[lmilcin]

Hull is definitely not decomposing or degrading. If left in peace at sufficiently high altitude it would look the same in a million years.

My bet is the issue is most likely stresses due to vibrations under pressure and pressure changes. It is complex but also well known problem. As the astro/kosmonauts move about the station, resupply dock, pressure changes, etc. some parts are being subject to constantly changing stresses while already being stressed due to pressure.

It might also be possible that there are some additional thermal stresses but I think it is less likely these are source of the problem.

[sailingparrot]

> My bet is the issue is most likely stresses due to vibrations under pressure and pressure changes.

So you are saying it's degrading?

[maxerickson]

These discussions about materials are often difficult, because there are meaningfully different processes that are lumped together in everyday language.

Mechanical stresses leading to failure at a particular point are certainly a form of degradation, but I believe they mean degradation in the sense where the entire body of the material is undergoing some change (like a plastic bottle fogging or such).

I think seeking clear descriptions is fine, treating it as a "gotcha" game is tedious and unnecessary.

[lmilcin]

I took liberty to look through the literature and it seems change of physical and chemical properties of material due to all types conditions (including physical stresses) is covered by the term.

I am not into mechanical science that much, I have always treated degradation as a kind of surface or volume phenomena where the material looses its properties due to temperature, radiation, age, chemical reaction, etc. For mechanical effects there are already very good terms like metal fatigue and stress induced cracking.

[waheoo]

> "gotcha" game is tedious

I agree but you can say the same thing in reverse. This is a public forums, you don't need to claim something isn't right because it doesn't fit the technical description.

[lmilcin]

Just stop this already.

The post said "is this materials decomposing or degrading".

While I may have not been precise about "degrading" part, we can assume the metal is definitely not "decomposing".

[waheoo]

Ah I think my reply went to the wrong person. Edit: Nope just under your comment is all.

My remark is at the person claiming tit for tat about the tat instead of the tit.

[HPsquared]

Degradation of the structural integrity, I'd say.