Twisting Cracks Aid Super Strength in Mantis Shrimp

Twisting Cracks Aid Super Strength in Mantis Shrimp

August 15, 2019 0 By Stanley Isaacs


(calming music) – The shrimp is trying
to actually hit the prey. The prey typically is crab, or it could be a shell of a snail. And it’s actually hitting at
20 or 30 meter per second. This, underwater, is
very, very high speed. When he hit, during that millisecond, where the wave propagation
go through the dactyl claw, it generates all these multiple spiral cracks. These spiral cracks
are actually beneficial because it promotes the spread of damage without allowing catastrophic failures. You wanna prevent that,
you want some kind of plastic deformation. We call this in fracture
mechanics, graceful failure. Now we can actually create
composite materials using 3D printing or traditional
composite fabrication procedures. We have a testing machine. We apply compression so
that basically these forces transmit into bending,
and then we observe how the crack goes, how it
twists, we follow that with digital image
correlations, we have a couple of cameras that actually follow the crack, follow the deformation of the material, and then we use that
information to compare with computational models
that allow us to see more into the material. One of the next steps, now is to actually extrapolate these ideas
into other materials. So, one idea is to use
this Bouligand Architecture in materials that are very, very brittle, like cement, like ceramics. So, designing materials
we still don’t have the perfect mathematical tool
to tell us how to combine material A and B. We need to do this
empirically, so it’s more trial and error. What best way to actually
look at trial and error than looking at nature
that actually try this for many million years of evolution?