Learning Forum

[venugopal.b]

Hi,
I am using "UPGEOM" command for a shell element in workbench. In the original model I have used cylindrical coordinate system to create dispalcements. After using "UPGEOM", I just want to know whether it updates only nodal displacements alone or coordinate system too? Because, I want to apply load in Cartesian coordinate system. If UPGEOm updates coordinate system, how to change it to cartesian coorinate system?

Regards

Venugopal B

[mjmiddle]

Upgeom just moves nodes to the deformed postions. All nodes and elements in the APDL solver have their own Cartesian CS. Nodal CSs should keep the same orientation in the deformed positions. Element CSs can change orientation as nodes are moved to deformed locations, but only if large deflection is on. But these are not the same thing as external defined CSs, which will not change orientation in the deformed model. Be careful about applying displacements in a cylindrical CS. The displacements in cylindrical CS get transferred to Cartesian directions at the time the load is applied so they can be applied to nodes. This is fine if you only apply radial or axial (Z dir), but if you apply circumferential displacement the model will not move as you expect. For small deflection analysis using small displacements, it's probably fine. Even if you don't apply a circumferential displacement, if the related body effectively rotates during analysis due to other loads, it will change the expected behavior of the radial and axial direction displacements. For large motion analysis, you should use a joint to apply rotational loads, such as revolute, spherical, cylindrical joints.