ABSTRACT

ABSTRACT: The aim of the biomimetic approach exposed in this paper is to find an efficient way to build freeform shells by assembling panels which transfer only normal and shear forces between the edges, besides generating a structure with higher redundancy and the possibility of adding panels without a temporary support for the structure. For engineers and architects, nature provides a vast source of inspiration for solving structural problems, as during the course of evolution biological organisms adapted their characteristics through natural selection, resulting in highly efficient structures and morphologies. Therefore, it can be helpful to translate important functional principles of biological models into technical solutions. This is the case of three plates with three edges meeting at just one point, known as 3-plate principle, which is to be observed frequently in biological structures. The 3-plate principle, which is common in the morphology and growth pattern of natural systems, is also found to be of a structurally optimum content, i.e. plates must not rely on carrying bending moments and torsion for their own stability. This is for instance the case of the sea urchin’s plate skeleton morphology, which served as biological inspiration for the research presented in the current paper. The two basic elements of plate structures are plates and lines of support. The plate is stabilized by resisting internal forces which lie in the plane of the plate itself. Each face in a pure plate structure may be reduced to carry plate forces only. On the other hand, the lines of support enable the transmission of normal and shear forces but no bending moments between the joints. Three plates with three edges meeting at just one point are necessarily to stabilize themselves, thus resulting in a bending bearing but not kinematic structure. By choosing irregular hexagonal patterns it is possible to create shells which are able to totally absorb bending moments without requiring a rigid connection between the modules.