1. The problem statement, all variables and given/known data Hi, guys! I am trying to work out with beam will buckle first, either a beam with a square cross section, 5x5 or a beam with a square cross section, 6x6 with a 1x1 square removed from the middle of the section. 2. Relevant equations 3. The attempt at a solution Well I'm not really sure as they have the same dimensions in a way, 5 for the 5x5 and 6-1 for the 6x6. But I am think that as a hollow cylinder is stronger than a full cylinder, the 6x6 with a hole in the middle will buckle second. Any help would be greatly appreciated!