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New lightweight material is stronger than steel

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Re: New lightweight material is stronger than steel

#101

Post by webmaven »

adrian_b wrote: post #70
montjoy wrote: post #2

> and can be easily manufactured in large quantities That seems promising. I have a couple of concerns - Can it be recycled? - How are new materials like this tested for toxicity?

It is quite certain that a 2-dimensional polymer cannot be recycled like metal, glass or a thermoplastic material, i.e. by remelting or by plastic deformation at high temperatures, because a 2-dimensional polymer cannot be deformed without breaking covalent bonds and it cannot flow in a liquid state. So this new material might behave like the existing cured polymeric resins, e.g. epoxy resins, which form a 3-dimensio…

You seem to be assuming that the 2D polymers extend indefinitely. If instead their growth is limited such that the molecules tile, overlap, and layer, they may be more amenable to manipulation such as thermoforming, thermosetting, etc.

Re: New lightweight material is stronger than steel

#102

Post by bungle »

albrewer wrote: post #97
Scene_Cast2 wrote: post #61

Just a heads up - strength is not a single metric. There is tensile (pulling), compression, and shear (sliding) strength. There's also Young's modulus (how much something stretches), fatigue limits (steel can work perpetually with deformations under a certain threshold). There's also specific strength (strength per kg) vs strength per volume and strength per dollar. Steel also comes in lots of different flavors, with…

> steel can work perpetually with deformations under a certain threshold[*] [*] Within a temperature range of about ~-30 °C to ~400 °C. Below that and the toughness goes way down so that it's prone to cracking. Above that and carbon starts to work its way into all those crystal structure discontinuities, preventing some percentage of the strain from being relieved each stress cycle (the "creep range"). That's just fo…

> Within a temperature range of about ~-30 °C to ~400 °C.

If the new material is plastic-like, it may have worse issues here?

Re: New lightweight material is stronger than steel

#103

Post by ghaff »

user_7832 wrote: post #100
ghaff wrote: post #91

Earlier quoted context omitted.

As I recall my material science, it's not so much that steel is weak in compression but, if you have a rod of steel (i.e. much longer than it is thick), if you compress it, it will buckle and shear. As you suggest--I'd have to look up the numbers--but a large cube of steel probably has similar strength with tensile and compressive loads. ADDED: In fact, if you deform a supported I-beam you get similar amounts of tens…

> but a large cube of steel probably has similar strength with tensile and compressive loads. Not just similar, but pretty much identical from what I recalled from my uni classes. Wikipedia for structural materials ( https://en.wikipedia.org/wiki/Structural_material ) also has this bit - >Steel is equally strong in tension and compression.

As I wrote in another comment, my material science and mechanical engineering is very rusty at this point. :-) But, yeah, I-beams basically wouldn't work if steel were weak in compression because, assuming a straightforward loading of a supported beam you're basically putting one flange of the beam in tension and the other flange in the equivalent amount of compression. So the fact that one part of the I-beam is strong would be pretty much irrelevant if the other part were weak.

Re: New lightweight material is stronger than steel

#104

Post by user_7832 »

cellis wrote: post #74
adrian_b wrote: post #70

Earlier quoted context omitted.

It is quite certain that a 2-dimensional polymer cannot be recycled like metal, glass or a thermoplastic material, i.e. by remelting or by plastic deformation at high temperatures, because a 2-dimensional polymer cannot be deformed without breaking covalent bonds and it cannot flow in a liquid state. So this new material might behave like the existing cured polymeric resins, e.g. epoxy resins, which form a 3-dimensio…

Your answer illustrates why, after all these years, HN is still one of the best places to lurk. As someone who forgot most of what he learned in HS chemistry, and didn’t take any collegiate courses, what material would you recommend to learn about this stuff?

Not the person you're replying to but William D Callister's Material Science and Engineering is a pretty standard engineering book I've seen used in my different universities across 2 continents (and have studied from too), so I'm going to say that it's a good starting point.

Re: New lightweight material is stronger than steel

#105

Post by inglor_cz »

lazide wrote: post #94
TylerE wrote: post #80

Earlier quoted context omitted.

Plenty of things are stronger than steel on a per pound basis. For instance, many aluminum alloys have about 60-80% the tensile strength of steel, but only 1/3rd the weight.

Titanium even more so. For those, they are actively swapped around where cost vs weight trade offs happen. steel vs aluminum vs magnesium, vs titanium in engineering application, where for example engine blocks, airplane parts, car parts, battery components, etc. all have a long history of this. It’s a complicated process because the trade offs are not simple cost/weight/strength. Steel has an nearly infinite fatigue…

Pressurization cycles is what killed the reputation of the first commercial civilian jet, the De Havilland Comet.

The British were good in early jet design and actually introduced jet aircraft into the non-military world, but the early hulls would fail catastrophically after a certain, relatively low # of cycles, tearing the fuselage apart mid-flight and killing everyone on board. After several such incidents in short order, the entire fleet was grounded and scientists came up with solutions, but by then, the reputation of Comets was tarnished and Boeing came with a competing 707 model.

These days, the UK does not have a domestic jet manufacturer anymore.

Re: New lightweight material is stronger than steel

#106

Post by TylerE »

inglor_cz wrote: post #105
lazide wrote: post #94

Earlier quoted context omitted.

Titanium even more so. For those, they are actively swapped around where cost vs weight trade offs happen. steel vs aluminum vs magnesium, vs titanium in engineering application, where for example engine blocks, airplane parts, car parts, battery components, etc. all have a long history of this. It’s a complicated process because the trade offs are not simple cost/weight/strength. Steel has an nearly infinite fatigue…

Pressurization cycles is what killed the reputation of the first commercial civilian jet, the De Havilland Comet. The British were good in early jet design and actually introduced jet aircraft into the non-military world, but the early hulls would fail catastrophically after a certain, relatively low # of cycles, tearing the fuselage apart mid-flight and killing everyone on board. After several such incidents in shor…

That wasn't really a cycles issue exactly, it was they used square windows rather than round, leading to stress concentrations.

Per your last point, BAE and Hawker are still around. The UK also does plenty of Airbus work.

Re: New lightweight material is stronger than steel

#107

Post by AnimalMuppet »

cbg0 wrote: post #77
throwaway4aday wrote: post #29

Earlier quoted context omitted.

It's potentially a thermoset plastic in which case it should be able to resist somewhat high temperatures (maybe 300C). So not fireproof but not terrible either.

As a comparison, various types of insulation are rated for 60/90 minutes at 1000 degrees Celsius, while some types of brick are rated for 180 minutes. If this material can't sustain similar temperatures, it's unlikely it will be used in construction.

Wait, what happens to brick after 180 minutes at 1000 Celsius? I assumed they would either burn or not burn, melt or not melt.

Re: New lightweight material is stronger than steel

#108

Post by ghaff »

lazide wrote: post #94
TylerE wrote: post #80

Earlier quoted context omitted.

Plenty of things are stronger than steel on a per pound basis. For instance, many aluminum alloys have about 60-80% the tensile strength of steel, but only 1/3rd the weight.

Titanium even more so. For those, they are actively swapped around where cost vs weight trade offs happen. steel vs aluminum vs magnesium, vs titanium in engineering application, where for example engine blocks, airplane parts, car parts, battery components, etc. all have a long history of this. It’s a complicated process because the trade offs are not simple cost/weight/strength. Steel has an nearly infinite fatigue…

>Several major accidents (including the top of an airliner coming off and sucking a flight attendant out over the pacific on the way to Hawaii)

It was actually an inter-island flight so lots of short flights (and therefore pressurization cycles relative to flight hours or miles). The amazing thing was that the plane was able to make an emergency landing.

https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243

Re: New lightweight material is stronger than steel

#109

Post by cbg0 »

AnimalMuppet wrote: post #107
cbg0 wrote: post #77

Earlier quoted context omitted.

As a comparison, various types of insulation are rated for 60/90 minutes at 1000 degrees Celsius, while some types of brick are rated for 180 minutes. If this material can't sustain similar temperatures, it's unlikely it will be used in construction.

Wait, what happens to brick after 180 minutes at 1000 Celsius? I assumed they would either burn or not burn, melt or not melt.

It's just one standard, it doesn't mean anything happens to the brick, they probably just stopped testing at that point.
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