A p p l i c a t i o n s o f M a t e r i a l P r o p e r t i e s w i t h i n t h e

B i o m i m e t i c E m e r g e n c e o f A r c h i t e c t u r e .

K i r s t i W i l l i a m sc 3 2 5 2 5 3 6

Kirsti WilliamsA p p l i c a t i o n s o f

M a t e r i a l P r o p e r t i e s w i t h i n t h e B i o m i m e t i c

E m e r g e n c e o f A r c h i t e c t u r e .

B A ( H o n s ) A r c h i t e c t u r e

L e e d s M e t r o p o l i t a n U n i v e r s i t y 2 0 1 2

Word Count (3,201)

Front cover image: Alpine Meadows Guild. 2007. Cotton Magnified100x [online]. [Accessed 27 November 2012]. Available from: < http://www.alpinemeadowsguild.org/fiber_microscopy.html >

03Introduction

Contents

04Construction

05Material

07Materials Science

08Fibrous Systems

11Material Matters

13Utilisation

16Multi-

functionality

17Progression

19Integration

01

14Occurrence

20Bibliography

‘“Biomimicry” is derived from the Greek meaning of life; bios,

and imitation: mimesis. Biomimicry is an innovation method emulating natures patterns and strategies.’

Benyus 2002: preface

02

Introduction

There is an emergence of biomimicry and biomorphism in our surroundings. More and more, building designs have taken inspiration from the natural world and each one reaps it’s own benefit. Biomorphism is simply a replication of form. A specific organism would be studied and analysed, and the physical elements would be taken forward and used as inspiration for a building form. Biomimetics, on the other hand, is an analysis of many aspects of an organism.

‘The study of the formation, structure, or function of biologically produced substances and materials and biological mechanisms and processes especially for the purpose of synthesising similar products by artificial mechanisms which mimic natural ones.’

Webster’s official definition (Ref 1) of biomimetics:

This definition includes behavioral attributes, relationship to its surrounding environments, or internal systems. Some may begin looking at a molecular level; the response of certain molecules to others; systematic networks; the actions of the molecules within networks; and the direct mannerisms and functioning of the organism in question. (Fig 1)

The aim of biomimicry is to find an ecologically advantageous interpretation of design, to provide a solution that no longer damages our environment but works with it - additive rather than subtractive. There are situations however, where applications of biomimicry can be costly and possibly ineffective.

03

Fig 1. Levels of detail from which biomimetic inspiration can be taken.

(Ref 1) Merriam-Webster. 2012. Merriam-Webster. Accessed 28 September 2012. <http://www.merriam-webster.com/dictionary/biomimetics?show=0&t=1354128545>

Construction

Research undertaken by the Institute for Computational Design and the Institute of Building Structures and Structural Design have determined the relationship between material behavior and form. As architects, we generally seperate these principles and deal with them individually. Form is determined first, then the material. Depending on the capability, it is applied to the form to create a stable structure for forces that the function suggests. The students and professors at these schools have looked at it the other way around; looking at the capabilities of the material, the forces which would be applied, and let the form be suggested by them. Based on the plate skeleton morphology of a sea urchin the Sand Dollar, they used a series of computational processes (Fig 2) to determine the best possible form if a specific material was used. In this case the material was thin plywood sheets (6.5mm). (Ref 2).

Victoria King wrote an article (Ref 3) about the pavilion in Archdaily:

04

‘The skeletal shell of the sand dollar is a modular system of polygonal plates, which are linked together at the edges by finger-like calcite protrusions. High load bearing capacity is achieved by the particular geometric arrangement of the plates and their joining systems. Therefore, the sand dollar serves as a fitting model for shells made of prefabricated elements.’

Fig 2. Computer based design allows for simulation of loads

Fig 3. Modular systems of polygonal plate components

Fig 2, 3 and (Ref 3). ICD | ITKE Research Pavilion 2011 / ICD / ITKE University of Stuttgart. 18 Jan 2012. ArchDaily. Accessed 28 September 2012. <http://www.archdaily.com/200685>Ref 2. Hensel et al. (2010) Emergent Technologies and Design, Oxon: Routledge

This research into materials and the application of the knowledge learnt can be applied in many other situations. If less material is required, there is less waste, less energy required to assemble, less energy needed to make the material in the first place. The construction indusrty as a whole can benefit from this.

As the plates meet at no more than three different points, (Fig 3) the loads are spread equally throughout the structure, as the joints react to each force. The cells adapt depending on applicable stresses. The result is an isotropic structure, which is manipulated by its surrounding environment.

Material

There is an increasing amount of concrete being used within the construction industry today. There are many variations, such as steel reinforced, fibre reinforced, with different densities, different properties. It is most popular due to its structural rigidity, cost effectiveness and, most importantly, the lifetime of the material is much longer than most large scale man made materials. The problem however, is the damage it causes to our environment. For every pound of portland cement created, almost a pound of carbon dioxide is released into the atmosphere. Biomineralisation expert Brent Constantz has discovered a way of creating concrete from carbon dioxide and water.

This is a response to the processes that happen on coral reefs, where the organisms utilise available elements to create a structural material where they can reside. (Ref 4). To acquire the same result, we generate billions of tons of carbon dioxide, heating and treating mixtures, whereas nature has been doing the same thing for billions of years, with only two substances. By looking at a deeper level of organismic behavior, and applying the theories to numerous situations, we can have a major impact on climate change. (Fig 4)

05

Fig 4. From something as organic as coral we can fabricate entire buildings

Ref 4. Madrigal, A. July/ August 2008 ‘Rethinking the Material World’ Dwell, Pages 164-168

‘Materials Science tends to be upstream. So if you want to change something big, you have to change the

material’

Paul Calvert - Materials Scientist. (Dwell magazine, Alexis Madrigal, July/August 2008: 164)

06

Biomimicry is not simply analysis and application. There are many situations where this would not be possible. For example, the fog basking beetle (Fig 5) resides in one of the most arid environments in the word. There is very limited water, yet due to the extremity of temperatures, fog moves across the sands in the early hours of the morning. The beetle collects the fog using both hydrophilic and hydrophobic surface materials, which allows the water to collect into droplets, which is then channeled into the mouth of the beetle. We could easily replicate the shell, apply materials that would have behavioral characteristics of that of the beetle, and multiply the proportions.

However, the solid surface would be so large it would force the wind and fog around it, rendering it pointless. Architectural designer Matthew Parker has provided a solution (Ref 5) to this by looking at a molecular level. By creating a spray that can be applied to a net, we can recreate the effects of the water repelling and attracting conditions that the beetle embodies. Through looking at the fundamental principles that the beetle sustains, we can provide a suitable solution relevant to the climates and constraints of the host environment.

MaterialScience

07

Fig 5. Namibian fog-basking beetle collects water droplets on itʼs hydrophilic and hydrophobic shell

Fig 5. Biomimicry Chicago. 2012. Namibian Beetle [online]. [Accessed 04/10/2012]. Available from: < http://biomimicrychicago.blogspot.co.uk/2012/03/humidity-be-gone-thanks-biomimicry.html>Ref 5. Medi, H, 2011. biomimicry Architecture : Sustainable architecture, Winter, pages 37-40. Accessed 21 September 2012 < http://www.academia.edu/1745247/Sustainable_Architecture >

‘Biology makes use of remarkably few materials and nearly all are carried by fibrous composites. There are only four polymer fibers: cellulose in plants (Fig 6), collagen in animals (Fig 7), chitin in insects and crustaceans (Fig 8) and silks in spiders webs (Fig 9). These are the basic materials of biology, and they have much lower densities than most engineering materials. They are successful not so much of what they are, but of how they are put together. The geometrical and hierarchal organisation of the fibre architecture is significant. The same collagen fibers are used in low-modulus, highly extensible structures, such as blood vessels. Intermediate-modulus tissues such as tendons and high-modulus, such as bone.’. (Ref 6)

The materials utilised may seem limited, but due to the molecular understanding that each organism has, it adapts the physical capabilities of each element and creates a solution much greater than the sum of its parts.

Fibroussystems

08

There are four main fibrous materials employed within the natural world:

Fig 6. Cellulose - extract from cypress wood

Fig 7. Collagen - consistent in human bone structure

Fig 6. Science Clarified. 2002. Scanning electron micrograph of wood cellulose [online]. [Accessed 15/10/2012]. Available from: <http://www.scienceclarified.com/Ca-Ch/Cellulose.html>Fig 7. The Gist. 2011. Collagen [online]. [Accessed 15/10/2012]. Available from: <http://thegist.dermagist.com/how-to-increase-collagen-and-elastin-production>Ref 6. Hensel et al. (2010) Emergent Technologies and Design, Oxon: Routledge page 15

The difference between the static material components that reside in our existing structures, and those employed within organic forms is the isotropic or anisotropic reactions. Our commonly used materials are isotropic, and the fibers react in the same way regardless of the direction of forces, whereas anisotropic have the structural capacity to adapt to the direction, to provide a stronger resistance. Environmental structures self-organise. They adapt to the changes of its surroundings and adjust in relation to it, without affecting its surroundings.

Fibroussystems

Achim Menges (Ref 7) discussed the aptitude of the structural integrity within a palm tree. The organism encounters a range of extreme environmental factors, and has adapted to prevent structural failure. Using hierarchical self-organisational material selection, it encompasses both soft and rigid fibrous structures, allowing a level of compensation within the composition.The high level integration allows the many different components to work together, without the need for joints. Structural failures in any particular medium mainly occur at connection points between two or more materials. However, if the fibers within have been fused and inter-linked together, there is no specific connection point at which additional pressures may cause deformation.

09

Fig 8. Chitin - Taken from a crabs shell

Fig 9. Silks - Spiderʼs silk spigots

Fig 8. Ifuku I. (2010) ‘Fibrillation of dried chitin’ Carbohydrate Polymers, Volume 81, Issue 1, May 2010Fig 9. How Stuff Works. 2011. Electron microscope image of a spider's silk spigots [online]. [Accessed 15/10/2012]. Available from: <http://science.howstuffworks.com/environmental/life/zoology/insects-arachnids/spider3.htm>Ref 7. Hensel et al. (2010) Emergent Technologies and Design, Oxon: Routledge pages 15-19

Fig 10. Stalasso - Neri Oxman:

Construction based on performance

requirements. Mimics mineralisation processes using ratio of stiff to soft

materials.

Neri Oxman presented a lecture on the organisation of form, and how the notion of form is created. She talks about optimisation, function, and the relevance of both. She looks at nature for inspiration, but at a much more detailed level than most previous attempts, mainly considering fibrous structures and utilising one material source and manipulating the characteristics to provide different results. One of her main points was to start looking at, ‘not what an object wants to be, but rather, what does a material want to be, what does an environment want to be?’. (Ref 7)

MaterialMatters

Normally architects find a form as a result of abstraction from many different factors. A series of materials are applied to this form, which is then taken to a structural engineer to analyse and determine if the chosen materials are feasible. Oxman, however, wants to turn that design process on its head by first choosing the material, and allowing the physical properties and structural abilities of it, and the environmental constraints of the site, form-find. This would result in a range of formations that would be at maximum structural potential. In other words, we no longer design the form, we design the process to find the form.

11Fig 10. Neri Oxman. 2009. Stalasso [online]. [Accessed 15/10/2012]. Available from: <http://web.media.mit.edu/~neri/site/projects/stalasso/stalasso.html>Ref 7. Vinnitskaya , Irina. ‘Neri Oxman: On Designing Form’ 29 May 2012. ArchDaily. Accessed 15 October 2012. <http://www.archdaily.com/238362>

One of the main abilities of organic matter is the ability to organise. Similar to the aforementioned palm tree, rather than the organism using a different material to provide the structural stem and the photosynthetic leaves, it organises the matter to provide applicable attributes depending on requirement. It provides stability in an isotropic manner (Fig 11), in which the material redistributes itself depending on the force applied. Most structural materials we use are anisotropic (Fig 12): the force is predetermined and structural systems are provided to compensate for them. For example, the grain in wood creates a stable element in one direction but not in another, and is less liable to structural failure if a force is applied against grain.

MaterialMatters

This makes it a successful structural material in situations where compression or tension parallel to the grain are applied. However, the shear strength and tensile strength perpendicular to the grain are in fact very low. Therefore, we use wood as beams to provide horizontal support. Other organic materials, however, provide isotropic structures. These structures are generally made of a series of overlapping fibres, set in multiple directions. This allows loads in any direction to be supported.

12

Fig 11. Isotropic fibres

Fig 12. Anisotropic fibres

Fig 11 and 12. Huang,C. (2012) ‘Anisotropic nanofibers’ (Scanned from) Biomaterials, Volume 33, Issue 6, February 2012, Pages 1791-1800

We have begun to replicate these effects in modern materials, using a method called tow-steering (Fig 13). This method computationally aligns fibres in many different augmentations, creating a material that is much stronger than those laid in particular perpendicular paths (Fig 14). Nasa have been developing this process and have noted ‘improvements in static bending stiffness and buckling moment[s]’. (Ref 8)

Utilisation

‘The tow steering capabilities inherent in the fiber placement machines are typically used to align the composite fibers with the desired structural load paths. While most of the research performed to date has been done on composite plates, another class of composite structure with many aerospace applications is the cylindrical shell, which is now being used for commercial aircraft fuselages, and may also be used as primary structures for load-bearing propellant tanks for future space launch vehicles’. (Ref 8)

13

This research is developing very quickly and is incredibly beneficial, Not only does it increase material structural abilities, it also results in ‘associated reductions in touch labor time, material wastage and part counts’. (Ref 8)

Fig 13. Tow-steered fibrous panel. Alignments are clearly visible

Fig 14. Different alignments which the computer-aided machine would follow to create the panel.

Fig 13. Lopes, C, S. (2007) ‘Tow-drops and overlaps’ (Scanned from) International Journal of Solids and Structures, Volume 44, Issue 25, December 2007Fig 14 and Ref 8. Chauncey Wu at al. (2010) Design and Manufacturing of Tow-Steered Composite Shells Using Fiber Placement, pages 1-9 Accessed 17 October < http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090019673_2009019111.pdf >

Occurrence

‘More than 300 different crystal forms of calcite have

been identified, these can combine to produce at least

1000 different crystal variations. People have a devil of a time getting

the crystal of interest to form, but Nature is very good at it. Calcium carbonate is

organised by the abalone along a matrix of protein and carbohydrate, much as the calcium in our teeth is layered into enamel. In particular, the abalone protein controls the growth, shape and eventual size of the calcite crystals. The abalone shell is about 95% calcite, with the remaining 5% composed of protein and carbohydrates.’. (Ref 9)

14Fig 15. Flikr. 2007. Abalone [online]. [Accessed 15/10/2012]. Available from: <http://www.flickr.com/photos/reikopm/476978807/>Ref 9. Edwards, S,A. (2006) The Nanotech Pioneers, Weinheim: Die Deautsche Bibliothek

There are other situations in nature that we are yet to replicate. One of these is the ability of spiders to create a silk that is

comparatively five times stronger than steel, and abalone shells that adapt its protein molecules to

redistribute the elastic qualities into areas where it is required. Abalone shells exhibit

properties that would be highly beneficial for us to recreate and

develop. The shell is one of the strongest composite materials known to man, and it’s makeup is simply a brick and mortar arrangement, with the materials effectively being similar to chalk and egg whites (Fig 15). Steven Edwards talks about the material qualities of them, and explains the variations within materials that allow these strong structures to be created.

Fig 15. Abalone shell - layers of calcium carbonate connected by sheets of protein.

If we can determine a way to manipulate materials in the way that Mother Nature does, we would then develop the systems to allow the materials to self repair in the way that

nature does. The problem at the moment being that recreating on a

nanoscale is a costly experience, but considering the technological advances

we are making, it is becoming more and more realistic. Another possible option would

be to develop a way to manipulate the organisms to create exactly what we cannot.

Occurrence

The shells are constructed of tiny tiles of calcite, which are built up to create the thickness. Due to this layering, it

becomes 3000 times more resistant to breakage than a single calcite crystal the same size. If

the shell is affected by an external force, the calcium carbonate fills the cracks and

regenerates, a form of self-repair. Another attribute of the makeup of this organism is that it is made up from only two of the 300 different forms of calcite. (Ref 10)

15

Fig 16. Abalone shell composed of overlapping calcium carbonate platelets.

Fig 16. Say People. 2012. Cross section of Abalone shell [online]. [Accessed 10 October 2012]. Available from: < http://saypeople.com/2012/01/15/3d-composite-reinforcement-with-low-magnetic-field-research/#axzz2DdJmSPyD>Ref 10. Edwards, S,A. (2006) The Nanotech Pioneers, Weinheim: Die Deautsche Bibliothek

Natural organisms do not move in a lineal direction. The route of behavioral attributes changes and adapts depending on the environment and surrounding organisms. We do not necessarily have to start generating physically acclimatising buildings, but to provide the latitude for availability. Every single organism on the planet is multifunctional. Oxman talked about how muscles provide stability and also a store for our energies. The shell of an egg, not only structurally supportive but thermally conductive. (Ref10) Benyus also gives a good example in a feather, ‘waterproof, airfoil, self cleaning, insulating, [and] beaut[iful] for sexual reproduction.’ (Ref 11) (Fig17).

Multi-functionality

16

Fig 17. A feather is a perfect example of multi-functionality

Fig 17. Photo Dictionary. 2010. eagle_feather [online]. [Accessed 28/10/2012]. Available from: <http://www.photo-dictionary.com/phrase/10329/eagle-feather.html#b>Ref 10. Vinnitskaya , Irina. ‘Neri Oxman: On Designing Form’ 29 May 2012. ArchDaily. Accessed 15 October 2012. <http://www.archdaily.com/238362>Ref 11. Benyus, J,M. (1997) Biomimicry: Innovation Inspired by Nature, New York: Harpercollins

If we can create buildings that are, not only multi-functional in use, but is created from multi-functional material components, we can start to create environmentally beneficial structures, not just buildings.

We have, for the last two and a half decades, been taking from the natural environment we live in, rather than learning from it’s abilities, which is leading to adverse consequences. Buildings should no longer be brick and

mortar, steel and concrete. They should be a synergistic solution adapted to the natural

environments in which it sits. Natural organisms favour ecological performance over form: this

should be a path we do not leave, and attempt to follow the footsteps of the

natural world.

There are many attempting to reverse the effects that we have had on the environment, and architects should not be exempt from this. If we can take inspiration from the living world and apply it to the designs for the modern world, we could greatly impact the future of our environment. The new generation of architects have a moral responsibility to provide sustainable designs.

Progression

It is understandable that starting on a molecular level may complicate some designs, however if we spent more time analysing our surrounding world, we may provide

solutions that do not deviate from the natural surroundings, nor destroy the

area it has been placed into, but add to it, and provide a stable habitat where

both humans and other species can thrive and learn.

There is no particular section of biomimicry that is indubitably the most successful. Each

approach provides a solution to a problem, but could benefit substantially if it took a more holistic view.

If a process is used to replicate the effects of nature, think about how it can be used in a multi-functional fashion. (Fig 18)

17Fig 18. Neri Oxman. 2007. Structural Skin [online]. [Accessed 10 October 2012]. Available from: < http://web.media.mit.edu/~neri/site/projects/monocoque2/monocoque2.html>

Fig 18. “Monocoque IIʼ by Neri Oxman: 3D printed structural skin - beautiful and structurally supportive.

Neri Oxman : ‘On Designing Form’

2012

‘We’re also designing behavior, and that’s what I

find so incredibly promising.’

18

Organisms adapt to their surroundings. This may be something we should examine more closely, and discuss the opportunities that lie waiting to be discovered, rather than invented. There are processes that nature has yet to do, which we have developed. Pumps have not been created, trees cannot grow into the heavens, and wheels are not integrated - other processes to allow motion are used. (Oxman lecture) We have advanced in terms of speed and size, but we are yet to conquer strength and self-repair.

With the technology of today we can see more clearly than ever before, at both atomic and galactic levels. We need to create foundations to allow the bridge between the natural and manufactured to form, and to do this succinctly we need to begin understanding the inner molecular structures within organic forms, and how they how they are employed.

Integration

By looking at the materials of the natural world, we can develop the materials available to us, adapting them to create biomimetic materials that have the opportunity to grow, self-repair, adapt. We should begin to allow symbiotic relationships with our natural world, and create and develop others in our emerging surroundings. Rather than cradle to grave, use closed loop systems. We need to learn to understand how these elements work, and scale it up not in dimension, but in the communication. If we can start making movements in the field of material, we are creating a stable platform on which architecture can grow.

19

Fig 19. “Beastʼ by Neri Oxman: different colours of material distinguishes between material loading abilities.

Fig 19. (Scanned image) Oxman, R. July/August (2010) ‘The New Structuralism’, Architectural Design, Volume 80, Part 4, Page 15 Ref 12. Vinnitskaya , Irina. ‘Neri Oxman: On Designing Form’ 29 May 2012. ArchDaily. Accessed 15 October 2012. <http://www.archdaily.com/238362>

Bibliography

Benyus, J,M. (1997) Biomimicry: Innovation Inspired by Nature, New York: Harpercollins

Edwards, S,A. (2006) The Nanotech Pioneers, Weinheim: Die Deautsche Bibliothek

Hensel et al. (2010) Emergent Technologies and Design, Oxon: Routledge

Pawlyn, M. (2011) Biomimicry in Architecture, London: RIBA Publishing

20

Books

Huang, C. Biomaterials, Volume 33, Issue 6, February 2012, Pages 1791-1800

Lopes, C, S. (2007) ‘Tow-drops and overlaps’ International Journal of Solids and Structures, Volume 44, Issue 25, December 2007

Lopez, M,I. Materials Science and Engineering : C, Volume 31, Issue 2, March 2011, Pages 238-245

Madrigal, A. July/ August 2008 ‘Rethinking the Material World’ Dwell, Pages 164-168

Menges, A. March/April (2012) ’Material Computation’ Architectural Design, Volume 82, Pages 44 - 52

Oxman, R. July/August (2010) ‘The New Structuralism’, Architectural Design, Volume 80, Page 15

Journals

Vinnitskaya , Irina. ‘Neri Oxman: On Designing Form’ 29 May 2012. ArchDaily. Accessed 15/10/2012. <http://www.archdaily.com/238362>

Chauncey Wu at al. (2010) Design and Manufacturing of Tow-Steered Composite Shells Using Fiber Placement, pages 1-9 Accessed 17/10/2012 < http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090019673_2009019111.pdf >

Medi, H, 2011. Biomimicry Architecture : Sustainable architecture, Winter, pages 37-40. Accessed 21/09/2012 < http://www.academia.edu/1745247/Sustainable_Architecture >

Merriam-Webster. 2012. Merriam-Webster. Accessed 28 September 2012. <http://www.merriam-webster.com/dictionary/biomimetics?show=0&t=1354128545>

ICD | ITKE Research Pavilion 2011 / ICD / ITKE University of Stuttgart. 18 Jan 2012. ArchDaily. Accessed 28/09/2012. <http://www.archdaily.com/200685>

Online

Videos

Bibliography

21

ImagesIn order of appearance

Front cover image (Online): Top News. 2010. Silk Spun by spiders. [Accessed 27 November 2012]. Available from: < http://www.topnews.in/usa/silk-fibres-could-pave-way-edible-optics-future-24966>

Fig 2, 3 (Online). ICD | ITKE Research Pavilion 2011 / ICD / ITKE University of Stuttgart. 18 Jan 2012. ArchDaily. Accessed 28 September 2012. <http://www.archdaily.com/200685>

Fig 5 (Online). Biomimicry Chicago. 2012. Namibian Beetle. [Accessed 04/10/2012]. Available from: < http://biomimicrychicago.blogspot.co.uk/2012/03/humidity-be-gone-thanks-biomimicry.html>

Fig 6 (Online). Science Clarified. 2002. Scanning electron micrograph of wood cellulose. [Accessed 15/10/2012]. Available from: <http://www.scienceclarified.com/Ca-Ch/Cellulose.html>

Fig 10 (Online). Neri Oxman. 2009. Stalasso. [Accessed 15/10/2012]. Available from: <http://web.media.mit.edu/~neri/site/projects/stalasso/stalasso.html>

Fig 11 and 12. (Scanned) Huang,C. (2012) ‘Anisotropic nanofibers’ (Scanned from) Biomaterials, Volume 33, Issue 6, February 2012, Pages 1791-1800

Fig 13 (Scanned). Lopes, C, S. (2007) ‘Tow-drops and overlaps’ International Journal of Solids and Structures, Volume 44, Issue 25, December 2007

Fig 15 (Online). Flikr. 2007. Abalone [online]. [Accessed 15/10/2012]. Available from: <http://www.flickr.com/photos/reikopm/476978807/>

Fig 17 (Online). Photo Dictionary. 2010. eagle_feather. [Accessed 28/10/2012]. Available from: <http://www.photo-dictionary.com/phrase/10329/eagle-feather.html#b>

Fig 18 (Online). Neri Oxman. 2007. Structural Skin. [Accessed 10 October 2012]. Available from: < http://web.media.mit.edu/~neri/site/projects/monocoque2/monocoque2.html>

Fig 19 (Scanned). Oxman, R. July/August (2010) ‘The New Structuralism’, Architectural Design, Volume 80, Part 4, Page 15

Fig 16 (Online). Say People. 2012. Cross section of Abalone shell [online]. [Accessed 10 October 2012]. Available from: <http://saypeople.com/2012/01/15/3d-composite-reinforcement-with-low-magnetic-field-research/#axzz2DdJmSPyD>

Fig 8 (Online). Ifuku I. (2010) ‘Fibrillation of dried chitin’ Carbohydrate Polymers, Volume 81, Issue 1, May 2010

Fig 14 (Online). Chauncey Wu at al. (2010) Design and Manufacturing of Tow-Steered Composite Shells Using Fiber Placement, pages 1-9 Accessed 17 October < http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090019673_2009019111.pdf >

Fig 9 (Online) How Stuff Works. 2011. Electron microscope image of a spider's silk spigots. [Accessed 15/10/2012]. Available from: <http://science.howstuffworks.com/environmental/life/zoology/insects-arachnids/spider3.htm>

Fig 7 (Online). The Gist. 2011. Collagen. [Accessed 15/10/2012]. Available from: <http://thegist.dermagist.com/how-to-increase-collagen-and-elastin-production>