Best beam mounting points?

Thread Starter

AlbertHall

Joined Jun 4, 2014
11,960
Suppose I have a 1 metre beam supported at two points, where would be the best locations for those supports to give even deflection at the ends and middle of the beam for the same load.
My guess would be 25cm and 75cm?
 

djsfantasi

Joined Apr 11, 2010
8,258
Your guess would be wrong. It would be 20cm and 80cm.

Don’t ask me for an explanation though. I remember the 20% and 80% rule from years of model railroading and set design.
 

Thread Starter

AlbertHall

Joined Jun 4, 2014
11,960
Thank you. I thought they should be further apart than my guess but the maths is beyond me.
I shall get screwing (if you'll pardon the expression!).
 

drjohsmith

Joined Dec 13, 2021
383
If I remember ..
Assuming it's a evenly distributed load ,
Then you have two cantileaver and one "bridge' , sorry can't remember proper name for bridge !
The cantilever ends have less support than the middle , where both ends are fixed,
Thus , the mount is as mentioned above much nearer to the ends than the 25 you mention.
I'm trying to find a ref as to how to calculate it, but 20 percent mentioned seems about right.
 
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