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Journal Club Theme of Jan. 1 2008: Role of Mechanics in Biomimetics

MichelleLOyen's picture

With the beginning of the year 2008, the iMechanica journal club moves to two topics per month.  This first topic will be highlighted here for 1-14 January, with the next topic starting on 15 January. 

There has been much recent buzz about biology and nature, and about materials and structures that are “biomimetic” or “bio-inspired”.  A key distinction here, when compared with fields like tissue engineering, is that although information is obtained from natural objects, including biological tissues, the end-applications are industrial and not necessarily biomedical.

The idea is that engineers and scientists can learn from nature and use what they learn to improve their engineered and technological outputs.  There are large differences between the way nature “does” things and the way human engineers do things, an effect quantified in the paper:

J.F. Vincent, O.A. Bogatyreva, N.R. Bogatyrev, A. Bowyer, A.K. Pahl,
Biomimetics: its practice and theory
J. R. Soc. Interface. 3, 471 (2006).

Mechanics has a clear role in using natural principles to engineer things with mechanical functions.  The original biomimetic system was “velcro” adhesive, based on the adhesion between burrs and dog fur.

A more current idea for adhesives and biomimicry is that of “gecko tape,” where an adhesive system is being designed based on the principles that allow geckos to walk up walls.  The first paper for this journal club issue—exploring the role of mechanics modeling and measurements in biomimetics—involves nanomechanical measurements of adhesion in an individual gecko seta by AFM:

Huber, G., Gorb, S., Spolenak, R. and Arzt, E., Resolving the nanoscale adhesion of individual gecko spatulae by atomic force microscopy, Biol. Lett., 1 (2005) 2 – 4.  

There are additional roles for mechanics beyond studying small-scale adhesion.  Many structural materials in nature, including bone and nacre (shell) are organic-inorganic composite materials.  The second paper for this issue concerns the mechanical properties of self-assembled protein matrices that were then mineralized by calcium carbonate in a process mimicking biomineralization.  

K. Subburaman, N. Pernodet, S.Y. Kwak, E. DiMasi, S. Ge, V. Zaitsev, X. Ba, N.L. Yang, M. Rafailovich. Templated biomineralization on self-assembled protein fibers. Proc. Natl. Acad. Sci. U.S.A. 103, 14672 (2006).

In this case, the mechanical properties of the newly constructed and novel materials are intrinsically interesting.  However, it is also useful to use mechanical testing as a means to gage whether the underlying structure of the new materials is similar to natural biomineralized composites.  

Our third paper considers device design based on mechanical sensing mechanisms used in insects.  

A novel strain sensor based on the campaniform sensillum of insects.  A Skordos, C Chan, G Jeronimidis and JFV Vincent.  Phil Trans R Soc A, 360, 239-254.

These three papers present several means by which mechanics can be useful in biomimetics, including providing techniques to studying a natural object (to be able to mimic it) and studying a material that was made by mimicking a natural process/material.  As the field of biomimetics continues to grow, there will be many additional opportunities for mechanical experiments and modeling in biomimetics.

Zhigang Suo's picture

Dear Michelle and Pradeep:

Thank you very much for lining up exciting 2008 Themes of the jClub!  iMechanica now has nearly 5000 registered users.  The number has way passed the expectation of early users.  In this phenominal growth of iMechanica, jClub has played a central role:  it shows a vibrant community working on diverse problems.  The depth and breadth of discussion are simply superb.  Even for a Theme far from my current interest, by reading the conversations between the experts, I have come away with some appreciation.

It seemed so long ago when Pradeep initiated a discussion, on 16 September 2006, for the establishment of the jClub.  Baby iMechanica was 5-day old then.  

Henry Tan's picture

Very interesting topic on gecko type cohesion! I am writing some comments on interface cohesive law, and found this discussion on gecko type cohesive law is very helpful.

For gecko type cohesion, since geckos have millions of hairs on each foot, their combined adhesive force is hundreds of times greater than what is required for the gecko to hang from a ceiling by one foot.

This serves as a great proof for what I am trying to established idea: interface cohesion is scale dependent!

Henry Tan's picture

A question to ask:

A gecko has millions of hairs on each foot. Why their combined adhesive force is only hundreds of times greater than what is required for the gecko to hang from a ceiling by one foot?

There must exist a unique adhesion mechanism that I do not know.

Perhaps the reason could be that not all hair filaments are engaged in the act of adhesion. It could be that the probabilities work out in such a way that  for each step the Gecko takes, only a few hundred individual hair filaments get entanged with the underlying surface.

 -Nachiket 

The topic is really nice and timely. I am sure that most members will learn something from the discussion and appreciate your work.

I attended a seminar on mimicking biology several weeks ago. The speaker, Prof. Roger Hanlon from Woods Hole, showed a camouflage octopus vedio, which may be of the interest of our members.

http://video.google.com/videoplay?docid=-4139449748454943279

Teng Li's picture

First all, congrats to Pradeep and Michelle for a fruitful year of iMech jClub in 2007!  It has been a vital part of iMech at its early begnining, and I'm sure it will still be in the future growth of iMech. Look forward to another successful year of iMech jClub!

This very first theme in 2008 is quite interesting. Biomimetics at micro-/nanoscale has been a surge of interest in the past several years. I'm also curious about any progress in the biomimetics field at macroscale. For example, the vehicles (in air, or under water) that can morph their structures during service to mimic birds or fishes.  Definitely mechanics plays an important role in enabling such morphing vehicles. I'm wondering if anyone can point out the state of the art in this emerging field. 

MichelleLOyen's picture

You are absolutely right, there is an entire additional category of biomimetics research concerned with animal dynamics and movement.  Particular areas of interest are walking, flight and swimming for making robots that move more naturally and easily than typical man-made robots.  I thought that the topic was too far from my own expertise to do justice with paper selection, but perhaps I can track down a volunteer to highlight this topic for a later issue of the j-Club this year.  Thanks much for bringing this up.

http://academic.brooklyn.cuny.edu/userhome/psych/fgrasso/people.html

 Frank Grasso

http://ciber.berkeley.edu/twiki/bin/view/CIBER/CenterRecruitment

Robert Full 

http://www.ted.com/talks/view/id/195

I find these two guys very interesting. 

I will most likely be working with Encyclopedia of Life in Sweden. I would like to set up a seminar about how we represent animals and plants movements in Stockholm. I'm looking for projects that deals with this. I don't really know how iMechanica works. 

Mats 

Rohit Khanna's picture

Hi All,

Well, one of the most awaited topic for me at least. Thanks to Prof. Michelle. 

Discoveries from the past elucidate that people have been inspired by nature. Joseph Paxton used the design of a lilypad to structure the Crystal palace, Wright bothers used the idea of bird wings to structure planes, material scientists used many naturally made structures like snow-flakes, honeycoumb structure to build a strong aircraft design. Being from materials background, i can recapitulate that the research in the field of material science has been evolved through many stages, metallurgist employed metal's ductility to improve brittleness, where ceramists are always interested in improving brittleness....and then comes composites which is a compromise between metal and ceramics, it has been fascinating that engineers have been successful in taking these materials to application stage. But question is: did they ever heard of biomimetics? I think it is the impulse which drives the science and technology. It is true that man made components are not as perfect as nature's. 

We have to learn a lot from nature.

As far as research in field of bone tissue engg is concerned, nowadays the urge is to build three-dimensional porous scaffolds to be used as implants inside the body. It has still not reached to clinical practices. It is a new emerging area which needs contribution from mechanicians, material scientists as well as biologists. Mechanicians can help us to understand the invivo stresses generated on implant and to surrounding tissues which are again time-dependent strains...so there is a need to understand viscoelasticity under such a situation..... material scientists need to design a strong and biocompatible and biodegradable material ....and of course the knowledge of cell biology is paramount.....you can now realize the Potential of the biomimetics field.which opens up demand and pathways for interdisciplinary commitments..it is definitely a promising field which is still untouched by many, and this is going to last forever. It needs a great contribution from great researchers like you.

Rohit 

 

Henry Tan's picture

Learn from nature and develop mechanics is good, but it is better to use nature directly and grow materials and structures.

Rohit Khanna's picture

Thanx Henry for the response. There are already materials and engineering structures  which are in use and are adopted from nature.

Nowadays the focus of biomimetics is shifting towards synthesizing and designing the materials which can be used an implants inside the human body(for e.g for bone tissue engineering applications). Existing knowledge is limited to understanding of materials and partially to design of such kind of materials. The missing component is the Functionality... how does cells responds to the surface of the material, do materials offer toxic response or leave products which are not biodegradable? Knowledge of the structure and design is just not sufficient, functionality invivo is the major consideration. That's where the role of mechanics is very important.

Rohit

 

Ying Li's picture

Interesting topic! Actuallyin our previous work, the sandwich structure of the dragonfly wing vein was supposed and its exceptional mechanical properties were also explored.  Recently, the direct experimental results on this sandwich structure were also found . We are trying to utilize this unique microstructure to design the the new micro air vehicle (MAV), especially ornithopter.

Rohit Khanna's picture

hi All,

I want to know about the inactivity of this discussion topic. Isn't it important to have a discussion on role of mechanics in biomimetics...or we don't have experts in this field in the current list of users.

I also have a question about why it was decided to have only 2 weeks . I hope some responsible member of the forum should be able to answer these.

  I am just curious to know about this.

 

Rohit 

Zhigang Suo's picture

Here is a thread of discussion on running a new Theme every two weeks.  The main points are

  1. Mechanics is a diverse field.  Few Themes will interest everyone.  There is no reason to select a Theme to interest everyone. (We can only have one President, but we can have many Themes.)  However, if a particular Theme does not resonate with a person, she would have to wait for a month for another new Theme.
  2. By removing the need to be popular, a Discussion Leader may better focus on the mission of the jClub: to foster discussion at the frontier of mechanics and its applications. 
  3. Much of discussion for the past Themes seemed to occur in the first 2 weeks following the initial posting.
  4. Even after a Theme has become an old one, you can always access it by clicking the tab Journal Club on the right side of iMechanica.  You can always discuss any old Theme further.

Of course, every change on iMechanica is just an experiment.  It would be interesting to hear from people on pros and cons of any change.

Pradeep Sharma's picture

Rohit,

Zhigang summarized very well the rationale for going to a two-week format for the j-club. His last point is particularly important, the frequency of the j-club, like so many other aspects of iMechanica are an experiment (inexpensive to conduct, I might add). We expect to re-evaluate the bi-weekly format at the end of this year.

Regarding discussion, different topics will generate different amounts of discussion. In my personal opinion, it is not the j-club mission to necessarily promote topics that will generate a "large" number of comments. As long as the topic remains of interest to cross-sections of the community, it is good. Often, and I know this from personal experience, many mechanicians are content to simply read the j-club (or for that matter other posts) but do not post comments. These mechanicians are, still, very much interested and appreciative of the actual posts. As example, the present issue on Biomimetics was very useful to me since I learned a lot about this subject (which happens to be outside my area). I posted no comments however, but followed the discussion carefully and read through some of the papers recommended by Michelle.

.

MichelleLOyen's picture

My summary of bone mechanics, materials science, and biomimetics is in the MRS Bulletin this past issue (January) which was where I derived the idea for this broader J-club topic on mechanics in biomimetics in other systems.   We are very excited to be preparing a potential new course on this subject for 2008-9 at Cambridge.

MichelleLOyen's picture

There is an article on biomimetics in National Geographic , highlighting yet again that this is one of the future directions for engineering. 

(How was it that biomimetics was missed in the NAE list of Grand Challenges in Engineering ?  I'm still convinced that they missed the boat with the medically-related topics they included, but even if you ignore direct medical applications, the idea of "learning from nature" to engineer new products and ideas has been quite prevalent in the last few years. )

Also interesting are processes and dynamics of nature.  I did some work as an undergraduate implementing a shape optimisation routine in ANSYS based on how trees and other living things add material where needed to eliminates stress concentrations, etc.  This can be done quite simply by converting the stress field to a temperature field after each loading cycle to artificially swell the elements.

Unfortunately, I didn't have time to explore this in depth, but got some interesting results for intersecting cylinders with bending.  It is a LOT faster than parametric optimisation for complex shapes, though it distorts the elements so you have to write your own remeshing algorithm.

 Useful for blended wing designs?  If anyone's interested, the refs are: Klaus Mattheck; Jim Wood, Strathclyde Uni, UK

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