Calculating KT for a hole
Calculating KT for a hole
(OP)
I am new to this website so forgive me. My question is I am in need of information that describes how to calculate stress concentration in a localized area due tapping an existing hole that has a cyclic life. To expand my question there is a rotating disk that has a certain amount of holes in it. Each one of these will be tapped and a threaded plug will go inside. I am trying to look for information that would tell me how to calculate what the consequences are from tapping the hole. By consequences I mean will I have a localized stress concentration, will the cyclic life of the disk be reduced, may I induce a localized crack that could propagate and reduce my life cycle, calculating Kt factor?
Thanks ahead of time for any information Matthew.
Thanks ahead of time for any information Matthew.





RE: Calculating KT for a hole
We need more information what is this disc, whats its function, what load is it under? can you upload a sketch.
desertfox
RE: Calculating KT for a hole
RE: Calculating KT for a hole
What load if any is put on the threaded plugs?
Also what stress levels do you have on the disc during service.
desertfox
RE: Calculating KT for a hole
RE: Calculating KT for a hole
If the holes are not in a stressed area then I don't think you have a problem and the only stresses you will generate is from screwing the plugs in.
Stresses can be estimated for threaded joints at this site below and I also give you the link for stress concentrations for holes for reference:-
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desertfox
RE: Calculating KT for a hole
I do have another question though, what should I read to find out information about the way to predict the residual stresses caused at the root of the tapped hole? I am looking to find a difference between fine, coarse, or rolled threads and there impact on tapping the hole?
RE: Calculating KT for a hole
Look at this site and scroll down to class numbers 28 to 32
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desertfox
RE: Calculating KT for a hole
Thank you very much for your thoughts and the information you have shared with me.
RE: Calculating KT for a hole
I've been looking for a paper I had that had considerable information about holes in disks and fatigue cracking from knife edge holes and rounded edge holes. I haven't found it as yet. Here is one article that may be of assistance.
http://ww
I would look to form the threads if possible instead of cutting same.
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NASGRO:
You might be able to find someone who has access to NASGRO to checkout your exact conditions.
http://
RE: Calculating KT for a hole
Sir did you happen to come across the paper you discussed in your post??
RE: Calculating KT for a hole
A. F. Grandt, Jr., "Stress Intensity FacTors for Some Thru-Cracked Fastener Holes," International Journal of Fracture, vol. 11, No.2, 1975.
You might do a search using Dr Grandt as keyword as for some reason his name popped up in the windmills of my mind.
http://cobweb.ecn.purdue.edu/~grandt/
I would also do a search on NASA. For some reason my system is getting error messages saying to allow Java Scripts when I Try to look at papers on their website.