JRscooby wrote:
Well sure gravity is a force on the whole unit. But the force I'm talking about is the equivalent of a 7000 lb hammer hitting upward where the suspension mounts.
That same hammer hitting upward at the suspension points is also hitting DOWN on the frame along to the ends (pressing down so it does not fly to the moon).
Or looked at the other way: if there were no force on the beam pushing down, they wouldn't need a beam going to the ends.
Note: a beam to only hold static load could actually be tapering down assuming an even weight distribution.
With only support in the center (and evenly distributed load) the mechanical model is (two) cantilever beams:
https://www.epsilonengineer.com/uploads/7/1/6/9/71698693/__5809977_orig.png
