[The bone, a complex construction. Thoughts of an architect].

Abstract

Having a precise knowledge of the construction methods of technical objects is helpful to understand the developing processes in nature, the patterns, the bearing capacity and the investment of energy and material of natural lightweight structures. An engineering framework out of bars and knots can be compared with a framework of bones--keeping in mind, however, that solid and soft components viz. bones, cartilage, sinews, muscles and filling liquids together are building a force guiding system. Such complex systems can most easily be explained by their development and "production". Fibre nets and networks provide flexibility and stiffness to the weak pneu- or hydroskeleton. Outer appearance and internal microstructure prove the bone to be a solidified and prestressed pneu. The load capacity of the bone is determined by the solid materials and the supporting, varying inner pressure in combination with the blood circulation. In contrast to that the pressure of cartilage made of similar materials is constant. All other force guiding networked fibre systems are supposed to have a bone-like structure with all states of solidification. Highly flexible fibre nets are capable of self-alignment, self-remodelling and self-repair. A likewise self-organization can be found in the inner fibre net of the bone. In case of a fracture callus will seal the damaged pneu. The net structure of a strained bone has routings similar to the hypothetical flow of forces within solid bodies. The author evolves the thesis that the bone in the course of its forming process as well as in its final stiffened shape can be looked upon as a pneumatic system with regard to its load-bearing behaviour.