Honeycomb Structures In Nature and Engineering

This post was inspired by a picture that distracted me while I was reading my biology book last year (hey, that Biology GIR was good for something/look for inspiration everywhere remember!)...

Reece and Campbell Biology 9th Ed.

It was in one of the introductory chapters under the subheading: "Theme: Structure and function are correlated at all levels of biological organization [1]." Note, this is not about how form follows function, rather exploring- "how a device works is correlated with its structure [1]."

The picture fascinated me because - well just look at that awesome internal structure! Imagine the first person who cut up a bird bone and saw that. It must have been amazing. If you've ever tried making something that flies, you really begin to appreciate lightweight yet strong structures (experimenting with balsa wood for example).

Here's another awesome picture, the photographer's caption reads: "Bird bone tissue. Coloured scanning electron micrograph (SEM) of cancellous (spongy) bone from a robin."

http://www.sciencephoto.com/media/203268/view

Geez, I mean just look at that. Try CADing that in SolidWorks...

I knew that honeycombs are used in applications for the aerospace industry, high performance automotive applications, and athletic sports equipment, but as I dug a little deeper, I realized they're really everywhere!

My curiosity led me to bees. How do bees know to build honeycombs for their hives? Here are two good articles that describe the answer to this question in more detail:

http://www.nature.com/news/how-honeycombs-can-build-themselves-1.13398
http://www.npr.org/blogs/krulwich/2013/05/13/183704091/what-is-it-about-bees-and-hexagons

Long story short, it turns out that it's a combination of their efficient natural organizational engineering and the natural laws of physics. 

http://www.npr.org/blogs/krulwich/2013/05/13/183704091/what-is-it-about-bees-and-hexagons

Where else do honeycombs appear? Well, in one of the most awesome materials ever: graphene. From Wikipedia, graphene is a crystalline form of carbon which is an "atomic-scale honeycomb lattice" essentially one atom thick of graphite. This material is being explored by companies such as IBM to design superior nanoelectronic devices [2].

http://en.wikipedia.org/wiki/Graphene

If nature knows that honeycombs are exceptional, of course it would be exploited by engineers. There's a company that makes aluminum honeycomb for example: http://www.corex-honeycomb.com/aluminium-honeycomb.aspx. I haven't designed anything that uses honeycomb structures - I know the FSAE team uses it in their race car - perhaps because it poses an interesting manufacturing problem. There are always tradeoffs.

What's better than honeycomb aluminum? Honeycomb carbon fiber. 

The BMW CRT (Carbon Racing Technology) - "BMW fitted it with cellular carbon honeycomb parts, including the bonnet, the bucket seats, the rear spoiler and the air-channeling element integrated in the front apron." I'm not sure why it's a sedan, but it's still beautiful. According to the site, they only made 67 at ~$185K each. 

http://www.thecarbonfiberjournal.com/?p=641

Apparently, they use carbon fiber reinforced plastic to manufacture this material: http://www.supercars.net/cars/5366.html

There's even a company developing honeycomb wheels for military applications (airless tires - what?):

http://www.resilienttech.com/

There are actually many versions of this tire too, for applications in bikes, motorcycles, and trucks. 

If my rant about honeycombs in nature didn't convince you, here is a great example of nature and engineering independently converging to a common solution:

Malcolm Burrows, found in: http://www.popularmechanics.com/science/environment/the-first-gear-discovered-in-nature-15916433

They are mechanical gears found in an insect (by Cambridge researchers) [3]. There are also some great videos on the findings:  http://www.sciencemag.org/content/suppl/2013/09/12/341.6151.1254.DC1

... but that's for another post. For now, I need to find something to make that uses honeycombs. 

[1] Reece, Jane B., and Neil A. Campbell. Campbell Biology / Jane B. Reece ... [et Al.].Boston: Benjamin Cummings, 2011.
[2] http://www.nist.gov/pml/div683/conference/upload/Sung.pdf
[3] http://www.sciencemag.org/content/341/6151/1254.full.pdf

Bio-Inspired Mechanical Design

Nature is a beautiful thing. 

Mechanical engineering is as much philosophy as it is a science. It's a beautiful discipline because it requires an understanding of the world, and an understanding of people.

I am always looking for inspiration everywhere I go, and in everything I do. I believe that Mechanical engineering requires inspiration and lifelong learning; and that one's life should be lived with passion so that everything one appreciates may become a source of knowledge and inspiration. This frame of mind is what inspired my paperweight:

In the book FUNdaMENTALS of Design [1], professor Alex Slocum states that one's "mind is a giant bio neural net, just waiting for new connections to be made!" By developing and practicing a systematic process to go about solving problems, one can develop a "rapid design reflex" to solve problems quickly and effectively "with a minimum of floundering!" He is a great advocate for deterministic design, and after taking two courses with him (Precision Machine Design, Development of Mechanical Products), I've tried to absorb his wisdom and form my own process largely inspired by his.

One's bio-neural-net gets bigger and better with more sources of knowledge and inspiration, from the broad to specific. As he says, with practice, both the process and the reflex become hard-wired into your net. I also believe that your net gets stronger under tension, and if you continue to face the tension, you can activate your net to produce something truly amazing. The best part about it, is that this tension should bring you happiness. 

In reality, the most brilliant designers are those that have a bio-neural-net programmed for deterministic axiomatic thought while simultaneously achieving rapid-fire multi-techno happiness enhancement [1].

Why am I bringing this up? Well this semester I am taking a course at MIT 2.S994 - Biomimetics, Biomechanics, and Bio-inspired Robots. Over the course of the class, we will learn how to design experiments, create dynamic simulations, and build a robotic device inspired by a particular animal (I haven't decided which one yet, but I have some ideas). The course is taught by Prof. Sangbae Kim, who is developing the cheetah bot at the MIT Biomimetic Robotics Lab [2]. He's a great lecturer and his passion for his work is contagious.

I'm starting a new blog to share the scientific articles from our course, which up until this point have focused on locomotion, as well as some specific creatures that inspire me. Stay tuned for more posts, but here is the first:

The mantis shrimp is one of my favorite animals.

http://www.chicagonow.com/greenamajigger/2013/04/the-peacock-mantis-shrimp-punches-hard-enough-to-break-aquarium-glass/

Not only because it is magnificent in appearance, but their eyes have some of the most incredible properties of any living thing.

http://photography.nationalgeographic.com/wallpaper/photography/photos/underwater-creatures/peacock-mantis-shrimp/

They also have one of the most interesting defense mechanisms:

http://www.backofthecerealbox.com/2012/06/hadouken-of-undersea-world.html

I wouldn't do justice describing it here, but you can find a nicely illustrated description here:

http://theoatmeal.com/comics/mantis_shrimp

and a funny and informative video about them here: 
https://www.youtube.com/watch?v=F5FEj9U-CJM

More to come - enjoy!

[1] http://web.mit.edu/2.75/fundamentals/FUNdaMENTALS.html
[2] http://biomimetics.mit.edu:8100/wordpress/