Huth's Method for modelling fastener stiffness

[StevenKatzeff]

thread2-192705
As an addendum to the above thread, if I have three shell elements of varying thickness connected with springs in an FE model, not working in double shear (the load is applied at the top shell), do I apply the Huth stiffness for each connection or do I use an average for both springs?

 

[ESPcomposites]

Generally speaking, you would input a unique flexibility for each unique scenario. So no, don't average them. That is just per the typical approach, for what its worth. There is a lot of variance in the data.

Thanks for bringing up the old thread. I have not seen it, but was aware of the "error" in the formuala. I believe it is just an error in the translation from the original German paper (I have both the ASTM and German).

Interestingly, at least one major company uses the ASTM version (which may be in error).

On a side note, depending on the problem, you can also check the sensitivity to dramatic changes in flexibility. Many problems are not very sensitive. But that will depend on how you are attaching the structure.

Brian

http://www.espcomposites.com