Bio-inspired kinetic curved-line folding with distinct flexible hinge-zones

This research investigates the development of a bio-inspired compliant mechanism for architectural applications and explains the methodology of investigating movements as found in nature. This includes the investigation of biological compliant mechanisms, abstraction and technical applications using computational tools such as finite element analysis (FEA). To demonstrate the possibilities for building envelopes of complex geometries procedures are presented to translate and alter the disclosed principles to be applicable to complex architectural geometries.

The development of the kinetic façade shading device Flectofold, based on the biological role-model Aldrovanda vesiculosa, is used to demonstrate the process and shows results of FEA simulations of kinetic curved-line folding mechanisms with pneumatic actuation and it provides information about the relationship between varying geometric properties (e.g. curved-line fold radii) and multiple performance metrics, such as required actuation force and structural stability.

Within in the framework of the Collaborative Research Center SFB-TRR 141: Biological Design and Integrative Structures we developed the first prototype for the flectofold, a compliant mechanism to fold and unfold glass fiber reinforced plastic (FRP) panels. The kinetic mechanism is extracted from the underwater carnivorous plant Aldrovanda vesiculosa which uses curved-line folding to propagate bending deformation of a stiffer middle rib into two lobes, symmetrical connected with living hinges.
The research is supported by the German research directory DFG.

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Institute of Building Structures and Structural Design
University of Stuttgart
Prof. Dr.-Ing. Jan Knippers

ITFT Institute for Textile Technology, Fiber Based Materials and Textile Machinery
University of Stuttgart
Prof. Dr.-Ing. Götz Gresser

PBG Plant Biomechanics Group, Botanical Garden
University of Freiburg
Prof. Dr. Thomas Speck

Axel Körner, Larissa Born,  Anja Mader, Saman Saffarian, Dr. Simon Poppinga, Dr. Simon Schleicher