Strange behavior of RBE2

Yuri S.

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. 

CUBE_Enforced_disp_1.hm

CUBE_Enforced_disp_3.hm

Enforced_disp_1.png

Enforced_disp_3.png

Simon Križnik

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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