system
Given the following post, respond as if you're commenting on Reddit:
human
Does a double hull on a pressurized vehicle, where the space between two hulls is kept at a pressure halfway between the interior and exterior pressure, actually reduce strain?

To clarify, this is a situation where you reduce the difference in pressure on any one piece of hull by having the inner hull only need to handle some of the difference, and the outer hull handle the other half of the difference. It makes sense to me that it would, but it also seems like one of those really reasonable sounding fallacies, where there's actually a pretty simple reason that it somehow wouldn't work at all. This could be a submarine or a spacecraft, although obviously the pressure strains on a spacecraft are very tame compared to those on a submarine.
gpt
A partially pressurized double hull would indeed reduce the forces on each of the hulls if designed that way. However, most double hulls are there for redundancy, not for reducing the forces involved. Double hulls are complicated to design and manufacture; it’s practically always easier and cheaper to overbuild one hull than to make one hull inside another. 

That double hull is extremely useful for telling if a hull breach has happened. If that intermediate pressure deviates from its set pressure, then that means either the interior or exterior hull has been breached, and they can tell which one failed by the measurement. Even in non-pressurized applications, it’s useful to tell if underground tanks or other tanks with dangerous materials inside are leaking before the leak actually makes it into the open.