3 ms·

If we could start from scratch, shouldn't cars be made of plastic to reduce weight?

by bttrfl 6y ago

GuB-42 6y ago
Fiberglass car bodies used to be a thing. But they mostly came back to steel now. Fiberglass and I guess plastic isn't good enough for structural parts with the current safety standards. And if you have to support your plastic parts with steel, you lose the weight benefits.
- bttrfl 6y ago
  Wouldn't the safety standards change if all cars would weight X% of current mass? According to quick googling cars got heavier: "The average new car weighed 3,221 pounds [1461 kg] in 1987 but 4,009 pounds [1818kg] in 2010." [1]. The weight of a trabant, which was probably a very badly engineered car, was about 600 kg [2] - 1/3 of a modern car. I imagine we could make cars today even lighter and if weight of all cars would be similar than the safety standards would be much different. [1] https://slate.com/business/2011/06/american-cars-are-getting-heavier-and-heavier-is-that-dangerous.html https://slate.com/business/2011/06/american-cars-are-getting... [2] https://en.wikipedia.org/wiki/Trabant https://en.wikipedia.org/wiki/Trabant
  - GuB-42 6y ago
    It will only matter on car vs car collisions. Fully loaded trucks and ground obstacles will still be a problem. Also I am not a mechanical engineer but it looks like steel is really good at absorbing energy from impacts. Plastics tend to shatter when the impact force is too great. I actually experienced a minor accident in a fiberglass car. No one was hurt because the chassis held everything in place but the body was completely broken.
mhh__ 6y ago
It's a tradeoff between weight and strength etc. High end cars (and most/all race cars) use carbon fibre for both bodywork and structural components.
frosted-flakes 6y ago
Wouldn't that increase weight? Steel is much stronger and not much heavier, so it can be made very thin while still being strong (unibody). Also, it would make recycling cars much more difficult.

If we could start from scratch, shouldn't cars be made of plastic to reduce weight?

by bttrfl 6y ago

If we could start from scratch, shouldn't cars be made of plastic to reduce weight?

Fiberglass car bodies used to be a thing. But they mostly came back to steel now. Fiberglass and I guess plastic isn't good enough for structural parts with the current safety standards. And if you have to support your plastic parts with steel, you lose the weight benefits.

bttrfl 6y ago
Wouldn't the safety standards change if all cars would weight X% of current mass? According to quick googling cars got heavier: "The average new car weighed 3,221 pounds [1461 kg] in 1987 but 4,009 pounds [1818kg] in 2010." [1]. The weight of a trabant, which was probably a very badly engineered car, was about 600 kg [2] - 1/3 of a modern car. I imagine we could make cars today even lighter and if weight of all cars would be similar than the safety standards would be much different. [1] https://slate.com/business/2011/06/american-cars-are-getting-heavier-and-heavier-is-that-dangerous.html https://slate.com/business/2011/06/american-cars-are-getting... [2] https://en.wikipedia.org/wiki/Trabant https://en.wikipedia.org/wiki/Trabant
- GuB-42 6y ago
  It will only matter on car vs car collisions. Fully loaded trucks and ground obstacles will still be a problem. Also I am not a mechanical engineer but it looks like steel is really good at absorbing energy from impacts. Plastics tend to shatter when the impact force is too great. I actually experienced a minor accident in a fiberglass car. No one was hurt because the chassis held everything in place but the body was completely broken.

mhh__ 6y ago

It's a tradeoff between weight and strength etc. High end cars (and most/all race cars) use carbon fibre for both bodywork and structural components.

frosted-flakes 6y ago

Wouldn't that increase weight? Steel is much stronger and not much heavier, so it can be made very thin while still being strong (unibody). Also, it would make recycling cars much more difficult.