It seems that with some configuration of slicing 3D printed parts can mimic the Shrimps’ Claw, which can lead to making stonger materials than traditional ones.
Originally shared by Gary Ray R
The Mantis Shrimp, Hardness and Toughness of the Claw Leads to Better Composites
The Mantis Shrimp is one of the most popular and studied little creatures around right now. Studying the Mantis Shrimp is as trendsetting in biology research, as is Graphene is in the materials world.
A short review of the Mantis Shrimp.
Mantis shrimp are a prime predator, and are found in tropical, sub tropical, and some temperate marine regions all over the world. There are about 400 different species, and they are roughly divided into two groups, depending on the main form of their front appendages: spearers and smashers. Spearers are the ones with spiny ‘claws’ that are sharp and spear their prey and smashers have club like ‘claws’ that they use to beat their prey to death. They range from drab brown to a wonderfully colorful peacock color scheme. They are aggressive and will hunt down and kill their prey.
One of the reasons to study these little creatures is because the some of the smashers (lovely term) have a club that is a formidable weapon.
The Striking Claw. From Wiki :
Both types strike by rapidly unfolding and swinging their raptorial claws at the prey, and are capable of inflicting serious damage on victims significantly greater in size than themselves. In smashers, these two weapons are employed with blinding quickness, with an acceleration of 10,400 g (102,000 m/s2 or 335,000 ft/s2) and speeds of 23 m/s from a standing start, about the acceleration of a .22 calibre bullet. Because they strike so rapidly, they generate cavitation bubbles between the appendage and the striking surface. The collapse of these cavitation bubbles produces measurable forces on their prey in addition to the instantaneous forces of 1,500 newtons that are caused by the impact of the appendage against the striking surface, which means that the prey is hit twice by a single strike; first by the claw and then by the collapsing cavitation bubbles that immediately follow. ⓐ
Hardness and Toughness of the Claw
I want to discuss the punching appendage, that little Mantis Shrimp fist of death. As we read earlier it is a fast as a .22 caliber bullet and needs to be very hard and tough to withstand the force of 1,500 Newtons, thousands of times in the lifetime of a Mantis Shrimp.
Inspired by the fist-like club of a mantis shrimp, a team of researchers led by University of California, Riverside, in collaboration with University of Southern California and Purdue University, have developed a design structure for composite materials that is more impact resistant and tougher than the standard used in airplanes. ⓑ
“The more we study the club of this tiny crustacean, the more we realize its structure could improve so many things we use every day,” said David Kisailus, a Kavli Fellow of the National Academy of Science and the Winston Chung Endowed Chair of Energy Innovation at the UC Riverside’s Bourns College of Engineering. ⓑ
The force created by the impact of the mantis shrimp’s club is more than 1,000 times its own weight. It’s so powerful that Kisailus needs to keep the animal in a special aquarium in his lab so it doesn’t break the glass. Also, the acceleration of the club creates cavitation, meaning it shears the water, literally boiling it, forming cavitation bubbles that implode, yielding a secondary impact on the mantis shrimp’s prey. ⓑ
In a previous paper the researchers had determined that certain regions of the claw:
Within each club is a scaffolding of fiber layers stacked in a corkscrew-like, or helicoidal, arrangement. The fibers are made of chitin, an organic polymer commonly found in insect and crustacean exoskeletons, while gaps between are filled with calcium carbonate and calcium phosphate. ⓒ
“When a small crack forms, it has to travel a very tortuous path, around and around the helicoid, in order to escape the entire club but runs out of energy and stays in the club,” Kisailus said. Helicoidal architecture has also been observed in the exoskeletons of some beetles and crabs. ⓒ
You can see that structure in the image below, the Mantis Shrimp is on the right.
The scientists used that same layered design and made carbon fiber epoxy composites. That is what is shown on the left of the image below. They made samples at three different angles of rotation and two control samples.
“In experiments outlined in the paper, which were led by Lessa Grunenfelder, who formerly worked in Kisailus’ lab and is now a post doctoral student at USC, carbon fiber epoxy composites were created with layers at three different helicoidal angles ranging from about 10 degrees to 25 degrees.”
They also built two control structures: a unidirectional, meaning the layers were placed directly on top and parallel to each other, and a quasi-isotropic, the standard used in the aerospace industry, which has alternating layers stacked upon each other in an orientation of 0 degrees (first layer), -45 degrees (second layer), +45 degrees (third layer), 90 degrees (fourth layer) and so on. ⓑ
Scientists performed a standard drop weight test to analyze impact resistance and energy absorption of the samples, examined the samples with ultrasound and performed a compression test.
The researchers used a drop weight impact testing system with a spherical tip that on impact creates 100 joules of energy at USC with their collaborator, Professor Steven R. Nutt. This replicates testing done by the aircraft industry. Following the tests, they measured external visual damage, depth of the dent and internal damage by using ultrasound scans. ⓑ
Results
The results were that the samples designed like the claw of the Mantis Shrimp performed better. Much better.
After dropping a weight vertically on to each sample using a control machine, the team assessed the damage. The unidirectional sample completely failed, splitting in two, while the quasi-isotropic sample was punctured through to the underside. The helicoidal sample showed some wear but overall was 49 percent less dented than the quasi-isotropic structure.
Using ultrasound waves and also confirming with computer simulation, the researchers found that the structure spread the damage laterally rather than vertically into the sample. ⓒ
In the end, the mantis shrimp’s design reigned supreme, with less denting and greater residual strength after impact. Potential applications for such a material could include aircraft and automotive panels, and athletic helmets and military body armor. ⓒ
Other researchers believe that the process for making this can easily be automated.
Mechanical engineer François Barthelat of McGill University, who was not involved in the study, believes this superior helicoidal composite could easily be mass produced.
“There are machines already to make this type of composite material, so what’s critical is the orientation of the fiber layer,” he said. “It would just be a matter of adapting the machines.” ⓒ
ⓐ http://en.wikipedia.org/wiki/Mantis_shrimp
ⓑ University of California, Riverside UCR TODAY
http://ucrtoday.ucr.edu/21670
ⓒ Washington Post Science
Tip of the hat to @Sam_Andrews
Original Research Behind Paywall:
Bio-inspired impact-resistant composites
♜ Of course you have to see Oatmeal comic on the wonders of the Mantis Shrimp.
Image: UCR Today
