minimum deflection of beam - posn of supports calc

huangyhg

minimum deflection of beam - posn of supports calc
i know this is a trivial question, but i vaguely remember noting a ratio for the quick positioning of a pair of supports under a uniformly loaded uniform beam such that deflection of the centre and equal overhanging ends is minimum.
am i dreaming this, or can anybody recall it, please?
oh, i guess i could figure it, but it's more fun to ask!
cheers to all.
nigelt
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hello nigelt,
i don't know about minimum deflection, because it depends on the second moment of area you are using, but i have a formula in my book of notes, which says -
for a uniformly distributed load, deflection at centre of beam to equal deflection at ends of beam, place supports at 0.553 x length of beam.
i have never tried this, so don't know how accurate this is. maybe you could do your calculation and report back.
regards,
neilmo
i've typically used 1/5 and 4/5 as support locations... i'll try a quick model to see what the real answer is... i'm not sure if the above is for strength or deflection...
dik,
for equal stresses, i have support spacing = 0.586 x length of beam. this is close to your 0.6.
regards,
neilmo
nigelt & dik,
have just checked my support spacings above on a beam program that i have and they work out just fine -
equal deflection support spacing = 0.553 x length
equal stresses support spacing = 0.586 x length
neilmo
neilmo
thanks... more stuff to add to the back cover of my steel handbook.
thank you for all the `stars`.
neilmo
thank you "neilmo" and "dik", i very much appreciate the time and trouble you took.
best regards,
nigel t