Researchers have developed a design structure for composite materials which is more impact resistant and tougher than the standard used in airplanes.
The peacock mantis shrimp, or stomatopod, is a 4- to 6-inch-long rainbow-colored crustacean with a fist-like club that accelerates underwater faster than a 22-calibur bullet.
Researchers, led by 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, an associate professor of chemical engineering, are interested in the club because it can strike prey thousands of times without breaking.
In experiments outlined in the paper, the researchers created carbon fiber-epoxy composites 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.
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.
Their results showed that the helicoidal samples, in general, displayed a significant increase, about 15 percent to 20 percent, in residual strength after impact compared to the quasi-isotropic samples.
The paper has been published online in the journal Acta Biomaterialia.
