Stress/Deformation on 3/4" NPT Fitting
Stress/Deformation on 3/4" NPT Fitting
(OP)
Hello,
I'm looking to determine, for a given torque on a plug, tightened into a 3/4" NPT coupling - to calculate the circumferential stress. Trying to determine whether the fitting is experiencing permanent deformation.
Thanks
I'm looking to determine, for a given torque on a plug, tightened into a 3/4" NPT coupling - to calculate the circumferential stress. Trying to determine whether the fitting is experiencing permanent deformation.
Thanks





RE: Stress/Deformation on 3/4" NPT Fitting
RE: Stress/Deformation on 3/4" NPT Fitting
Circumferential stress is not the problem. You need to look at thread load verses make-up torque, you need to examine stripping the cone of threads from the base metal, you need to settle the account on transverse loading or shear, bending stress. Bending is the number one killer on NPT threads.
Look at the mechanical engineering articles from the University of Tennessee. This will help you on your quest for the truth.
Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada
RE: Stress/Deformation on 3/4" NPT Fitting
This gives the ammo to approach this problem.
Very enlightening on the actions of NPT threads!
RE: Stress/Deformation on 3/4" NPT Fitting
Any helpful hints to get me started? I'm reviewing my engineering texts but know this is a question I've looked into before and never found a sufficient answer. I have access to advanced nonlinear FEA but that seems overkill to me. I'd like the spreadsheet solution.
Thank You