Interesting beam design

[trainguy]

Guys,

I need to design a beam that has a very different ultimate bending strength when loaded downward versus when it is loaded upward. (Actually its downward versus sideways, but I'm simplifying)

Imagining a rectangular tube as a section, if we laser cut a notch in the portion of the section that undergoes compression, and insert a metal plate with an interference fit, and we make sure that the reduced section meets shear, combined stress and fatigue requirements, could this work?

I would be using the "spacer" in bearing, to replace the compressive stress in the section. Under tension from a load in the other direction, the beam would have a much reduced S, or at least that's the hope. Some tack welding would be used to ensure the adjacent parts do not buckle locally when undergoing the primary bending stresses.

What do you think?

tg

 

[trainguy]

Guys,

I'm getting some excellent suggestions here. I can't get into too much more detail without divulging stuff that may be proprietary, even though it's just research.

dh, there is no striker, so the only thing that prevents coupler retraction is the carrier, and its so long because I'm designing a bellmouth that can swallow an entire AAR coupler head...

If you Google "push-back coupler", you'll see some related work...

tg

 

[JStephen]

Consider an assembly like a leaf spring, with all the leaves straight, and connected only at the center. Pushed one way, the whole thing has to bend. Pushed the other way, only the longest leaf has to deflect.

 

[engphila]

...sounds like you may be looking for a lateral "link" that can be designed to fail at a predetermined load.

engphila