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3D-printing a stainless steel bridge full of sensors
- q3k 8y agoTesting in production with good enough metrics is fine unless it's AN ACTUAL BRIDGE.
- geezerjay 8y agoI agree, but the bridge design appears to be extremelly robust (i.e., extraordinarily oversized) and it will be subjected to foot traffic, which has a negligible service load. It's a pretty sculpture that people can walk on. That's it.
- DrNuke 8y agoRobust aka oversized does not counter brittle fracture, though, which is the main concern with 3D-printed artifacts. It depends on the material / the alloy but also on the technological process we generally call printing.
- Robotbeat 8y agoIt actually does, since it reduces the local stress. Risk of fracture due to defects and repetitive loading is dramatically reduced (by order of magnitude or more) by increasing the material margins. It's a short foot bridge, so it's pretty easy to design it with significant enough margin. That said, it's not a very good idea nor a scalable solution to, like, anything. More like an art project.
- DrNuke 8y agoYes, you are basically saying that this particular artifact is just like a bridge-shaped pancake made of polystyrene and hosting very few ants at any given time. Which is actually an art project.
- Robotbeat 8y agoI think that's overstating it. This bridge is plenty strong, just very inefficient and expensive.
- geezerjay 8y ago> Risk of fracture due to defects and repetitive loading is dramatically reduced In this case I believe the design is due to concerns regarding the additive manufacturing process, which is prone to introduce a lot more defects than standard steel sections, and ina way that are hard to spot and to track.
- dsfyu404ed 8y ago>It's a pretty sculpture that people can walk on. That's it. Famous last words. https://www.miamiherald.com/news/local/community/miami-dade/article212571434.html https://www.miamiherald.com/news/local/community/miami-dade/... Bridges are supposed to be boring and functional. Fluffing them up with all sorts of over engineering to make them pretty tends to introduce unnecessary variables that are less well understood or less easy to account for or may be "unknown unknowns" which have the potential to reduce the strength of the structure. https://www.nytimes.com/2018/08/14/world/europe/italy-genoa-bridge-collapse.html https://www.nytimes.com/2018/08/14/world/europe/italy-genoa-... If you want to make a pretty art piece then make a fancy ornate bridge deck and slap it on top of your boring but functional steel I-beams that reliably carry rail, road and foot traffic worldwide.
- pasta 8y agoWell the bridge is approved and will be placed in Amsterdam
- ceejayoz 8y ago"Approved and placed" is hardly the same thing as "safe". Case in point: https://www.miamiherald.com/news/local/community/miami-dade/article212571434.html https://www.miamiherald.com/news/local/community/miami-dade/...
- TomMarius 8y agoYeah, exactly. https://www.dw.com/en/prague-bridge-collapse-leaves-4-injured/a-41629175 https://www.dw.com/en/prague-bridge-collapse-leaves-4-injure...
- JPDeckers 8y agoWalked on it last weekend. No more than 10 ppl were allowed on it at the same time. Guess they are still gathering data
- tantalor 8y agohttps://vimeo.com/239238204 https://vimeo.com/239238204 Video shows physical material tests and simulated structural tests. What else would you suggest?
- thatcat 8y agoIts not uncommon to leave stress strain sensors on bridges to know the state of the bridge even as it ages. Testing doesnt end when it goes into production for actual bridges. The best metric for measuring the bridges safety is strain under actual loading.
- xdze2 8y agoI would be curious to know the technological differences with https://www.relativityspace.com/stargate https://www.relativityspace.com/stargate
- opencl 8y agoMX3D describes their machine as "Standard Robot + Standard Welding Machine + MX3D’s proprietary software". The stargate machine appears superficially similar aside from using multiple 'print heads'. From their pictures and description it looks like one is a welder and one is a milling machine, no clue what the third one is.
- agumonkey 8y agoI was wonder how much of our world would change if we had bidirectional material design. Things that would communicate in one way or another their internal status just a bit, to avoid finding faults too late.
- pasta 8y agoOr use the data and feed it to the self learning program that will design the next bridge.
- agumonkey 8y agotrue but I appreciate objects that speak a bit instead or planning in advance and being in the blind afterwards
- LoSboccacc 8y agoI think external investigation will have the edge on self reporting sensor for quite a while, because bringing a xray/ultrasound machine place to place for a yearly inspection allow to split the machinery investment over a lot of structures. > to avoid finding faults too late even before fault discovery there's a lot of value in embedding sensors to tune simulators, so that the next generation product can improve in reliability, material costs or both while being cheaper to design.
- DrNuke 8y ago3D-printed structures behave very differently compared to your usual, continuous materials which are bolted, jointed or welded together, in that re-balancing loads and reactions. Another issue is how they cope with aggressive environments. This is a real-life experiment, something someone would however do, so let’s what happens. I’m confident they will be fine, we are even having 3D printed components for nuclear power plants already.
- Robotbeat 8y agoIn this case, it behaves like one giant weld, because that's what it is. Fairly well understood, and this has large margins so will be fine.
- rtkwe 8y agoAnd a weld executed properly with the same filler material acts more or less like a single piece of metal (minus any issues with the local heating of the pieces.
- haggy 8y agoDo you have experience with 3D printing? I have pretty extensive experience with 3D printing plastics and I can assure you that it's nothing like plastic weld. How is 3D printed steel like a contiguous weld?
- Robotbeat 8y agoThey literally use a welding machine on a robot arm, that's how. Powder bed metal 3D printing is different, however. (And I would argue that FDM is essentially plastic welding, too.)
- Robotbeat 8y agoThis looks incredibly expensive with a lot of touch labor. The surface is incredibly gnarly due to being basically made entirely of welds. You'd want to grind that puppy smooth on the railings, etc. One thing that I think is finally entering the mainstream is that 3D printing is actually a MUCH more labor-intensive process than typical mass production techniques.
- rtkwe 8y agoA lot of that work could also be automated though if they wanted. There are machines out there today for smaller parts that will use wire deposition like this to build the bulk rough outline of the part then machine away the rough outer layer for a precision part. Leaving it rough though I think is an intentional choice part of showing off the materials and processes used instead of hiding it. In reality I bet the surface isn't much worse than an unsmoothed stone or concrete.
- Robotbeat 8y ago> There are machines out there today for smaller parts that will use wire deposition like this to build the bulk rough outline of the part then machine away the rough outer layer for a precision part. Right, so all you're really saving is the first rough cut, which is normally pretty fast anyway. (And the chips can be recycled.) But now you also have to live with the material properties of welds, instead of a high quality, grain-oriented piece of forging stock. And you also have to move the part from one machine to another, then re-register it (dial it in to make sure the build is oriented correctly in the CNC machine's coordinate system). Not as bad for the hybrid machines which can do both operations, but still not great. Back to this bridge: Without post-processing by grinding/sanding/smoothing, you're reducing the material strength due to increased localized stress concentrations. This doesn't matter much in stiffness-dominated structures, but significantly reduces the performance for strength-dominated structures and structures which experience a lot of cyclical loading. I just don't think this is terribly scalable. Neat art project, though. EDIT:If you want to automate things, I think it probably makes more sense to automate using more conventional building methods... Cut standard beams to size, place and weld automagically, etc. It'd be much faster..... Like this: https://www.youtube.com/watch?v=rD9__jheNLg https://www.youtube.com/watch?v=rD9__jheNLg
- zwieback 8y agoKind of cool but also the type of wasteful project that gives "3D printing" a bad name.
- edoo 8y agoThere must be a large vision for something down the road given the partnership list and that the application is effectively frivolous. They solved 12m pedestrian bridges a long time ago.
- tachyonbeam 8y agoThis looks like it's a massive PR stunt more than anything. The kind of cool project big companies want to have their name associated with. I was hoping to find more details about the technology used to build it, the compromises involved, etc.
- gene-h 8y ago"Autodesk is supplying the cloud services that will power the bridge’s data collection and processing" So the first question is what happens when all these services eventually become obsolete over the bridges life time or if autodesk goes bankrupt?(Of course that may be unlikely if this proposed 'infrastructure as a service' business takes off) "These sensors will collect structural measurements such as strain, displacement and vibration," Now since the bridge has vibration sensors, could one not potentially do gait recognition on people walking across the bridge? And since all this data is stored in 'the cloud,' we now have a bridge which could potentially leak user data. Now to make a ridiculous slippery slope argument, the end result of this may be the house of cards construction building use in Vernor Vinge's Rainbow's End[0], where building s are literally constructed like a house of cards and computer controlled stabilization is used to prevent them from falling over. [0]https://en.wikipedia.org/wiki/Rainbows_End https://en.wikipedia.org/wiki/Rainbows_End
- Svoka 8y agoHopefully by the time Autodesk goes under, we'll have good understanding of how it behaves. Also, no need to dramatize, we have bridges without sensors. I guess surveyors would have to include this one as well.