Building my new machine, based on waterjet scrap and surplus industrial components. (as you do)
I modeled the column weldment in solidworks, as the materials to hand drove the construction of the column. I've done a frequency analysis here and am having a tough time interpreting the results.
The column is welded A36 steel, the base plate/mounting plate is 0.750" thick and 14.5"x12", the braces around the base are all 0.375" thick, the column tubing itself is 10"x6" rectangular hollow section with a 10mm wall thickness. The linear rail mountings are 1" plate steel, T-welded to 0.625" spacers to make room for the ball screw nut.
The column has a 3/8" thick top cap welded into close up the top end of the tubing, and all welds are V-grooved for full penetration TIG roots and 7014 cap passes. The top cap has not been welded in place yet, and I have not added the mounting pads for the ballscrew or the tool changer.
I have not started on the damping yet-I am concerned mainly with designing a rigid structure first, and pushing the resonant frequency up as high as I can get it before starting the damping process (which will bring the resonant frequency down as a byproduct of adding mass) so that I end up with a well damped rigid structure with as high a resonant frequency as possible.
Thanks for any advice-especially on how to set up and run the simulations.