Abstract
Textile membranes offer several advantages over present-day conventional construction techniques in the formation of curved geometries for external building envelopes. These benefits include: (1) possessing inherent flexibility and low self-weight; (2) having the ability to stretch and shear into doubly curved and/or non-developable surfaces (Houtman, 2015); (3) generating significantly less waste in manufacturing as no customised moulds are required as compared to fabricating cladding panels out of stiffer materials (Chudley & Greeno, 2015; Henriksen, 2017). ‘Graded Knit Skins’ explores an alternative membrane cladding system composed of bespoke machine-knitted textiles that are shaped by an assembly of bendable rods. This system benefits from the inherent elasticity of knitted textiles and low bending stiffness of the rods to function as modular façade panels that can be individually configured into non-developable curved geometries. This research will explore two avenues of control over the membrane geometry: (i) design of customised textiles using Computer Numerical Control (CNC) knitting technology and; (ii) design of the framing system using bendable rods for pre-tensioning and shaping the membrane. CNC knitting enables the manufacture of multi-material textile membranes, knitted from glass fibre and elastane yarns, with integrated channels for the insertion of the bendable rods. These rods buckle into curves and shape the textile along its edges and central regions. This creates doubly curved forms with large curvatures out of single pieces of bespoke membranes which need not undergo cut-and-join processes. Moreover, the use of lightweight and elastic components eases the assembly process as compared to traditional rigid frame or cable systems. A proposed design-to-manufacturing workflow is investigated through a series of curved panel prototypes with various non-standardised geometric types and the research culminates in a human scale pavilion. Furthermore, this thesis will demonstrate how this textile-rod assembly can be extended to prefabricate curved composite panels using the knitted textile as a flexible stay-in-place preform for lamination.