Conclusion

"It's been 13 weeks already? Wow"

And with that, the journey has finally come to an end.

Throughout the building of this blog, our eyes are opened to the plethora of inspiration that are to be grabbed from the nature. From artificial leaf that gather energy from the sun to applying different wing span design of birds into airplane, studying Engineering and Biomimetics shows us that nature is more than just to be preserved: its inner working can be mimicked into engineering to create products that functions, designed while reducing potential risks (or better, improve) the nature.

Regarding the subject of our research study, hedgehogs, it has been a fascinating experience studying this often under looked cute little creature. The beauty of quills of a hedgehog is more than just hardened pieces of keratin. By studying its form and function, it is possible to design a shock absorbing layer that can be implemented into protective gears such as knee pad. As a result of this implementation, knee pad shock absorbing performance can be improve significantly and therefore, reducing number of impact related casualties during accidents.

It is very hopeful that the study of hedgehog quills spans more that just its ability to absorb force during impact. One example of it is since hedgehog quills are basically made out of keratin, being able to artificially produce keratin could also be very beneficial to producing hard structures out of protein due to its compound versatility.

And of course, big thanks to everyone involved in the Engineering and Biomimetics module and production of this blog.

"That's All Folks!"

Reflection

Andrew Ng 

The most interesting aspect of the adoption of biomimicry of the hedgehog spines as a mode of shock absorbent. This allows a hedgehog to fall from high places without seriously injuring themselves, by rolling into a ball, thus making its spines erect. By conducting research and literature reviews on the spines of the hedgehog, and the mechanics of its deformation during impact was examined. The microscopic cross-section of the hedgehog spine was studied, and compared to quills, as they both fall into the hair category. It was later concluded that quills do not absorb much shock, and breaks easily as compared to quills. So, the hedgehog spines were used in order to adopt its characteristics onto our bio-inspired kneepads. I believe that this product has already been created by a company called Hedgemon, hence this proposed idea cannot be patented. This is because the functionality of our knee pads are similar to that of their hedgehog spine inspired helmet. This effectively removed the novelty of this idea, thus eliminating the patentability of this idea.

Working in a team has most definitely made this project easier, as research load was definitely lightened with the help of each group members. Tasks were assigned in accordance to the core competencies of each group member in order to efficiently finish this blog. As the group leader, I am proud of each member, as they attend meetings even though they are busy with their own personal commitments. Besides that, although not all team mates see eye to eye about everything, they were professional enough to put their feelings aside in order to reach a compromise. The creation of this blog has taught me that the nature is the best source of design inspiration, as evolution has resulted in organisms with certain special characteristic that can solve our everyday challenges.

Mohamed Ehab
Biomimetics was definitely a very interesting topic to study, nature have always fascinated me and seeking to understand it and discover it has always been a goal to achieve. Approaching nature through engineering biomimetics was interesting as it explained nature processes by relating it to our field of study, which made the subject even more approachable and exciting. Nature is very complex and organized, systems of organisms work together beautifully in a hierarchical order that should be a source of inspiration for any engineer or innovator. Seeking to perfect engineering processes and products through studying nature has proved to be very successful. It was mind opening studying some products that were developed through inspiration by nature.

Working to develop a product based on inspiration by nature with a group of course mates was new and interesting to us. It was a great experience learning more about hedgehogs and using their physical characteristics to further modify and improve an already existing product to serve users better and enhance their safety. I would like to thank all my team members for their hard work and professionalism during the module. Lastly the module was very eye opening and I plan to continue to study nature and get further inspiration from its complex systems.

'Arif Akmal

Hedgehogs, other than being cute, it didn't occur to me that hedgehog quills also function as shock absorber (only to be informed by my teammates during group formation stage of this assignment). This natural characteristic is very useful for hedgehogs, who spent most of the time on a tree needed to jump of the tree to escape from predators allowing the hedgehogs to curl itself into a ball and land on the ground unscathed. Upon further researches and literature reviews, there have been numerous amount of researches related to bio-mimicking the structure of hedgehog quills and how it is arranged with the ultimate goal of applying the nature inspired feature into safety gear such as helmets and knee pad. As mentioned by Andrew Ng, product who integrate such idea has already been produced thus eliminating any opportunities of patenting this idea. Nevertheless, researchers are striving to delve into the unique capability of hedgehog quills and new ideas are being produced as we speak.

I had a blast working with this team. Tasks are effectively assigned to each of the team members competency in the research area. Use of technologies were integrated into the module, making assignments more engaging and fun. Furthermore, team members are committed into completing this assignment even when each of us are busy with other projects from other modules. Akin to nature working together in keeping the balance of the earth's ecosystem, each and every team members managed to pull themselves together towards finishing the blog assignment for Engineering and Biomimetics module and with that, I'm proud of the team.

Aatif 

As a chemical engineer, the main task is often linked to process control and process designing. All of the modules are thus designed as such, however Engineering and Biomimetics is different in that regard. It is a module that is linked to engineering in a unique way and allows thought development that is unusual to regular engineering designs. By accessing nature and its “products”, humans have learned a great deal not only in the modern era but since the dawn of humanity. Various applications of biomimetics are becoming common and is one of the ways forward for engineering design since it is a means for sustainable development that humans crave so much right now.

Hedgehog’s biology is a recent target for engineers and innovators. Hedgehog spines are looked at with great interest and deep understand down to their unique design of shock absorption. This inspired the team to apply the hedgehop spine shock absorption design to elbow and knee pads.

My personal task for this project is listed as “Industrial Application: Shock Absorbing Elbow and Knee Pads” in the blog. The design process of the pads was complicated since many aspects had to be considered due to the fact that the team did not want to have a reductive view but a holistic view to the project. This required effort on the design part and finding suitable materials as well as other aspects such as funding had to be considered heavily. Biomimetics have found a home in engineering applications and many unique and interesting applications exists in the world right now. The application of the hedgehog spine design as a means to shock absorbing elbow and knee pads in an industrial environment is a sound and unique approach to a product that is long overdue for an upgrade. The design is unique and provides the user with much safer working gear then currently present in the market, which means it is likely to be success among workers and other users alike. Due to this uniqueness and no such design available in the market it can be easily patented.

I would personally thank my team for working hard on the project and making it a success in terms of coming up with a design, that is not only workable but has a high chance of success. Their hard work, co-operation and effort helped in overcoming the hurdles faced during the project. Overall, the with the effort put in by all the members, the project was easier to handle and all the tasks were completed with great efficiency and a positive approach.

Muhd. Yasir 
There is more to hedgehogs than meets the eyes. Previously, I have never thought that hedgehog quills can act as a shock absorber. Having own three cute hedgehogs as pets myself, I rarely see these cute animals use these their quills other than to defend themselves. This may also because I have never expose them to dangerous heights and let them fall just to observe their shock absorbing quills in action. I was so afraid to try it also because hedgehogs are also known to have shortsighted eyes. They would not be able to guess the height if I leave them on a high edge. If they do jump, it would probably injure them and make me as an owner sad. Having said that, hedgehogs are still wild animals that are largely domesticated, so hedgehog owners like me might think that there are soft and gentle creatures even though in reality they do climb tall trees in search of food and occasionally, they may fall from these trees to avoid predators or unintentionally.  
Doing this project has opened my eyes about the possibilities of biomimicry applications not just to hedgehogs, but also to other animals that we may see every day as common animals that do not have any biomimetic values. In fact, a lot of new successful engineering designs today are somewhat based on biomimicry application thanks to the hard work of engineers and researchers. I am therefore grateful that this quite new field of engineering biomimetics is gaining more and more attention from aspiring researchers that would help make the world a better place. 

Reverse Engineering Worksheet

1. Examine the biological artifact with the intent of discerning
  

What does the pet do?
Hedgehogs are spiny animals that belong to the Erinaceinae family. They are nocturnal as they get most active at night and they feed on insects, snails and frogs. Hedgehogs are covered in spines made of keratin, that they use a defense mechanism when are attacked by a predator. They also protect hedgehogs from impacts, as they commonly fall from trees.  
How does it work?
Wild hedgehogs climb trees to find food. Sometimes they fall by accident from heights as high as 30 feet, as a hedgehog falls toward the ground, it rolls into a ball and its spine absorbs the shock protecting its face and body. The reduction of impact could be explained due to the decrease in area of impact, which lessens the pressure put on the hedgehogs when it falls.


2. Engineering Inspiration
 

New Product
The ability of a hedgehog to absorb shocks using its spines could be used in multiple applications to reduce impacts. Knee impacts in sports such as football and rugby and in motor cycle accidents can cause a lot of injuries that are very difficult to fix. Such as ACL sprains and tibia plateau fractures. This makes the hedgehog spine mechanism a valuable innovation to be applied to knee protectors that would work in minimizing the impact forces.  
3. Reflection  

Do you think the product will work if it is manufactured? As innovations from nature has been used by nature for a hundred of years, it has already been tested and works. But due to the differences in application, material, size of the use it will be applied it a lot of research and development has to be put into the product. Therefore, if the correct material and shape is used the knee pads could have a great impact force reduction that would save thousands of knee injuries annually.  
Do you think you can raise funds? Due to the increase in the popularity of crowdfunding products and websites and the widespread use of knee pads in athletes and motorcyclists, there will be a large crowd that will be willing to help us to raise the funds necessary. But to accomplish the following goal, it is necessary to target the right crowd and to create a crowdfunding page on a popular platform and add attractive content and rewards that would attract potential customers.

Do you think engineers explore solution from nature into their invention? Engineers have always been exploring solutions from nature and applying it into the products they design. This includes applications in structures and aerodynamics of airplanes and ships. Nature will always be used as a platform for innovation for engineers.

Industrial Application: Shock Absorbing Elbow and Knee Pads

Existing Elbow/Knee Pad Designs 

Industry is a field that is need of constant equipment updates due to new challenges and dangers alike. Among these equipment, the most common to be ignored are elbow and knee pads. The current design of elbow and knee pads existing in the market is based on foam padding. Foam padding contains air, which acts as the shock absorbing material. Once the air is compressed, there is very little that stands in the way of the approaching object and the knee of the person, meaning the user is at great risk to forces greater than the threshold of the pad. To counter this, gel pads are introduced, with the addition of gel in the already existing foam padding. This gel provides extra shock absorbing capabilities however, in the case of torn elbow/knee pad, this gel will leak out rendering the knee pad useless. Besides the disadvantage mentioned, when gel is added to the elbow/knee pad, it increases the size of the pad, making it bulky as well as heavy. 

The New Elbow/Knee Pad Design 

The design of elbow/knee pad must be strong enough to withstand harsh working environments and strong forces yet be lightweight and compact for a comfortable experience. With these aims in mind, the spines of the hedgehogs can fit the design perfectly. Hedgehog spines can withstand considerable incoming damage as they are able to protect the hedgehog’s body from falls up to 10 meters high. Spines are able to perform this action due to the presence of air pockets within each spine, providing extremely high strength to weight ratio and thus, able to prevent the spines from breaking and buckling. From literature review gathered, hedgehog spines under humid conditions can withstand forces of 8 Joules even after multiple collisions. 

Replacement Material for Spines 

The spines of hedgehogs are made of a material called keratin. Since keratin is a biological material and therefore difficult to gain access to, a suitable alternative must be utilized instead. The material needs to be lightweight, durable and low cost, so people who work in the industry can easily afford it. Acrylonitrile butadiene styrene (ABS) fits the criteria of material required. It has high impact resistance, easy to machine and thermoform [1], Figure 1.

Figure 1. ABS Material for Hedgehog Inspired Elbow/Knee Pads

Viability of the Design 

The viability of every product is based on the three pillars of sustainability, which are economic viability, environmental sustainability and social feasibility. The product is economically viable since it is made of cheap materials. It has environmental sustainability due to the fact it has very low hazards associated with it. And it is socially feasible since the design is basically done to help people working in the industry, to improve their safety and comfort in the working environment. 

Funding for the Project

Even though the cost of the ABS material is cheap, the designing, modeling and construction of the prototype and eventually the final product will require considerable cash input. Due to the fact this design is done by a team of students, who do not have any organization backing them, as well as the fact that funding is a challenge faced by every engineer and inventor, the project will be funded by the crowd. In order to make the usual crowd aware of the project and its implications on the safety of the workers in an industrial environment and even day to day activities such as driving a motorbike or riding a bicycle, a crowdfunding platform will be utilized. There are many crowd funding platform, however the most popular at the moment is “Pozible”. All the details about the project, including the release date will be provided to the crowd. This use of such platform not only allows for collection of funds but acts as a free advertising zone and also as a direct feedback zone on the product itself. 

Biomimicry and Inventions

Application of hedgehog spines for production of elbow/knee pads is the not first time an engineer or inventor has taken inspiration from nature to find solutions to existing problems. One of the most famous invention that was inspired from nature is the road stud reflector. During night time when light is shined onto a cat’s eye, it reflects the light back given the eyes a glowing effect, Figure 2. It also reveals the location of the cat. Similar effect is used for road stud reflectors we now see on all the roads, Figure 2. Road studs reflectors have the same working principle and are one of the safety requirements for all roads now. Another example is beak of the bird called kingfisher. Japanese inventor studied the design of kingfisher and came to the conclusion it has the highest drag reduction possible due to the design of its beak. They utilized the kingfisher beak design to the design of the beaks of bullet trains. There are many other inspirations from nature that have led to major inventions throughout the world. Biomimicry is a major aspect of engineering and invention and must be studied and applied whenever possible. The use of biomimicry leads to an overall better design that be cost effective and environmental friendly. 

Figure 2. Roads Studs (Top) and Cat Eyes (Bottom)

References 

[1] “Outstanding impact resistant low cost plastic, easy to machine and thermoform,” p. 2355, 2016. 

Hedgehog Quill as a Potential Shock Absorber.

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.

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.

References

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

Hedgehog Spines - Potential Bio-mimicry Inspiration

Hair is a product of evolution that can only be found in mammals. Hairs can have various functions to mammals, which include signaling, sensing the environment, camouflage, to retain body warmth as wells as a signal to ward of predators, or to find a mate. Quills and spines are a form of modified hair which are common in four groups of mammals. These groups are:

1.            Hedgehogs (Erinaceomorpha: Erinaceidae, Erinaceinae)

2.            Tenrecs (Afrosoricida: Tenrecidae, Tenrecinae)

3.            Echidnas (Monotremata: Tachyglossidae)

4.            Rodents (Rodentia)

Quills and spines both serve different purposes although they have a hard and thick outer layer of keratin. Quills act as a defensive armor for porcupines, as they are long, highly irregular in length and they break and separate from the host’s body quite easily. Spines on the other hand serve as a shock absorber for hedgehogs as they are all of the same length all over hedgehog, embedded well in the skin, curved slightly and firm.

The spines of the hedgehog consists of many contained air pockets that are separated by a regular spacing of septum coupled with longitudinal stringers. The cross section of the structure of hedgehog spines can be viewed from Figure 1. The existence of the network of air pockets in the spines give them a high strength to weight ratio. Besides that, the air pockets helps prevent breakage of spines as well as buckling.

Figure 1: Cross section of the hedgehog spine.

The mechanical properties of spines across different species may vary depending on the microstructure of the spine. Figure 2 shows the microstructure of the Erinaceus europaeus spine, whereas figure 3 shows the microstructure of the Hemiechinus sp spine. The septa of the former is much more widely spaced, and has longitudinal stringers that are much deeper as compared to the latter. This piece knowledge is crucial, as the internal structure of the hedgehog is essential in order to successfully design knee-pads which can absorb any excess shock. By varying the depth of the longitudinal spine, as well as the distribution and thickness of the septum, the amount of shock that can be absorbed by the aforementioned knee-pads can change tremendously.

Figure 3: Transverse (a) and longitudinal (b) section of Hemiechinus sp spine. Scale is 100 µm

Figure 2: Transverse (a) and longitudinal (b) section of Erinaceus europaeus spine. Scale is 100 µm

By using the concept of bio-mimicry, the hedgehog’s spines can be model as a potential for impact resistant materials and structures. There were many experimental studies that were conducted in the past on the mechanical properties for the spines of the hedgehog. From those studies, the critical Euler bulking force for a single hedgehog spine was identified to be about 6N and this was found by conducting bending and compression test on the spines of the hedgehog. Moreover, tests for the consistency of the durability performance of the hedgehog’s spine were also studied upon as it is important for various applications such as concussion mitigation for the football helmets [4]. Among the tests that were conducted was the dynamic impact test by using a dual-arm crash pendulum. Figure 4 shows the schematic of the pendulum apparatus during the trial of collision on the hedgehog’s spine that has been retrieved from a naturally deceased hedgehog.  
 

Figure 4: Impact test on hedgehog spine using pendulum

After the test was conducted, it was found that the spines in the humid sample has minor damage and remains intact after a consecutive of 5 collisions of each being 8 Joules. However, the spine which was of the dry sample shows a significant amount of breakage after just 2 collisions of each being 8 Joules.

Figure 5 shows the results of the hedgehog spine after impact testing [5].

Hence, from this literature study, this concept of using the hedgehog’s spines or quills that acts as the animal’s safety mechanism can provide some promising applications in future materials. In this study, the design hedgehog’s spines are used to redesign elbow pads and knee pads for motorcyclist as improve the mechanical properties and reduce impact of motorcyclist when acted upon.

References

[1]      http://animaldiversity.org/collections/spinesquills/

[2]      http://dlx.booksc.org/15100000/lib....pdf

[3]      http://www.hedgehogcentral.com/quills.shtml

[4]      http://sci-hub.cc/http://journals.sagepub.com/doi/pdf/10.1177/1045389X9000100109

[5]      http://sci-hub.cc/http://www.sciencedirect.com/science/article/pii/S175161611630039X

Introducing Hedgehog

African Pygmy Hedgehog (Atelerix Albiventris)

Hedgehogs have been around for the last 15 million years share a distant similarity to shrews (family Soricidae) and does not experience any significant changes since then. It belonged in the Erinaceinae subfamily in the eulipothyplan family Erinaceidae. Seventeen species of hedgehog are discovered through parts of Europe, Asia and Africa. New Zealand however, is an area where hedgehogs does not originally belong to and can only be found in the region after introduction. Hedgehogs are not native to Australia and other than the already extinct Amphechinus genus, no other hedgehogs are species native to the Americas.  

Their spiny protruding spines or quills are technically hairs made stiff with keratin. Contrary to general belief, hedgehog spines are not poisonous or barbed and unlike porcupines, do not detached easily from their bodies. Quills detachment only occurs during “quilling”. Like shedding, quilling is a process where the immature spines fall out as they are replaced with stronger, adult spines. It can also occur when a hedgehog contract disease or under extreme stress. 

European Hedgehog (Erinaceus Europaeus)

Skeletal System of a Hedgehog

All species of hedgehogs possess ability to roll into a tight ball as a defensive manoeuvre. This caused their spine to roll outwards. This is enabled by two large muscles that spans along the back of a hedgehog. When the creature rolls into a ball, its body, feet and belly is tucked inside the outside layer of quills. This helps hedgehogs to protect themselves from imminent danger from predators; forest hedgehogs are prey to carnivorous birds and ferrets while smaller species are often hunted by foxes and wolves. Since hedgehogs often spend most of their time on trees away from the ground, it rolls into a ball and jump towards the ground in the event of an attack. Their quills absorb the impact of the fall as the body touches the ground. This is the aspect that is deemed unique for a hedgehog and will be the subject for this research. 

Other unique characteristics that hedgehogs have include: 

• PRIMARILY NOCTURNAL. Some species can be found sleeping throughout large portion of the day under bushes, grass or dens dug in ground. Depending on the temperature, species and food abundance, wild hedgehogs can enter themselves into hibernation. 
• FAIRLY VOCAL. They communicate through grunts and squeals depending on species. 
• ANNOINTING RITUAL. As it encounters a new scent, it will lick and bite the source. A scented froth the formed in its mouth and is pasted on its spine using its tongue. This is believe to camouflage the hedgehog from the predators in the area and to some cases, generating a poison that can be used to infect predators that are poked by it spines.  
• NATURAL IMMUNITY TO VENOMS. Hedgehogs, among opossums, mice and moles, have some degree of immunity against some snake venom. This is made possible due to the protein erinacin in the animal's muscular system. However, it is only available in small amounts and viper crushing bite might still be fatal. In addition, hedgehogs contain mutations in the acetylcholine receptor that prevents binding against another snake venom, α-neurotoxin.