Embedded Sensors to Monitor Production of Composites : From Infusion to Curing of Resin

The need for using light-weight and high-strength fibre reinforced polymer in different applications has increased in the past few decades. The ideal product offers excellent mechanical and chemical properties with much lower weight compared to traditionally used metals. Initially, the fibre-reinforced polymers are being produced by trial and error iterations. This causes a very expensive product, with random quality and lack of reproducibility. There is a need to replace trial and error experiments with knowledge-based approaches. Using sensors for in-situ production to monitor the results in a reliable and repeatable way gives a high-quality composite product and optimizes the time and cost of the process. One of the common manufacturing processes of fibre-reinforced polymer composite is resin infusion in dry fabrics. The resin impregnates the fibrous textile through the existence of a pressure gradient in the fibrous mat, which is generated by a vacuum pump or by a resin injection at high pressure. The impregnation of the dry textile is a result of the pressure gradient between resin inlet and venting point in the mold. Therefore, the most relevant measurement to detect the resin front and the changes of resin hydrostatic pressure is measuring the pressure directly inside the laminate. In this study, pressure sensors provide real-time information about the resin front in laminate and the changes of resin hydrostatic pressure during the infusion. Different pressure sensors and interconnection techniques were examined to minimize the size of the sensing element in the composite. After complete impregnation of the fibres, the curing degree of the resin has to be measured. Microscale interdigital capacitive sensors with a perforated substrate of polyimide are designed and fabricated. The sensors are fabricated on polyimide substrate with a thickness of about 5 micrometers. The polyimide is thermally stable up to 450 degree celsius. Therefore, the sensor can be used for a variety of processes even with high-temperature curing requirements. They have a volume of around 0.1 mm3. The miniaturized dimensions of the sensor enables it to remain in the composite product with the negligible diminishing of mechanical properties. The metallization of the sensor is insulated with metal oxide built up from the metallization itself. This insulation layer enables measurement in electrically conductive carbon fibres. The sensors will remain inside the composite material for structural health monitoring during the life-time of composite. Ideally, the sensors for online process monitoring of composites should be made of the identical fibres or resin in that composite. This will eliminate the wound effect in the host material. To obtain sensorial material, a high-performance resin for aerospace application, type RTM6, is mixed with different plasticizers. The cured mixture of the resin is thin and flexible. An interdigital comb structure is screen-printed on the newly developed substrate. The curing degree of the RTM6 resin in glass and carbon fibres is measured by screen-printed planar interdigital sensor on flexible RTM6. Having sensors for online process monitoring is important for industry 4.0 to autonomously produce fibre reinforced composites in a so-called smart factory . Both, pressure sensors and interdigital capacitive sensors in this thesis can be used for online process monitoring. They will provide a knowledge-based approach for high-quality and low-cost products

Modellierung und experimentelle Untersuchung von materialintegrierten Sensoren

The thesis is divided in a theoretical and an experimental part. In the theoretical part investigations on the foreign body effect of a sensor in a material in terms of mechanical, thermal and thermo-mechanical loads are done. The second part is based on experiments on the foreign body effect to prove the results of the first part. Therefore temperature and force sensors are integrated in epoxy resin, aluminum and steel

Interior Materiality

The knowledge of materials and finishes is the bridge that links conceptual design to real-world application. It is among the core content of virtually all interior architecture/design curricula, moreover, access to up-to-date information on emerging technologies and trends is a key exigency for the contemporary designer. Accordingly, this book is authored to form a comprehensive resource for the “hows” and “whys” surrounding the functional and aesthetic contributions of a wide selection of materials and finishes used in multiple spatial design contexts. The knowledge base presented here is not only useful in shaping spatial experience, ensuring occupant well-being, and employing sustainable thinking but also beneficial in managing budget and schedule while enabling the delivery of top-quality work. The book investigates fundamental material properties, performance criteria, as well as sector-specific standards, regulations, and guidelines, with a special focus on concerns surrounding occupant health and safety as well as environmental impact and sustainability concerns. Furthermore, fabrication, installation, and maintenance issues were explored in detail. Various information collection and organization conventions are also discussed with regard to detailing, specification, estimation, and documentation of materials and finishes. The goals of the book can be listed as follows: ● Developing a vocabulary and knowledge base to comprehend and communicate concepts and paradigms associated with the history, classification, manufacturing, evaluation, fabrication, installation, and maintenance of materials and finishes. ● Identifying a broad range of materials and finishes, considering their aesthetic and performance properties, and understanding their utilization with regard to creative design intent, client expectations and requirements, user needs and experience, and incorporating life cycle implications. ● Providing a basis for achieving physical and psychological well-being for occupants, understanding the impact of changing social, cultural, economic, and ecological context, and eliminating negative environmental and social outcomes.https://newprairiepress.org/ebooks/1042/thumbnail.jp

The perceptual qualities of concrete : a change in paradigm

La recherche porte sur la perception de qualité des artefacts en béton, et ce depuis la perspective disciplinaire du design industriel. Afin de documenter et examiner les applications et perceptions contemporaines de ce matériau, nous nous attardons à l’évolution des technologies du béton en termes de recettes, techniques de mise en forme, usages, ainsi que ses différentes appréciations. Une revue de littérature a permis de formuler la problématique et d’organiser les données recueillies afin de répondre à nos questions de recherche. Ainsi, nous avons identifié certains événements marquants ayant provoqué des développements importants dans l’évolution du béton. De plus, nous avons regroupé plusieurs témoignages illustrant différentes perceptions du matériau dans des contextes d’usages variés. Les résultats de la recherche ont été interprétés en mettant de l’avant une méthodologie qualitative de recherche. Nous avons également étudié une sélection d’artéfacts en béton à travers des observations empiriques non participatives ainsi que deux cas sélectionnés. Cependant, ce type de recherche à la première personne est influencé par l’auteure, ses expériences vécues, son bagage culturel ainsi que son regard disciplinaire. Ainsi, il était important de valider ces observations teintées par l’appréciation de l’auteure, et ce en triangulant les données avec celles regroupées de documents historiques, scientifiques, techniques et médiatiques. Plusieurs méthodes et outils analytiques ont été mobilisés afin d’organiser les résultats de la recherche. Des cartes chronologiques nous ont permis d’isoler et d’illustrer les étapes déterminantes ayant affecté l’histoire du béton (i.e. la découverte du ciment Portland, etc.). À des catégorisations, nous avons pu classer et comparer certaines données plus spécifiques aux recettes et applications du matériau (i.e. les bétons primitifs – modernes, les bétons structuraux – non-structuraux, etc.). Des cartographiques sémantiques nous ont permis d’interpréter les témoignages compilés des différentes perceptions du béton et ce en se basant sur une échelle sémantique bipolaire (i.e. le béton est laid – beau, le béton est froid – chaud, etc.). Enfin, nous nous sommes basés sur le cadre d’expériences de produits et matériaux (product and material experiences framework) proposé par Desmet et Hekkert (2007) afin d’interpréter les appréciations des artéfacts en béton recueillis à travers la revue de littérature ainsi que les observations empiriques à la première personne. La recherche montre que la perception de qualité du béton fait face à un dualisme qui oppose ses avantages techno-économiques avec son impact environnemental ainsi que la détérioration prématurée de sa surface. Malgré l’appréciation générale de sa versatilité, accessibilité et performance technique, une prise de conscience collective semble rendre les acteurs plus conscients de l’empreinte écologique résultant du cycle de vie du béton. De plus, la recherche démontre que les idéologies sont en train d’évoluer vers des pratiques et modes de vies plus durables malgré les habitudes de surconsommation de la société moderne. En mettant moins l’emphase sur la perfection superficielle, les designers sont de plus en plus motivés à trouver inspiration dans des pratiques plus sensibles et résilientes afin de trouver des solutions durables face aux enjeux urbains. Les dernières tendances révèlent l’émergence d’alternatives plus éco-responsables et innovantes comparées au béton traditionnel. Ainsi, nous trouvons des recettes de béton plus écologiques (i.e. substitution du ciment Portland avec des produits dérivés d’autres industries, etc.) ou des techniques de mise en forme plus optimisées afin de réduire les pertes en offrant un langage esthétique surprenant (i.e. impression 3D, etc.). Ces technologies donnent naissance à de nouvelles applications du béton dans différents domaines inattendus en dehors de l’architecture et de l’ingénierie (i.e. design de produits, art, cinématographie, etc.). La recherche met en lumière changement de paradigme quant à la perception de qualité du béton qui semble être entrainé par la migration des idéologies sociétales vers un modèle qui trouve de la valeur et de la beauté dans les imperfections. Ainsi, des acteurs semblent de plus en plus apprécier le béton avec ses imperfections naturelles, et ont tendance à plus vouloir préserver les artéfacts vieillissants.The research investigates the quality perceptions of concrete artifacts from an industrial design standpoint. In order to document and examine how the material is being used and perceived nowadays, the study looks into the evolution of concrete technologies including its recipes, manufacturing techniques, and uses, as well as its appraisals. A literature review helped us understand the problem field and organize the data amassed in order to find answers to our research questions. We were thus able to identify the critical milestones that triggered change throughout concrete’s historical evolution, as well as gather different testimonies of its perceptions within various contexts. Qualitative research methods were used to interpret our findings. We validated the data based on selected cases as well as non-participatory empirical observations of urban concrete artifacts from a first-person view. This method is influenced by the author’s lived experiences, cultural background, and disciplinary gaze. Therefore, it was necessary to complement the author’s interpretation by triangulating the data retrieved with information gathered from historical, scientific, technical, and mediatic literature. The results were organized and analyzed using various analytical tools and methods. Timeline mappings were used to isolate and illustrate critical milestones triggering change and important developments (e.g. the discovery of Portland Cement, etc.). Categorizations helped us clarify and compare the data gathered to provide a more specific overview of concrete recipes and uses (e.g. primitive – modern concretes, structural – non-structural recipes, etc.). Semantic mappings allowed us to interpret the complied testimonies on how concrete artifacts are perceived in addition to helping us isolate semantic qualities within a bipolar semantic space (e.g. concrete is ugly – beautiful, concrete is cold – warm, etc.). Lastly, a product and material experiences framework (Desmet & Hekkert, 2007) was used to interpret concrete artifacts’ appraisals as found within the testimonies retrieved, in addition to the first-person empirical observations. The research revealed that concrete’s quality perception is facing a dualism which draws attention to its ecological footprint as well as its surface’s premature deterioration with time. Although many seem to appreciate the material’s versatility, accessibility, and structural performance, the dualism can be partially attributed to the evolving collective consciousness which makes actors more aware of concrete’s environmental impacts across its lifecycle. The study thus showed that, despite modern society’s production and consumption habits which focus on the superficial perfection of the material world, ideologies are seen to be evolving and are increasingly interested in more sustainable practices and lifestyles. This can help motivate designers to seek inspiration from emotionally-durable and resilient principles, thus allowing them to better address urban challenges. The latest trends revealed new concrete mixes (e.g. substitution of Portland Cement with by-products of other industries, etc.) and manufacturing techniques (e.g. 3D-printing, etc.) which can offer eco-friendly and innovative alternatives to traditional concrete productions. These emerging solutions are seen to pave the way for unexpected applications in various fields (e.g., product design, art, cinematography, etc.), thus attracting other disciplines beyond engineering and architecture. The changing paradigm in the perception of concrete artifacts shows that value and beauty are not always associated with superficial perfection. In fact, more and more actors are found to reject premature obsolescence by embracing materials’ natural and imperfect behavior as they age with time

Design for automated manufacture of composite structures

New trends in manufacturing highlight the growing use of composite materials to produce lightweight, high performance structures. This requires the design stage to account for complex manufacturing constraints, and as industry begins to move towards automated manufacturing of composites, the more complex manufacturing constraints can introduce severe limitations to the design space, reducing the opportunity for designers to optimise a product. To address these limitations, this research proposes strategies for implementing design for manufacture specifically accounting for automated manufacture of composite structures. As a composite design develops, more detail is added, increasing the design fidelity. Typically design for manufacturing practices are only applied when the design fidelity is detailed enough to see individual plies. However, by implementing design for manufacturing practice at earlier stages of the design, when the design fidelity is low and design change is easy to implement, the greatest performance and manufacturing gains can be achieved. This research aims to develop a design process that uses digital technology to facilitate design for automated manufacture for composite structures. This research uses a systematic approach to create a generic design process and supporting tools, capable of identifying the key manufacturing constraints, and accounting for them at the earliest possible stages of the design. The proposed design process uses a strategy to apply design for manufacture using digital tools, and identifies actions required to enable automated composite manufacturing. The development of the design process is guided by the capture of the current industrial design practices. The proposed process is validated through the design and manufacture of an industrial demonstration structure, produced using an automated composite manufacturing process. The results from validation confirm the hypothesis that it is possible to have a generic design process to support the design for automated manufacturing of composites components

Herstellung und Charakterisierung eines flexiblen kapazitiven Sensors für die Überwachung von kohlenfaservertärkten Polymeren

The following thesis deals with the modeling, development and technology of a miniaturized interdigital sensor on flexible substrates to measure the degree of curing during manufacturing of the carbon fiber reinforced plastics. The special feature of the sensor is a very thin flexible substrate. Despite the small thickness, the film of the polyimide has a very good mechanical, thermal and chemical stability. This reduces the foreign body effect and makes it possible to leave the sensor in the compound material for long term use. The FEM simulations are used to calculate the sensor capacitance in the air and the sensitivity of the sensors to different types. In the technological implementation, all microsystem technology processes are realized on SI wafers. At the end of the manufacturing process, the flexible sensor of the second generation can be peeled off back from the silicon substrate. After the sensor characterization with different media the sensors with isolated electrodes are embedded in to CFRP. During the curing process, the implemented interdigital sensors provide the necessary data for online process monitoring. The complete curing of the CFRP plate is confirmed by using differential scanning calorimetry analysis. To demonstrate the secondary use of the flexible interdigital sensor in the context of structural health monitoring is proved the water intake of the CFRP plate with integrated sensor

Inventory of repair and strengthening methods with iron and steel

This study aimed at producing a report (inventory) on stabilization / repair / strengthening materials, methods and technologies used for the structural restoration of structures including cast iron, wrought iron and steel members. A detailed literature survey was carried out by reading as much document as possible using different database including UPC library and after all the courses studied throughout this advanced master study it may be concluded that regardless of the technique decided to be applied in a restoration project, it is very important that any repair or strengthening must be based on a correct diagnosis of the problem by determining the real cause of the observed defects, and if the cause is still active by eliminating it. Otherwise the repairs will be short-lived. There is a parallel in the field of medicine: any treatment must be preceded by a correct diagnosis

Fabricate

Bringing together pioneers in design and making within architecture, construction, engineering, manufacturing, materials technology and computation, Fabricate is a triennial international conference, now in its third year (ICD, University of Stuttgart, April 2017). Each year it produces a supporting publication, to date the only one of its kind specialising in Digital Fabrication. The 2017 edition features 32 illustrated articles on built projects and works in progress from academia and practice, including contributions from leading practices such as Foster + Partners, Zaha Hadid Architects, Arup, and Ron Arad, and from world-renowned institutions including ICD Stuttgart, Harvard, Yale, MIT, Princeton University, The Bartlett School of Architecture (UCL) and the Architectural Association

Interface morphology in polylactic acid-sisal fibre composites

COPYRIGHT Attention is drawn to the fact that copyright of this thesis rests with its author. This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with its author and that no quotation from the thesis and no information derived from it may be published without the prior written consent of the author. This thesis may be made available for consultation within the University Library and may be photocopied or lent to other libraries for the purposes of consultation. i