- #1
RobertsBrown
I am trying to determine the failure mode of an aluminum aircraft fitting. It's a standard AN814-3D, if that matters.
Material is 6061-T6. Book tensile strength is 45,000 psi.
Thread is a 0.375-24 standard 60 degree UN thread.
Thread relief is 0.310 diameter.
I.D. of fitting is 0.125 diameter.
The assembly spec. is 25 ft-lb when assembled dry. Failure point is between 24 and 26 ft-lb in actual practice. I am trying to persuade my client that their process engineer didn't do his homework, but the only way to do that is to 'show my math'. I can easily determine the effective area at 0.064 in^, and the tensile strength is known, and if I wuss out and forget about friction and sticktion, then I just need to find a formula that gives me linear tension from rotational input into a screw system. This is where I am currently stuck.
This is probably as basic as it gets, but I can't seem to work it out.
Any help is appreciated.
Material is 6061-T6. Book tensile strength is 45,000 psi.
Thread is a 0.375-24 standard 60 degree UN thread.
Thread relief is 0.310 diameter.
I.D. of fitting is 0.125 diameter.
The assembly spec. is 25 ft-lb when assembled dry. Failure point is between 24 and 26 ft-lb in actual practice. I am trying to persuade my client that their process engineer didn't do his homework, but the only way to do that is to 'show my math'. I can easily determine the effective area at 0.064 in^, and the tensile strength is known, and if I wuss out and forget about friction and sticktion, then I just need to find a formula that gives me linear tension from rotational input into a screw system. This is where I am currently stuck.
This is probably as basic as it gets, but I can't seem to work it out.
Any help is appreciated.