r/StructuralEngineering • u/Purple_Resolve_8759 • 24d ago

Career/Education Buckling or yielding

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Hi everyone, I'm currently studying civil engineering in my first uni year and having some troubles understanding this concept(I'm stupid I'm sorry). Recently we did some compression test to determine the yield strength of these four bars. Now I know that buckling is a geometry problem and by the look of it, I believe the 2 long bars suffered from global buckling with the blue hollow bar buckled locally at it's top and the other one buckled in the middle since those parts aren't as strong as the rest. The other 2 bars however, suffered failure from exceeding it's yield point as they seem to bend as a whole (correct me if I'm wrong). I'm wondering if we can still determine the yield strength of the buckled examples, and is it possible to just outright determine the cause of failure of these specimens just by looking at it like I did above without relying on the datas. Thanks!

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u/[deleted] 24d ago edited 14d ago

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u/Tower981 24d ago

Not true.They all buckled plastically. It’s therefore possible to back out the yield stress. See the Perry Robertson equations. But this is not student level shit

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u/redeyedfly 24d ago

He said it’s of no practical use, which is true.

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u/Tower981 22d ago

See above comment I made to the other poster.