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Old 06-07-2017, 07:41 AM
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AlexPeterson AlexPeterson is offline
Join Date: Sep 2005
Location: Maple Grove, MN
Posts: 2,109
Default Some ME thoughts on the soon to be obsolete shim...

The loading scenario is essentially identical to the same system without a shim, assuming both sides of the shim are flat surfaces. The previous post is right in pointing out that your analysis model is not correct.

As others have said, the bolts will have some amount of bending strain in their center, depending on how much clearance the holes have. Additionally, one or both ends of the bolts (head and nut ends) could contain a bending moment. Whether or not these latter two exists depends on how much clearance the holes have. Without analysis and understanding the exact bolt geometry upon torquing, it is not possible to know how much margin is consumed by the angular deformations.

Additionally, understanding cyclic fatigue loading of bolts in systems like this is not simple, and requires understanding the elasticity of all members in the stack, among other variables.
Alex Peterson
RV6A N66AP 1600+ hours
Maple Grove, MN
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