Self-assembling material pops into 3D

Get 50% off your first month of KiwiCo. Use code STEVEMOULD at kiwico.com/ste...
This bistable auxetic material gets bigger in all directions when you stretch it. It's also becomes 3 dimensional!
The paper by Tian Chen and colleagues is:
Bistable auxetic surface structures, ACM Transactions on Graphics (TOG), 40(4), 1-9. (Chen, T., Panetta, J., Schnaubelt, M., & Pauly, M. (2021) dl.acm.org/doi...
You can find the cut patterns and other recourses here: github.com/UH-...
Tian is currently working at the Architected Intelligent Matter Laboratory: aim.me.uh.edu/
Here's my video about flexible polyhedra: • The object we thought ...
Veritasium video about compliant mechanisms: • Why Machines That Bend...
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[@SteveMould]

I never mentioned: The rubber sheet is the stuff you use to makes stamps. It handles a laser well for etching which also makes it a good material for laser cutting, which is how these cuts were made! The sponsor is KiwiCo: Get 50% off your first month with promo code STEVEMOULD at kiwico.com/stevemould

[@tinnguyenanimations522]

how did this video come out 1 minute ago but your comment if from 18 hours?

[@wolfassassin359]

Mechanical press channel confirmed?

[@arrianmian7294]

Space bra

[@VindicusVore]

I can also see huge potential for this in the space industry, especially for colonization.

[@tinnguyenanimations522]

@@mickeyfilmer5551 ah, ok, thanks

[@ofiasdfnosdf]

For some reason I find that shape with the two domes very pleasing.

[@kolvis6626]

i wonder why

[@Fiyaaaahh]

You must be a male squirrel.

[@Myhuky]

An interesting structure indeed

[@gerunkwon2598]

neurons: activated

[@jelly.212]

Gay it means you like balls

[@SilverSlayer]

He made a bra for robots 🤖

[@csn583]

*cyborgs

[@shreddedtwopack6625]

Kinda revealing for a bra

[@xilm22]

I was just thinking that

[@Kim-ej2xm]

I was thinking the same thing

[@Lilly-Lilac]

@@shreddedtwopack6625also has no support, so it’s not good for any purpose

[@DOITWITHDAN]

Lore accurate boobie armor

[@Nycticc]

Ain’t no way you have almost 1.5m subscribers and only have 46 likes and no replies in this comment

[@DccToon]

hi dan how are you doing

[@Cyber98ta01]

emergency bra

[@4rl0ng]

One piece moment lol

[@ronmit-p5g]

insta boobs

[@mattyphilpotts3745]

"Bi-stable auxetic structure" is not as cool as "space bra"

[@arrianmian7294]

100% that is literally what i comment too

[@nuno.g.pereira]

If I had boobs I would wear that

[@DW-indeed]

*bi-stable. The subtitles are wrong.

[@mattyphilpotts3745]

@@DW-indeed I'll be honest, that was my typo rather than the subtitles... I didn't have them on 😂

[@tepafray]

I'd actually be curious if there's a practicality to a "space bra", like being able to print to your exact size and shape.

[@jeff-jo6fs]

what an aesthetically pleasing shape

[@QelerQr]

mhmmm mate sure "aesthetically pleasing"

[@flyinggorilla124]

Lmfao

[@fadedvibes89]

Very aesthetic and very pleasing

[@HydraulicPressChannel]

Great music choice on press clip :D

[@roifpramudia]

i like this reference

[@hikolanikola8775]

haha nice!

[@Mr_Wh1]

3:42 - Yes, a very interesting shape indeed.

[@Mr.DirpyThe1st]

Just imagine wearing it

[@kabobawsome]

I can see uses for this as is, tbh. Imagine attaching a light, stretchy material to the interior of this, in the shape of a strapless bra (which hooks for attachable straps). Well, now you have a bra that lies perfectly flat in a drawer or suitcase. You could do very very similar ideas with containers, like backpacks or purses or lunch bags, or even sleeping bags or tents. In fact, most of the use-cases I can think of this, before you get to the molecular level, at least, are in light civilian camping equipment. Seems just absolutely perfect as is for it.

[@Killthefish]

But it would never lie flat for a bra, backpack, bag or whatever you used or made, it will always be just as thick as a real bra at minimum, and for the "molecular level" why does it matter anyway? You want a bra that is so thin you might as not have one on? It doesn't make much sense, the strenght of the material corresponds to the thickness so no, it would never be flush with a draw even if it was made even smaller, a item has to have a mass and space to be a item, and dont think I'm just saying this about one of the examples it works for all the rest, you have a bag, ok now the bag is weak because its very thin so you can only carry maybe 1/4 of a normal real backpack which is useless seeing how a bag can basically be put anywhere once its empty, a purse? Sure maybe but it's still easier to you know, buy a purse instead of hoping oneday we create super strong, thin and elastic material that can be used for anything more than greenhouse walls or covers on your milk, the tent one is much better but still has issues, this would never stand up again a light breeze and if it was the size of a tent, it would be HUGE and harder to use because tents roll up, this would have to be kept flat in one piece until you needed it and then you still would need supports, pegs and a cover otherwise all you have is a plastic sheet with holes in

[@HajileMalach]

​@@KillthefishYou sure yap a lot for being completely wrong 💀

[@TomG-f4r]

Spider thread

[@Killthefish]

@@TomG-f4r spider thread would make better kevlar, BUT it's so hard to get/and turn into thread that there is literally no point, it would be stronger than steel, move flexible than kevlar and we still dont see a point in using it because we can basically make a synthetic version, spider silk is also very expensive and honestly not very sustainable

[@GladionD.Pierce]

@@Killthefish cHiLl

[@AM23.]

The fact that a painting, 100s of years old, when applied to a material becomes a really neat process of scientific mechanics and geometry, is kind of crazy

[@BLEKSIDE]

aliens

[@wormbigail]

Like?????? How much else is hidden hehe geometry is weird

[@foxylovelace2679]

Math is math I guess

[@SierraNovemberKilo]

​@@wormbigailSacred Geometry - its an area of study in its own right.

[@corbanbausch9049]

@@BLEKSIDE humans, actually. Humans with math.

[@UCXEO5L8xnaMJhtUsuNXhlmQ]

The heat map at 7:00 is possibly the best visual demonstration I have ever seen for a level curve on the graph of two variables. I genuinely hope that younger students will see this video before they cover the topic in classes because it would make it so much easier to grasp it. Or at least it would have helped me a lot. Your videos never cease to impress.

[@BryGuy418]

Wish I could like this comment multiple times. I was thinking the same thing, that visual representation helped my brain process the rest of the information he was sharing on the screen in that moment.

[@robertofontiglia4148]

It seems to me like the best possible example of a level curve for the graph of a function of two arguments would just be... The actual level curves on topographical maps?!? What am I missing?

[@ozok17]

@@robertofontiglia4148this example might be useful in showing an application that doesn't require a third dimension in space, and can instead be indicated by colour in the 2D graph, which might help some students understand why bother with such graphs in the first place rather than just popping out into 3D. Sorry I don't think I'm quite describing this well. Anyhow, different students find different examples relevant in different amounts; for you, the best example might be a topo graph, while for this commenter the heat maps shown here felt even more illuminating. sometimes things get described (and understood) more absolutely than relatively, perhaps because that's easier to convey, even though it's sometimes only an approximation of what is meant. dunno.

[@JKLProjects]

Perfect material to make bras and hats that fold flat for packing into suitcase 👌

[@ahadmrauf]

I'm a Mechanical Engineering PhD student researching auxetic sheets (specifically how to embed actuation and sensors while manufacturing them to create smart robotic skins), great video on the topic! It's awesome to see more public attention given to the work done by Mina (6:27) and Tian (3:55), they're doing lots of cool work in computational graphics and design optimization on the subject!

[@EliasMheart]

Not asking you to dox yourself, but are there papers you'd recommend as a start?^^ Sounds very interesting

[@saffron6744]

@@EliasMheart I second this, I'd love to learn more about it

[@Daniel-mg1lk]

I'm a Mechanical Engineering student, and Tian was one of my Professors! Small world! It's awesome to see cool research done. I go to the University of Houston, he teaches Computational Fluid Dynamics and Solid Mechanics.

[@CRAZED4MORE]

Would be interesting to see these structures made of Nitinol which has some similar applications

[@justinfleming5119]

That is an interesting structure. I'm very interested in the structure of that thing.

[@memelord7804]

💀

[@acelophobicindividual8924]

the point of making it that shape is possibly to gain popularity...

[@Arunkumar-cd3bo]

Very intriguing structure indeed!

[@rhov233]

You might say that it is so interesting, that it may apply transformative forces on secondary structures as well!

[@GladionD.Pierce]

hehehe

[@vindi167]

this feels futuristic, im glad the world is getting more advanced like this

[@ultracreador]

Quiero un fembot hecho de ese material

[@Cutecat0987]

U speak like a time traveler

[@r0260064]

Can you imagine clothes from these materials? Completely flat in one state, perfectly fitting in another? Seems amazing to me

[@azrobbins01]

Don't forget see-through.

[@r0260064]

@@azrobbins01 seems cool for the summer :)

[@danceswithbadgers4024]

@@azrobbins01 quiet part out loud! Shhh😂

[@khanjannimavat8135]

​@@azrobbins01you can probably put some fabric between joints to make it opaque. Then it would work perfectly

[@MarieLuiseOrland]

Yes! This one thing looked like a bra. How cool would it be if the bra were flat while washing and storing but in the perfect shape while wearing?!

[@namewarvergeben]

0:10 an interesting structure indeed ( ͡° ͜ʖ ͡°)

[@Gabriel-s6v2h]

💀☠️

[@dynamicgecko1213]

During a very technical and academic explanation, hearing "the dome shape or whatever" at 7:28 made me laugh for some reason

[@dangevad]

For your whiteboard cube contraption: Attach any random tiles from the board game "tsuro" and both states will be legitimate placements. You could also drive yourself fully insane trying to find the specific "Carcassonne" tiles that would work

[@rianfelis3156]

Not that hard. The only real requirement that the cubes have is that when you open it up, opposite sides of any void are identical, while the other two sides are a mirror image of that. So with the Carcassonne tiles, just surround any single void with a single color, and you're set. I suspect he is only having difficulty because he wants the edges to be clean, which requires three sides of any of the corner pieces to be clean.

[@gristlelollygag]

you could make an algorithm to check that game that i never heard of and will not even attempt to spell

[@Kyle-nm1kh]

​@rianfelis3156 anyone who plays with rubiks cubes will figure out how it works.... and THEN try and solve it

[@PartanBree]

Similar to the Tsuro idea, you could make a very fun toy with roads on it which rearrange themselves as you push and pull it.

[@MischaKavin]

Protein based bistable structures reminded me of an old idea: crunchy gum. Not really a reason to develop the tech in its own right, but it's an accessible tech demo, and probably a great stim

[@M4TCH3SM4L0N3]

I want to try crunchy gum! That sounds incredible!

[@gabrieltorres7168]

I'm almost convinced that's a thing. Cause iirc there's a stimulating gum I heard of before.

[@Some_Awe]

i want this

[@ARVash]

Give us the crunchy gum

[@b9y]

What's crunchy gum?

[@schrodingr]

Me in the first minute: An interesting structure indeed.

[@GladionD.Pierce]

hmmmm

[@DjDuncman]

Awesome. Thank you. Also, absolutely perfect Hydraulic Press Channel allusion!

[@piokul]

3:43 I'll give it to you that this shape indeed attracts attention.

[@GladionD.Pierce]

hmm

[@CapablePimento]

The Hydraulic Press Channel reference was inspired! Bravo!

[@Lou-Mae]

Looks like some flat-pack, intensely uncomfortable bras.

[@JamesTM]

This was my thought exactly.

[@EmilFr]

The new Himmelbjerget bra from IKEA (I know, I know, Himmelbjerget is in denmark, but it was the funniest skandinavian sounding word that I could think of that might be understood by at least some people)

[@YTIsTakingOverMyLife]

1:22 Haha you had my eyes bawling at the shout out the hydraulic press, absolutely genius Steve!

[@Tome_Wyrm]

I was amazed it took me this much scrolling to find the first comment to mention Lauri or the Hydraulic Press Channel

[@MeppyMan]

As soon as I heard the music I laughed, before I even realised why. Brains are weird. This was awesome and clever.

[@jaredkennedy6576]

I'm rather unhappy that HPC doesn't have the music anymore.

[@Tome_Wyrm]

@@jaredkennedy6576 I apparently haven't seen a video of theirs in a while. They haven't had the intro for almost 2 years now (last one I found was Jan 2022 on the Cheetos into Donut video and then Sept 2021 before that) ... that's sad. The music was so iconic that I heard like 4 notes and immediately knew it was a HPC reference. And now with the last two "normal" videos I kinda wonder if Steve's been putting these things in for ages and I just finally got two of them. (The Technology Connections one being the previous one)

[@SideshowBen206]

😭

[@bosstowndynamics5488]

That Hydraulic Press Channel joke straight up killed me, I love how you're the master of friendly parody of other KZbin channels at this point

[@theblode1337]

i haven't watched HPC in years, you hit me so hard in the nostalgia bone

[@user-op8fg3ny3j]

Why did you remove the wirtz pump video?

[@flayncele]

prolly had some mistake in it lol

[@cadekachelmeier7251]

If this results in the development of bras that can lie flat when you store them, the world will be a much better place.

[@MikeTrieu]

I wonder if you could make an auxetic structure out of shape memory alloy. Then it would expand and contract automatically when heat is applied. Might make for some handy window shades.

[@Roxor128]

That would be a great retrofit for all those stupidly-designed houses with windows facing west!

[@drworm5007]

​@@Roxor128imagine being so stupid though, that you thought energy efficiency was the only goal of building design.

[@Skyra_0]

This could be an amazing product.

[@appa609]

Sure if you want to pay $20,000 for your window shades

[@francesmcbride4592]

Work is currently being done on this in some universities! Super cool stuff.

[@jaynoneyodamnbuisness1499]

That's pretty cool a braw that could be bought from a vending machine

[@fredhair]

The fold-away bra! I love it.

[@vale.antoni]

The amount of references to other creators, and the seamlessness of them all is truly astounding

[@powersurge91]

Leaf-spring Constrictor Bra.... Box it, Print it, Ship it!

[@bigboss97]

That reminds me of the plastic "ball" I have. It also has two stable configurations. Similar to the 9 squares, but it expands in 3D and changes colour on flipping.

[@RobertPodosek]

Always blue always blue always blue

[@madselena3111]

Hoberman sphere?

[@bigboss97]

@@madselena3111 No, but I've got that one, too. The changing color ball has two stable configurations. I've got a video showing that. But I don't think I'm supposed to post links here 🙂

[@MyDreamLife]

Good Bra design. I approve of it.

[@giantbonsai8950]

We were all thinking it ;)

[@VoiceSnacks]

“This could be a groundbreaking technology with a multitude of sophisticated applications, what should we make first?” “Booba.”

[@smellfish1430]

2:27 you can make a bunch of plusses + on each square. This will always make a plus when rotated 90 degrees

[@Sammy-yq8ix]

Genius yet rudimentary n pragmatic

[@Orc_2000]

Feels a bit cheap, though

[@BMarie774]

I was sent some packing paper like this and it entertained me for hours. I still think about it. It can lay flat, be folded up, but you could also wrap it perfectly around a ball. It could be used like regular paper, or it could be turned into structural padding. It could conform to any shape. Yet also to back to being a flat piece of paper. The uses for it are boundless and go well beyond just protecting items in packaging.

[@rawkhawk414]

Steve now has a video where he talks to the creator and team that designed that very packing paper lol!

[@Satirical_whit]

I never considered myself particularly brilliant, but I appreciate how you were able to explain all of this. It was perfectly understandable and kept my attention throughout. Super fascinating topic as well. 10/10 im glad to be a new subscriber

[@hellothere_1257]

You should try making a version that's flat when extended and becomes curved when squished rather than the other way around. I'd love to see how that works out.

[@SteveMould]

They made that! But I didn't get to film it.

[@nicholaslau3194]

A piece of paper is flat when extended but curved when crushed

[@chudite]

@@SteveMould Hi Steve, loved this video. Just out of curiosity, do these shapes break easily due to the amount of stress applied to the points of rotation with every use?

[@orena932]

​@@chuditeI assume if you notice your strain energy being too much and causing failure you can make the energy valley less deep by choosing a different t and theta value. This would make the stretched conformation less stable but won't put as much stress on the components. They probably do lots of model simulations to optimize a stable but durable material.

[@chudite]

@@orena932 Yeah, sounds about right

[@Erekai]

Steve, I love your channel so much, because every video invariably achieves at least two things: 1) it shows me something I've never even thought about before (whether because it's something I never knew existed, OR it's something I HAVE seen but never really given it much of a second thought), and 2) it's ALWAYS absolutely fascinating and keeps me gripped the entire time. I love it. Thank you for doing what you do!

[@L33tSkE3t]

I feel like these would be great for quickly building structures for habitats on the moon and mars. They could be easily packaged for space flight and quickly erected to serve as the support structure that a strong airtight fabric could be draped over and fastened to.

[@InteloPL]

Yes and no. That structure would be 10-20 meters each way. Unless you pack it like an origami, which could save space, as you'd need 1.2x5x5 space to create a 5x5x5 cube.

[@aurasalmu7612]

Thanks for the sudden HYTRAULIK PRESS TSÄNNEL jump scare. :D :D

[@MarioGoatse]

Genuinely one of the best channels on KZbin. All of the science, all of the cool, and none of the pretentiousness.

[@synderach]

On a large scale id like to see this used for "building" structures. Imagine a tent that sets itself up just by tacking down one end and pulling on the other.

[@iliketowatchducks]

Interesting shape indeed Steve.

[@markuskunath5815]

i see another man of culture

[@Ajaykrishna97_]

Interesting structure indeed

[@almondthedude]

This kinda reminds me of how I think puffer fish expand their spines. 🐟-> stretch -> 🐡expands the entire body.

[@davidboston7943]

I just recently defended my PhD thesis in which I developed multistable, adaptive structures from a zero-poisson-ratio cellular material for aerospace applications. Great explanation of the topic!

[@jacobgriswold7215]

When I watched you speak about KiwiCo I cried. My parents were not there for me growing up and so everything I know is a true accumulation of gems like you in the community spreading the word about true knowledge and gatekeeping nothing. Everything you post is genius and makes my brain itch in all the right ways I cant thank you enough for keeping me optimistic and thinking. Thank you cool internet uncle Steve Mould, truly captivating.

[@hugodesrosiers-plaisance3156]

I feel you. When Steve said "they think like makers, now" it really reached me.That's a whole other level of wholesomeness.

[@Coastfog]

I feel you bro, I experienced the same, just with books, since the internet wasn't really an easily accessible thing when I was a kid. You need to *know* that this is not your fault and you deserve to be seen and respected and cared for and liked and loved, without conditions. You can have that in your life, it's a tough journey, I know, but also an immensely rewarding one. Your parents can't take that away from you.

[@conodigrom]

Physics: How many points of failure do you want? Designer:YES

[@angrybearironworks3233]

I think this would be a great way to make tent frames, maybe just drape a cloth over the lattice, and you have a shelter. This is super cool, and I’d like to learn more

[@taylor6713]

Everyone that works in a costuming departments need to see and know this, like imagine a futuristic movie using this type of material as armour in metal.

[@mothMagnets]

R.I.P. headphone users 9:17🤯

[@davedavem]

Some people at my old place of work made a material that was bistable at the molecular level. It wasn't auxetic, but it did exhibit negative thermal expansion (it got smaller when heated), which was pretty cool. Switching between stable states was chemically, rather than mechanically driven -they added water for one state and organic solvent for the other. We published the water containing structure in nature chemistry. Good times 😁

[@uiopuiop3472]

when when you make negative nitinol 😬😬

[@boinxi]

This is like an unexpected mix of engineering and a psychedelic experience

[@CYXXYC]

2:16 the image has to have a 4-fold rotational symmetry in each square what you can draw is just an independent circle in each of the squares i think how it would always work, is that you split every square into 4 triangles by using their diagonals, and ensuring every triangle has the same image. i think it is only possible with a single stroke if you draw circles as large as the squares themselves, so they touch each square edge of their squares, and that way you can cross from one square to another via those touching points

[@CYXXYC]

instead of circles you can use rhombuses and even make them concave (which would look like circles that cross the boundaries)

[@natecurtis3159]

Just put a cross in each square

[@CYXXYC]

@@natecurtis3159 crosses also work, they are kinda like inverted rhombi or they are like shifted rhombi just so we are on the same page, the image most likely has to be drawn without releasing the marker and without overdraw (do not draw over an existing line, probably except for touching points)

[@havel6060]

3:00 everyone know you can balance it by pressing booth finger at the same time

[@Ciubowski]

9:12 WARNING HEADPHONE USERS!!

[@RetroAnts]

Ty

[@genralty]

couldve gotten that warning a few seconds earlier preferably, only scrolled down here to find any comments mentioning it after i was playing this in the background and my ears blew up

[@CheapoPremio]

"... in turns into a br... into this interesting shape! Yes very interesting shape."

[@Gayraygamer29]

Why did you just remove your new video on wirtz pumps?

[@uberarius]

Nice shape.

[@100lal]

I enjoyed the nod in the music at 1:23 to Beyond the Press Channel.

[@Zeraphor]

"Hej teenage son, I invented something new and cool! Look how cool science is!" _"W/e, I am more interested in boobas atm"_ "... I guess I can make those too ..."

[@Qwizzyx]

I laughed my ass off at the hydraulic press gag😂

[@richardverheyen6373]

I’d be really interested to learn more about the activation wave of those shapes and how they could be activated in zero gravity

[@alaskanalain]

You could shake it?

[@droidigan]

That material saw its chance and took it

[@ynotawoody]

Not “more interesting”; TWICE as interesting. (03:36)

[@NotSoMax]

It’d be interesting if there was a way to make a similar structure that’d fill in the negative space, so you’d have 2 flat sheets, and then when expanded it’d be one solid sheet, but I doubt the math would work out that way :/

[@TheUndeadGraduate]

That would also require the pivot points to intersect each other, otherwise, making the "hinge points" half depth, like wood joinery, would make them too weak and likely to break upon expanding. If you didn't need or mind the intersecting points to be thicker than the rest of the sheet, it might be doable though...

[@bobmackay1856]

Hm! Is the hinged structure that forms the negative space also going to be bistable and auxetic, or would it be floppy? Presumably TheUndeadGraduate's objection could be satisfied equivalently by having each polyon include a second layer with the same shape slightly inset to fit the holes on the positive structure.

[@NotSoMax]

@@TheUndeadGraduate yeah tbh I assumed half depth joints were implied because otherwise they physically wouldn’t be flush and kinda ruin the whole point, but it’s a good clarification I do think it’d be more fragile and more material dependent but I’m more interested on the math for a negative shape that matches the same curve. I think realistically the negative layer would just be more flexible and have more “holes” in the second flat sheet, so it wouldn’t hold its form as well on its own.

[@nak2Edits]

Stay strong, fellas, its not what you think it is.....

[@markm0000]

This would be pretty cool as a umbrella.

[@RajasPoorna]

"The algorithm thinks you'll like... this video next" PERFECT!!

[@tdata545]

NICE you discovered the fold flat bra. NEAT.

[@briangooch4561]

It's always so interesting to see trends in the STEM world. Mark Rober's video today covers some similar stuff.

[@Saiku]

"it's a material" _material assembles into its shape_ Me: "BOOBS"

[@haruhisuzumiya6650]

I see that I'm not the only one with gutter level pleasure centres for neuron activation

[@Drujd]

3:30 Interestingly i just came from Mark Rober's lastest video that pretty heavily features compliant mechanisms - which I hadn't heard of by name before today. A bit of an odd coincidence

[@CidiKvr]

10 seconds into the video, and i'm already seeing possibilities with this... like compact bras

[@nodata7778]

bro really made a bra from 2122

[@harrytodhunter5078]

R O B O B R A

[@giantslug6969]

Ah yes, an interesting shape. I want to hold this shape.

[@stevencase3289]

that shape is definetly interesting it just reminds of something i just cant put my mouth on what it is

[@TheRexisFern]

Side field question, how many thumbnails did you make for this video? I clicked on a "red material" one, but there's a "green material" one for the mix. Are these Steve Moulded or youtube generated?

[@SteveMould]

I'm in the beta for KZbin's A/B testing thumbnail feature. I give it 3 options and serves them randomly to get an idea of which one works best.

[@jannsander]

What did you make these parts from? Looks like some laser cut rubber... Although it would be cool to print such parts, I think the much bigger achievement would be a multi material structure on a larger scale. Maybe something with hinges and leaf springs. Then I could see some real applications in spaceflight, mobility etc. Maybe this is just my lunchbox-hinge trauma, but I somewhat dislike compliant mechanisms. The medical application seems sensible though. Edit_: didn't read your comment... How many cycles does this rubber last? I feel this stamp rubber is quite easy to overstretch.

[@philippw4769]

"lunchbox-hinge-trauma" xD

[@bythelee]

The benefit of "lunchbox-hinge trauma" is that you can get flexible movement (typically a hinge) without needing multiple moving parts that rub against each other. A door hinge made from two pieces screwed to the frame and door, with the rotational movement facilitated by a piano-wire shaft connecting them, will always wear out eventually. If the designer has done a proper job and managed the maximum stress of the single-piece "trauma" hinge, it will never fail. Incidentally, suspension mounts on Formula One racing cars have been rigidly mounted flexible struts for many years now. No bearings to fail... (or allow slack / excess movement).

[@jannsander]

Yes, you are absolutely right. Compliant mechanisms are super easy to manufacture and are often the "better" solution to a problem. I sometimes opt for compliant mechanisms when designing printed parts, but I always pay close attention to ensuring that the angle difference is as small as possible by stretching out the bending over a longer piece of material. My "lunchbox-hinge-trauma" probably results from the decision to prioritize footprint or material savings over a proper hinge. If the arc were, for example, 5mm in diameter and a bit thicker in return, I'd say it should hold up much longer. Here, it seems like we have very little freedom in modifying the shape of the "tiles" by adding longer pieces that can distribute the bending bc. we have to maintain the bistable properties. In the example pieces shown, the triangles are basically rotating around their (compliant) corners, which seems to me like the least optimal utilization of the material's flexible properties. At least, I can't imagine how a part ten times the size would hold up if made from rubber. I can't think of a concrete use case for 'lifesize' bistable auxetic mechanisms yet, but I'm sure someone will. @@bythelee

[@chaos.corner]

@@jannsander The problem becomes that for materials stiff enough for most purposes, hinge points have to be extremely thin and even then, the stiffness will cause issues. Throw in that many plastics deteriorate with time, losing their plasticity and it cuts down their usability even more. Which is not to say they don't have their place. One nice thing is that modern technologies often make it easy to use mixed materials so the main structure can be the stiffer material while the hinge can be softer and yet the join between the two can be very good. That's a bit beyond many hobbyists so far though.

[@chaos.corner]

@@mal2kscSure. But you may as well use typical hinges then. This option allows you to print-and-done. It's definitely not that far out of the range but dual nozzle stuff is a level or two up.

[@BasicTechGirl]

These new bras of the future look cool 🤣

[@KillerHelix]

~ I had made dozens of those fortune teller thingies and thought "Why don't we, like, make cardboard and latex/silicone stuff that does this?" ~

[@XenoWeeb]

Two small domes... I like it

[@washcode9613]

This is really cool! I wonder if it would be possible to get tri-stable or higher degree-stable material structures, where there are further minima in the graph of the energy needed to stretch it

[@smoky749]

8:30 u have to massage those domes

[@unknown_guy5366]

💀☠💀☠

[@TimberTrainer]

Good job getting on the eye catching design for any man.

[@DanBurgaud]

0:25 a Bra? serious?

[@Requiemes]

Forbidden bra

[@Krejii05]

Looks like something batman would use for his armour lol

[@GarviHere]

0:03 monke neurons activated

[@楊學翰-m5i]

Cool see-through bra

[@Antis_need_A_life]

0:10 THIS IS MY NEW BRA! THANK YOU, STEVE MOLDY, I LOVE YOU!

[@thelee3781]

are there any tristable patterns? i don't know if i have just broken the fourth dimension or some sh*t but i find this really pleasing and satisfying to watch and would be really interested if this even works theoretically. love your videos :) please keep on being this good at what you're doing❤

[@samavis4869]

Any of these patterns that buckle into 3D shapes are actually tristable because they can buckle up or down. In general you can create structures that have many stable states. But if you only have a single degree of freedom that can be manipulated (expansion) then you're somewhat limited in how many states that you can get.

[@feha92]

Well, if you have a theoretical material like in the video, except where one state produces a dome shape... then yes. You would have unexpanded, dome-shape expanded, and bowl-shape expanded (push dome down and lift its edges to invert it). BUT WAIT, WASN'T THAT EXACTLY THE SHAPE SHOWN? SO OP LIED WHEN HE CALLED THEM BISTABLE IN THE VIDEO?!?

[@thelee3781]

@@samavis4869 this actually makes a lot of sense, but as @feha92 said, this would then mean this isn't actually a bistable pattern

[@Kyle-nm1kh]

​@@thelee3781it's tristable technically. But the flat ones are bistable.

[@RelatedGiraffe]

10:00 I think the reason Steve got kids was for the lulz of watching them fail at simple things

[@lordalbert5606]

8:50 Absolutely mindblowing. Literally having chills as a med student hoping to go into cardiology. Made me read up on some research about auxetic stents and auxetic cardiac patches. Crazy