Fish scales inspire flexible armoured gloves
Protective clothing should combine both hardness (resistance to puncturing) and flexibility. But the hardest materials are usually stiff. This is solved by pieces of hard substance on a softer sheet, e.g. lorica squamata, Roman armour with metal scales sewn onto cloth.
Now engineers at McGill university in Montreal have modelled armour on the scaly skins of fish with overlapping scales, such as bass and alligator gar (picture above). They experimented extensively on the skin and the scales themselves to find out how hard and tough (resistant to fracture) they are, and how they break. The engineers found that the smaller scales are more puncture resistant, and they are “the toughest collagen-based material known.”1
The researchers used computer modelling to work out the best arrangement, then made scales from strips of a hard ceramic, alumina (Al2O3), 0.6 mm thick, and glued them to a stretched elastic strip. When the strip was released, the scales slid over the next scale and thus overlapped. This arrangement of scales was then glued to a soft elastic silicone membrane.
It was found that this membrane with the scaled armour was still very flexible, but it didn’t compromise hardness. Rather, the armour was actually more puncture-resistant than a continuous layer of ceramic. Furthermore, even after multiple punctures, the armour retains its resistance, even when the punctures are only two scales apart.
Of course, there was the normal fact-free homage to evolution:
“Over millions of years of evolution, animals have developed highly efficient protective systems to resist mechanical threats from predation, intraspecies fighting and hazardous environments.”2
But as usual, evolution didn’t contribute any genuine scientific insights into how the armour worked, or even how it arose. The researchers certainly didn’t rely on random mutations and natural selection to make their armoured gloves! This is one of many examples of human engineers learning from nature’s Creator—a rapidly expanding field called biomimetics or biomimicry.3
References and notes
- McGill University, Protective wear inspired by fish scales: Ceramic-covered gloves offer industrial workers increased protection from piercing, sciencedaily.com, 24 January 2017. Return to text.
- Martini, M. and Barthelat, F., Stretch-and-release fabrication, testing and optimization of a flexible ceramic armor inspired from fish scales, Bioinspiration & Biomimetics 11:0066001, 13 October 2016 | doi:10.1088/1748-3190/11/6/066001.. Return to text.
- See the articles under creation.com/design#biomimetics. Return to text.