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Random Engineering, Physics, ..., Concepts and Ideas - #88 by Windy_Skies
Carl Moore – An Introduction to Cam Design 1
Carl Moore – An Introduction to Cam Design 2
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
For the last few years, drop-stitch kayaks have become more and more common on the market and are increasingly establishing themselves in the field of inflatable kayaks. There are different designs of drop-stitch kayaks. There are models where only...
Est. reading time: 15 minutes
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
Grown in days
Ecovative’s animal-free hides rely on the natural technology found in mycelium. The secret to mycelium’s Super Material properties lies in its self-replicating scaffolding structure. Forager™ hides grow in 9 days, versus months or years to raise a cow, sheep, or pig.
How to Use Grow-it-Yourself Material
BioDesign Challenge – Mushroom Materials 101
Resources — Biofabricate (mycelium, bacteria, yeast, algae)
The Next Nature Network is a 21st century nature organization that wants to go forward – not back – to nature. We stir debate, create events, exhibitions, publications and products that bring biology and technology into balance.
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.
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:
Recent Advancements in the Development of Inflatable Multi-Hull Boats Utilizing Drop-Stitch Fabric
The development and use of drop-stitch technology has been around since the early 1950’s when Goodyear and the U.S. Government began experimenting with inflatable airplanes. In 1991, CDI Marine (then Band Lavis and Associates) conducted a feasibility study for the U.S. Navy to develop a concept design for a 4-meter inflatable combat rubber raiding craft utilizing drop-stitch fabric. The purpose of this project was to determine if drop-stitch technology could be adapted to small inflatable boats to improve their performance, i.e., seakeeping and speed.
Over the past 20 years, the design of inflatable high performance hullforms has expanded to include more sophisticated multi-hull hull forma that, for performance purposes, require rigid appendages of wood and aluminium to be attached to the hulls in order to achieve the proper hull shape. The initial design concerns raised with respect to the rigidity of the attachment points were resolved. Test results bore out the feasibility of such attachments to the degree that specific hard attachments can now be confidently employed in new designs. This development leads the way for future boats that are larger and with more powerful engines. Such past proposals to build large boats with composite after bodies, containing powerful Personal Water Craft (PWC) waterjet propulsion packages, are now within the realm of reality with minimal risk.
Starboard Inflatable Woven Technology for Inflatable Paddleboards
"CHARACTERIZATION OF DROP-STITCH CONSTITUENT MATERIALS AND INFLATED PAN" by Ryan A. Buglio Abstract
Drop-stitch inflatable structures are of increasing significance in aerospace, naval, and military applications. The advantages of drop- stitch inflatable structures are high strength to weight ratios, rapid deployment capabilities and ease of storage. The stiffness of the structure increases with inflation pressure and is dependent on the material properties of the panel skin.
The objective of this research was to characterize the constituent material properties and mechanical response of drop-stitch inflatable panels subjected to various load conditions. This research aimed to characterize the nonlinear elastic response of drop-stitch inflatable panels by using a new material system in comparison to previous studies. These characterizations included three dimensional digital image correlation, uniaxial and biaxial loading, and panel inflation and bending experiments.
Material properties of the drop-stitch inflatable panel skin were experimentally determined across multiple experiments utilizing three dimensional-digital image correlation. In addition, three dimensional digital image correlation was used to characterize panel skin surface displacements and strains in a way not done before in previous drop-stitch structure research.
The results of this research found that relevant material properties of the dropstitch inflatable panel were able to be experimentally determined through multiple different experiments, however these material property values are extremely sensitive to load conditions. Further research is required to accurately predict the structural behavior from constituent characterization data.
Buglio, Ryan A., “CHARACTERIZATION OF DROP-STITCH CONSTITUENT MATERIALS AND INFLATED PANEL RESPONSE” (2020).
Open Access Master’s Theses. Paper 1856.
"CHARACTERIZATION OF DROP-STITCH CONSTITUENT MATERIALS AND INFLATED PAN" by Ryan A. Buglio
Some old results when searching for “airmat” (as used in the
Structural Considerations of Inflatable Reentry Vehicles 19980228194 - Copy.pdf (726.7 KB)
Structural Considerations of Inflatable Reentry Vehicles
The state of the design art for inflated structures applicable to reentry vehicles is discussed. Included are material properties, calculations of buckling and collapse loads, and calculations of deflections and vibration frequencies. A new theory for the analysis of inflated plates is presented and compared with experiment.
Structural Fabric Program
JO Miller, E BILKSY - 1962 - apps.dtic.mil
A structural fabric investigation, related to aerospace applications, was initiated to provide a means of manufacturing large low-density Airmat structures made of metallic cloth and yarns capable of small volume packaging. The effort included an investigation into the problem of …
The purpose of this program, as related to aerospace application, is to provide a means of manufacturing large low-density AIRMAT* structures made of metallic cloth and yarns capable of small volume packaging.
The work reported herein was accomplished during the seventh quarterly period under contract AF33(600)-43036. During this period, the loom design was finalized and fabrication of the major portion of the loom parts and assemblies was completed. The design of the take-off mechanism was completed and fabrication was underway. A site for the loom was selected and preparations are underway for loom installation.
The aforementioned efforts are directed toward the development of a loom procurement specification and the actual procurement of a loom capable of producing a low-density AIRMAT in the order of 20 feet wide with a maximum depth of 8 feet.
https://archive.org/download/DTIC_AD0628050/DTIC_AD0628050.pdf DTIC AD0628050: INFLATABLE STRUCTURE TEST PROGRAM
Small specimen tests (elevated temperature with internal pressure) were performed to predict the ability of a CS-105 silicone elastomer coated AIRMAT model to withstand the environment of a hypersonic wind tunnel (900- 1500?F). The specimens all leaked badly in the expected wind tunnel temperature range. This indicated the probability of subsequent model failure. The wind tunnel model tests were successful however. Influence coefficient and vibration tests, both at room and elevated temperatures, were performed on AIRMAT models in support of flutter research. As before, the models could not withstand elevated temperature (800?F or above). The laboratory model inflation pressure was 10 psi compared with the wind tunnel model inflation pressure of about 2 psi. Time at temperature and/or an oxidizing atmosphere could be failure factors. Further testing of CS-105 coated AIRMAT structures is needed to evaluate the influence of load, pressure, temperature, and environment on coating characteristics and wire strength.
The process starts by joining two pieces of polyester woven support fabric with thousands of fine polyester
thread 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.
I guess this is a high cost barrier of entry for this technology.
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.
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
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.
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: