Vibration Test: Anodized Aluminum

[wearules]

I recently had a vibration test done on a case. Inside was another sizeable component. The case had aluminum rails mounted inside (almost similar to a C channel) and the component had a rail on each side (a simple flat bar mounted to component). The component rail slides into the C channel very snug. After a vibration test we saw black on all rails, internal and component, where they were rubbing together. Is this common during a vibe test or should I consider other options?

https://files.engineering.com/getfile.aspx?folder=5f95d5e8-c4f3-48bb-b9d8-673f761ada79&file=rail.PNG

https://files.engineering.com/getfi...2-7236-472e-a2d3-01920cecf0d2&file=rail_2.PNG

 

[IRstuff]

How was the component bolted down?
What was the composition of the black residue?

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

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[SwinnyGG]

The black residue is very likely to be aluminum oxide powder, created by fretting of the two aluminum parts against each other during vibration.

Yes, this type of result is common in a vibration test.

We cannot tell you whether this is acceptable or not- it's your test, you have to decide.

 

[Tmoose]

A "snug fit" is generally no protection against micromotion, and fretting.

The joint needs to be clamped hard, Whether to preserve your fixtures and parts, or to actually make the product-under-test survive the test.

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Lubrication can help a lot too.

Kluber has some high-tech assembly pastes.
Here is one -

https://www.klueber.com/blog/usa-ca...al-assembly-paste-for-frictional-connections/