Mixed Fasteners in a Doubler

[Miner89r]

I am reviewing a doubler installation that was originally to use (23) 5/32" MS20470AD protruding head rivets. Because of clearence issues and edge distances a couple of the rivets have been changed to flush heads and a couple more have been reduced in size to 1/8" . I know that you shouldn't mix fastener types within a joint but since these are all rivets is this acceptable?

I'm a young engineer and new to aircraft stress analysis. Thanks for your help.

 

[Lcubed]

Miner89r (Aerospace)
Since all the fasteners are hole-filling, you should be able to mix them. It is not uncommon to find different size rivets in patterns. However you need to redistribute the load using the actual strengths of the various rivets and be sure that the strength of the pattern is adequate.
Regards,
Lcubed

 

[motaniciu]

Hello Miner,
I have a suggestion(or oppinion whatever)...If you are talking about a big doubler than it's ok to user different rivets,different pattern; when I say big doubler I mean for example surround doors.For small doubler expl antenna doubler it is better not to combine the rivets because experimental results shows that the stress distribution is not the same;the method presented in Bruhn or Niu is not working properly.
Hope it is helpfull to you.
M

 

[Lcubed]

Hi motaniciu,
Could you give me a reference for what you say? I'd like to use it and keep it on file.
Regards,
Lcubed