Column buckling in a pin jointed structure

[xJJx]

<< Mentor Note -- thread moved from the schoolwork forums to the ME forum because it's more of a general question >>

Hi, in these column bucking notes (photo attached below) it says that bar BC will buckle first out of all the other bars in compression, but it does not explain why. I know it has the highest compressive force in it and also the longer length, but what if the bar had the highest comrpessive force but the shortest length? Would it still be the critical bar?

 

[PhanthomJay]

It didn't explain why, but you did nicely. If there was a different problem where there were to be a larger force in a compression member with smaller length, you'd have to check that one also to see which controls for the compression case. Or you might have a smaller load and longer length that controls. While in any case not exceeding the yield or breaking or failure compressive stress of the material.