A novel rapid additive manufacturing concept for architectural composite shell construction inspired by the shell formation in land snails.

State-of-the-art rapid additive manufacturing (RAM)-specifically fused filament fabrication (FFF)-has gained popularity among architects, engineers and designers for the quick prototyping of technical devices, the rapid production of small series and even the construction scale fabrication of architectural elements. The spectrum of producible shapes and the resolution of detail, however, are determined and constrained by the layer-based nature of the fabrication process. These aspects significantly limit FFF-based approaches for the prefabrication and in situ fabrication of free-form shells at the architectural scale. Snails exhibit a shell building process that suggests ways to overcome these limits. They produce a soft, pliable proteinaceous film-the periostracum-which later hardens and serves, among other functions, as a form-giving surface for an inner calcium carbonate layer. Snail shell formation behavior is interpreted from a technical point of view to extract potentially useful aspects for a biomimetic transfer. A RAM concept for the continuous extrusion of thin free-form composite shells inspired by the snail shell formation is presented.

Towards a theoretical clarification of biomimetics using conceptual tools from engineering design.

Many successful examples of biomimetic products are available, and most research efforts in this emerging field are directed towards the development of specific applications. The theoretical and conceptual underpinnings of the knowledge transfer between biologists, engineers and architects are, however, poorly investigated. The present article addresses this gap. We use a 'technomorphic' approach, i.e. the application of conceptual tools derived from engineering design, to better understand the processes operating during a typical biomimetic research project. This helps to elucidate the formal connections between functions, working principles and constructions (in a broad sense)-because the 'form-function-relationship' is a recurring issue in biology and engineering. The presented schema also serves as a conceptual framework that can be implemented for future biomimetic projects. The concepts of 'function' and 'working principle' are identified as the core elements in the biomimetic knowledge transfer towards applications. This schema not only facilitates the development of a common language in the emerging science of biomimetics, but also promotes the interdisciplinary dialogue among its subdisciplines.