Bio-inspiration from Turtle's Shell - Skiboard

Skiing is a type of recreational activity where participants use skis to glide on snow. The ideal ski (also known as skiboard) can withstand high levels of pressure in turns and also able to maneuver. These two features usually require two different types of skis:

1.       Expert skiers that preferred rigid skis

                                 2.       Intermediate-level skiers that preferred flexible ones

But a new type of ski is able to combine the two different features of the skis into a design based on the turtle scales. This design allows the skis to be able to maneuver while entering and exiting turns, at the same time stiffen up in the middle of several turns to improve the skis’ grip on the snow. The turtle shell design was a joint effort based on a research institution from École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland, Institute for Snow and Avalanche Research (SLF) and a Swiss ski manufacturer.

Figure 1. Turtle's shell structure and cycling-loading analysis trend result

The idea of mimicking the morphology of turtles was introduced by Véronique Michaud, a researcher at EPFL. She stated, “The scales of a turtle interlock, like a jigsaw puzzle, and they are connected by a polymer. When turtles breathe, the scales separate slightly and the shell becomes flexible. But when an external shock occurs, the shell tightens and stiffens”. 

The new ski design was conducted by embedding aluminum plates with a snake like shape fissure into precise locations at both ends of the skis. When the skis bend in one turn, the plates at both sides of the gap come together and the ski stiffens, allowing the skier to achieve stable and precise turns. As the skier comes out from one turn, the gap reopens allowing the ski to be more flexible again and easy to handle. Hence, the alminum plates function like scales and a special type of rubber between the plates is similar to the polymer exist in the turtle shell. The ski design was shown as follows:

Figure 2. The mimicking of turtle's shell structure on skiboard. 

The newly designed ski was proven by Olympic ski champion, Tina Maze as she attempts to utilize the new design for a ride. She stated, “As the pressure on the skis gradually increases during turning, the skis really gripped the snow and were stable. I was impressed by the ease with the plates coming together and separate.”

The new design also improves the safety during the turn which prevents skiers from falling down causing severe injuries, and worst case, it could cause fatality since skiing is hurtling down with steep slopes.

References

1. L. Pessina, "Ski design inspired by turtle scales", MEDIACOM, 2015. [Online]. Available: https://actu.epfl.ch/news/ski-design-inspired-by-turtle-scales/. [Accessed: 03- Jul- 2016].