"Ned Simmons" wrote in message
wrote:
A potential failure mode of a slender beam is somewhat analogous to
column buckling.
https://en.wikipedia.org/wiki/Buckling#Lateral-torsional_buckling
==============================That could particularly be a problem for a beam made from two channels that are loaded near the outer edge of the lower flange, although when I tested for it by leaving out the bolts that join the webs the channels deflected to nearly the max extreme fiber stress for A36 steel without twisting. I had turned the trolley wheels to match the flange angle so they rode on their inner edges if the flange twisted downward. The channels also didn't twist much when I bent them beyond the yield point to straighten them.
The Harbor Freight 1300# electric hoist starts with a jerk that noticeably increases the deflection of the beam. I didn't measure the deflection because I don't want to be that close on a stepladder if anything fails.
A potential failure mode of a slender beam is somewhat analogous to
==============================That could particularly be a problem for a beam made from two channels that are loaded near the outer edge of the lower flange, although when I tested for it by leaving out the bolts that join the webs the channels deflected to nearly the max extreme fiber stress for A36 steel without twisting. I had turned the trolley wheels to match the flange angle so they rode on their inner edges if the flange twisted downward. The channels also didn't twist much when I bent them beyond the yield point to straighten them.
The Harbor Freight 1300# electric hoist starts with a jerk that noticeably increases the deflection of the beam. I didn't measure the deflection because I don't want to be that close on a stepladder if anything fails.