Universität Stuttgart
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Item Open Access Integrative Planung und Herstellung von freigeformten Verbundtragwerken aus CFK und Beton(Stuttgart : Institut für Tragkonstruktionen und Konstruktives Entwerfen, Universität Stuttgart, 2017) Waimer, Frédéric; Knippers, Jan (Prof. Dr.-Ing.)Die geometrische Komplexität von freigeformten Flächentragwerken in der gegenwärtigen Architektur lässt sich kaum noch wirtschaftlich umsetzen. Die Realisierung ist mit hohen Fertigungs- und Planungskosten verbunden und daher nur wenigen Bauvorhaben vorbehalten. Die herkömmlichen Bautechniken, Bauweisen, Materialien und Planungsprozesse sind Ursache für die hohen Kosten. Faserverstärkte Kunststoffe, automatisierte Fertigungsverfahren und digitale Planungsmöglichkeiten scheinen ein hohes Potential zu besitzen, dieser Problematik entgegenzuwirken. In der vorliegenden Arbeit wird eine neue Flächenverbundbauweise, bestehend aus einer verlorenen karbonfaserverstärkten Kunststoffschalung (CFK) und Beton, vorgestellt, die es ermöglicht freigeformte Flächentragwerke effizienter umzusetzen. Der Fokus liegt dabei auf der Untersuchung des Tragverhaltens, der Herstellung der freigeformten verlorenen Schalung und der Planung der Bauweise. Die ermittelten mechanischen Eigenschaften der entwickelten kraftschlüssigen Verbindung zwischen Schalung und Beton zeigen, dass auf eine Stahlzugbewehrung verzichtet werden kann. Dies erlaubt es einerseits aufwendige Bewehrungsarbeiten zu vermeiden und andererseits die Schalendicke zu verringern. Die Korrosionsbeständigkeit und Dauerhaftigkeit der CFK-Verbundschalung ermöglicht es dabei, die Bauteile mit einem schlankeren Querschnitt auszuführen. Die Herstellung der Verbundschalung erfolgt durch einen neuen Ansatz in der Faserwickeltechnik. Der Schwerpunkt der Entwicklung liegt dabei auf der geometrischen Ausbildung des Wickelkerns und der Simulation des Wickelvorgangs mittels computergestützter Berechnungsverfahren. Die Integration von zusätzlichen Fertigungsschritten ermöglicht ein Verfahren, das es erlaubt, freigeformte flächige Bauteile zu fertigen. Das Faserwickelverfahren beschränkt sich bisher auf die Herstellung von Bauteilen mit geschlossenen Querschnittsformen. Die Vorteile des klassischen Verfahrens, wie hoher Faservolumengehalt, geringe Fertigungskosten, kurze Prozesszeiten und hohe Ausführungsqualität, sind dabei weiterhin gegeben. Aufgrund der festgestellten starken Wechselwirkung bei der Planung von Geometrie, Tragwerk und Fertigung, ist für die entwickelte Bauweise eine üblicherweise getrennte und in Reihe geschaltete Bearbeitung der Planungsaufgaben nicht zielführend. Um die Vorteile der Flächenverbundbauweise voll auszuschöpfen, wird in dieser Arbeit abschließend eine integrative Planungs- und Optimierungsstrategie vorgestellt. Diese ermöglicht es, die Eigenschaften von Geometrie, Herstellung und Tragverhalten in ein optimales Verhältnis zu bringen. Die verfolgte Strategie führt zusätzlich zu einer Verkürzung der Planungszeit, einer Reduzierung der Kosten für Planung und Fertigung, sowie einer ästhetischen und ressourcenschonenden Konstruktion. Zur Bestimmung der optimalen Lösung wird ein stochastisches, metaheuristisches Optimierungsverfahren entwickelt, dessen Funktionsweise auf der Nahrungssuche der E-Coli Bakterien beruht.Item Open Access Structural optimization of grid shells based on genetic algorithms(2011) Dimcic, Milos; Knippers, Jan (Prof. Dr.-Ing.)In the 21st century, as free form design gains popularity, free-form grid shells are becoming a universal structural solution, enabling merger of structure and facade into a single layer - a skin. The subject of the presented work is the optimization of grid structures over some predefined free form shape, with the goal of generating a stable and statically efficient structure. It is shown how combining design and FEM software in an iterative, Genetic Algorithms based, optimization process, stress and displacements in grid shell structures can be significantly reduced, whereby material can be saved and stability enhanced. Within this research, design and static analysis software are combined in order to perform a statical optimization of grid shells, generated over a given free form surface. A plug-in for Rhinoceros 3D (software based on NURBS geometry representation) is developed, that uses Genetic Algorithms as an optimization method and implements automated iterative calls to Oasys GSA (commercial FEM static analysis software) in order to generate a statically optimal grid shell. To make this possible, within this research some new types of automatic grid generation are developed. Voronoi diagrams were used together with the adapted Force-Density method to develop a new type of grid structure that we called Voronax. In the presented work it was shown that, using the same free form surface, and using the same number of joints and structural members, we can generate much more efficient grid shells, when compared to the standard (uniform) grid structures, simply by modifying the structural grid, i.e., rearranging the structural members of the grid shell. The work presented offers an explanation of the entire method and how it can be constructed. The results of the experiments are there to prove its efficiency and credibility. Once it is proved that the method works, its application can take various forms and be left to the creativity of the user and the requirements of the specific project.Item Open Access Fibrx rocking chair : design and application of tailored timber as an embedded frame for natural fibre-reinforced polymer (NFRP) coreless winding(2023) Pittiglio, Alexandra; Simpson, Ailey; Costalonga Martins, Vanessa; Dahy, HanaaThe building industry needs to innovate towards a more sustainable future and can do so through a combination of more renewable material choices and less wasteful fabrication processes. To address these issues, a hybrid material and fabrication system was developed using laminated timber veneer and natural fibre-reinforced composites (NFRPs), two materials that are leveraged for their potential of strategic material placement in additive processes towards programmed material behaviour and performance. The main contribution is in the hybrid fabrication approach, using thin, bent laminated veneer as an embedded frame for coreless filament winding of NFRP, which removes the need for temporary, wasteful formwork that is typically required to achieve structurally performative bent timber or FRP elements. Integrative methods are developed for the design, simulation, and fabrication of a rocking chair prototype that illustrates the architectural potential of the developed fabrication approach.Item Open Access Tensegrity FlaxSeat : exploring the application of unidirectional natural fiber biocomposite profiles in a tensegrity configuration as a concept for architectural applications(2024) Renner, Markus; Spyridonos, Evgenia; Dahy, HanaaMaterial selection is crucial for advancing sustainability in the building sector. While composites have become popular, biocomposites play a pivotal role in raising awareness of materials deriving from biomass resources. This study presents a new linear biocomposite profile, fabricated using pultrusion technology, a continuous process for producing endless fiber-reinforced composites with consistent cross-sections. The developed profiles are made from flax fibers and a plant-based resin. This paper focuses on the application of these profiles in tensegrity systems, which combine compression and tension elements to achieve equilibrium. In this study, the biocomposite profiles were used as compression elements, leveraging their properties. The methods include geometrical development using physical and digital models to optimize the geometry based on material properties and dimensions. A parametric algorithm including physics simulations was developed for this purpose. Further investigations explore material options for tension members and connections, as well as assembly processes. The results include several prototypes on different scales. Initially, the basic tensegrity principle was built and explored. The lessons learned were applied in a final prototype of 1.5 m on a furniture scale, specifically a chair, integrating a hanging membrane serving as a seat. This structure validates the developed system, proving the feasibility of employing biocomposite profiles in tensegrity configurations. Furthermore, considerations for scaling up the systems to an architectural level are discussed, highlighting the potential to enhance sustainability through the use of renewable and eco-friendly building materials, while promoting tensegrity design applications.Item Open Access Bending-active plates : strategies for the induction of curvature through the means of elastic bending of plate-based structures(Stuttgart : Institut für Tragkonstruktionen und Konstruktives Entwerfen, Universität Stuttgart, 2017) La Magna, Riccardo; Knippers, Jan (Prof. Dr.-Ing.)Commonly referred to as bending-active, the term has come to describe a wide variety of systems that employ the large defor-mation of their constituent components as a primary shape-forming strategy. It is generally impossible to separate the struc-ture from its geometry, and this is even more true for bending-active systems. Placed at the intersection between geometry, de-sign and engineering, the principle objective of this thesis is to develop an understanding of the structural and architectural po-tential of bending-active systems beyond the established typolo-gies which have been investigated so far. The main focus is set on systems that make use of surface-like elements as principle build-ing blocks, as opposed to previous and existing projects that pre-dominantly employed linear components such as rods and laths. This property places the analysed test cases and developed proto-types within a specific category of bending-active systems known as bending-active plate structures. The first chapters serve as a general introduction to the topic. An overview of relevant recent projects is presented in the introduction, followed by a discussion on the scope of research on bending-active structures. The following chapters lay the theoretical basis in terms of geometry of surfaces and mechanical behaviour of plates. This dual and complementary description serves as the necessary background to understand the limits and potential associated to the deformability of plate elements. The following chapter delves into the first of the two strategies developed as part of this research. Termed form conversion, this approach establishes a one-to-one relationship between the initial base surface and its bending-active discrete counterpart. The chapter proceeds with the presentation of a series of full-scale prototypes that were realised to test the validity of the form con-version approach. Geometrical and mechanical features are dis-cussed in the conclusion of the chapter. The second developed method, named integral approach, is pre-sented in the next section. This approach takes advantage of the inherent deformation properties of explicitly designed material patterns. The description of the method is followed by the presen-tation and discussion of the prototypes chosen to test the integral approach. Finally, the thesis concludes with a critical discussion of the presented approaches and a discussion on potential developments for future research.Item Open Access Bio-modules : mycelium-based composites forming a modular interlocking system through a computational design towards sustainable architecture(2023) Abdelhady, Omar; Spyridonos, Evgenia; Dahy, HanaaIn a resource-constrained world, raising awareness about the development of eco-friendly alternative materials is critical for ensuring a more sustainable future. Mycelium-based composites (MBC) and their diverse applications are gaining popularity as regenerative, biodegradable, and lightweight alternatives. This research aims to broaden the design potentials of MBC in order to construct advanced systems towards a novel material culture in architecture. The proposed design method intends to explore the design and fabrication of small-scale components of MBC to be applied in modular systems. Mycelium-based modular components are being developed to fulfill the geometrical requirements that allow for the creation of a lightweight system without additional reinforcement. The modules are linked together using an interlocking system. Through computational design and form-finding methods, various arrangements of the modules are achieved. An initial prototype of five modules is created to demonstrate the ability of the system to form various geometrical configurations as a result of the used workflow. The proposed application aims to expand the scope of the use of mycelium-based composites in modular systems and to promote architectural applications using bio-based composite materials.Item Open Access Material und Form - was ist in welcher Situation günstig für Tragwerke? zugleich: Konstruktives Entwerfen beobachtet(1996) Tokarz, BernhardJedes feste Material ist ein potentielles Baumaterial: Stein, Stahl, Keramik, Glas, Segeltuch, Holz, Schilf, Erde, aber auch Wasser, ja sogar Wasser, denn Bauen ist ja nicht nur Wände und Dächer herstellen, sondern auch ein Klima, in dem wir gern leben. Was ist aber gut wofür? Wir müssen, bei genauerem Nachdenken, weiterfragen: in welcher Situation? Zu welcher Zeit? In welchem Land? In welchem Klima? Denn was nützt es, wenn ich weiß, Stahl nimmt Zugkräfte mit dem geringsten sichtbaren Volumen an Konstruktion und dem geringsten Konstruktionsgewicht auf, wenn ich ihn nicht bekomme oder wenn er an dem Ort, wo ich ihn verwenden möchte, zehnmal so teuer ist als Holz für die gleiche Leistung - oder ständiger Pflege bedürfte in der aggressiven Atmosphäre, der er ausgesetzt ist, damit er gegen Korrosion geschützt bleibt, wogegen vielleicht eine alternative Konstruktion aus Mauerwerk und Erde die Zugkraft gar nicht erst entstehen ließe?Item Open Access Structural optimization through biomimetic-inspired material-specific application of plant-based natural fiber-reinforced polymer composites (NFRP) for future sustainable lightweight architecture(2020) Sippach, Timo; Dahy, Hanaa; Uhlig, Kai; Grisin, Benjamin; Carosella, Stefan; Middendorf, PeterUnder normal conditions, the cross-sections of reinforced concrete in classic skeleton construction systems are often only partially loaded. This contributes to non-sustainable construction solutions due to an excess of material use. Novel cross-disciplinary workflows linking architects, engineers, material scientists and manufacturers could offer alternative means for more sustainable architectural applications with extra lightweight solutions. Through material-specific use of plant-based Natural Fiber-Reinforced Polymer Composites (NFRP), also named Biocomposites, a high-performance lightweight structure with topology optimized cross-sections has been here developed. The closed life cycle of NFRPs promotes sustainability in construction through energy recovery of the quickly generative biomass-based materials. The cooperative design resulted in a development that were verified through a 1:10 demonstrator, whose fibrous morphology was defined by biomimetically-inspired orthotropic tectonics, generated with by the fiber path optimization software tools, namely EdoStructure and EdoPath in combination with the appliance of the digital additive manufacturing technique: Tailored Fiber Placement (TFP).Item Open Access Integrative structural design of non-standard building systems : coreless filament-wound structures as a case study(Stuttgart : Institut für Tragkonstruktionen und Konstruktives Entwerfen, Universität Stuttgart, 2023) Gil Pérez, Marta; Knippers, Jan (Prof. Dr.-Ing.)Our society is experiencing the emergence of novel nonstandard building systems unlocked by digital technologies in the building sector. The utilisation of computational design processes and digital fabrication, coupled with the exploration of new materiality, bring the potential to break with conventional ways of building. However, they also demand new ways of designing and proving the structure's safety. This dissertation aims to develop an integrative structural design methodology and workflow to design, optimise and validate non-standard building systems. Therefore, a multiscale, digital-physical approach is proposed, which combines structural simulation with small-scale models and material testing, allowing the structure's optimisation and proof of safety. The first two chapters explain the research motivation, objectives and contextualisation. Historical remarks are given to understand the evolution of structural design and the key aspects that created innovation and non-standard systems in the past. Coreless filament winding (CFW) is also introduced here as a representative example of non-standard building systems. Chapter three contains the publications that describe the development of the integrative structural design methodologies through coreless filament wound structures as a case study. All the publications are supported by CFW specimens or full-scale built demonstrators, including BUGA Fibre Pavilion, Maison Fibre and LivMatS Pavilion. Chapters four and five summarise the results, generalising the workflow from CFW structures to non-standard building systems into four sub-methods: multi-level modelling and evaluation; structural characterisation; integrative design; and optimisation and safety verification. The discussion locates the integrative structural design in the historical context and analyses the strategies to prove the safety of other non-standard systems. The conclusion emphasises the potential of this methodology to shorten the gap between research and industry, facilitating the realisation of innovative structures.Item Open Access Topology-driven form-finding : interactive computational modelling of bending-active and textile hybrid structures through active-topology based real-time physics simulations, and its emerging design potentials(Stuttgart : Institut für Tragkonstruktionen und Konstruktives Entwerfen, Universität Stuttgart, 2020) Suzuki, Seiichi; Knippers, Jan (Prof. Dr.-Ing.)The inherent relation between aesthetic qualities and structural efficiency inherent on bending-active and textile hybrid structures is associated with a vast range of design opportunities for generating innovative architectural solutions. Exploring those opportunities is a non-trivial task demanding to expand outside current geometric modeling paradigms and develop an insightful and methodological simulation-based design practice. Considering that dynamic methods, such as Particle Systems (PS) and Dynamic Relaxation (DR), have become an important research trend with major advances only focused on speeding up numerical convergence, the main focus of this work is to develop a comprehensive approach for enabling topologic transformations with real-time physics named topology-driven form-finding that, during conceptual stages, can serve to extend design spaces by improving modeling freedom. A general introduction to bending-active and textile hybrid structures is presented in chapter 2. The following chapter then serves to introduce basic principles of PS and DR methods with an overview of mechanical formulations and integration schemes used throughout this work. Chapter 4 introduces the theoretical framework regarding the development of a generic topologic model with geometric and mechanic embeddings for the implementation of PS models supporting topologic transformations on the fly. Chapter 5 proceeds with the presentation of implementations along with a description of design and modeling implications. Different case studies in which the conceptual design development has been conducted via topology-driven form-finding approaches are presented in chapter 6. Finally, this thesis concludes with a discussion of methods and models developed, and a number of recommendations for future research.