Any standard relation between diameter of middle hole and the width of the plate? I know theoretically if we make relation between diameter of the hole and the width, it equals infinity! However, experimentally there should be a standard relation that at least give a valide width compared with very small diameter? Any idea? Or standard please?
This question will be only related with fracture research and crack investigation study.
State of stress for infinite and finite width is explained very nicely at the given link. This should help you to decide the geometry. According to the calculation given any d/W < 0.05 (d = dia of hole, w=width of the plate) will give you a stress concentration >2.8.
Hope this helps you.
http://www.fracturemechanics.org/fm/hole.html
Thanks Afshul. However, I have not found what I am looking for. Let me make it more clear:
I have to make semi infinite plate assumption and very small hole in it. If we see stress concentration is always start from 3 and its decrease when we go far away from the hole till the width of the plate. I want to make an assumption that say "at this diameter of hole and this width" stress concentration effect is zero. Can you see what I am looking for now?
I do not know, if I got your point exactly. Specially what did you meant by " at this diameter of hole and this width stress concentration effect is zero." Also what do you meant by semi-infinite plate. Correct me if I am wrong that you meant a hold in an infinite plate as in the attached figure.
However, what I mean to say that once for a configuration you are close to a Kt of 3, you are approximately simulating an infinite width plate and if it is so then the effect of hole on the stresses will die down after a distance of 2d or 3d (d = dia of hole) (as shown in attached figure that after a distance of 1d stress is same as far field stresses).
You can also try doing a simple FE simulation to see the effect of hole.
http://www.fracturemechanics.org/fm/images/hole/holestress_9.svg
It seems you have said what I am looking for. Yes, that is it, so 2D away from hole edges. The only question is left, is there any mathematical formula behind this assumption. The assumption is look like has been found empirically! Do you know any "mathematical solid answer" that say 2D away from hole edge the effect will be neglected?
Thanks a lot Afshal.
No, its now empirical. For infinite plate stresses are given in the same link I share earlier also. The very first 3 formulae. You can plot sigma_theta at theta=0 and plot it w.r.t 'r' for a given 'a', you will get the answer.
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