Taking inspiration from the
yellow fattail scorpion, which uses a bionic shield to protect itself against
scratches from desert sandstorms, scientists have developed a new way to
protect the moving parts of machinery from wear and tear. A report on the research
appears in Langmuir.
Zhiwu Han, Junqiu Zhang, Wen Li,
and colleagues explain that “solid particle erosion” is one of the
important reasons for material damage or equipment failure. It causes millions
of dollars of damage each year to helicopter rotors, rocket motor nozzles,
turbine blades, pipes, and other mechanical parts. The damage occurs when
particles of dirt, grit, and other hard material in the air, water, or other
fluids strike the surfaces of those parts. Filters can help remove the
particles but must be replaced or cleaned, while harder, erosion-resistant
materials cost more to develop and make. In an effort to develop better
erosion-resistant surfaces, Han and Li’s group sought the secrets of the yellow
fattail scorpion for the first time. The scorpion evolved to survive the
abrasive power of harsh sandstorms.
They studied the bumps and
grooves on the scorpions’ backs, scanning the creatures with a 3D laser device
and developing a computer program that modeled the flow of sand-laden air over
the scorpions. The team used the model in computer simulations to develop
actual patterned surfaces to test which patterns perform best. At the same
time, the erosion tests were conducted in the simple erosion wind tunnel for
groove surface bionic samples at various impact conditions. Their results
showed that a series of small grooves at a 30-degree angle to the flowing gas
or liquid give steel surfaces the best protection from erosion.
