Learning from bumpy scorpion armour
The yellow fat-tail scorpion, or north African desert scorpion, Androctonus australis, spends much of its time at the surface. This exposes it to harsh sandstorms that can strip paint from steel, but the scorpion seems to be protected.
Han Zhiwu of Jilin University, China, and his team realized that the reason must be in the scorpion’s outer coating, or exoskeleton. So they analyzed it under a microscope, using ultraviolet light that makes the material, chitin, glow (fluoresce).1
They discovered tiny dome-shaped granules 10 microns high and between 25 and 80 microns across (there are 1,000 microns (μm) per millimeter 25,400 per inch).2
Then Han et al. tested the scorpion armour pattern against smooth armour on a computer simulation (Computational Fluid Dynamics (CFD). They found that the domes deflected the virtual airflow, which reduced the erosion rate by 50% compared with smooth. Then they tested real steel plates in a real sandstorm, albeit artificially generated by compressed air. The nearest they could get to the scorpion pattern was grooves that were 2 mm apart, 5 mm wide, and 4 mm high. Even this turned out to reduce the surface erosion by 20% compared with smooth steel. Not as good as the microscopic patterns on the scorpion exoskeleton, but still a big improvement.
Such ‘solid particle erosion’ by atmospheric dust causes millions of dollars of damage to helicopter rotors, turbine blades, and many other fast-moving surfaces, and it’s much worse in the desert.3 Dr Han suggests that rough surfaces could prolong their active lives.
We have seen before how the bumps on humpback whales also greatly improve whales. Some fans have been modelled on them.4 This scorpion armour is just another in the widening field of biomimetics.5 Certainly these human scientists are performing first-rate science in this field, but they are just making copies—what does this say about the Maker of the originals?
References and notes
- Han Zhiwu, et al., Erosion resistance of bionic functional surfaces inspired from desert scorpions, Langmuir 28(5):2914–2921, 2012 | DOI: 10.1021/la203942r. Return to text.
- Not a scratch: Scorpions may have lessons to teach aircraft designers, Biomimetics, economist.com, 4 February 2012. Return to text.
- Scorpions inspire scientists in making tougher surfaces for machinery, sciencedaily.com, 25 January 2012. Return to text.
- Humpback whale flipper inspires fan design, Creation 33(3):11, 2011; cf. creation.com/flighty-flippers. Return to text.
- See also the articles under creation.com/biomimetics. Return to text.