Browsing by Author "Wood, Dylan"

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Open Access
Cross-sectional 4D-printing : upscaling self-shaping structures with differentiated material properties inspired by the large-flowered butterwort (Pinguicula grandiflora)
(2023) Sahin, Ekin Sila; Cheng, Tiffany; Wood, Dylan; Tahouni, Yasaman; Poppinga, Simon; Thielen, Marc; Speck, Thomas; Menges, Achim
Extrusion-based 4D-printing, which is an emerging field within additive manufacturing, has enabled the technical transfer of bioinspired self-shaping mechanisms by emulating the functional morphology of motile plant structures (e.g., leaves, petals, capsules). However, restricted by the layer-by-layer extrusion process, much of the resulting works are simplified abstractions of the pinecone scale’s bilayer structure. This paper presents a new method of 4D-printing by rotating the printed axis of the bilayers, which enables the design and fabrication of self-shaping monomaterial systems in cross sections. This research introduces a computational workflow for programming, simulating, and 4D-printing differentiated cross sections with multilayered mechanical properties. Taking inspiration from the large-flowered butterwort (Pinguicula grandiflora), which shows the formation of depressions on its trap leaves upon contact with prey, we investigate the depression formation of bioinspired 4D-printed test structures by varying each depth layer. Cross-sectional 4D-printing expands the design space of bioinspired bilayer mechanisms beyond the XY plane, allows more control in tuning their self-shaping properties, and paves the way toward large-scale 4D-printed structures with high-resolution programmability.
Open Access
Development of a material design space for 4D-printed bio-inspired hygroscopically actuated bilayer structures with unequal effective layer widths
(2021) Krüger, Friederike; Thierer, Rebecca; Tahouni, Yasaman; Sachse, Renate; Wood, Dylan; Menges, Achim; Bischoff, Manfred; Rühe, Jürgen
(1) Significance of geometry for bio-inspired hygroscopically actuated bilayer structures is well studied and can be used to fine-tune curvatures in many existent material systems. We developed a material design space to find new material combinations that takes into account unequal effective widths of the layers, as commonly used in fused filament fabrication, and deflections under self-weight. (2) For this purpose, we adapted Timoshenko’s model for the curvature of bilayer strips and used an established hygromorphic 4D-printed bilayer system to validate its ability to predict curvatures in various experiments. (3) The combination of curvature evaluation with simple, linear beam deflection calculations leads to an analytical solution space to study influences of Young’s moduli, swelling strains and densities on deflection under self-weight and curvature under hygroscopic swelling. It shows that the choice of the ratio of Young’s moduli can be crucial for achieving a solution that is stable against production errors. (4) Under the assumption of linear material behavior, the presented development of a material design space allows selection or design of a suited material combination for application-specific, bio-inspired bilayer systems with unequal layer widths.
Open Access
Material programming for fabrication : integrative computational design for self-shaping curved wood building components in architecture
(Stuttgart : Institute for Computational Design and Construction, University of Stuttgart, 2021) Wood, Dylan; Menges, Achim (Prof.)
Form and structure play critical roles in architecture yet the processes required to produce performative geometries often require tremendous resources and physical effort. Advances in computational design and the programming of digital fabrication machines have increased variety, precision and automation in the production of building components. However, the underlying processes of generating material form still rely predominantly on brute-force methods of shaping. This research presents an alternative, material programming approach to the fabrication of building components in which shape is generated by activating the material’s inherent capacity to change in relation to external stimuli. The concept is investigated through the development of an innovative method of self-shaping manufacturing for load-bearing curved wood building components. The dissertation introduces material programming in the context of architectural design, fabrication processes, wood materials and existing self-shaping and development of a computational design-to-fabrication approach. In parallel the challenges of upscaling and predictability are addressed through computational mechanics and physical prototyping. The concept is then adapted and implemented through the design and production of components for a building demonstrator, the of the material system. The material programming approach is therefore shown as a simple yet sophisticated method of fabrication for a novel, ecological and effective architecture.