Toughest material for space ships

Eridanus1

What is the highest tensile strength material known to man? can we use for builsing a space ship or o neil habitat?

I think it has to be titanium based, but what is it. Is it possible to alloy titanium with something exotic like ---- e.g uranium? No?

enigma

If I had to guess, I'd say carbon nanotube. Unfortunately, that's not something you can make walls out of.

Steel is stronger than titanium. The reason titanium is used in space applications is because it is relatively strong while being much lighter than steel.

PerennialII

Yeah, titanium is up there for a very good reason. Strength - toughness wise my favorite are maraging steels, have yield beyond 2000 MPa and still exhibit tolerable values of fracture toughness.

Cliff_J

Well since the craft needs to be launched from the surface weight is important. Something like the carbon composities have very high tensile strength/density ratios.

Impact resistance is also important as evidenced from the last shuttle failure.

Well, unless you watch the discovery channel where they show wacky Troy Hurbertise (bearsuit guy) claiming he has a paste that would have saved the shuttle. Of course Rude Goldberg was published but that was more entertainment merit where science and logic were removed for humor. Here is a photo that needs no caption as the infamous bearsuit guy demonstrates his material's fire resistance on TV.
http://207.234.149.110/images/bearsuitguy.jpg

Anyways, cost, availability, durability, resistance to temperature swings, et cetera are all factors that need to be addressed.

I would guess possibly some steel alloy may have the best tensile strength but some materials might find some exotic that surprasses that. Regardless, one parameter doesn't choose perfect material.

Cliff

cronxeh

http://207.234.149.110/images/bearsuitguy.jpg

ROFL.. Oh man I didnt know MechE forum could be so much fun


Edit: Since I dont want to be the next Tribdog on PF here is my input to this thread:

Concrete is good for compression forces but bad for Tensile forces. There is a delicate balance between those forces and their weight for space applications. Considering a complex system, some materials will be good for tensile strenght (carbon nanowires), and some would be good for compression forces. But as far as I know there is no material thats excellent for both - if there is they are patenting it as we speak

hypatia

I'm thinking of ceramic or foam based glass...it has to be heat proof too. Perhaps with a inner structure of carbon fiber.

PerennialII

MMCs etc. exotic composites do have favorable strength properties over a wide range of conditions (such as temperature), but the data I've seen usually predicts some problems toughness - wise. Don't know whether someone has overcome this (?) / how high toughnesses can be attained, and of course many problems can be avoided with intelligent enough design. Traditional carbon fibres have easily tensile strengths around 3.5 GPa (and way over), so no wonder use of composites would be a good choice.

ohwilleke

Ideally, if you were building for interstellar travel in a mature technological environment, you'd try to manufacture as much of the ship as possible in orbit and obtain it from space based mines on asteroids and the moon and the like.

It isn't obvious to me, however, that space craft need to have exceedingly high tensile strength. The structure has to handle accelleration that can't be that much above 1G for a sustained basis, support a 1 atmophere externally directed pressure, provide meaningful radiation shielding, and handle micrometeorite impacts from the side with no added velocity due to the movement of the craft. If they are moving very fast, you'd probably be better off with a fairly modest strength main vehicle with those specifications and a frontal shield to handle high impact encounters. You can probably achieve those parameters with lead lined aluminium.

Speed

Depends on the application of the space ship.

If you're talking short term, disposable craft then you have a whole range of lightweight materials to use, such as plastics and various alloys. Pretty much what is used today.

If you're talking long term, "generational" spaceships where generations live there until they reach a destination star, then you're pretty much forced to use metals because they're the easiest to fabricate parts, repair and replace. Because of the mass of such ships, they will probably have to be built in orbit or a low G asteroid/moon/planet using raw materials mined on site.

russ_watters

If you build the craft in space and launch it from space, strength is actually relatively unimportant for the craft itself. However, since the materials still need to be launched into space, weight (or rather, strength to weight ratio) is important. So that means an aluminum alloy or titanium.

Speed

The density or weight of the metals won't be much of an issue if you mine them on site. It is however true that denser metals offer better protection against radiation than lighter ones like Al or Ti.

Arctic Fox

Some ceramic-related ideas;



http://www.sglcarbon.com/gs/prodser/...ond/index.html

Alumina (Al203)

Macor

Shapal

SkepticJ

Now this can't be right because if titanium is really strong and much lighter than steel then titanium is stronger by mass.


The ideal material would most likely be an alloy of different stuff. If some way is found to glue carbon nanotubes into a material that has good compressive strength, maybe that flexible concrete stuff. Aerogel is the best insulator I know, save for a vacuum. Don't know about aerogel? Look it up on www.nasa.gov

FredGarvin

Titanium has a better strength to weight ratio than steel, but it's overall strength is less than that of steel. Granted overall strength is going to depend on what alloys you are looking at on bot the Ti and steel sides.