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Local over-stress

Question asked by Serhey Moroz on Jun 18, 2013
Latest reply on Jun 19, 2013 by Serhey Moroz

Hello colleagues

Is there any one from structural or mechanical professional who can sugest on my little concern.

I am testing coal bin for stress. It's 1/4 thick shell and a lot of stiffeners everywhere. Stiffeners are 1/2 thick and in general look OK, except a few local overstresses at corners. Please look at picture attached.

We all know that it's right location for maximum stress at that case, but do we really should be concerned on that? It's about 95 KSI at the corner which is 3 times over stress for A36. At the same time just a little out of corner I have only 5 KSI, which is 6 time under stress. Is that really the case when we have to over-kill our stiffener thickness because of a little local stresses? Even though, displacement at corner is only 2.5 mm, which is nothing comparing to bin sizes. I tried to round of corner, it's getting even worse, for some reason.

Well, I kind of spent a lot of thinking on this, it looks safe to me for sure, not going to fall appart. But is there any practical advice can anyone provide me? In terms of what kind of problem should I expect and what the practical way to judge or avoid local overstresses on FEA models?

Thank you