How much wear is acceptable?
How much wear is acceptable?
(OP)
So if there is a wear mark from rubbing, how much wear is acceptable. I have often seen a figure of 10% wear as being minor, and occasionally 20%, but is there any accepted data I could use to substantiate leaving the wear mark and just blending the damage to a smooth contour.
Generally I'm dealing with secondary structure, nacelle systems and what not. In this specific instance I have a fitting on a translating sleeve that is a lug .295 thick and .625" wide with a wear mark .035 deep by .250" wide, and smooth bottomed where the actuator was rubbing against the fitting. So this is over the 10% the thickness, but a cross sectional loss of only 2.4% which in my engineering judgement is minor.
Without specific allowable damage limits is there any accepted data I could use justify this?
What factors should i be thinking about when making a judgement call like this? (Obviously primary vs. secondary structure but also sheet metal, vs. bonded structure vs. fittings with lugs etc.) Which of these would make sense to have a more restrictive limit compared with others which would be less critical?
What would be a reasonable cross sectional loss to have as a hard figure to not exceed? I was thinking perhaps 5% cross sectional loss after blending to a smooth contour would be acceptable.
Thanks,
-Kirby
Generally I'm dealing with secondary structure, nacelle systems and what not. In this specific instance I have a fitting on a translating sleeve that is a lug .295 thick and .625" wide with a wear mark .035 deep by .250" wide, and smooth bottomed where the actuator was rubbing against the fitting. So this is over the 10% the thickness, but a cross sectional loss of only 2.4% which in my engineering judgement is minor.
Without specific allowable damage limits is there any accepted data I could use justify this?
What factors should i be thinking about when making a judgement call like this? (Obviously primary vs. secondary structure but also sheet metal, vs. bonded structure vs. fittings with lugs etc.) Which of these would make sense to have a more restrictive limit compared with others which would be less critical?
What would be a reasonable cross sectional loss to have as a hard figure to not exceed? I was thinking perhaps 5% cross sectional loss after blending to a smooth contour would be acceptable.
Thanks,
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.





RE: How much wear is acceptable?
at a minimum I'd put something between the worn parts, as a sacrificial wear strip.
As for the worn parts, I'd look at where they're worn. presumably there's nothing in the SRM (I'm sure you'd've looked first).
another day in paradise, or is paradise one day closer ?
RE: How much wear is acceptable?
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.
RE: How much wear is acceptable?
another day in paradise, or is paradise one day closer ?
RE: How much wear is acceptable?
... not that I have ever designed anything that could be installed wrong.
Mike Halloran
Pembroke Pines, FL, USA
RE: How much wear is acceptable?
I was mostly hoping for direction on substantiating what I think of as a standard practice but nowhere covered by what I think of as accepted data for a repair. Also for more experienced hands to share their estimate of what wear limits are acceptable in various situations.
Thanks,
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.