Fastener Proof Testing
Fastener Proof Testing
(OP)
Greetings all,
One of our project teams has expressed interest in performing proof testing on single point failure fasteners to verify structural integrity rather than choosing other nondestructive evaluation methods. Our written standards for this testing specify that fasteners be proof tested to 75% of the MTR utlimate tensile load. However, no one seems to know where this 75% came from. Does anyone else you this standard or think they can shed some light on this mysterious 75%?
Thank you!
One of our project teams has expressed interest in performing proof testing on single point failure fasteners to verify structural integrity rather than choosing other nondestructive evaluation methods. Our written standards for this testing specify that fasteners be proof tested to 75% of the MTR utlimate tensile load. However, no one seems to know where this 75% came from. Does anyone else you this standard or think they can shed some light on this mysterious 75%?
Thank you!





RE: Fastener Proof Testing
RE: Fastener Proof Testing
RE: Fastener Proof Testing
However, if you won't do that, then test the joint - as it is used in your appliation. Do not test only one component of the joint (the fastener).
RE: Fastener Proof Testing
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Fastener Proof Testing
Using proof testing for anything beyond that simple purpose is not a good idea IMHO. Try to redesign the structure to elimiminate the single point failures. Threaded fasteners have so many stree risers on them anyway that they are notorious failure points. (I keep trying to eliminate the stress risers, but every time that I do, the nuts slide off....a little fastener humor there). The other possibility is to grossly overdesign that portion of the structure so that in-service failure just isn't going to happen.
Dick
RE: Fastener Proof Testing
If you know the batch number you can double check according to the spec.
RE: Fastener Proof Testing
Several of us here question this testing method as well. But of course before discrediting it completely, we have to figure out where it came from and why it was initially considered acceptable for these purposes.