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Tesla, TSLA & the Investment World: the Perpetual Investors' Roundtable
- Thread starter AudubonB
- Start date
Strength requirements are not the same in all axes at all points in a vehicle, and can vary dramatically. An internal structure with a light skin orients its loadbearing elements exactly where they're needed. If your frame is the skin, you have to significantly vary the skin thickness, and even that doesn't give you full axis control, since it's planar. Also, strength-to-weight of an exoskeleton doesn't drop off linearly with weight reduction (e.g. thinning); it drops off exponentially. I'd have to look up the equations, but if I remember right in terms of strain it's to the second power, and for deflection, to the third power.
Again, though, there may be some hybridization potential. But I want people to keep their expectations in check. If you're all expecting everything to suddenly go polygonal... just, don't get disappointed.
ED: 2d moment of inertia of the cross section (m^4) is t^3/12. Stress in a beam length L supported on both ends over a gap with force F applied at a point in the middle is (t/2)*F*L / (4 I) = F*L / (2/3 * t^2). So yes, stress per unit declines proportional to thickness squared. As for deflection, with a modulus of elasticity E, it's F*L^3 / (48*E*I) = F*L^3 / (4*E*t^3). So yes, proportional to thickness cubed. Good, my memory still functions at least somewhat
To restate the consequences: halve the armor weight, and you quadruple the stress from a given force and 8x the deflection.
This also reiterates the reason why if you want to stop stress / deflection in an accident, you ideally want physically thick beams. Moment of inertia rises so fast with thickness relative to mass. Which is why buildings are built with trusses rather than just "exoskeletons" - a truss raises the effective thickness. And it's why you build out of hollow tubes and I-beams rather than solid bars.
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Noticed my wife quietly surfing on the web. Went for a shower. Came out and noticed an email on my phone. This is what I saw.
Sigh......
Sigh......
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PG&E probably just shut down power in the Bay Area due to imminent fire risk from all the pouring rain we are getting
anthonyj
Stonks
pz1975
Active Member
Works great! Now I have a Cybertruck to sit next to my die-cast Model 3!
EVNow
Well-Known Member
No. They said there will be some low volume of cars coming out of GF3 in Q4.
MartinAustin
Active Member
CT deposits may have slowed down day-by-day since the reveal, but I think there will be a Thanksgiving bump. Many folks on the fence about it will enjoy talking with friends & family over the dinner table and through the weekend, and I would not be surprised if it's enough to spur a new tweet about deposits later on Sunday, in time for the markets to analyse again on Monday.
(Just a USA issue of course, deposits in other areas of the globe will continue their slow-down)
(Just a USA issue of course, deposits in other areas of the globe will continue their slow-down)
Surely they have a backup somewhere in the Midwest or something as well for disaster recovery situations.
I think 250k is already plenty for Elon to be getting on with. He's already said he didn't think they would get that many orders. He needs to figure out where to get batteries and build them now.
SW2Fiddler
We Are Cognitive Dissidents
Noticed my wife quietly surfing on the web. Went for a shower. Came out and noticed an email on my phone. This is what I saw.
Sigh......
This was her argument. You can literally fill a fridge with beer, roll it up the built in ramp...and plug it in. Now thats facility.
Canadian chicks. Whadayagunnado.
I'll add (relative to my edits here - Tesla, TSLA & the Investment World: the 2019 Investors' Roundtable) that I highly doubt that all of the strength is in the skin. Rather, I imagine that they're doing something like hat stringers or whatnot welded to the skin. In that design, the skin is still an integral part of the strength-absorbing structure rather than just being dead mass. But it's not the only structural mass. Gotta stretch significantly out of plane if you want to get a high moment of inertia.
Indeed, Musk specifically made an airplane analogy. Well, airplanes use stringers in addition to their skin. He also mentioned Starship. Starship, likewise, uses hat stringers.
Indeed, Musk specifically made an airplane analogy. Well, airplanes use stringers in addition to their skin. He also mentioned Starship. Starship, likewise, uses hat stringers.
How does Rivian have even a tiny prayer of building enough to accommodate their vehicles, Ford's vehicles, and Amazon's delivery vans? Also, how TF do you not mention Tesla even once in that article Reuters?
For years we transported chest freezers on wheels to trade shows. It would have been awesome to be able to plug into the bed of the truck holding them. Edit, you don't want to ask what was in the freezers. (rats and mice, frozen rats and mice)
From the TD Ameritrade newsfeed for Tesla:
November 27, 2019 2:58 pm ET
S&PGR Affirms Four Ratings On Three SolarCity LMC Rtgs Deals
Dow Jones
November 27, 2019 2:58 pm ET
S&PGR Affirms Four Ratings On Three SolarCity LMC Rtgs Deals
Dow Jones
Can probably roll up a smallish jacuzzi too and get the beer from the fridge without leaving jacuzzi.
humbaba
sleeping until $7000
Given that the API appears to be broken it does seem like they put all their eggs in one basket, whether that is Fremont or elsewhere. That doesn't fly and will become a bigger issue the more vehicles there are. I really didn't think it would be done like that. Even where I work we have considerable redundancy. But it was for me as well so it appears to have been across the nation. (working now)
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