The construction industry, as it is known today, has been operating for almost as long as humanity has been in existence and in almost the same way as it did during its inception during the Bronze Age. While humans have made consistent progress in the types of building materials that are used in construction, the concept of heating, beating, and/or treating materials to make them suitable for use has largely remained true for millennia. Since the industrial revolution, the use of fossil fuels to create new synthetic materials and the standardization of building codes contributed to the use of stronger materials whose properties have been easier to control than natural materials. The construction industry has been recalcitrant in its utilization of new techniques and materials that stray from the conventional uses of concrete, steel, and timber; however, with the knowledge of a rapidly changing climate as well as demographic shifts in human populations throughout the world towards cities, the concept of sustainability has all but rushed to the fore to mitigate the damage that is and will be caused by these cultural and climatic tectonic shifts. Biomimicry is a potential tool in the implementation of sustainability in engineering and construction and although biomimicry as a concept is new within the field of structural engineering and construction, it is one of the primary tools of technological progress utilized throughout history. The term “biomimicry” is derived from the words “‘bios’ and ‘mimicry’ coming from Greek meaning ‘life’ and ‘imitation’ respectively” (Yiatros et al., 2007). The key tenet of biomimicry is to mimic nature to take advantage of the efficiency crafted from billions of years of evolutionary progress. This mimicry can be found in the engineering of the Shinkansen Bullet Train in Japan to mimic the quick and smooth flight of kingfisher birds thereby reducing the noise and electricity use of the final design. Biomimicry can also be observed in the sensors on newer cars which detect movement in the immediate vicinity of the vehicle and alert the driver of potential hazards, similarly to how locusts avoid colliding with each other when they travel in swarms due to the sensitivity and efficiency in their eyesight.
Biomimicry can also be explained with similar terms including synthetic biology, biomimetics, biomaterials, or bioinspired structures. While these terms are not completely interchangeable, they offer slightly differing insights into the aspect of biomimicry that is being discussed. The term ‘biomimetics’ was first coined by Otto Schmitt in the 1950s and “relates to the development of innovative and new technologies through the distillation of principles from the study of biological systems” (Pachego-Torgal, 2015). Biomaterials are materials created using a biological process and bioinspired structures, for instance, are an example of biomimicry which can utilize biomaterials or synthetic materials which in and of themselves mimic a biological process. Iconic author on the basics of biomimicry, Janine Benyus, described nature’s manufacturing process as having four distinct aspects; life-friendly manufacturing processes, an ordered hierarchy of structures, self-assembly, and templating of crystals with proteins. The first methodology details how, “nature manufactures its materials under life-friendly conditions – in water, at room temperature, without harsh chemicals or high pressures” (Benyus, 2009). This contradicts the methodology of “heat, beat, and treat” which Benyus explains in her book as the conventional method of materials engineering and manufacturing. “Nature thrives when three characteristics – effectiveness, efficiency, and multifunctionality – are intricately tied, causing an organism’s structural form to be dictated by the mutualism of these traits” (Chen et al., 2015).
Biomimicry in Engineering
Nature has been mimicked in many engineering fields throughout history and to great effect in the advancement of technology. More recently, robotics mimics the locomotive aspects of animal behavior. Sensors have been developed that mimic biological eyes where cameras have long used technology whose apertures borrow from the inner workings of the lenses in the eyes of mammals. More complex sensors use multiple apertures to mimic the compound eye in insects (Wright & Barrett, 2013). The field of biomimicry has some of the most application in the field of materials science, but other engineering disciplines have been able to take advantage of the biomimicry concept. The most desirable natural materials that researched in terms of potential for mimicry are materials such as bone, ligaments, timber, shells, and scales. These materials provide a hierarchical structuring which is the foundation of structural integrity in most natural structures (Pereira et al., 2015). This hierarchical structuring employs meticulously arranged components from the nanoscale to the microscale, through to the macroscale to guarantee properties that help the material in question withstand the elements. This hierarchical structure, which will be discussed in further detail throughout this literature review, is combined with engrained composite action between natural structures to provide a material which is very desirable for mimicry in synthetic materials. Not only are materials themselves the focus of biomimicry in engineering but bioinspired manufacturing processes are as well. Biomineralization and self-assembly are among the biological manufacturing processes that are explored in this literature review. New technologies that utilize biology are allowing for the completely new creation of biological materials and natural tissues with no real natural analog. That is, materials can be synthesized to mimic the properties of disparate polysaccharides and proteins that occur in nature (Keating & Young, 2019). This technology is known as synthetic biology. Synthetic biology is an emergent field in engineering which has become synonymous with the concept of biomimicry. Synthetic biology, however, relies heavily upon the development of engineered organisms for industrial-scale processing of chemical sand materials (Ball, 2018). This is the logical next step in implementing bioinspired structures in an applicable way. This biotechnology has also been used in other industries including the pharmaceutical industry where insulin is regularly produced from genetically engineered Escherichia coli bacteria cells or yeast cells. Many pharmaceutical products are created today from fermentation of engineered microorganisms (Ball, 2018). Synthetic biology constitutes different concepts to differing fields of study, but this concept can also hold the key to the melding together of the fields of engineering and biology. Synthetic biology provides a way for biologists to understand natural biological systems while chemists use the concept to develop molecules. For engineers, biology can be viewed as a technology that can facilitate the design of biological systems (Oldham et al., 2012).
Biological Ethos vs. Engineering Ethos
A thorough understanding of the concept of biomimicry requires a thorough understanding of both biology and engineering. Biology is a hard science with a rote base which can spout forth many possibilities in applied science. Engineering, however, is an applied science with many theoretical bases which also provide many possibilities but considerably fewer opportunities to stray from the basic methodology explored. In other words, biology and engineering have differing ways of study and present differing ethos. An important difference between engineers and biologist can be seen with the use of standardization. While engineers are very familiar with the use of standardization, this isn’t the case for biologists and hard scientists in general. MIT scientist Tom Knight once wrote that those differences could be illustrated by the following example ‘‘A biologist goes into the lab, studies a system and finds that it is far more complex than anyone suspected. He’s delighted, he can spend a lot of time exploring that complexity and writing papers about it. An engineer goes into the lab and makes the same finding. His response is: ‘How can I get rid of this?’’’ Meaning that contrary to biologists, engineers excel at eliminating irrelevant complexity in order to build something that works and is fully understood (Pachego-Torgal, 2015). Christopher Voigt, a synthetic biologist at the Massachusetts Institute of Technology, also stated that, “Materials science and biology speak different languages and they are good at using different types of material” (Ball, 2018). It is important that an interdisciplinary approach be taken to combine these two differing philosophies effectively and harmoniously. This literature review seeks to understand biomimicry and search for a research topic from the perspective of a structural engineer. This paper also seeks to determine a curriculum that can encourage a structural engineer to implement the mindset and ethos of a biologist in order to deliver an application that utilizes biomimicry in structural engineering. According to Pereira, “The transfer of a concept or strategy observed in Nature into a new material is not trivial, requiring first a careful analysis and study of the natural model, and then a certain degree of creativity, interpretation and abstraction in order to identify the underlying principles and mechanisms” (Pereira et al, 2015). For these reasons engineering students should acquire a more interdisciplinary course of study. A regimen that includes experimental investigation, numerical analysis, and testing must be implemented. And the most important step is to determine a biological prototype for research (Hu & Feng, 2015).
Around the globe, the built environment, infrastructure, and climate change remain some of the most pressing scientific issues of our time. The presence of emerging nations beginning and continuing to build more infrastructure to accommodate population growth is a concern that can possibly have the negative effects of this issue mitigated by implemented bioinspiration in the built environment. Developed nations also face the same problems with the addition of crumbling infrastructure that must be repaired or replaced. Concepts covered in this review, for an acceptable curriculum for structural engineers interested in biomimicry, related to the creation of new bioinspired materials could pertain to emerging nations where infrastructure is being constructed at a breakneck pace. Concepts related to retrofitting existing structures through bioinspiration or determining biomimetic methods for structural health monitoring could be useful in developed and developing nations plagued with issues of crumbling infrastructure.
References
Ball, P. (2018). Synthetic biology—Engineering nature to make materials. MRS Bulletin, 43(7), 477–484. https://doi.org/10.1557/mrs.2018.165
Benyus, J. M. (2009). Biomimicry : innovation inspired by nature. Perennial.
Chen, D. A., Ross, B. E., & Klotz, L. E. (2015). Lessons from a Coral Reef: Biomimicry for Structural Engineers. Journal of Structural Engineering, 141(4), 02514002. https://doi.org/10.1061/(asce)st.1943-541x.0001216
Hu, N., & Feng, P. (2015). Bio-inspired Bridge Design. In H. K. Lee, F. Pachego-Torgal, J. Labrincha, C. Yu, & M. Diamanti (Eds.), Biotechnologies and Biomimetics for Civil Engineering (pp. 235–254). Springer.
Keating, K. W., & Young, E. M. (2019). Synthetic biology for bio-derived structural materials. Current Opinion in Chemical Engineering, 24, 107–114. https://doi.org/10.1016/j.coche.2019.03.002
Oldham, P., Hall, S., & Burton, G. (2012). Synthetic Biology: Mapping the Scientific Landscape. PLoS ONE, 7(4), e34368. https://doi.org/10.1371/journal.pone.0034368
Pachego-Torgal, F. (2015). Introduction to Biotechnologies and Biomimetics for Civil Engineering. In H. K. Lee, F. Pachego-Torgal, J. Labrincha, C. Yu, & M. Diamanti (Eds.), Biotechnologies and Biomimetics for Civil Engineering (pp. 1–20). Springer.
Pereira, P., Monteiro, G., & Prazeres, D. (2015). General Aspects of Biomimetic Materials. In H. K. Lee, F. Pachego-Torgal, J. Labrincha, C. Yu, & M. Diamanti (Eds.), Biotechnologies and Biomimetics for Civil Engineering (pp. 57–80). Springer.
Yiatros, S., Wadee, M. A., & Hunt, G. R. (2007). The load-bearing duct: biomimicry in structural design. Proceedings of the Institution of Civil Engineers - Engineering Sustainability, 160(4), 179–188. https://doi.org/10.1680/ensu.2007.160.4.179