This project focused on the development of a generic shape- and fibre path-finding method for tow-steered composite structures by implementing the dynamic process of ‘adaptive growth’. Informing the design process by concepts such as adaptive response and environmentally sensitive growth as observed in natural systems a composite shell structure is being developed whose structural performance, mechanical properties and microclimatic conditions vary as a function of its material organization and distribution in response to extrinsic stimuli.
The aim in this research is to exploit the attributes stemming from fibre articulation, in order to extract maximum performance. First, the physical environment is being simulated and the design domain is being defined: The problem in this project is that of a cylindrical beam structure on which certain loads are imposed (pressure, gravity and vertical load on the main movement path) and supports are determined. The cylindrical surface is being populated by a pointcloud, whose points are being interconnected through a Delaunay algorithm. The resulting structure, comprised by tetrahedral, is being evaluated through a simple Finite Element Analysis which for a given set of materials, density and elasticity, produces a value for the objective function, that in this case is stress and strain levelling. The nodes that indicate the lowest values of stress and displacement act as attractors and trigger the self-organisation of the system in search of equilibrium. The classification of each node and their re-organization to accommodate the stress forces is an iterative process that aims at the generation of the global form according to the axiom of uniform stress. This process is stopped when points tend to oscillate around the same solution. This obtained geometry is further analysed through finite element analysis to extract information on the occurring type of stresses, their intensity and directions. The nodes that indicate the most stressful point areas along the structure are extracted in order to act as fibroblasts cells that will restructure their environment to regulate tension, by releasing fibres along the principal stress trajectories. The same process in natural systems is called fibrogenesis.
The design process is intricately linked with the chosen manufacturing method, that of tow-steered fiber lay-up. The algorithimic process defines the reference paths which are the curves traversed by the centre of the applicator head of the tow-placement machine during the fabrication. Fibre paths alter locally in such way so that they do not disrupt the continuity of stress flowing in the fibres.
AA Emergent Technologies and Design (M. Hensel, A. Menges, M. Weinstock)
Christina Doumpioti, Architectural Association, London, 2006-08