What’s the toughest bulk material? Is it a metal or a rubber? Is there a difference between the toughest bulk material per unit volume and the toughest bulk material per unit mass?

I’m looking for a wire or ribbon of material to absorb energy in tension by either elastic (preferred) or plastic deformation.

Rubbers are supposed to range in toughness from 1 to 100 kJ/m^2, but which rubber is toughest and where do I get some?

PS, one of the toughest plastics is polyethylene, so tough that it’s used in plastic shopping bags.

> Rubbers are supposed to range in toughness from 1 to 100 kJ/m^2, but which rubber is toughest and where do I get some?

Oops. That should be 1 to 200 kJ/m^2.
The toughness of Kevlar is about 80 J/g.

How can you measure the same thing in J/m^2 and J/g?

The Rev Dodgson said:

How can you measure the same thing in J/m^2 and J/g?

Nobody knows, m’lord, nobody knows.

OCDC said:

The Rev Dodgson said:

How can you measure the same thing in J/m^2 and J/g?

Nobody knows, m’lord, nobody knows.

possibly not.

10 futuristic materials

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Engineers from the Karlsruhe Institute of Technology, Germany have been able to create a lightweight yet strong material that replicates the intricate architecture of the human bones using 3D laser lithography technique. Its applications can be found in the material used for the construction of future spacecrafts owing to the super light weight property and high tensile strength. The material created by the German researchers is said to have the highest strength-to-weight ratio of any engineered cellular structure yet. Their research work speaks volumes about how changes at the micro and nano scale in the architecture of key structural elements can significantly improve the material’s performance.

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mollwollfumble said:

I’m looking for a wire or ribbon of material to absorb energy in tension by either elastic (preferred) or plastic deformation.

In tension, I don’t know of anything that beats Kevlar.

Need to know how much force, desired rebound/recovery time, and cycle frequency. There’s several options.

Rule 303 said:

Need to know how much force, desired rebound/recovery time, and cycle frequency. There’s several options.

OK. If 2 metres of Kevlar then force (including factor of safety) = 5 kg = 50 N. Force decreases in proportion to maximum elongation. Say Kevlar has a maximum elongation of 3.6%. Then 2 metres some rubber with a maximum elongation of 36% would only need to carry 50*3.6/36 = 5 N.

Rebound/recovery time, not important but longer is better.

Cycle frequency – only 1 cycle.

mollwollfumble said:

Rule 303 said:

Need to know how much force, desired rebound/recovery time, and cycle frequency. There’s several options.

OK. If 2 metres of Kevlar then force (including factor of safety) = 5 kg = 50 N. Force decreases in proportion to maximum elongation. Say Kevlar has a maximum elongation of 3.6%. Then 2 metres some rubber with a maximum elongation of 36% would only need to carry 50*3.6/36 = 5 N.

Rebound/recovery time, not important but longer is better.

Cycle frequency – only 1 cycle.

you might have to rig something up with a heavy weight attached to the strap you want to use

it might be trial and error

you could always film the strap being stretched to see how much it stretches in use

If you are alergic to layex try polyisoprene.

There’s already products available off-the-shelf that might suit your need. Something like this:

is designed to absorb force in several ways, only one of which has a rebound cycle (and that’s days in duration).

There’s plenty of other options – Ask if you want more.

Thanks Rule 303. I hadn’t though of rigging supplies.