Carbon strands thinner than a hair are arranged in a matrix of interlocking tetrakaidecahedrons predicted by Kelvin to be “the best shape to fill an empty three-dimensional space with equal-sized objects using minimal surface area.”
In this tightly interlocking 3 dimensional geometry there is a certain degree of tensegrity, which allows for the expansion and contraction of “kelvin cells”.
Nano-architecting it in that way allows for an “in and out” compression of the material during contact rather than having it dent or puncture.
The new nanomaterial can apply to armor plating, protective coatings, and blast-resistant shielding desirable in defense and space applications.
Carbon is usually brittle, but not under this sponge like configuration.
“Historically this geometry appears in energy-mitigating foams, says Carlos Portela (MS ’16, PhD ’19), assistant professor of mechanical engineering at MIT and lead/co-corresponding author of the Nature Materials paper.
“While carbon is normally brittle, the arrangement and small sizes of the struts in the nano-architected material gives rise to a rubbery, bending-dominated architecture,” he says.
This technology is similar in spirit to shape shifting metamaterial technology, except for the formerly mentioned is capable of changing in response to temperature, humidity or other more complex environmental conditions rather than just compressing in and out upon impact.
However there is another kind of “graphene power armor” I wrote about a while back that could absorb and convert this type of kinetic energy from impact in to usable electricity to power the suit.
Not to mention it also utilizes the opposite strategy. Instead of “bouncing back” it hardens upon impact.
Picture from linked MIT article