 on one of its sides.
The model works with an enforced displacement (SPC and SPCD on the master node of the RBE2) equal to 3 (DOF1=3 for both SPC and SPCD), but whenever I reduce the displacement to 1, the RBE2 loses its rigidity and deflects in a strange way.
The two conditions are completely identical for what regards the rest of the model.
Does anybody have some hint which explains this behavior of the model?
Thank you.
The two models and a .png preview of the results are attached.
Best Answer
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The issue is you have dof1=1 in the SPC and dof1=1 in the SPCD, which means these imposed displacements are superposed. There are two solutions:
-set the dof1=0 in the SPC
-remove the tload from loadstep, since dof1=1 in the SPC will do the same thing as dof1=1 in the SPCD (redundant).
Note that in the nonlinear static, loads or displacements are ramped up linearly by default. Only use TLOAD if the loading function is nonlinear.
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1
Answers
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Hi,
make sure to also constrain the master node of the RBE2 in all degrees of freedom to prevent unwanted deflections.
1 -
Thank you very much for your help!
May I also ask why, imposing a displacement equal to 1 (DOF1=1 of SPC and SPCD), I obtain a displacement of 2 in the results?
Thank you again.0 -
The issue is you have dof1=1 in the SPC and dof1=1 in the SPCD, which means these imposed displacements are superposed. There are two solutions:
-set the dof1=0 in the SPC
-remove the tload from loadstep, since dof1=1 in the SPC will do the same thing as dof1=1 in the SPCD (redundant).
Note that in the nonlinear static, loads or displacements are ramped up linearly by default. Only use TLOAD if the loading function is nonlinear.
Hitting the like button is a easy way to show appreciation for the help.
1 -
Thank you for the clear explanation.
Yuri0