Hacker News Reader

Comment by varenc | Hacker News Reader

I don't know if the writer really understood what's going on there. Those models are just plastic. Understanding how to make strong shapes is useful for eventually building real structures with graphene in the future, but nothing about that research used graphene.

I think they're saying that if that plastic model was graphene then it would be 5% as dense and 10x as strong as steel...but no such thing was actually created. The title here is pretty click baity.

View on HN

Title is very click-bait. The MIT News article it links to is much more informative: http://news.mit.edu/2017/3-d-graphene-strongest-lightest-mat...

So they show that a graphene gyroid structure could be quite strong compressively. Now, the challenge is actually make such a structure. Making a template for graphene to grow on like this is bound to be quite challenging, minimizing the amount of defects in such structure even more so!

They have a pretty plausible-sounding (I am not an aerogels expert) synthesis route based on cyclic annealing of graphene flakes, and they have molecular dynamics calculations to back it up. In the open access research paper [0] there's some discussion of the defects that form in the MD simulations, so that's baked into the mechanical property calculations to some extent...

I agree that actually synthesizing this stuff still remains a big challenge, but at this point I think it's just engineering.

[0] http://advances.sciencemag.org/content/3/1/e1601536.full

Yes that was what I got out of it, and at the same time I am totally updating the Slicer infill pattern on my 3D printer to make stronger structures :-)

While this is worth trying for the sheer coolness of it, I'm a bit skeptical about how it will perform. For FDM things are much weaker in the Z-direction than they are in the x-y plane.

Exactly correct, the Z direction is a challenge in FDM printing. I built some "strength tester" forms (basically thinks I could crush or pull apart or bend) to understand what sort of structural stability could be expected out of a given filament and the process in general.

So https://en.wikipedia.org/wiki/Euler%E2%80%93Bernoulli_beam_t... https://en.wikipedia.org/wiki/I-beam I think this is essentially MIT finding that the structure of graphene in 3d is also an extremely efficient beam/plane regardless of material. Which is a very cool empirical discovery even if it doesn't mean much for graphene as a building material.

I think it's very cool especially because it applies to things other than graphene. With all the issues producing graphene inexpensively, if we can get some great strength and durability increases in low-density constructions with other materials that could be a real boon.

Reply on news.ycombinator.com