5 ms·

Negative post here - interesting research but shame on reuters / researcher for pretending this is biomimicry. The article does not say at all how the concrete

by PEJOE 6y ago

Negative post here - interesting research but shame on reuters / researcher for pretending this is biomimicry. The article does not say at all how the concrete has anything to do with lobster shells. Further, rotating layers to change the bulk performance of materials composed of anisotropic plies is very old technology developed originally for aerospace / racing applications. Ansys has an entire package devoted to the analysis of structures made from anisotropic materials in this way.

sradman 6y ago
See FIG. 1. Hierarchical microstructure of the cuticle of the lobster (Homarus americanus; based on existing studies) from the paper: https://www.liebertpub.com/doi/10.1089/3dp.2020.0172 https://www.liebertpub.com/doi/10.1089/3dp.2020.0172
- PEJOE 6y ago
  > Further, rotating layers to change the bulk performance of materials composed of anisotropic plies is very old technology developed originally for aerospace / racing applications. > Ansys has an entire package devoted to the analysis of structures made from anisotropic materials in this way. Also, if you read your link paper, they are not doing anything different that what has been known for a long time in long-fiber composites - see: https://www.liebertpub.com/cms/10.1089/3dp.2020.0172/asset/images/medium/3dp.2020.0172_figure2.jpg https://www.liebertpub.com/cms/10.1089/3dp.2020.0172/asset/i...
  - sradman 6y ago
    > they are not doing anything different that what has been known for a long time in long-fiber composites They are using a new material (concrete) and in-situ fabrication technique (extrusion/printing) that is at an early stage of development and doesn't seem to be performing well. I'm assuming that the type of empirical data produced by these experiments is a prerequisite to developing a finite element model for these materials/techniques. The worst case here is that civil engineers have to reinvent the knowledge that you believe other engineering disciplines have mastered using different materials. Computer guided in-situ reinforced concrete seems quite novel to me; perhaps that is a reflection of my own knowledge gap.
analog31 6y ago
>>> ...rotating layers to change the bulk performance of materials composed of anisotropic plies is very old technology developed originally for aerospace / racing applications. Indeed the original engineered composite material: Plywood.
- ozborn 6y ago
  I believe plywood has piles/fibers orthogonal to each other, in this video they were laid over diagonal to the underlying concrete.
  - hausen 6y ago
    Some higher-quality plywood does have layers whose grain is at 45 degrees to the adjacent layers: https://www.globalpp.co.uk/blog/why-do-plywood-layers-run-in-different-directions/ https://www.globalpp.co.uk/blog/why-do-plywood-layers-run-in...
    - JoBrad 6y ago
      That seems like a typo. The title says “opposite”, and just before specifying 45 degrees, the article says the layers are at a “right angle” to one another. Looking at their other products, they seem to differentiate on bonding strength and surfacing, which is pretty common.
- TT3351 6y ago
  Isn't concrete an engineered composite material to begin with? It's ancient. AFAIK plywood is an 19th century invention.
  - BariumBlue 6y ago
    Plywood was used for shields by the Romans, I'm fairly certain the Vikings, and wikipedia mentions the Greeks and Egyptians used it as well. From what I can tell from a quick google, it does seem to be a casualty of the Dark ages though.
ghostbrainalpha 6y ago
I'm confused. They printed a helicoidal pattern, which is basically a flattened spiral which was absolutely inspired by the Lobster shell. Why doesn't that qualify as biomimicry?
ericol 6y ago
Did you actually read the article? > Their bio-mimicking spiral patterns improved the overall durability of the 3D printed concrete... That's like, the 4th paragraph in the article published by the university.
ChuckMcM 6y ago
So it is a bit click baity, sure. But how many people really think about anisotropic plies? (cool word, anisotropic, by the way) Folks who have done 3D printing figure out pretty quickly that the orientation of the print can have a large effect on the various structural properties of the thing printed. I basically spent the first couple of months printing various test objects in different orientations to get a better understanding of this. For that reason, the paper gives a reasonable way to approach the question of "how can I make this stronger?".
- rwcarlsen 6y ago
  I feel like plywood is a really common thing that a lot of people know to have alternating/anisotropic layers of wood grain
  - ChuckMcM 6y ago
    Agreed, that is a great example. That an oriented strand board or OSB.
  - JoBrad 6y ago
    Plywood alternates grain patterns at 90° to each other. OSB uses the same technique, but with shredded wood instead of sheets. Neither use the 3D twisting method outlined in the article.
tantalor 6y ago
> very old > originally for aerospace / racing applications That's a wild take on "very old"! I bet you can find even older examples, e.g., textiles
- ajuc 6y ago
  Composite bows were made thousands of years ago using this principle. Tendons glued in alternating layers.
  - tantalor 6y ago
    I suppose shooting an arrow is a primitive form of aerospace (missile).

by PEJOE 6y ago

sradman 6y ago

See FIG. 1. Hierarchical microstructure of the cuticle of the lobster (Homarus americanus; based on existing studies) from the paper: https://www.liebertpub.com/doi/10.1089/3dp.2020.0172 https://www.liebertpub.com/doi/10.1089/3dp.2020.0172

PEJOE 6y ago
> Further, rotating layers to change the bulk performance of materials composed of anisotropic plies is very old technology developed originally for aerospace / racing applications. > Ansys has an entire package devoted to the analysis of structures made from anisotropic materials in this way. Also, if you read your link paper, they are not doing anything different that what has been known for a long time in long-fiber composites - see: https://www.liebertpub.com/cms/10.1089/3dp.2020.0172/asset/images/medium/3dp.2020.0172_figure2.jpg https://www.liebertpub.com/cms/10.1089/3dp.2020.0172/asset/i...
- sradman 6y ago
  > they are not doing anything different that what has been known for a long time in long-fiber composites They are using a new material (concrete) and in-situ fabrication technique (extrusion/printing) that is at an early stage of development and doesn't seem to be performing well. I'm assuming that the type of empirical data produced by these experiments is a prerequisite to developing a finite element model for these materials/techniques. The worst case here is that civil engineers have to reinvent the knowledge that you believe other engineering disciplines have mastered using different materials. Computer guided in-situ reinforced concrete seems quite novel to me; perhaps that is a reflection of my own knowledge gap.

analog31 6y ago

>>> ...rotating layers to change the bulk performance of materials composed of anisotropic plies is very old technology developed originally for aerospace / racing applications. Indeed the original engineered composite material: Plywood.

ozborn 6y ago
I believe plywood has piles/fibers orthogonal to each other, in this video they were laid over diagonal to the underlying concrete.
- hausen 6y ago
  Some higher-quality plywood does have layers whose grain is at 45 degrees to the adjacent layers: https://www.globalpp.co.uk/blog/why-do-plywood-layers-run-in-different-directions/ https://www.globalpp.co.uk/blog/why-do-plywood-layers-run-in...
  - JoBrad 6y ago
    That seems like a typo. The title says “opposite”, and just before specifying 45 degrees, the article says the layers are at a “right angle” to one another. Looking at their other products, they seem to differentiate on bonding strength and surfacing, which is pretty common.
TT3351 6y ago
Isn't concrete an engineered composite material to begin with? It's ancient. AFAIK plywood is an 19th century invention.
- BariumBlue 6y ago
  Plywood was used for shields by the Romans, I'm fairly certain the Vikings, and wikipedia mentions the Greeks and Egyptians used it as well. From what I can tell from a quick google, it does seem to be a casualty of the Dark ages though.

ghostbrainalpha 6y ago

I'm confused. They printed a helicoidal pattern, which is basically a flattened spiral which was absolutely inspired by the Lobster shell. Why doesn't that qualify as biomimicry?

ericol 6y ago

Did you actually read the article? > Their bio-mimicking spiral patterns improved the overall durability of the 3D printed concrete... That's like, the 4th paragraph in the article published by the university.

ChuckMcM 6y ago

So it is a bit click baity, sure. But how many people really think about anisotropic plies? (cool word, anisotropic, by the way) Folks who have done 3D printing figure out pretty quickly that the orientation of the print can have a large effect on the various structural properties of the thing printed. I basically spent the first couple of months printing various test objects in different orientations to get a better understanding of this. For that reason, the paper gives a reasonable way to approach the question of "how can I make this stronger?".

rwcarlsen 6y ago
I feel like plywood is a really common thing that a lot of people know to have alternating/anisotropic layers of wood grain
- ChuckMcM 6y ago
  Agreed, that is a great example. That an oriented strand board or OSB.
- JoBrad 6y ago
  Plywood alternates grain patterns at 90° to each other. OSB uses the same technique, but with shredded wood instead of sheets. Neither use the 3D twisting method outlined in the article.

tantalor 6y ago

> very old > originally for aerospace / racing applications That's a wild take on "very old"! I bet you can find even older examples, e.g., textiles

ajuc 6y ago
Composite bows were made thousands of years ago using this principle. Tendons glued in alternating layers.
- tantalor 6y ago
  I suppose shooting an arrow is a primitive form of aerospace (missile).