Up to 2016, there are over 27 million registered vehicles in Malaysia. Out of this number, about 10 million are registered motorcycles or about 37% of the total registered vehicle [1]. The number of motorcyclists on Malaysian roads keeps increasing each year. The possible reason behind their growing number is because to some road users especially city commuters, motorcycles are preferable because of their ability to dodge traffic easily on the well-congested areas. That being said, using motorcycles however increase the risk of accident to up to 17 times than car. This claim is supported by the alarming fact that at least 1% of registered motorcyclists get involved in road accidents [2]. These accidents happened because of rider’s fault of not obeying traffic and also from carelessness of other road users.
Fatalities and serious injuries in motorcycle accidents can be reduced in a lot of ways. Of course, governments need to implement and enforce strict traffic laws including regulating speed limits and requiring motorcyclists to wear proper safety equipment. Another way to tackle this challenge is to design better safety gears that motorcyclists use like helmets and safety pads inside jackets. Helmets are the more crucial equipment than the padding because they protect human skull and brain. The present technology gives helmets that are generally able to absorb impact head on during a single collision [3]. However, during accidents, there are chances that when the impact hit the motorcyclist head off-center, limbs and other exposed joints, the rotational energy failed to be absorbed by the protective gear and passes directly to the victim’s body. Furthermore, most current helmets and padding do not perform well when dealing with multiple hits to protect the victim against concussion.
One of the solution to save motorcyclist lives may lies within the nature. Hedgehogs, in their natural behavior, climb tall trees in search insects and food to eat. They tend to fall out of trees a lot, either by accident or sometimes they fall purposely to escape from predators. As hedgehog falls, it rolls into a ball and let the quills absorb the impact [4]. Therefore, inspired by hedgehog quills that keep the hedgehog safe and unharmed during impact of falling from tall trees, some researchers have use hedgehog-inspired bio-mimicry to design better helmets.
Most protective gears that are available today usually have three layers of protection, the hard polycarbonate outer shell, the shock absorber in the middle layer and the padding in innermost layer. The bio-mimicry from the hedgehog quills can be applied to improve the middle layer. The current shock absorber protects against linear straight-on collision, but does not do well when protecting the victim’s head against concussion due to multiple hits from different direction. When the brain is knocked against multiple side of the skull, it can get twisted or rotated from its regular position. This is where rotational give can be added to the shock absorber by introducing liners inspired by hedgehog quills [3].
Similar to hedgehog, the liner has quills on it that can bend and twirl around each other quills in all different directions. This liner is made out of elastic polymer material and will return back to its original form after an impact. The layout of the liner would be throughout majority part of the helmet. This allows the liner to interact and overlap with each other which helps spread the impact of this hit.
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| Figure 1: Liner prototype inspired by hedgehog quills [3] |
This hedgehog-inspired liner is still under on-going research. What researchers have done so far is using deceased hedgehog to proof shock absorbing ability of hedgehog quills. Though in their natural environment, hedgehog quill’s orientation is controlled by muscle contraction. Nevertheless, dynamic impact testing of sample hedgehog quills shows impact absorption capabilities when they are arranged in certain orientation which mimic the natural model. This confirms the role of the quills to protect the hedgehog during impact better. From the economics point of view, if the cost of this improvement in helmets and elbow/knee pad designs outweigh the cost of medical bills and loss of lives associated with head and brain injuries, this liner inside helmet’s middle layer could be added in major brand’s helmet.
1. http://cru.miros.gov.my/4thCIIA/Motorcycle%20Crashes%20in%20Malaysia_day2.pdf
2. https://www.miros.gov.my/1/dl.php?filename=Motorcycle%20Vol1.pdf
3. https://www.inverse.com/article/25760-hedgehog-spine-quills-hedgemon-helmet-concussion
4. https://asknature.org/strategy/spines-work-as-shock-absorbers/#.WUf4DlFLeiM
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