Larissa Born

Abstract

A continuously adjustable façade shading system functionalized with photovoltaics enables, besides adaptive shading, energy harvesting by solar tracking. This requires large bending motion in two directions. In this paper, the development of an appropriate façade module – FlectoSol – is presented. To achieve motion of ±80°, first time two pneumatic actuators are integrated into a GFRP-elastomer hybrid composite. To improve energy efficiency resp. air pressure consumption of actuation without impairing shading, a parametric study is performed. In detail the influencing criteria of the bending motion “overlap of the actuators” resp. “stiffness ratio of the actuator-surrounding GFRP” and their effect on the target parameters “bending angle”, “shadow width” resp. “air pressure consumption” are analyzed. It could be stated that the “stiffness ratio” only effects the air pressure consumption, but the “overlap” also effects the shadow width. The bending angle itself is, up to ±80°, only limited by the absolute laminate stiffness.

Abstract

Polymer concrete has proved to be advantageous in machine building for many years thanks to its excellent damping properties. Until now, its use was limited to machine beds due to its comparatively low tensile strength. Its use in moving structural components has not been possible until now. Recent research results have shown that this challenge can be met by integrating prestressed carbon fibers. Until now, the production of samples out of prestressed fiber-reinforced polymer concrete has been carried out according to fixed specifications. It is not yet clear whether these specifications are suitable to fully exploit the potential of the material. Samples manufactured to these specifications show at least a large scatter in bending stiffness. Within the scope of this paper, the existing manufacturing process is validated by the variation of process steps. Specifically, this involved the use of a shaker, variation of the dwell time in the mold, variation of the resin content, and the procedure for impregnating the fibers. The characterization of the samples showed that the scatter could only be reduced by increasing the dwell time. However, this leads to a decrease in bending stiffness and, thus, is not suitable for further improvement of the novel material.

Abstract

Adaptive façades can greatly impact a building's energy balance by responding to external climates and by regulating internal conditions. With the integration of solar energy harvesting components, they have the potential not only to reduce the energy loss of buildings but also to gain energy. This premise has been tested within the framework of bio-inspired compliant mechanisms for adaptive façade elements, developed at the University of Stuttgart. Due to the flexible kinematic behavior of bio-inspired adaptive architectural elements, an innovative and simple alternative to common, more complex applications of adaptive façade components is obtained. The research presented aims at establishing the environmental criteria that will lead to an improved energy performance of a building using elastically deformable, adaptive faҫade elements with integrated photovoltaics. Through simulations and physical testing, the influence of daylight, solar radiation, and the building´s thermal balance are evaluated. The findings of this research are showcased on an adaptive façade consisting of pneumatically actuated, glass fiber-reinforced plastic laminates with integrated photovoltaics, assembled at Botanical Garden in Freiburg, Germany. Relying on environmental sensing, this façade is able to adapt over time in response to solar conditions with the goal of finding the right balance between low-energy building operation, high indoor environmental quality, and high energy harvesting. This study provides a novel, integrative design method utilizing adaptive building envelopes that successfully react to varying environmental conditions in an energy-efficient and cost-effective manner.

Abstract

Photovoltaik (PV) spielt im Ausbau eines CO2-freien Energiesystems eine zentrale Rolle, dabei können durch die Integration von PV in Sonnenschutzsystemen bisher unbedachte Flächen für die Energiewende aktiviert werden. Ein Lösungsansatz sind PV-integrierte Sonnenschutzsysteme, beispielsweise adaptive Fassadenelemente aus faserverstärktem Kunststoff (FVK) und applizierten PV-Modulen. Die PV-Integration führt jedoch zu großen Herausforderungen in der übergeordneten Gebäudesteuerung, da im Steuerungskonzept für solche Sonnenschutzsysteme eine gesamtheitliche Lösung berücksichtigt werden muss. Die zentralen Aufgaben dieses Steuerungskonzeptes sind die Regulierung des Tageslichteintrages in den Raum und gleichzeitig die Verhinderung von Blendung, die energetische Wirkung auf das Gebäude sowie den PV-Ertrag im Zeitschritt zu maximieren. In dieser Arbeit wird ein Steuerungskonzept vorgestellt, bei dem auf Basis einer modellbasierenden Evaluierung mit einer Software Steuerungsfunktionen abgeleitet und in eine bestehende Gebäudesteuerung integriert werden.

Abstract

Mineral cast, also referred to as polymer concrete, is a type of composite material commonly used in the construction of machine tools. It consists of mineral fillers and a thermosetting matrix and is used as an alternative to grey cast iron due to its improved damping properties, lower thermal expansion and density. However, due to its poor tensile and bending properties, it is not suitable for use in load-bearing or moving machine components. In order to open up such components as further application possibilities and to be able to use the advantages of mineral cast, the tensile properties must be improved. In order to achieve the durable bearing of tensile loads, prestressed carbon fibre reinforcements are investigated. The presented research aims to enhance the tensile properties of mineral cast through the integration of pre-stressed carbon fibre reinforcements. The study investigates the suitability of using rovings in contrast to pultruded rods for this application. The adhesion of the reinforcement within the mineral cast is evaluated with pull-out tests, and the impregnation behavior of prestressed rovings in the mineral cast is examined through micrographs. Results from the tests indicate that the pull-out forces of rovings are more than 200 \% higher than those of comparable rods with the same fibre content. However, prior consolidation of the rovings is necessary for complete impregnation.

Abstract

Der Bau moderner, lichtdurchfluteter Gebäude, die damit verbundene Erwärmung im Gebäudeinneren und die daraus folgende hohe Klimaanlagennutzung, um die Temperatur möglichst konstant zu halten, hat einen zunehmenden Energieverbrauch zur Folge. Daher wird, im Kontext der Ressourceneffizienz, die Verschattung solcher Gebäude zunehmend relevant. Um ein Aufheizen im Gebäudeinneren zu vermeiden und somit den Energieverbrauch durch Klimaanlagensysteme zu reduzieren, sollten solche Verschattungssysteme nach Möglichkeit extern angebracht werden. Herkömmliche bewegliche Mechanismen beruhen auf Starrkörpermechanismen, die gelenkig miteinander verbunden werden. Insbesondere bei komplex gekrümmten Glasfassaden führen diese mechanischen Gelenke zu wartungsintensiven Konstruktionen. Eine robustere Lösung ist ein adaptives System, dessen Beweglichkeit aus lokaler Materialnachgiebigkeit resultiert. Steife Komponenten eines Bauteils können dabei um eine biegeweiche Rotationsachse bewegt werden. Für diesen Anwendungsfall wird in dieser Arbeit ein Hybridverbundmaterial bestehend aus Elastomer und duroplastischem Faserverbundkunststoff entwickelt, das die Integration lokal nachgiebiger Bereiche in ein steifes Bauteil erlaubt. Das Material wird so ausgelegt, dass es die Anforderungen an ein Außenfassadenbauteil erfüllt. Kern der Arbeit ist die Darstellung der innerhalb dieser Arbeit aufgebauten Methodik zur Entwicklung von Gelenkbauteilen aus Faserverbundkunststoff und die Vorstellung der Auslegungskriterien, die bei der Bauteilauslegung Berücksichtigung finden müssen. Innerhalb dieser Arbeit wird überdies ein zyklischer Biegeprüfstand entwickelt, der die Biegung eines Prüfkörpers, dessen Abmaße denen eines Zugprüfkörpers nach DIN EN ISO 527-4 entsprechen, um 180° in beide Rotationsrichtungen, erlaubt. Der Krafteintragswinkel ist während der Biegebewegung konstant und die Kraftmessung erfolgt direkt über Biegebalken ohne Reibungsverluste. Er ist die Grundlage für die experimentelle Untersuchung der Auslegungskriterien von FVK-Gelenkbauteilen. Im Anschluss an die Biegeprüfung ist, aufgrund der Abmaße des Prüfkörpers, eine Zugprüfung in Anlehnung an DIN EN ISO 527-4 möglich. So kann eine vergleichende Aussage über die Restzugfestigkeit zyklisch geprüfter FVK-Gelenkbauteile getroffen werden. Zunächst werden die Materialien hinsichtlich der Anforderungen an Außenfassadenbauteile geprüft und ausgewählt. Es erfolgt die Berechnung der Biegesteifigkeit und Zugfestigkeit des unsymmetrisch aufgebauten Hybridlaminats sowie die Festlegung der Auslegungskriterien. Abschließend wird, auf Basis von mechanischen Prüfungen der Auslegungskriterien und Regressionsanalysen, ein Modell aufgestellt, das die Prognose der mechanischen Eigenschaften eines FVK-Gelenkbauteils sowie die Festlegung der Bauteilgeometrie unter Vorgabe der Restzugfestigkeit nach 5.000 Lastspielen erlaubt.

Abstract

Adaptive shading devices are of special interest in the context of global need for reducing greenhouse gas emissions. To reduce mechanical complexity of kinetic architectural applications, the investigation of bio-inspired compliant mechanisms has proven to be a promising approach. Thus, a coherent integrative design framework for bio-inspired kinetic folding mechanisms has been developed. This includes the abstraction process of biological principles, such as kinematic behaviours, actuation, as well as materialisation principles. A computational design and simulation model is built to analyse the kinematic and kinetic behaviour of the abstracted biological principles under consideration of specific materialisation and fabrication parameters and constraints. The design and simulation model builds the basis for an automated fabrication process, as well as for interaction and active control of the physical application. The development of the ITECH Research Demonstrator 2018-19, a large-scale compliant folding mechanism, inspired by the folding behaviour ladybug wings (Coleptera coccinellidae), serves as a case study of the developed process. The folding motion of the demonstrator is facilitated by distinct elastic hinge-zones with integrated pneumatic actuators.

Abstract

Regarding modern, daylight-flooded buildings with large window façades, appropriate shading systems to improve the energy consumption of climate controlling systems are becoming more relevant. Building envelopes contribute largely to the temperature control and should be at best installed on the outside to prevent the interior from heating up. Preferably, those systems work with minimum maintenance and maximum robustness, covering as much of the window area as possible. Previous shading systems were mostly based on rigid-body mechanisms using error-prone joints. Components, whose movability is achieved by a local compliance of the material, offer a way to avoid the usage of mechanical joints. Within this paper, a new fiber-reinforced plastic (FRP) façade shading demonstrator called “Flexafold” is presented. Its opening and closing movement are controlled by pneumatic cushions which are integrated directly into the laminate set-up. The Flexafold shows thereby the possibility of producing self‑supporting, adaptive FRP components whose actuators are integrated into the component and thus protected in exterior applications. The functional principles and components of Flexafold, e.g. the locally compliant FRP material, the folding pattern and the integrated actuator system, are explained within this paper. Furthermore, a comparison to existing adaptive façade shading systems “flectofin®” and “Flectofold” is given.

Abstract

Bridges and roofs are often supported by branched steel columns. Their production is usually expensive and consumes a great deal of energy. In nature, plants manage to form similarly strong and frequently even more complex branch systems through natural growth processes. They can effortlessly withstand mechanical loads, such as their own weight, wind pressure, snow load, or the heavy weight of fruit. In order to find out about the success strategies of ramified trees and shrubs and to learn from them for architecture, we need more than a detailed look at the form of ramification and inside the plants. We also need computer models and new materials and methods for the production of branched support structures in building construction to succeed in transferring the biological concepts to technology.

Abstract

Compliant mechanisms of fiber-reinforced plastic (FRP) have been developed to reduce the mechanical complexity of kinetic systems. In a further step, pneumatic actuation was integrated into the set-up of the FRP, offering lightweight, slender, and inconspicuous actuation. Inflation of an integrated cushion causes rotation through the asymmetric material lay-up. Inspiration from the ultrastructure of pressurized veins in arthropod wings has led to the development of a thin layer of elastomer surrounding this pneumatic cushion to avoid delamination. T-peel tests revealed that the elastomer forms a higher adhesion to itself than to glass-fiber-reinforced plastic (GFRP) layers with an epoxy matrix. The angle-pressure relationship for specific GFRP samples with a defined compliant hinge zone was investigated physically and numerically, showing good consistency between the two. Further, a mathematical model, taking into account the bending stiffness of the cushion-surrounding FRP layers, was developed, and a parametric study was conducted on the actuation angles.

Abstract

Biology can provide exciting ideas for the development or improvement of technical products. As a rule, the underlying principles are first investigated using a feasibility demonstrator, which does not represent a finished technical product but nevertheless, on the whole, is intended to “function” like the finished product. However, there is a long way to go from this first prototype to a product that is ready to use or to a convincing building method. In this process, numerous ideas that at first seem interesting and promising have to be abandoned. Many aspects must be investigated in parallel, and plausible solutions need to be found, not only in terms of reliable and durable functionality, but also in terms of commercial viability and resource-efficient manufacture. In addition, it is important that an innovative product is accepted in the market. In the case of architecture, this means-above all- that the product is esthetically appealing, because without that aspect, there will not be much interest even if the product functions well.

Abstract

Plants have neither muscles nor “classic” local joints-and yet they can move. In the course of evolution, efficient movement mechanisms and esthetic movement forms have developed. Architects and engineers, in cooperation with biomechanists, are benefiting from this botanical “offering” and drawing inspiration for the development of new types of facade shading systems for modern buildings.

Abstract

Within the collaborative research center Biological Design and Integrative Structures (CRC TRR 141), a research team of biologists, architects and engineers from Freiburg, Tübingen and Stuttgart is working on the development of biomimetic and bioinspired structures for implementation in architecture and building construction. One of the projects in this research center deals with the kinematics of planar, curved and corrugated plant surfaces as concept generators for deployable systems in architecture. It is an example for methods of engineering science at the interface between biology and architecture. The contribution will provide an insight into the process of analyzing the waterwheel plant Aldrovanda vesiculosa, a carnivorous plant that catches its prey by a quick closing movement of a snap trap consisting of two lobes attached to a midrib. At a first glance, the mechanism resembles the one of the famous Venus flytrap; however, it appears to be quite different from a mechanical point of view. In fact, a key aspect in the research presented here is the development of mechanical models and performing corresponding finite element analyses of the plant with the aim to obtain a better understanding of the compliant mechanism of Aldrovanda vesiculosa and its actuation. The latter is related to a change in turgor pressure in a so-called motor zone, adjacent to the midrib, possibly combined with prestressing effects. Apart from this scientific contribution to technical biology or reverse biomimetics, the abstraction of the trapping movement and its implementation in a façade element (Flectofold) as an example of biomimetic architectural design are briefly described.

Abstract

Based on a textile technology known from carpet manufacturing (tufting) respectively z reinforcement of fibre-reinforced plastics (FRPs), a new process has been developed for interface connections between two FRP component parts: tufting of pre-fabricated FRP pins during preform manufacturing. Both preform and tufting loops are impregnated simultaneously. Afterwards so called "tufting pins" protrude out of plane of the FRP plate or into the inside of a 3D FRP hollow structure, for example a cylindrical component. The hollow structure can be filled with a core material in particular to enhance mechanical properties. In the case of micro-gaps caused e. g. by shrinkage of the material the pins close these micro-gaps between core and FRP-hull or rather maintain mechanical contact between hull and core. In extensive tests the general adhesion properties between pinned FRP and concrete as a filling material as well as the influencing variables of the tufting process with regard to their effects on mechanical parameters were investigated. Decisive influencing factors result both from the textile process as well as the component design. It is shown, how the tension load of a tufted FRP connection increases depending on the reinforcing fibre material as well as the number of tufting pins.

Abstract

Within the collaborative research center Transregio 141 ‘Biological Design and Integrative Structures. Analysis, Simulation and Implementation in Architecture’, the authors work in an interdisciplinary team composed of biologists, structural engineers, and textile engineers developing novel technical branchings as structural elements for architecture inspired by branchings in nature. Branchings are common in structures of plants and construction and have to fulfill structural demands in both fields. As resource efficiency is a vital factor allowing plants to resist competitive stress, beneficial load-bearing principles found in plants might, in an abstracted manner, also improve technical support constructions. To discover these principles, the biomechanics of selected plant branchings were investigated by FE-simulations. The observed principle of continuous fiber courses from the stem into the branch yields stiff and strong connections also favored in artificial joints. The key challenge is to produce technical branchings with a continuous fiber arrangement. This is enabled by a newly developed braiding process for branched structures. The design of the branched large-scale demonstrator at the Museum of Natural History in Stuttgart for the exhibition ‘baubionik’ (construction-bionics) reveals the potential for future architectural applications with individually variable knot geometries. The findings of the investigation mark a starting point for a novel braided concrete-fiber-reinforced plastic composite construction for branched supporting columns with both high aesthetical and load-bearing demands as a potential competitor for current construction methods of cast steel knots or labor-intensive welded steel pipe joints.

Abstract

In modern architecture branched supporting structures are increasingly used. Until now, these branched columns can only be produced in an extensive and cost-intensive way. A new concept made of fibre-reinforced plastic (FRP) serving as a formwork and a load-bearing hull for a concrete core makes it possible to produce a wide variety of different forms and geometries. To enable the potential of complex branched geometries, especially continuous load-confirming fibre arrangements over the entire braiding hull and large diameters, an advanced braiding technique to create triaxially braided preforms is required. This paper focuses on recent developments of an advanced braiding process to fabricate a multi-layered complex structural geometry on a 144 bobbins radial braiding machine and the adaptation of stationary threads until now regulated by spring force into ones operated electronically. With the new braiding technique, branched performs with triaxial braids were produced. Subsequent to impregnation with a thermosetting resin and annealing, the FRP-hull is poured with concrete. To evaluate a potential load increase of load capacity of the concrete core due to the confinement of FRP-hulls compression tests are conducted. In comparison to plain concrete specimens the mechanical parameters of fibrereinforced plastic-concrete-composites show a significant increase in compression strength.

Abstract

Hingeless shading systems inspired by nature are increasingly the focus of architectural research. In contrast to traditional systems, these compliant mechanisms can reduce the amount of maintenanceintensive parts and can easily be adapted to irregular, doubly curved, facade geometries. Previousmechanisms rely merely on the reversible material deformation of composite structures with almost homogeneous material properties. This leads to large actuation forces and an inherent conflict between the requirements of movement and the capacity to carry external loads. To enhance the performance of such systems, current research is directed at natural mechanisms with concentrated compliance and distinct hinge zones with high load-bearing capacity. Here, we provide insights into our biological findings and the development of a deployable structure inspired by the Flexagon model of hindwings of insects in general and the hierarchical structure of the wing cuticle of the shield bug (Graphosoma lineatum). By using technical fibre-reinforced plastics in combination with an elastomer foil, natural principles have been partially transferred into a multi-layered structure with locally adapted stiffness. Initial small prototypes have been produced in a vacuum-assisted hot press and sustain this functionality. Initial theoretical studies on test surfaces outline the advantages of these bio-inspired structures as deployable external shading systems for doubly curved facades.

Abstract

This paper presents results of the investigation of two biological role models, the shield bug (Graphosoma italicum) and the carnivorous Waterwheel plant (Aldrovanda vesiculosa). The aim was to identify biological construction and movement principles as inspiration for technical, deployable systems. The subsequent processes of abstraction and simulation of the movement and the design principles are summarized, followed by results on the mechanical investigations on various combinations of fibers and matrices with regard to taking advantage of the anisotropy of fiber-reinforced plastics (FRPs). With the results gained, it was possible to implement defined flexible bending zones in stiff composite components using one composite material, and thereby to mimic the biological role models. First small-scale demonstrators for adaptive façade shading systems – Flectofold and Flexagon – are proving the functionality.

Abstract

Brücken und Dächer werden oft durch verzweigte Stahlstützen getragen. Diese sind in ihrer Herstellung meist teuer und energieaufwendig. In der Natur gelingt es Pflanzen, ähnlich stabile und häufig noch komplexere Verzweigungen durch natürliche Wachstumsprozesse zu bilden. Sie können mechanischen Belastungen mühelos standhalten, wie zum Beispiel ihrem Eigengewicht, Winddruck, Schneelast oder schweren Früchten. Um den Erfolgsstrategien verzweigter Bäume und Sträucher auf den Grund zu gehen und von ihnen für die Architektur zu lernen, bedarf es nicht nur eines genauen Blicks auf die Form der Verzweigung und ins Innere der Pflanzen. Auch Computermodelle sowie neue Materialien und Methoden für die Herstellung verzweigter Stützstrukturen im Bauwesen sind für solche Übertragungen in die Technik notwendig.

Abstract

Smart and adaptive outer façade shading systems are of high interest in modern architecture. For long lasting and reliable systems, the abandonment of hinges which often fail due to mechanical wear during repetitive use is of particular importance. Drawing inspiration from the hinge-less motion of the underwater snap-trap of the carnivorous waterwheel plant (Aldrovanda vesiculosa), the compliant façade shading device Flectofold was developed. Based on computational simulations of the biological role-model's elastic and reversible motion, the actuation principle of the plant can be identified. The enclosed geometric motion principle is abstracted into a simplified curved-line folding geometry with distinct flexible hinge-zones. The kinematic behaviour is translated into a quantitative kinetic model, using finite element simulation which allows the detailed analyses of the influence of geometric parameters such as curved-fold line radius and various pneumatically driven actuation principles on the motion behaviour, stress concentrations within the hinge-zones, and actuation forces. The information regarding geometric relations and material gradients gained from those computational models are then used to develop novel material combinations for glass fibre reinforced plastics which enabled the fabrication of physical prototypes of the compliant façade shading device Flectofold.

Abstract

Pflanzen besitzen weder Muskeln noch „klassische“ lokale Gelenke – und können sich dennoch bewegen. Im Laufe der Evolution sind effiziente Bewegungsmechanismen und ästhetische Bewegungsformen entstanden. Aus diesem „Angebot“ der Botanik schöpfen Architekten und Ingenieure in Zusammenarbeit mit Biomechanikern Inspiration für die Entwicklung neuartiger Verschattungssysteme für moderne Gebäude.

Abstract

In technical constructions, movements are usually achieved by articulated rigid elements. In such cases, the most common cause for failure is mechanical abrasion. Plants are able to perform reversible movements without employing “true” hinges and possess an anisotropic material structure. Moreover, plants generally mechanically adapted to local stress- and strain-concentrations. By this, plants are of high interest for the field of biomimetic architecture since deployable structures, e-g- common shading systems, usually incorporate “classical” technical hinges. The internal structure of plants resembles fiber reinforced plastics (FRPs) consisting of a shaping matrix enveloping reinforcing fibers. By using FRPs in construction engineering, it is possible to generate anisotropic properties within defined regions so that stiff and elastically deformable areas in one component are achievable. The movement principle of traps of the aquatic, carnivorous plant Aldrovanda vesiculosa (waterwheel plant) serves as inspiration for a bio-inspired shading system, Flectofold.

Abstract

In architecture and construction engineering, a vast number of connections and branched columns in frame structures exist that are exposed to high static and dynamic loads. The manufacture of many of these elaborate structures is both time-consuming and costly. Industry has no solution for cost-effectively producing aesthetic and mechanically stable branched columns. This challenge is addressed by the development of branched structures inspired by branched biological concept generators such as Schefflera arboricola. Here, we present methodological approaches allowing the reconstruction of the outer shape and inner structure of complex branching regions, such as in S. arboricola, by using and combining three-dimensional-image stacking of histological thin sections, micro-computer-tomography (μCT) imaging and laser scanning. Computer-aided design (CAD) and Finite Element (FE) models of such structures can then be produced that not only help to provide a better understanding of the functional morphology and biomechanics of the biological concept generator, but also render the basis for the intended biomimetic transfer to branched columns consisting of a braided hull filled with concrete. The current project results are mainly based on the analysis of S. arboricola branching and the results of a previous research project (SPP 1420) in which biomimetic branched fibre-reinforced plastic (FRP) columns inspired by the branching structure of Dracaena were produced. Currently a biomimetic hull geometry that can be manufactured industrially is developed. Initially, branched FRPs based on triaxial braids with readily adjustable mechanical properties are filled with concrete and thus shall achieve sufficient mechanical properties for application and cost-effective fabrication in the building industry.

Abstract

Plant movements can inspire deployable systems for architectural purposes which can be regarded as ideal solutions combining resilient bio-inspired functionality with elegant natural motion. Here, we first give a concise overview of various compliant mechanisms existing in technics and in plants. Then we describe two case studies from our current joint research project among biologists, architects, construction engineers and materials scientists where the aesthetic movements of such role models from the plant kingdom are analysed, abstracted and implemented in bioinspired technical structures for sustainable architecture. Both examples are based on fast snapping movements of traps of carnivorous plants. The Waterwheel plant (Aldrovanda vesiculosa) captures prey underwater and the Venus flytrap (Dionaea muscipula) snaps in the air. We present results on the motion principles gained by quantitative biomechanical and functional-morphological analyses as well as their simulation and abstraction by using e.g. Finite Element Methods. The Aldrovanda mechanism was successfully translated into a similarly aesthetic and functional technical structure, named Flectofold, which exists in a prototype state. The Flectofold can be used as a façade shading element for complex curved surfaces as existing in modern architecture.