I am attempting to calculate the deflection in the attached stainless steel gr304 frame using the simulation add-in with Solidworks PREMIUM 2017.

I have attached the files with 60000n force applied to each of the 2 large plates and 3000n force applied to each of the four smaller plates.

The frame sits on the floor on the open ends of the four vertical weldments (2 x250mm and 2 x 100mm)

I can attached a fixed geometry to the base joint of the 100mm vertical weldments but this option is not available for the 250mm vertical weldments.

How can I attach fixed geometry to stop the issue with under-constrained bodies when creating the mesh and running the study?