Biomimetic Fiber-Reinforced Compound Materials

During the last years, many efforts have been made to transfer results of quantitative analyses of functional morphology and biomechanics in plants into technical applications. These attempts have been increasingly successful as is proven by the increasing number of biomimetic products on the market (e.g. paints based on the Lotuseffect® among many others, see Bar-Cohen (2006) and Masselter et al. (2010a)), of which the top 100 biomimetic products have generated about 1 billion Euros in 2005 to 2008 (Bushan, 2009). These successes are the result of the long period over which the form-structure-function relationships of the plants have been investigated and understood. Of the broad spectrum of biomimetic products, fiber-reinforced composites represent some of the most successful biomimetic technical applications. The potential of developing biomimetic fiber-reinforced compound materials is very high because 1) the fiber-matrix structure in plants is comparable to those in technical materials and 2) the complex fiber-matrix structures in plants are organized in at least five hierarchical levels (Masselter et al., 2009b, 2010a; Speck T. et al., 2007), from the molecular scale over the nanoscale and microscale to macroscale (Jeronimidis, 2000a). Quantitative analysis of this hierarchical structuring of plants is generally being increasingly recognized as one of the most important keys for understanding the form-structure-function relationships in plants (see Fratzl, 2007). This method allows interpreting and abstracting the interaction between the structural components in plants that possess different mechanical properties and in consequence, building a new generation of lightweight but stiff fiber-reinforced biomimetic compound materials (Masselter 2009b, 2010a,b; Speck, O. et al., 2005; Speck, T. et al., 2007; Speck, T. & Speck, O. 2008). In a biomimetic project, dealing with the development of fiber-reinforced compound materials the most important assets are the biological concept generators, which can be linear (unbranched) or branched, thereby mirroring the structures that are present in technics. Branched structures as Yand T-shaped branched components are very common in many fields of technical applications (Fig. 1). In plants, these branchings have to bear high static and dynamic loads that form a complex overlay of different loading modes: bending, compression-tension and torsion (Jeronimidis, 2000b). In technics, similar loads often drastically decrease the life time of a technical component causing wear and material fatigue