Читать книгу Rethinking Prototyping - Группа авторов - Страница 6

The M1 textile hybrid project is formed via a multi-hierarchical arrangement of glass-fibre reinforced polymer (GFRP) rods of varying cross-sectional dimensions, which are structurally integrated with Polyester PVC membranes and polyamide-based textiles. The primary structure, in Fig. 2a, is formed of a series of interleaved loops emerging from only three foundations at the boundary. The meta-scale bending-active structure morphs between gridshell-like moments and free-spans stabilized by the tensile membranes. A secondary system (Fig. 2b) provides additional support through a series of interconnected cells embedded within the longest spanning region of the structure. Working to disintegrate the homogeneous nature of the textile membrane, the cells are differentiated in their form and orientation. The levels of hierarchy coalesce to form a clear span of up to eight meters with a total structure weighing only 60kg, while simultaneously generating variation in all scales of the spatial architecture.

Such articulation in behaviour and geometry is arrived at through an intricate exchange between various modes of form-finding. While the form-finding of tensile membrane structures considers stress harmoniously as an input variable, the form-finding of bending-active structures commonly results in varying stress distributions based on a comparatively large number of geometric and mechanical input variables. Therefore, the process of form-finding in the development of bending-active and, furthermore, textile hybrid structures eschews the consideration of structural optimisation. Aligning all input variables to form a functioning equilibrium, which satisfies both mechanical behaviour and contextual constraints, becomes the challenge within the form-finding processes and overall design framework. Due to this unique combination of freedom and complexity, it is shown through this research that a single computational technique alone does not offer the necessary flexibility and insight for developing textile hybrid structures. Rather, the combination and integration of multiple modes and techniques of design into a structured framework is shown to be necessary for the exploration and rationalization of complex textile hybrid structures.

Fig. 2 Multi-hierarchical textile hybrid system (Ahlquist and Lienhard, 2012)

These modes of design, in prototyping through form-finding, include physical models, spring-based computational studies and finite element analysis. Via physical experiments, specifications of topology and approximations of geometry are derived. Through spring-based modelling, also referred to as mass-spring methods or particle systems, variation is generated in the interactions between bending resistance and tensile forces (Ahlquist et al. 2013). In finite element analysis, fixed topological arrangements are inputs for exploration of specific mechanical relationships, force equilibria and further structural investigations (Lienhard et al. 2012). Each avenue serves to advance and articulate design aspects of the textile hybrid while also establishing the degree of fidelity towards the overall design framework.