Reply To: Apply rotational stiffness to a base

[peteroznewman]

Select the bottom face of your block and insert a Spring in the Connections folder. In the Details window, change the Scope to a Body-Ground spring and change the Behavior of the Mobile side (bottom face) to be Deformable.  Deformable means that the individual nodes in the face will have the freedom to move according to the loads distrubuted to them by the Deformable connection, but that the average motion will be controlled by the spring’s master node.

The spring created in Mechanical is a Longitudinal spring, COMBIN14, which is not what you want, but you can override that spring type with another spring element called a COMBI250 by using a Command Object under the Spring object in the model Outline.

A COMBI250 allows you to define six spring constants for the 3 translational and 3 rotational stiffness values.

Look up the COMBI250 element in the Mechanical APDL, Element Library section of the Help system. One line of the APDL code will switch the element type to COMBIN250 and other lines of code will provide the Real Constants for the spring stiffness values.

Here is one example of the needed code.  Here is another example.