Learning Forum

[BenediktaSchmidt]

Hi,

I want to study a compressed beam in Ansys Mechanical APDL. To model the beam I used shell elements and MPC184 Elements (rigid beam), so that the beam extreme sections remain plane. he problem itself doesn't need any constraint, because it is auto-equilibrated, but to run the analysis on Ansys I need to prevent the rigid body motion (translations and rotations).

[peteroznewman]

Use the word Vertex when referring to the 3-2-1 method. Applying constraints to edges would not be a valid 3-2-1 method.
Using Rigid Elements on the edges of the section prevents the Poisson's Ratio expansion when the compression is applied, which generates a stress along the web and flange edges.
Use the Deformable type of Rigid Elements to fix this.

[peteroznewman]

The deformable rigid element is called the RBE3 element.

[BenediktaSchmidt]

Thanks for the answer. Where do I find these elements? In Ansys Mechanical Apdl I haven't seen them.

[peteroznewman]

I don't use Mechanical APDL to build models. The ANSYS Help under the R commands has the RBE3 command.
https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v212/en/ans_cmd/Hlp_C_RBE3.html