No abstract

Textile technology is a traditional approach to additive manufacturing based on one-dimensional yarn. Printing solid rods onto pre-stretched textiles creates internal stresses upon relaxation of the pre-stretch, which leads to buckling-induced out-of-plane deformation of the textile. Similar behaviors are well known to occur also in biological systems where differential growth leads to internal stresses that are responsible for the folding or wrinkling of leaves, for example. Our goal was to get a quantitative understanding of this wrinkling by a systematic experimental and numerical investigation of parallel rods printed onto a pre-stretched textile. We vary rod thickness and spacing to obtain wavelength and phase coherence of the wrinkles as a function of these parameters. We also derive a simple analytical description to rationalize these observations. The result is a simple analytical estimate for the phase diagram of behaviors that may be used for design purposes or to describe wrinkling phenomena in biological or bioinspired systems.

Despite the cutting edge developments in science and technology, architecture to a large extent still tends to favor form over matter by forcing materials into predefined, often superficial geometries, with functional aspects relegated to materials or energy demanding mechanized systems. Biomaterials research has instead shown a variety of physical architectures in which form and matter are intimately related (Fratzl, Weinkamer, 2007). We take inspiration from the morphogenetic processes taking place in plants' leaves (Sharon et al., 2007), where intricate three-dimensional surfaces originate from in-plane growth distributions, and propose the use of 3D printing on pre-stretched textiles (Tibbits, 2017) as an alternative, material-based, form-finding technique. We 3D print open fiber bundles, analyze the resulting wrinkling phenomenon and use it as a design strategy for creating three-dimensional textile surfaces. As additive manufacturing becomes more and more affordable, materials more intelligent and robust, the proposed form-finding technique has a lot of potential for designing efficient textile structures with optimized structural performance and minimal usage of material.

This paper explores the potential of robotic needle felting for customized production of nonwoven textiles and their architectural applications. The possibility to program the robotic movement and locally control fiber density and distribution allows the design of nonwoven, heterogeneous materials with graded properties not by differentiating their chemical composition, but rather controlling their mechanical structure. We propose a parametric design and fabrication workflow relying on a 6-axis robotic arm. We describe design techniques for the generation of felted surfaces with varying material properties and their translation to instructions for robotic felting, as well as the physical fabrication setup. Within our research, the ability to locally differentiate material properties is further explored to create three-dimensional folding behaviors. We study how fiber densities affect their folding ability and geometry, examine qualities of resulting edges, analyze how they affect folding and finally design targeted folded structures by informing the felting pattern. While robotic felting has not yet found significant applications in architecture, the designs and prototypes demonstrate its potential in the architectural context, as it suggests new solutions for recyclable, circular building components or surfaces.