Hanaa Dahy

Abstract

The 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.

Abstract

Under 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).

Abstract

The application of non-renewable building materials including concrete and metals in construction industries have caused a major impact on the environment including the destruction of more than 45% of the global resources, the consumption of 35% of energy and nearly 40% of energy-related emissions (UN Secretary-General’s High-Level Panel on Global 2012). In order to help in reducing these extending impacts, the building sector started considering three reduction of these dreadful impacts through increasing the environmentally-friendly building materials with Natural Fiber Reinforced Polymer Composites (NFRP), specially through WPCs (Wood Polymer Composites) since the 90s. The use of natural fibers in composites form in the building sector is historically applied since the phrase time when straw and mud were mixed to form the first known bricks in history. After the discovery of cement, it became the largest dominant material in the industry till our current time, in spite of its huge environmental damage. Natural fibres (NF) have been mostly applied in non-structural applications. Accordingly, this paper discusses applying reinforcement scenarios in the form of novel core and veneer reinforcement to enhance a load-bearing capacity to reach to improved mechanical properties that could enable building a demo- shell construction system. In this research natural fiber reinforced polymer composite (NFRP) produced from agricultural residues in the form of straw fibres (SF) mixed with three different types of polymers including (polylactide (PLA), a TPE (Thermoplastic elastic polymer) and high-density polyethylene (HDPE)) were developed through extrusion processes, then laminated or veneered to elevate the material properties needed to be reached to apply in load-bearing structures. The thermoplastic elastic polymers (TPE) were applied to enhance elasticity and flexibility in reaching sophisticated geometries. The mechanical strength was controlled by veneering. The targeted and reached material properties were applied in structural simulations that were later used in predicting the structural performance of a physical experimental shell construction that were built to validate the settled hypothesis of reinforcement of elastic/semi-elastic lignocellulosic cores to be applied in load-bearing systems. The paper will highlight the material samples development and testing, followed by an analysis and interpretation to the possibility of usage and appliance in load-bearing structures. Finally, the physical built demonstrator in the form of the experimental shell construction is shortly illustrated to showcase the validity of the settled hypothesis.

Abstract

This research demonstrates an integrative computational design and fabrication workflow for the production of surface-active fibre composites, which uses natural fibres, revitalises a traditional craft, and avoids the use of costly molds. Fibre-reinforced polymers (FRPs) are highly tunable building materials, which gain efficiency from fabrication techniques enabling controlled fibre direction and placement in tune with load-bearing requirements. These techniques have evolved closely with industrial textile processes. However, increased focus on automation within FRP fabrication processes have overlooked potential key benefits presented by some lesser-known traditional techniques of fibre arrangement. This research explores the process of traditional bobbin lace-making and applies it in a computer-aided design and fabrication process of a small-scale structural demonstrator in the form of a chair. The research exposes qualities that can expand the design space of FRPs, as well as speculates about the potential automation of the process. In addition, Natural Fibre-Reinforced Polymers (NFRP) are investigated as a sustainable and human-friendly alternative to more popular carbon and glass FRPs.

Abstract

Fiber Reinforced Polymers (FRPs) are increasingly popular building materials, mainly because of their high strength to weight ratio. Despite these beneficial properties, these composites are often fabricated in standardized mass production. This research aims to eliminate costly molds in order to simplify the fabrication and allow for a higher degree of customization. Complex three-dimensional shapes were instead achieved by a flat reinforcement, which was resin infused and curved folded into a spatial object before hardening. Structural stability was gained through geometries with closed cross-sections. To enable this, the resource-saving additive fabrication technique of tailored fiber placement (TFP) was chosen. This method allowed for precise fibers’ deposition, making a programmed anisotropic behavior of the material possible. Principles regarding the fiber placement were transferred from a biological role-model. Five functional stools were produced as demonstrators to prove the functionality and advantages of the explained system. Partially bio-based materials were applied to fabricate the stool models of natural fiber-reinforced polymer composites (NFRP). A parametric design tool for the global design and fiber layout generation was developed. As a result, varieties of customized components can be produced without increasing the design and manufacturing effort

Abstract

It has become clear over the last decade that the building industry must rapidly change to meet globally pressing requirements. The strong links between climate change and the environmental impact of architecture mean an urgent necessity for alternative design solutions. In order to propose them in this project, two emergent fabrication techniques were deployed with natural fiber-reinforced polymers (NFRPs), namely tailored fiber placement (TFP) and coreless filament winding (CFW). The approach is explored through the design and prototyping of a stool, as an analogue of the functional and structural performance requirements of an architectural system. TFP and CFW technologies are leveraged for their abilities of strategic material placement to create high-performance differentiated structure and geometry. Flax fibers, in this case, provide a renewable alternative for high-performance yarns, such as carbon, glass, or basalt. The novel contribution of this project is exploring the use of a TFP preform as an embedded fabrication frame for CFW. This eliminates the complex, expensive, and rigid molds that are traditionally associated with composites. Through a bottom-up iterative method, material and structure are explored in an integrative design process. This culminates in a lightweight FlexFlax Stool design (ca. 1 kg), which can carry approximately 80 times its weight, articulated in a new material-based design tectonic.

Abstract

Driven by the ecological crisis looming over the 21st century, the construction sector must urgently seek alternative design solutions to current building practices. In the wake of emergent digital technologies and novel material strategies, this research proposes a lightweight architectural solution using natural fiberreinforced polymers NFRP, which elicit interest for their inherent renewability as compared to highperformance yarns. Two associated fabrication techniques are deployed tailored fiber placement TFP and coreless filament winding CFW, both favored for their additive efficiencies granted by strategic material placement. A hypothesis is formed, postulating that their combination can leverage the standalone complexities of molds and frames by integrating them as active structural elements. Consequently, the TFP enables the creation of a 2D stiffnesscontrolled preform to be bent into a permanent scaffold for winding rigid 3D fiber bodies via CFW. A proof of concept is generated via the smallscale prototyping and testing of a stool, with results yielding a design of 1 kg capable of carrying 100 times its weight. Laying the groundwork for a scaledup architectural proposal, the prototype instigates alterations to the process, most notably the favoring of a modular global design and lapped preform technique. The research concludes with a discussion on the resulting technoimplications for automation, deployment, material life cycle, and aesthetics, rekindling optimism towards future sustainable practices.

Abstract

Carbon fiber composites embody lightweight and strength and is a well-integrated material in various fields of engineering. In spite of its excellent material properties, it is not frequently found in architecture and design applications. In this project, the intention is to research how the material's most prominent qualities can be applied to create a lightweight furniture design. The furniture object was chosen as an example of a small architectural component with a structural capacity of holding a human body weight between 60-90 Kg. In particular, carbon fiber composites display an impressive tensile strength, and with the aim of exploring this feature, a case-study of a full-scale, hanging carbon chair was conducted. To develop a design, optimize it and realize it, an integrated design and fabrication process was developed. It combined material research, computational design, and a novel fabrication method for filament materials.

Abstract

Choosing building materials is usually the stage that follows design in the architectural design process, and is rarely used as a main input and driver for the design of the whole building’s geometries or structures. As an approach to have control over the environmental impact of the applied building materials and their after-use scenarios, an approach has been initiated by the author through a series of research studies, architectural built prototypes, and green material developments. This paper illustrates how sustainable building materials can be a main input in the design process, and how digital fabrication technologies can enable variable controlling strategies over the green materials’ properties, enabling adjustable innovative building spaces with new architectural typologies, aesthetic values, and controlled martial life cycles. Through this, a new type of design philosophy by means of applying sustainable building materials with closed life cycles is created. In this paper, three case studies of research pavilions are illustrated. The pavilions were prefabricated and constructed from newly developed sustainable building materials. The applied materials varied between structural and non-structural building materials, where each had a controlled end-of-life scenario. The application of the bio-based building materials was set as an initial design phase, and the architects here participated within two disciplines: once as designers, and additionally as green building material developers. In all three case studies, Design for Deconstruction (DfD) strategies were applied in different manners, encouraging architects to further follow such suggested approaches.

Abstract

Due to the high amounts of waste generated from the building industry field, it has become essential to search for renewable building materials to be applied in wider and more innovative methods in architecture. One of the materials with the highest potential in this area is natural fibre-reinforced polymers (NFRP), which are also called biocomposites, and are filled or reinforced with annually renewable lignocellulosic fibres. This would permit variable closed material cycles’ scenarios and should decrease the amounts of waste generated in the building industry. Throughout this paper, this discussion will be illustrated through a number of developments and 1:1 mockups fabricated from newly developed lignocellulosic-based biocomposites from both bio-based and non-bio-based thermoplastic and thermoset polymers. Recyclability, closed materials cycles, and design variations with diverse digital fabrication technologies will be discussed in each case. The mock-ups’ concepts, materials’ compositions, and fabrication methods are illustrated. In the first case study, a structural segmented shell construction is developed and constructed. In the second case study, acoustic panels were developed. The final case studies are two types of furniture, where each is developed from a different lignocellulosic-based biocomposite. All of the presented case studies show diverse architectural design possibilities, structural abilities, and physical building characteristics.

Abstract

Technological advancement culminating in a globalized economy has brought tremendous improvements for mankind in manifold respects but comes at the cost of alienation from nature. Human activities nowadays are unsustainable and cause severe damage especially in terms of global depletion and destabilization of natural systems but also harm its own social resources. In this paper, a sustainability assessment method is developed based on a bio-inspired sustainability framework that has been developed in the project TRR 141-C01 “The biomimetic promise”. It is aims at regaining the advantages of societal embeddedness in its environment through biological inspiration. The method is developed using a structured approach including requirement specification, description of the inventory models on bio-inspiration and sustainability assessment, creation of a bio-inspired sustainability assessment model and its validation. It is defined as an accompanying assessment for decision support, using a six-fold two-dimensional structure of social, economic and environmental functions and burdens. The method is applied and validated in 6 projects of TRR 141 and its applicability is exemplarily shown by the assessment of “Bio-flexi”, a biobased and biodegradable natural fiber reinforced plastic composite for indoor cladding applications. Based on the findings of the application the assessment method itself is proposed to be advanced towards an adaptive structure and a consequent outlook is provided.

Abstract

Natural fibres retrieved from annual agricultural by-products offer diverse advantages, when applied as a main ingredient in biocomposite building materials. These fibres, such as straw and other non-wood fibres are annually renewable and are worldwide available having the lowest cost, in comparison to other natural fibres available in the industrial fibre market. In this paper, the author presents three case studies of natural fibre reinforced polymers (NFRP), discussing the agro-fibre densification, different architectural designs for customized applications and fabrication stages. The natural fibres were compounded with three different biopolymers: a thermoplastic, a thermoset and an elastic thermoplastic one. This allowed variations in the final designs and geometries that can be reached, but caused a necessity of changing the fabrication technique in each case accordingly. To prove the applicability of the developed products, mechanical properties and environmental assessment were analyzed.

Abstract

Cellulosic fibres retrieved from annual agricultural by-products offer diverse advantages when applied as a main ingredient in biocomposite building materials. Within this paper work, the application possibility of non-wood straw fibres in innovative building products is highlighted. Fabrication efficiency is reached here through reducing the number of industrial processes and additives needed to manufacture the final biocomposite products. The natural mineral contents of the straw selected (rice straw) were investigated at 20% fibre load as active flame-retardant fillers in combination with two types of bio-based synthesized thermoplastics poly-lactic acid (PLA) and Lignin. Flammability behavior and morphological examinations of the resulted building materials were tested. Through post-fabrication techniques including vacuum thermoforming processes, a variety of cladding panels with different architectural designs were achieved. The applied fibres were not chemically treated. Instead, the fibres were mechanically densified, maintaining the inner natural minerals contents. The results have shown promising possibility of applying straw fibres as partial replacement of classic flame-retardants especially in combination with bioplastics. The straw based green biocomposites were proved to offer high ecological, economical and aesthetic input in the building industry.

Abstract

Aus dem Bewusstsein für globale Umweltbedingungen, Nachhaltigkeitsprinzipien, ökologische Effizienz und architektonische Bedürfnisse heraus wurde in diesem Forschungsvorhaben das Potenzial von Reisstroh in der Bauindustrie sorgfältig untersucht. Reisstroh (RS) wurde als Beispiel für faserigen Pflanzenabfall gewählt, da diese Naturfasern weltweit zur Verfügung stehen, aber immer noch in großen Mengen auf den Feldern verbrannt werden. Die Zerstörung des nutzbaren Pflanzenmaterials führt zu Verlust von Energie, gleichzeitiger Luftverschmutzung und negativer Klimaveränderung. Bisher finden bereits Strohballen in der Bauindustrie Verwendung. Diese können jedoch die verfügbaren Strohmengen nicht aufnehmen und haben technische und ästhetische Nachteile. Demzufolge wurde hier vorgeschlagen, Stroh als Hauptbestandteil eines Bioverbundwerkstoffes anzuwenden, sowohl als Faserrohstoffquelle, als auch als ökologischen Füllstoff. In diesem Vorhaben wurden drei Bioverbundkunststoff-Gruppen aus Reisstroh und organischen Polymeren entwickelt. Die technischen Eigenschaften dieser Proben wurden auf ihre Verwendungsmöglichkeit in der Architektur hin getestet und analysiert. Zunächst wurde eine Reisstrohfaserplatte mit elastischem Binder und einem Faseranteil von 80% entwickelt. Diese erwies sich von hoher ökonomischer und ökologischer Bedeutung für eine mögliche architektonische Anwendung, die bisher erhältliche Faserplatten so nicht aufweisen. In der zweiten Baustoffgruppe wurden zwei thermoplastische RS- Biokomposite entwickelt, denen Reisstroh zu 20% Gewichtsanteil eines mit Silikat angereicherten Öko-Füllstoffs beigegeben wurde, um es als brandhemmendes Additiv im Zusammenwirken speziell mit Biokunststoff bewerten zu können. Biokomposite mit RS-PLA und RS-Lignin zeigten erhöhte Flammbeständigkeit aufgrund des 20%igen Fasergewichtsanteils. Die Entflammbarkeit von RS-Lignin-Biokomposit erreichte eine andere Materialklasse, nachdem Zellulose durch Reisstroh ersetzt wurde. RS-PLA wies erhöhte Flammbeständigkeit im Vergleich zu RS-PP auf, die weit unterhalb der Klassifizierung lag. Diese Ergebnisse leisten einen neuen wissenschaftlichen Beitrag auf diesem Gebiet, was bisher so nicht untersucht wurde. Als drittes entstanden zwei RS- Bioharz-Biokomposite, in denen 20% Gewichtsanteil RS-Fasern mit zwei Bioharzsystemen gemischt wurden. Dabei verwendete man je nach Art des jeweiligen Harzes unterschiedliche Herstellungsmethoden. Es fand ein Vergleich zwischen einem entsprechend zusammengesetzten RS-Biokomposit mit auf Erdöl basierendem Harz statt. Diese Gegenüberstellung machte deutlich, dass die RS-Bioharz-Biokomposite mechanischen Belastungen nicht so gut gewachsen waren wie RS-erdölbasierte Biokomposite. Dennoch zeigten die RS-Bioharz-Biokomposite eine hohe Witterungsbeständigkeit, wenn sie pigmentiert waren. Das könnte von großer Bedeutung sein, wenn diese umweltfreundlichen Materialien für Fassaden mit komplexen geometrischen Formen eingesetzt werden. Die drei entwickelten Reisstroh Biokomposit-Gruppen zeigen weitere Anwendungsmöglichkeiten von Fasern aus landwirtschaftlichen Reststoffen in der nachhaltigen Bauindustrie. Faser verarbeitende Industrien, wie Faserplattenherstellung und Produktion geformter naturfaserverstärkter Komposite, können Strohfasern aus der Agrarproduktion als sehr ergiebige und preiswerte Rohstoffquellen nutzen. Folglich kann durch die Verbreitung von billigeren und umweltfreundlicheren Biokomposit-Produkten in architektonischen Anwendungen die GesamtC02-Biilanz verbessert und teure fossile Rohstoffe und langsam nachwachsende Holzprodukte, die noch immer den Markt bestimmen, ersetzt werden.