If it's rated to 6000lbs, and you test it at 6000lbs, it certainly _shouldn't_ be destructive.

It should go back as long as the test stays below the yield point: https://en.wikipedia.org/wiki/Yield_(engineering) ... but there is also fatigue: https://en.wikipedia.org/wiki/Fatigue_(material) . This is just for raw material though, I'm not sure how it works on the connectors.

If you only do a few cycles under the yield point, fatigue isn't going to be an issue. If you ran 10^5 or more on a fatigue critical part, then I'd start to question it.

Those struts are also used in the stages that are about to be reusable, so my guess is that they're supposed to withstand the flight conditions multiple times. That would hint the equivalent tests should also not be destructive to the material.

The post said they're rated to 10,000lb and failed at 2000. Sounds like there's a lot of margin between the highest force expected and the rated level, so they could test somewhere between the two.

From what I understand they are designed for 10,000lb rated/certified for 6,000lb and only need to withstand 2,000lb. They found one/some struts in stock that failed at/below 2,000lb. Does anyone have some other interpretation? It seems like every place I read one of those numbers it's different.