
Elon Musk's Hyperloop is viable, says maker of simulation software - T-A
http://www.businessweek.com/articles/2013-09-18/elon-musks-hyperloop-will-work-says-some-very-smart-software
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icambron
#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
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
Apple doesn't need publicity. They're essentially the biggest smartphone out
there.

~~~
stirbot
You buy ANSYS because you need it, not because you were compelled by an
advertisement to have the latest version.

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dragonwriter
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.)

~~~
crazytony
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?

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misnome
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.

~~~
InclinedPlane
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.

~~~
tptacek
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.

~~~
ericd
Oakland has BART access, what other last-mile infrastructure are you referring
to?

WRT destructive disruptions, I believe there was a section dealing with sudden
tube repressurization. If the failure mode is effective, it seems like an
attack would be less destructive than one on a train, due to the smaller pod
size.

If CapEx is much lower, and energy cost is lower, the ticket price should be
lower, unless the maintenance cost is much higher (it may be due to exotic
requirements, but it's not fair to say that what he's describing bears no
relation to actual cost structure - it's just not complete).

No idea about the routing/tunneling estimates. Were his per-mile tunnel cost
estimates much lower than normal?

The motion sickness complaint seems like it would have legs, since there won't
be any view of the horizon - your eyes will be reporting a static environment
outside your body, and your inner ear will be doing very much the opposite.
Then again, planes experience turbulence and mild G forces and have the same
characteristic for most passengers of not seeing the horizon. Maybe motion
sickness was a much larger problem in the past, based on the presence of barf
bags at every seat.

~~~
tptacek
Musk's plan runs from Hayward to Sylmar. Both are up to 45 minutes from the
HSR endpoints in traffic.

Musk's plan specifically calls for TSA-style security.

Your third point is nonresponsive to the argument. The ticket cost will
reflect opex, but Musk's plan doesn't include it.

Yes, his per-mile tunnel cost estimates were extremely low.

Airplanes occasionally experience motion-sickness-inducing G's. Hyperloop pods
will every trip. You'd at least want to know if the design is a vomit comet
before you sank billions into it, would be the right point to make here.

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robomartin
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.

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

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

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

~~~
toomuchtodo
Right, but what if its not feasible on land due to thermal expansion, but is
feasible underwater with slightly higher power requirements to overcome air
resistance? Just a thought.

~~~
ahelwer
The design is intended to be robust with regard to leaks (pumps can overcome
some leakage to keep interior at a near-vacuum). This would not work
underwater.

~~~
mapt
Pumps can overcome a _small amount_ of leakage - from tiny cracks between bolt
threads, etc - places that an un-reactive gas can make it through a huge
pressure differential. In shallow water, one has the viscosity of water to
work with, which makes this much easier in liquid phase.

What I don't know is how pumps, and cracks, would react to gaseous H2O versus
gaseous N2; Or if perhaps a liquid with low offgassing potential could be used
as a boundary layer to seal cracks instead of water (which, while much higher
viscosity than a gas, remains lower than most liquids).

One big advantage of any submersed liquid approach: Earthquake resistance.

~~~
mapt
Additional notes: My main theory before the announcement was that the concept
used a fast-speed-of-sound, low-density STP hydrogen tube and maglev rather
than slow-speed-of-sound air tube, or an expensive-to-seal vacuum tube. An STP
hydrogen tube hovercraft levitation model still seems pretty damn attractive
to me, especially with a sealing liquid buffer of some sort - it cancels out
the problem of water-vacuum interface, and in water, flammable seals, as well.

------
crazytony
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.

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

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dangero
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.

~~~
jlgreco
_" 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...)_.

~~~
robbiep
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

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

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loudmax
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.

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

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

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

\--top 1940 scale-model builder

~~~
jlgreco
_" I think it is quite viable."_

 _" beyond question"_

One of these people is speaking in foolishly strong terms.

------
Shivetya
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.

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shishir1
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..

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

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gkoberger
Slightly misleading. They said "it could work".

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

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

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triggercut
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.

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rorrr2
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

~~~
loceng
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 ...

~~~
lisper
> 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."

~~~
loceng
Okay, not sure if I missed that or if edited - either way this is a far
different situation from maintaining a full vacuum.

~~~
lisper
There's no such thing as a "full vacuum". 100 Pascals is 0.1% of atmospheric
pressure at sea level. It's pretty frickin' close to a "full vacuum". If
there's a leak anywhere in the tube you're boned.

~~~
loceng
By full vacuum I was referring to the conditions you have in space. And no -
when you have even a slight allowance for a margin of 'error' or leakage -
that's all you need to balance things out. And if the leakage is higher, it's
a matter of efficiencies reducing - not complete failure.

------
WalterSear
"Not on your life, my hindu friend!"

~~~
icecreampain
Downvote, eh?

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

~~~
stbtrax
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.

