Any recommendation for screw set design for vib and shock environment

[Mirui]

Material is aluminum AL6101.
There are 3 single parts and connected by several M2.5 screws. Each part weight about 150grams
Screw will be M2.5 SS.
Target shock are 40G at x,y,z.

Currently what we do are
1. using loctite on screw
2. using thread insert

Any suggestions to ruggidize the design are welcomed.

 

[Strong]

You might consider recessed fits so the parts take the shear load and not the fasteners.

Walt

 

[Mirui]

Thanks Walt, I like this idea.

 

[drawoh]

Mirui,

Use a torque wrench.

--
JHG

 

[IRstuff]

Just to survive or meet some sort of performance requirement? And how many/often are the shocks?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[Mirui]

Thanks, we do specify toruques on each screw when tighten them.
Thanks.

 

[Mirui]

We need to meet MIL-STD-810G vibration and shock test, for shock, it is 40G at x,y,z and 4 times each axis, 12 in total.

 

[Tmoose]

Is this the first iteration of the design, or are you ruggedizing because testing has revealed deficiencies?

No offense intended, but knowing just the mass and the screw size leave your design, and the reactions at the fastneners, up to my imagination, and the results ain't pretty.

http://geekandsundry.com/wp-content/uploads/2015/04/1-Butter-Battle-Book.jpg

https://ccnyarted.files.wordpress.com/2012/02/marshmellow2.jpg