MS14218 / BACR15FV rivet fatigue data

[MNLiaison]

Does anybody know of published data that quantifies the fatigue benefit of the MS14218 / BACR15FV riveted joint in comparison to a MS20426 or NAS1097 riveted joint of 2024-T3?

Regards,

MNLiaison

 

[Fatstress]

MNLiaison, as you know generally the fatigue performance of a structural joint, for instance in a sheet metal lap joint, will be depending on the :

1. Number of rivet rows
2. Rivet diameter, and
3. Rivet type

Regarding the rivet types, you need to compare qualitatively the hole filling capability (heat treated or not) after rivet installation and the clamping force it can produce (depending on the squeezing force). Other than that, you just have to do some fatigue testing or find out if somebody has already done it and and make it public.

 

[rb1957]

for my 2cents, you're comparing a boeing rivet to two different types, a full CSK (MS20426) and a shallow CSK (NAS1097) ... these are used in different applications for different reasons, so it'd be reasonable to compare to one or the other depending on the head type.

also i'd be really surprised if there is a comparison that you can quote, and that applies to your application.

lastly, a rivet is a rivet, for all their minor differences (apart from head type, that is). i think you get more variation in fatigue performance from the design specifics and the installation processes than you get from using a different manufacturer's rivet.

 

[der8110]

Published, no. Proprietary, yes. All other things being equal, you can achieve up to 4X fatigue life. The Briles BRFZ or MS14218 or BACR15FV does this by better hole filling (in the straight bore of the "countersink") and having edges that are not too sharp.

Advertising slogans are true, but to get more than that, you'll have to buy enough product to get test data.

 

[WKTaylor]

MNLiaison...

Look at MIL-HDBK-271/102... hase just about everything You need to Know about installing these rivets... and replacements in-case of structural repair.

I had long discussions with fastener-test engineers regarding these "special" rivets and conventional 100-deg flush heads.

MS14218 and BACR15FV rivets rivets are impossible to install "by-hand" methods in production: quality falls wayyyy-off, leading to degraded fatigue and shear-strength performance [based on statistical analysis of thousands of installations]. However, if Installed using automated methods [including feed-back QA loops] then quality can be maintained and fatigue benefits derived.

Conventional flush head rivets, driven properly by hand, tend to have sligtly lower shear-allowabls and fatigue performance than machine-installed MS14218 and BACR15FV rivets. HOWEVER. Inconsistent hand installation of MS14218 and BACR15FV rivets drives-down the statistical reliability, such that they can [statisticaly] perform MUCH worse than conventional flush head rivets [Exception: conventional rivets incorrectly driven in too-deep-a-countersink are worst-of all].

Regards, Wil Taylor