Urine Powered Generator Invented By Four African Girls

[Netpackrat]

I think there are a lot of reasons why body parts get replaced rather than repaired these days. Some of them are structural, as you mentioned, but the skilled labor required to straighten panels is a lot more expensive and doesn't really exist anymore in sufficient quantity compared to semi-skilled labor that can swap parts. And given the semi-skilled labor that actually works in body shops, nobody wants a repair job that re-uses damaged panels, even though in theory a quality job can be had (but this requires a higher skilled worker, again). Add in the huge logistical improvements of the last couple decades, where even junkyard inventories are wired into the system, and sourcing good used parts is a lot faster and easier than it used to be. As much as it pains me to admit, old fashion hammer and dolly skills just don't make as much sense in the modern repair environment.

[Termite]

Also, we need to start rating vehicles in efficiency per passenger mile, or per ton mile (for cargo vehicles).

This is why ships, river barges, and trains are so spectacularly efficient at freight hauling.

[Aglifter]

A) I'm not trying to argue engineering too much with those of you who stuck with it - I ran away into biochem after the first 2 years.

B) All mass can influence, as far as vectors, is what direction the joined mass moves. Deformation, etc is all dependent on strength.

C) All aluminum cars are already here - Jag and Lotus are both on Al chassis.

D) Yes, the engineering will be more complicated. Steel is "dumb", you can use simple structures, and be sloppy w. the engineering, and allow the inherent integrity of steel to cover some problems.

E) You are right about the failing issues. A designed structure - Al, polymer, etc - doesn't deform, until catastrophic failure, usually. A more controlled failing could be possible, but its safer to just put a very high strength structure in place.

It might be better to keep the thin steel body panels, etc and use polymers for the "cage" elements - those kind of impacts total the cars, regardless. (Yes, frames can be "straightened", but they are never trusted again. If your car gets into that kind of impact, it will never be pass tech again, at least at the PCA events I used to work at A&M.)

I still think the final destination is the same direction computers/phones/etc have been going. There is more nostalgia present in some cars - but the overwhelming majority of them are viewed as, mostly, disposable.

[MiddleAgedKen]

The downside is the kind of damage they suffer from minor collisions - tell somebody their minor fender bender means that their 2 year old 40K dollar car, that they're still making payments on, is basically totaled, and you'll have lawsuits flying left and right.

IF federal law mandates a 50+ mpg fleet average, that's the price we are going to have to pay. There really isn't another option.

Thunderdome! The auto lobby vs. the trial lawyer lobby! Two lobbyists enter! One lobbyist leaves!

Or the industry is sued into oblivion because each lobby managed to buy enough legislators to produce a stalemate, and nobody understands the Law of Unintended Consequences.

[Greg]

B) All mass can influence, as far as vectors, is what direction the joined mass moves. Deformation, etc is all dependent on strength.

That's like saying "all a freezer does is make things cold".

Influencing the vectors is exactly the point. It is precisely why mass is important in a collision, because influencing those vectors determines just how *bad* the collision is going to be (how severe in terms of change in velocity and energy applied) for each party. The general rule of thumb is, more mass = you hurt less.

[Aglifter]

You confused your issues. You are concerned with "how severe the changes in velocity are". That can be fixed with means other than mass.

You are much, much, safer hitting, say a wall/tree/other "immovable" object in a modern, light, well-designed car, than, say in a 1960s Lincoln Continental, or getting T-boned in many modern pick-ups, because there was no structure there to save you.

[Greg]

You confused your issues. You are concerned with "how severe the changes in velocity are". That can be fixed with means other than mass.

There's more than one way to alter that. All other things being equal, in a collision between objects, increasing your mass means you will experience less change in velocity. It's basic physics. First you manage not to understand the implications, then you change the subject. OK.

You are much, much, safer hitting, say a wall/tree/other "immovable" object in a modern, light, well-designed car, than, say in a 1960s Lincoln Continental, or getting T-boned in many modern pick-ups, because there was no structure there to save you.

Did you actually read where I wrote:

(Mind you that paradoxically, excessively rigid steel structures can be worse in collisions than steel structures that deform.)

Deformation increases the distance (and therefore time) over which velocity changes occur, thus directly reducing the acceleration you are subject to in a collision.

Of course you have to realize it's not an either-or, more than one factor can and will influence the end result of how you will be affected by a collision. Being in a more massive vehicle, and being in a vehicle that deforms will both tend to reduce the acceleration you experience.

[Aglifter]

There's more than one way to alter that[referring to velocity change experienced by the occupants]. All other things being equal, in a collision between objects, increasing your mass means you will experience less change in velocity. It's basic physics.

I doubt there's anyone on this board who doesn't understand the concept of inertia. I wasn't arguing that mass didn't do that - I was arguing that there are alternatives - which you seem to accept.

First you manage not to understand the implications, then you change the subject. OK.

A) This comes off as a combo of "I am a Yankee,", and "I'm spiffy for going to MIT." I promise, you aren't the smartest person on this board - nor am I, for that matter. That I perceive that comment as jackassery, could merely be a cultural clash.

(Mind you that paradoxically, excessively rigid steel structures can be worse in collisions than steel structures that deform.)

Yes, I read this, but that's not germane. Those pick-ups and old sedans don't fail because they are too rigid, they fail because they have mass, but no strength against and impact. (Put some of the Lincoln Continental convertibles on a lift, open all 4 doors, and the chassis will bend. Those pickups fail terribly on a side impact, because there isn't any structure on the side to resist the impact, if it gets hit above the chassis.)

Rigidity is not the flaw of the vehicles I mentioned. Nor is it, inherently, a flaw. Again, going to race cars/Lotus/Sports cars in general, their design embraces that rigidity.

Deformation increases the distance (and therefore time) over which velocity changes occur, thus directly reducing the acceleration you are subject to in a collision.

Yup, decreased rate of deceleration. (of the occupants.) That's been my point, however poorly expressed - mass, etc are merely means to achieve that.

Of course you have to realize it's not an either-or, more than one factor can and will influence the end result of how you will be affected by a collision. Being in a more massive vehicle, and being in a vehicle that deforms will both tend to reduce the acceleration you experience.

[/quote][/quote]

Again, that was my point. You can use deformation in lieu of mass.

[Yogimus]

From the scenes I have seen, materials and general vehicle weight have little effect on the damage the driver suffers in a wreck with a stationary object... HOWEVER: The amount of damage suffered by lighter vehicles in impacts is MUCH greater. When an SUV meets a smart car, the smart car (and its occupants) will be dealing with the trauma.

[HTRN]

This is somewhat relevant..

A Japanese EV is set to become the worlds most aerodynamic production vehicle. It's somewhat odd looking, but to me, it's a likable odd - it reminds me of a Citroen DS..

Take that body shape, use CF bolt on body panels over an aluminum chassis, make it a "big battery" hybrid that uses a Direct injection 2cyl with a 1liter.. Use low RR tires... It wouldn't surprise me to see it get 100mpg on the highway.