Self locking material

[ranfer]

Is there a material that behaves like a seat belt ? Locks when fast pulling and allows movement during slow pulling ?

[Carrock]

Silly putty.

[Strange]

More generally, some classes of non-newtonian fluids: https://en.wikipedia.org/wiki/Non-Newtonian_fluid

[ranfer]

Thank you for all the responses,

Also searched for "D3O goo", that is also performing in a similar way.

[Phi for All]

11 hours ago, Carrock said:

Silly putty.

The problem here is that it snaps if stretched too quickly, such as in the case of a seat belt in a collision. It would make a great bumper though, wouldn't it? Or boxing gloves?

[Carrock]

29 minutes ago, Phi for All said:

The problem here is that it snaps if stretched too quickly, such as in the case of a seat belt in a collision. It would make a great bumper though, wouldn't it? Or boxing gloves?

I was rather intending a fun/annoying quick answer.

I wouldn't be very keen on any seat belt that went rigid just when I wanted it to spread out stresses...

It does have lots of potential uses such as you've suggested. It's 'only' a matter of engineering.

My favourite (Daedalus in New Scientist) was as the paving for (very) short stay parking.

[Phi for All]

4 minutes ago, Carrock said:

It does have lots of potential uses such as you've suggested. It's 'only' a matter of engineering.

A liner for bike helmets, maybe. Also, it would be funny to challenge someone to a duel with Silly Putty gloves (they look like rubber, hit like a rock).

12 hours ago, ranfer said:

Is there a material that behaves like a seat belt ? Locks when fast pulling and allows movement during slow pulling ?

I don't think a single material has all the properties you'd need for the kinds of stress you're talking about. Seat belts have multiple systems, including the woven straps for restraint, the tension mechanism, height adjustor, and latch mechanism. 

Also, the seat belt is a proven mechanism. It's ubiquitous from mass production and therefore inexpensive. Anything new has lots of hurdles to overcome in terms of cost efficiency vs lives saved. It's estimated that seat belts save about 15K lives every year in the US alone. 

[TOTAL_IDIOT]

Mix corn startch and water. It's called 'oobleck'. Great example of exactly this.

[Phi for All]

3 hours ago, TOTAL_IDIOT said:

Mix corn startch and water. It's called 'oobleck'. Great example of exactly this.

Same problem silly putty has. Stretch it too quickly and it snaps. It only stretches when pulled/pushed slowly. 

Perhaps a new material isn't needed. Maybe current materials can be woven differently, given different twists of the fibers to impart different energies and strengths. As an example, if you wet a cloth towel, then stretch it from both ends the way a seat belt is stressed, the water stays in the towel. But if you give the towel a few good twists first, when you stretch it from the ends it will squeeze the water out as if pressed laterally. The twists change the way the fabric deals with energy, so perhaps this might make a better belt, but I think the OP is asking for a "substance" rather than a better woven fabric belt.

[Strange]

6 minutes ago, Phi for All said:

Perhaps a new material isn't needed. Maybe current materials can be woven differently, given different twists of the fibers to impart different energies and strengths.

You made me think of the Chinese finger trap: https://en.wikipedia.org/wiki/Chinese_finger_trap

There are various medical uses for this.

[Phi for All]

1 minute ago, Strange said:

You made me think of the Chinese finger trap: https://en.wikipedia.org/wiki/Chinese_finger_trap

There are various medical uses for this.

I could see this being used for attaching hoses to devices. If you grabbed the hose up at the attachment point, you could easily slip it off the coupling. If you just yanked on the hose, the woven part would tighten up and hold on to the coupling.