Design guidance for removable cantilever

[trainguy]

Hi guys.

Picture a single leg cantilevered table on a passenger railcar, that is allowed to yield in bending under accident conditions, but not allowed to become fully detached from the floor.

Does anyone have a reference I can use to size a moment connection of a round tube (approx 4 in dia) fitting over a smaller, thicker tube that is firmly welded to a base?

If I use thru bolts (or other screws)and I do not consider contact between the 2 parts, I need lots of bolts. If this were a tightly fitting assembly, I'd need almost no bolts, due to friction and contact, until lots of rotation has occurred, which is allowed in this particular load case.

I will use some bolting to prevent the cantilever from completely separating after occurence of the plastic moment.

Any ideas for calc methods (excluding nonlinear FEA)?

tg

 

[desertfox]

Hi trainguy

Do you mean a propped cantilever table?
Can you post a pic or sketch of your problem?

desertfox

 

[GregLocock]

If I'm picturing it right I'd size the bolt to prevent the leg separating from the base by tearing outunder say 2000N vertical separation laod (2g on a heavy man). I wouldn't fret about the analysis it is the loads that you don't know/can't predict.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[dcarr82775]

If the pieces nest tightly, then it is just the bending stress in the pipes.