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Submitted via IRC for AndyTheAbsurd
Hyperloop One claims that its prototype ultra-fast train has completed a first full systems test in a vacuum, reaching a speed of 70 mph. The sled was able to magnetically levitate on the track for 5.3 seconds and “reached nearly 2Gs of acceleration,” according to the company.
The test was conducted privately but Hyperloop One offered some video that included footage from testing. Based on that footage plus a few seconds of additional b-roll shared with media, a lightweight skeleton sled uses a linear motor to accelerate, levitates briefly, and then comes to a halt as the brakes are applied.
Hyperloop One was created as an answer to a challenge from Tesla and SpaceX CEO Elon Musk, who wrote a white paper envisioning a mode of transportation that would send pods at speeds greater than 700mph using a low-friction environment and levitation using air bearings.
Source: Ars Technica
(Score: 2) by Arik on Friday July 14 2017, @12:53PM (3 children)
No, it's not infinite force and it doesn't need to be.
"A tiny dent, etc would at first just create a tiny leak."
No, in fact, that's very often not what happens. Instead the tiny dent compromises the structure enough that it's no longer able to resist the atmospheric pressure and it collapses suddenly.
"Why would that happen? Buckling leads to leaks (and you can independently detect buckling with external sensors) which leads to near instant leak detection."
A tube holding a temperature differential works very much like an arch holding up a building works. The curved structure can withstand incredible compression, but if you first set the compression, then cause some tiny bit of damage to the structure, it can collapse almost instantaneously as well.
So by the time you detect the leak it may well be too late to do anything about it.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by Nuke on Friday July 14 2017, @07:40PM
While I think the Hyperloop will be a white elephant, your argument is just not true. You can design a vacuum vessel to withstand dents, it is just a matter of how strong you make it and the nature of the material. Assuming the Hyperloop designers have some sanity, they will not create a design that is on the brink of implosion.
The comparison with an arch is misleading as people wil think of a masonry one, and masonry is brittle and also cannot withstand much tension. A Hyperloop tube (or steel arch) would be made of structural steel which is mallable and work-hardening. I have done structural analysis of major structures (at nuclear power stations) and the consideration, and analysis of departures from perfect geometry is routine. Even masonry arches don't collapse just like that - the medieval arch bridges in Europe are doing fine, despite plenty of your "tiny bits of damage", and worse.
If you make a big enough dent in a Hyperloop tube then eventually it might implode, but to make such a dent we would be talking about bombs or aircraft crashes, which no transport mode can withstand anyway. We do consider aircraft and bombs hitting power stations though.
(Score: 1) by khallow on Friday July 14 2017, @10:50PM (1 child)
As Nuke noted, it depends what you make the structure out of and what the load is. There are arches which can withstand a lot of damage. If this shell is built so that it barely withstands atmospheric pressure under the best of circumstances, then someone is doing it wrong. There should be ample margin of safety precisely because we don't want this collapsing like an aluminum can.
(Score: 1) by baldrick on Saturday July 15 2017, @03:46AM
each car should be checking the structure - a la intelligent pig
... I obey the Laws of Physics