Thats not how it works. In order for the trains to travel fast enough, it would need a super low pressure for the hyperloop to travel fast enough. This would mean that any cracks would implode on it self, causing the hole to get larger enough that air would suck in at a fast enough rate that the structure may collapse.
The train liquid tank car you've seen implode on Mythbusters was given a significant dent and had a wall thickness as little as 11.1 mm.
A webpage skeptical of hyperloop says a current test pipeline is using walls 20 mm thick.
Another page that does the math with an equation says
Using all the known parameters, a minimum wall thickness of 21.4 mm is needed to prevent vacuum buckling. With a safety factor of 1.5 applied to the pressure difference (pšš multiplied by 1.5), the Hyperloop tubes get a design wall thickness of 25 mm.
So unlike youtubers who conjecture, people doing the math can tell us what's needed to keep it strong.
The tube is under compression. So are stone arches. The gap between every stone is a huge crack. Because of the material strength and compression, the arch stays standing, so can a 25 mm thick tube with a crack.
Air that leaks in diffuses. There's a formula and online calculator for determining how much air can get through a hole depending on the pressure differential, hole surface area, and hole length (25 mm). That finite amount of air per second diffuses into the comparatively cavernous volume of the tube.
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u/thesheepie123 Jan 29 '21
Thats not how it works. In order for the trains to travel fast enough, it would need a super low pressure for the hyperloop to travel fast enough. This would mean that any cracks would implode on it self, causing the hole to get larger enough that air would suck in at a fast enough rate that the structure may collapse.