Elon Musk's Hyperloop is viable, says maker of simulation software

http://www.businessweek.com/articles/2013-09-18/elon-musks-hyperloop-will-work-says-some-very-smart-software

by T-A • 13 years ago

175 96 13 years ago

businessweek.com

WalterSear• 13 years ago

"Not on your life, my hindu friend!"

icecreampain• 13 years ago

Downvote, eh?

It appears as if there are tightasses here that haven't seen the monorail Simpons episode.

stbtrax• 13 years ago

This is not reddit, and it seems to be a problem with engineers of a certain age, but no one wants to constantly hear your 20 year old cartoon references throughout the day. Also I am incredibly glad that the most prominent south asian on network TV isn't a white dude's impression of a stereotypical immigrant.

InclinedPlane4• 13 years ago

It's a good joke but HN isn't about jokes, people are trying to having a conversation on a topic and random jokes merely make that more difficult.

gkoberger2• 13 years ago

Slightly misleading. They said "it could work".

FTA: "I don’t immediately see any red flags. I think it is quite viable."

epistasis• 13 years ago

What is misleading? Was there a different title at some point?

gkoberger2• 13 years ago

EDIT: Title was changed since I posted that. It originally said "it will work".

RoboTeddy• 13 years ago

On viability: what's the state of the tunnel thermal expansion issue?

(Last I heard, it seemed like there might not be easy workarounds)

kornork• 13 years ago

Yeah, this seemed like the biggest killer, besides inertia and politics.

My friends and I were wondering aloud if you could put a slight bow in the pipe - so instead of expanding lengthwise, the pipe might raise and lower at certain places. Of course, none of us are engineers in that sense.

nether• 13 years ago

1. Most of the tubes would need some bowing anyway for curves, since they can't find a perfect straight path from LA to SF

2. Tests show that tubes where L >> D, thermal expansion is linear along the length. If you restrained both ends you'd get the buckling in the interior sections that you describe. That might even be a bigger problem though because it would affect the path geometry and alter the attitude control requirements of the pods. I think the wrinkling in the tube skin would also be more dangerous than just letting it stretch.

toomuchtodo2• 13 years ago

I am not an engineer outside of IT, but what if you submerged the hyperloop in the pacific between SF and LA? Would thermal expansion no longer be an issue because you're using the ocean as a thermal sink? And you can provide enough positive air pressure to keep water out of your loop.

vec• 13 years ago

Yeah, but one of the big bullet points is that the tube should be at negative air pressure in order to reduce air resistance.

erikpukinskis2• 13 years ago

My understanding is that the thermal expansion is taken care of near the stations with a telescoping section. So the tube then has to be free floating, i.e. not attached to the pylons.

mbrubeck2• 13 years ago

http://www.leancrew.com/all-this/2013/08/hyperloop/ goes into this in more detail (and is skeptical that it can work as described in the Hyperloop Alpha white paper).

robbiep2• 13 years ago

I wonder if they could use carbon fiber? It has near zero thermal expansion.

I have this awesome vision of some big machine sitting at both ends where they knit fibres together, cure it then just basically extrude the thing the whole way and meet in the middle.

Yes it's expensive but with the magic of science and a bit of hand waving surely our processes have advanced to the point where this is becoming feasible?

Unfortunately I have no idea if a carbon fibre tube is suitable to operating at sub atmospheric pressures...

misnome• 13 years ago

I'm not exactly impressed by this analysis. I don't recall anyone questioning whether putting a cylinder in a vacuum tube was possible, mainly that it would be horrendously difficult to design, build, tunnel, and reach the high safety margins required, relatively inefficient compared to the alternatives, and that there was lots and lots of hand waving over the real details.

They've simulated a vacuum tube, and found that it works.

InclinedPlane4• 13 years ago

If you'd actually described any relevant aspect of Hyperloop your criticism might have more credibility, as it stands it has none. Hyperloop is not a vacuum tube train, and the primary mechanism it relies on is non-trivial.

tptacek5• 13 years ago

In your rush to point out the error he made about vacuum tubes, you missed his point, which is that the criticisms of the Musk plan don't revolve around the concept being infeasible to execute, but rather that the concept isn't cost-effective or, for that matter, nearly as customer-friendly as the proposal suggests.

Specific points that you'd want to address if you were purporting to rebut Hyperloop criticisms:

* Because Musk's plan can't leverage existing last-mile infrastructure the way HSRs do, it delivers riders from one very inconvenient location to another, adding 1-2 hours of additional transit time to SF-LA.

* Because (by Musk's own admission) destructive disruptions of his pod-in-tube runs are catastrophic in a way that they aren't with HSRs, his plan requires TSA-style airport security, adding an additional 15-30 minutes to every trip.

* The cost estimates for the Hyperloop captured only its capex costs and not its operating expenses, so that the per-ticket prices derived from its proposed cost bore no relation to its actual cost structure.

* That the tunneling and viaduct cost estimates given in the Hyperloop proposal were so low that they constituted a revolutionary breakthrough in urban planning and structural engineering in their own right; in other words, if he can dig a Hyperloop-capable tunnel for the price his plan suggests, or run an elevated tube as cheaply as he suggests, why waste time with Hyperloops? The answer would be that he can't do either of those things.

* That the routing he proposes, particularly with regards to mountain passes, are wildly optimistic, and that a realistic routing will result in a longer run and significantly increased costs.

* That the forces involved on passengers in the Hyperloop exceed the tolerances allowed for existing HSRs in ways that are likely to make motion sickness a signficant problem.

This article appears to address none of them, and your comment appears to be premised on the idea that those criticisms hadn't been made.

vwinsyee• 13 years ago

There is no (hard) vacuum tube in the Hyperloop design. This analysis did not simulate a (hard) vacuum tube.

derekp7• 13 years ago

This is actually one of my biggest disappointments with the Hyperloop announcement. Musk said early on that it wasn't a vacuum tube. But in the end, we have a tube with vacuum pumps, and an air pressure much lower than that of Mars. In my book, that is close enough to a vacuum tube that it sounds like purposeful mis-direction on Musk's part. I.e., when he said (when he first mentioned the idea) that it isn't a vacuum tube, it would have been more honest to say that it isn't a complete hard vacuum tube. Would have cut out on some of the more wild speculations.

peatmoss• 13 years ago

As a planner, my biggest questions are around land acquisition. It's not usually the kit that's the super expensive part of these projects. That said, I suppose it's possible that the land requirements for the hyperloop are less.

I meet a lot of curmudgeonly planners who like to downplay the potential impacts of new technology (hyperloop, self-driving cars, etc.), but I'm open to the possibility of truly disruptive tech. Still, I have a hard time imagining that the land acquisitions will be that much cheaper for hyperloop.

vidarh2• 13 years ago

A large point of the proposal was the massively reduced land use requirements coming from using a structure on pylons, and from having most of it follow the existing highway on land that's already publicly owned.

The assumptions regarding land use were pretty well covered in the PDF Elon Musk released.

ssmoot2• 13 years ago

It appears the simulation was only of the pods. Not the whole system.

willvarfar• 13 years ago

Well, if there's one thing Elon's teams at Tesla and SpaceX know, its engineering. He has some top talent.

seanherron• 13 years ago

I was really hoping this was from the developer of SimCity.

rorrr22• 13 years ago

Sure, when they figure out how to

1) keep hundreds of miles of tunnels in near vacuum

2) keep said tunnels intact in a seismic area

3) get all the land rights

4) all of the above at a reasonable price

loceng3• 13 years ago

It's not a vacuum system ... I don't understand where people are getting this idea.

Seismic activity will be taken into consideration.

Land rights are part of proposed cost.

Estimates based on current costs ... and Elon said likely to find more efficiencies to make it cheaper ...

lisper2• 13 years ago

It's not a vacuum system

(S)he didn't say it was. (S)he said "near vacuum." And that comes straight from the hyperloop paper:

"Just as aircraft climb to high altitudes to travel through less dense air, Hyperloop encloses the capsules in a reduced pressure tube. The pressure of air in Hyperloop is about 1/6 the pressure of the atmosphere on Mars. This is an operating pressure of 100 Pascals, which reduces the drag force of the air by 1,000 times relative to sea level conditions and would be equivalent to flying above 150,000 feet altitude."

joshmaker• 13 years ago

It's not a vacuum system ... I don't understand where people are getting this idea.

http://www.teslamotors.com/sites/default/files/blog_attachme...

Page 12: "The pressure of air in Hyperloop is about 1/6 the pressure of the atmosphere on Mars."

Sounds like a near vacuum to me.

vectorjohn2• 13 years ago

1-3 are already figured out, they are not hard problems or very different than the existing proposed HSR line. 4 is addressed and the only part that you can't really know until you dive into actual implementation. It is estimated though.

rorrr22• 13 years ago

Figured out? Where do we have long near-vacuum tunnels in a seismic area?

dragonwriter2• 13 years ago

The article makes it sounds like this somehow counters the criticism of the Hyperloop, but all the criticism I saw was of the cost estimates of the infrastructure, the utility of a route with the proposed termini, and the idea that a paper concept with no demonstrated prototype was a serious near-term alternative to high speed rail, while the issues this addresses is the basic viability of the "pod in a tube" mechanism (which it says is basically sound in outline -- but needs to be done in a different way than actually proposed in Musk's paper.)

So, it's basically a validation that the part was least criticized is probably basically viable in some form, though perhaps not the actual form proposed by Musk.

(And the one part of the pod-in-tube engineering that was seriously criticized -- the proposed mechanism for addressing thermal expansion over long stretches -- is also not addressed by this discussion.)

crazytony2• 13 years ago

I wish we had a more detailed delta (including pricing) on the 'as proposed' vs 'as modeled'.

What does reshaping the vehicle do to the cost and fitness for purpose?

crazytony2• 13 years ago

The Ansys simulation showed very uneven stress markings alongside the body of the pod. “We see a lot of shear stress areas,” Sovani says.

They didn't study it but I wonder what the stress on the curved portions of the tube wall would be? If the vehicle is prone to shear failures, I would imagine the tube would be as well.

gametheoretic• 13 years ago

Structural superiority of Tacoma Narrows beyond question. Automobile farers can expect to enjoy bridge commute for centuries to come.

--top 1940 scale-model builder

jlgreco2• 13 years ago

"I think it is quite viable."

"beyond question"

One of these people is speaking in foolishly strong terms.

dangero• 13 years ago

I'm still hung up on what happens if there's an emergency on board? Yes, bathroom related would be one, but what about something like a heart attack? Are there any other forms of mass transit that don't allow for an emergency stop or at least the possibility of gaining reasonable assistance from another person on board? I guess the closest comparison would be an intercontinental plane, but planes have space to move around and bathrooms.

jlgreco2• 13 years ago

"what about something like a heart attack?"

Well, with an average of 15 minutes until you arrive at the other end, where presumably EMTs are already waiting, I don' think you really need a close comparison. 15 minute response times are hardly unheard of and you can put yourself in a much more isolated situation just driving down the road in a car in some of the less dense parts of America.

I don't think this is a problem that actually needs a solution (though the public may very well demand one irrationally, much like the safety concerns the public is going to have with self-driving cars that are safer than human drivers...).

robbiep2• 13 years ago

I agree, I don't see the damage. In most real life situations anything that doesn't kill you immediately can wait 15-20 minutes, and when you get out the other end you can have great medical treatment. Anything that requires you to be seen by some serious medical support faster than that will generally kill you regardless of the situation (ie. Left Main coronary embolism which kills 250,000 Americans a year)

Edit: complete misuse of iatrogenic. Too little sleep. Whoops

coldtea• 13 years ago

I'm still hung up on what happens if there's an emergency on board? Yes, bathroom related would be one, but what about something like a heart attack? Are there any other forms of mass transit that don't allow for an emergency stop or at least the possibility of gaining reasonable assistance from another person on board?

Well, how it's different from a regular high speed train? (Besides reaching it's destination much much faster?) Where would a regular high speed train do an emegergency stop?

Other methods could be even worse, despite far more popular. A taxi in a traffic jam for one. You'd probably need more than 15 minutes to get to a hospital.

vidarh2• 13 years ago

This is idea of "it's an emergency, we must stop the train" is often completely flawed. Lets say you trigger an emergency stop. Now what?

In all likelihood you are going to be further from a hospital or any qualified assistance than you would if you let the train continue at full speed. If you're really unlucky, you're in the middle of nowhere.

chadwickthebold• 13 years ago

'Ansys...has fed the Hyperloop specifications into a computer..'

I love technical explanations like this. I think the specifications could have used more salt.

icambron3• 13 years ago

#1: "We need some publicity. Maybe we can ride Hyperloop's hype coattails."

#2: "Yeah, we could simulate it and talk about the results in technical sounding but vague terms that we can't be meaningfully challenged on. But what do think will get more publicity, saying it will work or that it won't? There's plenty of latitude in the specs for us to end up with either."

#1: "That it will, of course. We want our customers to think they'll be validated by our software, not shot down. But make sure you provide a little advice so it's clear that we add value. And also hedge a bit so that just in case Hyperloop is a technical disaster, we don't look terrible."

#2: "Sounds good. I'll call Bloomberg and see if they have any spots available for vacuous puff pieces."

#1: "Was that a vacuum joke?"

NamTaf• 13 years ago

Ansys does not really need publicity. They're essentially the biggest multiphysics FE package out there.

That said, Bloomberg news as an outlet to explain technical info is always doomed for failure.

chad_oliver• 13 years ago

Apple doesn't need publicity. They're essentially the biggest smartphone out there.

neurotech1• 13 years ago

I'm under the distinct impression that the decision if the Hyperloop is built is less about technical details and more about project cost.

It's not like the engineers working with Elon Musk are taking a break from designing rockets - oh wait - The engineers at spaceX build rockets that go into orbit.

pintglass5• 13 years ago

more about project cost

And freedom. If you commute with a hyperloop, can you stop by the grocery store on the way home? Not easily.

But beyond cost and freedom, there is practicality. For a while I wanted to take the bus to work, but it would take 4 hours to get there (including 10 miles walking) and only 30-40 minutes in a car. They would provide a bus to make it only 30-40 minutes if there were enough people like me to take the bus, but how do they know? They never asked.

Here are the directions the government-sponsored online tool gave me for how to commute to work (miles rounded up):

03:04AM - start walk 8 miles from home address, 05:59AM - arrive at bus stop, 06:01AM - start first leg of bus trip, 06:15AM - stop first leg of bus trip, 06:17AM - start second leg of bus trip, 06:38AM - stop first leg of bus trip, 06:38AM - start walk 2 miles from stop, 07:09AM - arrive at work

I could do that if I had a collapsible bike and could shower and change at work, but I can't (and won't).

guiambros• 13 years ago

Do you seriously think that Musk 1) needs some cheap "publicity", or 2) he didn't do quite a bit of simulations before releasing the very first whitepaper?

Again, this guy is sending rockets to space - and back. He has a couple of thousand rocket scientists and physicists at his disposal. Ansys is just getting to conclusions they have achieved long ago.

icambron3• 13 years ago

Do you seriously think that Musk 1) needs some cheap "publicity", or 2) he didn't do quite a bit of simulations before releasing the very first whitepaper?

The dialog implies neither of those things.

Edit: but also, yes, I think those things.

triggercut• 13 years ago

How many large scale infrastructure projects has this software company executed and delivered? Oh, they just supply software to people that do do that? Ok.

robomartin• 13 years ago

My friends in aerospace always say that there are two kinds of folks who believe simulations: Those who write the software and those who have to use it to justify their existence. Everyone else knows there's can be huge gaps between simulation and reality. Granted, things improve over the years but c'mon, who are they kidding.

“I don’t immediately see any red flags,”

Says the simulation guy.

Really?

“I think it is quite viable.”

Says the simulation guy. Again.

Hmmm. I'm not building rockets or cars but, you know what, I'll bet you --simulation guy-- a good dinner this thing is as viable as trying to evolve a flying elephant in a lab. You might theoretically be able to get there with enough time, but in practical terms it is impossible.

For starters I want someone to explain how we are going to build massive columns along the middle of Interstate 5 every 100 meters for four hundred miles.

And then tell me how we are going to do that and put a four hundred mile tube on top of it (let's ignore impossible construction details) for six billion dollars when building an incredibly short (by comparison) bridge in San Francisco cost the same?

Simulations like this one are like special effects in movies. They look great and make you feel like we are living in the future but they are far --very far-- from being realized. Look at something like C3PO. Thirty six years have passed and we are nowhere near such a robot being realized.

Me thinks simulation guy wants free publicity.

shishir1• 13 years ago

Having Symmetry and exact shape is more of an optimization issue. Ansys numerical simulation tools are not really needed for feasibility check. Hand calculations are sufficient, mostly taken care of in the alpha design document. However, the issue of having sufficient space to store steam is somewhat unclear and needs some brainstorming..

Shivetya• 13 years ago

Technically viable possibly, and about as economically viable as all other rail solutions offered so far in the US. Speed isn't the issue with rail, its point A and point B, well that isn't really fair. The number one obstacle to rail has always been politicians who take any well conceived route and demand it go to their hometown.

loudmax• 13 years ago

I really hope this project gets off the ground. I don't know if it will prove financially viable in the end. Maybe the most it will accomplish is serve as an experiment to tease out aspects of high speed transportation that would work from those that don't.

Progress is made by pushing the envelope of what's feasible. The biggest shame of all would be to become a society that is so afraid of making mistakes that we can't move forward.

Elon Musk's Hyperloop is viable, says maker of simulation software

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