Drop Stitch Inflatables - and some random concepts and ideas on growing and casting structured materials

This comment, and the first 5 comments below it, were split from Random Engineering, Physics, ..., Concepts and Ideas - #88 by Windy_Skies

Cam design:

Carl Moore – An Introduction to Cam Design 1
Carl Moore – An Introduction to Cam Design 2

Pterosaur neck:




Computer animations: https://www.cell.com/cms/asset/be636c66-c303-4104-8664-6571946051f4/mmc2.mp4 | https://www.cell.com/cms/asset/524e9c21-9935-4e21-9f3b-b0ac18e4cfc6/mmc3.mp4

An internal computerized tomography scan of an azhdarchid pterosaur neck bone shows several spokes, which might have allowed them to support their long necks and lift prey*.* Williams et al./iScience

Toucan beak:


Drop-stitch (kayaks):


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The above ideas like the Pterosaur neck and the Toucan beak are difficult to produce if you’re not 3d printing them. But 3d printed parts often don’t have great tensile strength and are brittle.

One idea is to 3d print the thing you want, but with the solid parts hollow. You can then try (sand) casting with metal, or another material.

Another idea is to try to use your hollow print as a scaffold in a bioreactor or hydroponics tank and try to grow/deposit plant roots, or keratin, or another material.


Molding Mycelium — The Roots Of Mushrooms — To Tackle Plastic Pollution: interview


How to Use Grow-it-Yourself Material

BioDesign Challenge – Mushroom Materials 101

Resources — Biofabricate (mycelium, bacteria, yeast, algae)

Why “biofabrication” is the next industrial revolution | Suzanne Lee

And these biofabricated bricks are nearly 3 times stronger than a concrete block.

Growing Cement with Nature | Ginger Krieg Dosier

I like this talk. They seem to be a growing company and have had significant orders. They are working on developing an alternative for ready mixed concrete.

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This looks really interesting for a wing. Though I dont see how it could not be supported by a bridle… (dropstitch)

I’d like to see a dropstitch loom (in action). I haven’t been able to find that yet. I wonder if looms exist that can make (compound) curves.

Some results searching for “dropstitch”, that might answer some questions:

Starboard Inflatable Woven Technology for Inflatable Paddleboards



Some old results when searching for “airmat” (as used in the Goodyear Inflatoplane):

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The process starts by joining two pieces of polyester woven support fabric with thousands of fine polyester drop-stich-view-1thread lengths. This base material is made in strips from five to ten feet in width. Up to 400 needle heads may be used in the setup. Each needle sews a continuous, evenly spaced thread, back and forth between the two pieces of woven fabric, locking them together into an incredibly strong unit. These drop-stitch sewing machines are marvels of complexity. When a change is made in the spacing distance between the two pieces of woven fabric, it can take over 20 days to remove and replace the required needles.

Not your average household sewing machine. I guess this is a high cost barrier of entry for this technology. But for sure one could be able to get in touch with someone who owns one of these machines.

Seems very 2D to me. I guess there is untapped potential in varying the distance between the layers dynamically, as well as changing the direction of the fibers.

My guess is any robot could do this, but very slowly.

I am wondering by you «namedropping» mycelium and drop stitching at the same time, if you are considering organic ways to do the drop stitching, perhaps even stonger and with more evenly spread fibers. For instance - i would assume it may be possible that mycelium fibers are grown in a medium that may later be dissolved and removed, leaving only the lightweight fibers.


Which won’t do for prototyping. So I was trying to find existing looms to see if I could understand how they work and replicate it but using less or no automation for one-off production, using jigs, or perhaps later some automation (mid-scale manufacturing). But I think the production process is then perhaps sufficiently different that knowing how drop-stitch looms work won’t help you much anymore.

Using a broad definition of “considering.” It’s just a very neat idea and fun to imagine.

Not just mycelium.

You could try growing a rigid material or an inflatable. I was thinking more of growing or pouring rigid materials into a sacrificial (3D printed) mould to make a rigid material, because that seems easier; lower tensile strength requirements and no need to make it airtight.

But let’s say we wanted to pour/grow an inflatable. Easier than drop-stitch I think then would be something like this:

This is then more of mix between an inflatable and a rigid material. The tensile strength of your fiber doesn’t need to match that of nylon and you have less issues with your channels being too fine for your material to flow/grow through. This will be bumpy when inflated though, for that then there is for example this idea: Biomimicry: airfoils inspired by humpback whales, seals, and other animals

Growing a foam to replace styrofoam seems easier. But I don’t know the densities and compressive strengths of the different possible materials, yet.

Without knowing the specifics, I think this has a lot of immediate potential:

The possibilities are endless, especially in Europe where you have an infinite supply of private customers used to brick construction. You can sell bricks for houses, Gaudi or LOTR inspired flat-pack garden houses and garden walls with no need for mortar, paving stones, and so on. If you can grow the stones quickly enough you can do made to order, cutting down on your inventory cost.

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I split the above comments from Random Engineering, Physics, ..., Concepts and Ideas - #88 by Windy_Skies

Francois Barthelat “Micro-Architecture, ​Shape-Changing Materials”

One thing he talks about is crack propagation, which you can control with weak interfaces. I think one way you could do this is with segmented wings, for example: