Up until now kinetic and adaptive building systems have mostly been utilised in building as rigid components or flexible membranes — usually guided or fixed along a straight translation axis or rotational movements which results in geometrical constraints.
At the Institute of Building Structures and Structural Design (ITKE) at the University of Stuttgart, a first prototype of the flextofold has been developed within in the framework of the Collaborative Research Centre, utilising biological design and integrative structures.
The flectofold offers an innovative approach by using a compliant mechanism to fold and unfold glass fibre reinforced plastic (FRP) panels. The kinetic mechanism has been developed after analysing 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 concept of a distinct hinge zone by differentiated material distribution can be transferred to technical applications such as a façade shading system.
The element is fabricated as one flat piece, and the differentiated bending stiffness within the panel is achieved by a number of locally adapted glass fibre fabric layers and fibre orientation within the structure. The closing movement is actuated by an integrated pneumatic actuator which allows accurate and gradual control over the folding. Once the pressure is released the stored elastic energy is used to unfold the panels.
The Felctofold principle is adaptive to a wide range of geometries and allows effective shading for double curved free form facades.
The Project Team:
- ITKE Institute of Building Structures and Structural Design – Prof. Dr.-Ing. Jan Knippers, University of Stuttgart
- ITFT Institute for Textile Technology, Fiber Based Materials and Textile Machinery – Prof. Dr.-Ing. Götz Gresser, University of Stuttgart
- PBG Plant Biomechanics Group, Botanical Garden – Prof. Dr. Thomas Speck, University of Freiburg
- IBB Institute for Structural Mechanics – Prof. Dr.-Ing. habil. Manfred Bischoff, University of Stuttgart
Photo credit: “ITKE / University of Stuttgart”. Material used in the preparation of this article has been drawn from ITKE / University of Stuttgart.