Smart Bio Materials

  growth manipulation of calabash Chair of Structures and Structural Design  

Against the background of an increasing environmental awareness of the population, the demand for environmental-friendly and sustainable produced products have evolved to be one of the most important influences on the design and development of investment and consumer goods. This rethinking is especially in the building industry, with all of its massive environmental impact in form of energy and resource consumption, of high relevance. The building sector is one of the biggest consumers of raw-material - about 30 – 50% of the overall consumption material in Europe, which lies between 1200 and 1800 million tons a year, are used for the establishment of new buildings and rehabilitation of existing construction.

5-10% of the overall power consumption of all EU-States are omitted to the production of building material. Therefor the substitution of conventional building material such as steel, with regenerative and bio-based resources depicts a promising alternative to reduce the use of resources and energy in the building sector and raise the recyclability of the building material.

 

Growth and construction in nature as role model for innovative technical solutions

Humans have always received inspiration from the variety of living things and formations of nature to expand their world of artefacts and products. Natural role models have had different ways of impact on the human world: Nature is imitated (mimesis), which means the way in which nature had designed living things and ‚constructed them is what served as a model to artifacts and products, to redesigned their world and lives in a more versatile and comfortable manner. Natural schemes of order and structure (basis), on what grounds natural structures form and build themselves, artificial systems are transferred. Furthermore, humans have been interested in the processes, with which things in nature are converted or how natural structures and systems are build or induced (genesis).

If nature served as a role model until now, to find technical approaches for human-made constructions and processes, we know today, that natural constructions and processes are highly efficient regarding use of material and function.

 

Viking ships, stave churches and conducted lime trees

Reconstruction of a viking ship (skudelev ship) with bend ‚knes‘ to attach beams Reconstruction of a viking ship (skudelev ship) with bend ‚knes‘ to attach beams

In the German-speaking area, especially Thuringia and Franconia, it was common during the medieval era to shape lime trees, which were planted in the town center as a symbol of a meeting point or a tribunal space, with the help of pillars and scaffoldings, to the branches to form a widened marquee, shade roof or a floor support structure. To make use of such a tree-floor of a shaped lime tree, planks and stairs were added (Graefe, 2014).

 

Shaped natural constructions and building elements made from shaped nature products

During the interdisciplinary research project TEPHA (Technical Product Harvesting) at the RWTH Aachen, biologists, ecologists, mechanical engineers and architects analyze the possibility of technical use of shaped plants and plant parts, for example in the production of cases, building elements and building constructions. Due to the shaping during the growth process bio-based semi-finished products result, that profit form the mechanism of natural topology optimization. Other advantages of such a production of semi-finished products lies within the climate considerate manufacture as well as the higher recyclability of the final product. For this purpose, plants like bamboo (Phyllostachys) and alder (Alnus), as well as lignifying fruit such as the calabash squash (Lagenaria siceraria), are brought into shape regarding experimental growth studies with the help of shapes in definite geometry. After the growth period, the biomorphic body will lignify and can be transformed into a pressure-resistant and dimensionally stable semi-finished product. Mushrooms are in this context an additional element of observation with great implementation potential, since in comparison to other plants mushrooms have a extracellular matrix, which can growth three-dimensional in all directions. The mushroom matrix can therefore grow into any outer shape and be stabilized afterwards with the addition of resin or other rigidifying liquids.

 

Growth Simulation

L-System for a shrub plant by Prusinkiewicz (Prusinkiewicz 1990) Chair of Structures and Structural Design L-System for a shrub plant by Prusinkiewicz (Prusinkiewicz 1990)

Adding to the idea to use trees and bushes to shape twigs, branches and trunks or to build complete support structures, the question in terms predictability of the plant growth and structure regarding geometry, dimension, cross-section and strength comes up. Hereby, it is possible to connect to the already existing bases of the Functional Structural Plant Model (FSPM). The FSPM builds on a diagrammed plant Typology. This plant morphology, meaning the order, number and organization of the building of knots, stems, leaves and buds, is given through the help of the Lindenmayer-System. It is possible to respect procedures of different time spans and thickness growth as well as mechanisms of different trope types.

For the formulation of a question, an algorithm of form a structure optimization or evolutionary algorithm are consulted to formulate a question regarding the structural properties such as geometry, cross-section and resistance, and combined with the FSPM.

 

Outlook

growth manipulation of calabash Chair of Structures and Structural Design growth manipulation of calabash

The direct and indirect reproduction of nature in artifacts and technical products is a human approach of long tradition. Nature orientated and inspired artefacts and construction distinguish themselves through their high efficiency regarding the use of material and its reached results.

Throughout the climate change, the reduction of the carbon footprint has reached explosive nature, which caused the dispute of natural genesis process in a scientific and systematic manner and their potential implementation in technology, to be of great importance. Next to a partially complex procedural Mimesis, the possibility lies in the influence of natural growth process, especially of plants, so that blank or semi-finished products of artefacts or technical objects or even full building construction can evolve. To do that, the natural growth of different possible plant must be analyzed, to predict the growth conditions under all influences. To extend this method the biomechanical knowledge must be expanded and combined with the simulation technology. A goal could be a new, sustainable world of products and artefacts close to nature, which may substitute energy efficient products with time.

 

Related Research

Technical Product Harvesting

Growth and construction in nature as role model for innovative technical solutions.

Fungal-based building materials

Research on  the technical foundations for applications of fungal mycelium in load bearing building components.