Dimpled fastener design allowables
Dimpled fastener design allowables
(OP)
Hi, I am working on a project using a countersunk fastener and dimpled .020 sheet (CP70 titanium) fastened to 7075 Aluminum. Struggling to find an industry standard on how to calculate the design allowable for sucjh a joint. We are using a 130 degree countersin with Hi-Lite pins.
Any help in finding an 'approved/recognized' methodology for this appreciated.
Any help in finding an 'approved/recognized' methodology for this appreciated.
RE: Dimpled fastener design allowables
YOU will have to test and develop Your own MMPDS-equivalent allowables.
NOTE.
I know with ~99% certainty that 130-Deg dimples [double-dimples or dimples-into-countersinks] 'mechanical allowables' [~=MMPDS] have NOT been characterized.
I've never heard of dimpling Titanium sheet... unsure how You would even do it 'consistently' for a shallow 130-Dimple... and get a clean-round hole. VERY HOT and enlarge the hole on install????
Regards, Wil Taylor
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RE: Dimpled fastener design allowables
RE: Dimpled fastener design allowables
you may find some data in old Mil Handbook 5 ... I seem to remember some tables there.
A suggestion ... you are almost certainly going to limited by sheet failures, so maybe use rivets (lighter) ?
Have you considered welding ? spot or line ??
another day in paradise, or is paradise one day closer ?
RE: Dimpled fastener design allowables
https://www.eng-tips.com/viewthread.cfm?qid=496518
Consider using chemically-milled sheets so that you can fully countersink at the fasteners but still maintain thin panels between fastener rows.
RE: Dimpled fastener design allowables
why CSK ? why not protruding head ? Even if covered ...
1) push fastener through the covering layer, or
2) recess (or thru-hole) in the covering layer (to clear the head)
another day in paradise, or is paradise one day closer ?