Spinning Smooth and Striated: Integrated Design and Digital Fabrication of Bio-homeomorphic Structures across Scales

We present a design approach and structural system exploring interrelationships between digitally fabricated tensile membranes and biologically spun fiber-based structures. The approach builds upon from related research into biologically driven design, demonstrating a suite of design tools and techniques for achieving biologically augmented heterogeneous structural systems with spatiotemporal granularity across scales. The structural system is comprised of three sub systems, namely a network of vertical rods, robotically-spun fiber, and biologically-spun fiber. The first acts as a scaffold for the secondary subsystem such that a 3-dimensional tensile fiber structure is constructed and augmented over time via the tertiary subsystem. We coin the term bio-homeomorphism to describe structures that present biologically augmented topological isomorphism. The structure is comprised of a 1mX1mX1m cube. Its construction combines robotic winding using a computer-numerically-controlled (CNC) machine with biological spinning using silkworms. The compounded system expresses structural, spatial, and material property variation across scales, mediating the silkworms’ behavior. In turn, the deposition of silk informs the spatial configuration of the final structure. The secondary subsystem is digitally fabricated from a single 1-dimensional thread in which material variations that impact silkworm motility and deposition behaviors can be encoded. These can be subsequently decoded through the fabrication process into the final spatial arrangement. The toolpath compensates for rod deflection and enables biological silk spinning to take place; the deposition of silk informs the structure’s tensile properties by locally stiffening it. This results in a novel structural typology combining biological and robotic fabrication: ‘smooth’ and ‘striated’.