Interrelations and transitions between different architectures

Different types of fibrous composite architectures are often seen together, sometimes with one type grading into another. By using several examples of such transitions, nine types of structures have been linked together by arrows in a diagram (Fig. 6.1). This diagram is an illustrated extension of the one constructed by Bouligand and Giraud-Guille (1985). This approach suggests a common origin for such structures and also integrates liquid crystalline analogues. If a mobile liquid crystalline phase proves eventually to be involved in the development of these systems, it will show how it is possible to change architecture, either from location to location or in sequence. In either case, different types of structures may co-exist.

Detailed evidence for the linkage analysis used in constructing Figure 6.1 is given later. Use is made of information from both plants and animals. The nine types of architecture represent variations on a few themes; these are parallel, orthogonal (which may be regarded as a 90° helicoid), and various other angles of helicoids (e.g. 60°, 45°, 10°, 1°). Other orientations are random, planar, polydomain, and cylindrical. The purpose of constructing Figure 6.1 is to show common principles in structure and development across a range of plant and animal skeletons.

The transitions between structural types are thought to rely upon the transient mobility of the fibrous component within the matrix. Liquid crystals are mobile and show transitions between textures.