Zu Beginn des Forschungsvorhabens wurden im Rahmen der Teilprojekte B1 und B2 des SFB 532 alkalibeständige Glas- und Carbonrovings eingesetzt, die zu offenmaschigen 2D-Textilien verarbeitet wurden. Untersuchungen des Verbund- und des Tragverhaltens der Verstärkungsstrukturen in Pull-Out- und Dehnkörperversuchen haben gezeigt, dass das Potential der Verstärkungsfasern aufgrund einer unvollständiger Durchtränkung der Bewehrung nicht vollständig ausgeschöpft werden kann. Auch Defizite bei der Produktionstechnik wurden erkannt und für zukünftige Entwicklungen analysiert. Um das Potential der verwendeten Verstärkungsfaser vollständiger auszuschöpfen, wurden innovative Garnkonstruktionen, die sich positiv auf den inneren und/oder den äußeren Verbund auswirken, entwickelt und erprobt. Anhand von Versuchsreihen auf der Textilebene wurden unterschiedliche Textilparameter, wie Art der Bindung, Gittergröße und Wirkfadenspannung, identifiziert, die unmittelbar die Tragfähigkeit der Verbundbauteile beeinflussen. Für die gängigen Produktionstechniken Laminieren, Gießen, Spritzen, Schleudern und Extrudieren wurden entsprechende Bewehrungskonstruktionen abgeleitet, die den Anforderungen des jeweiligen Prozess angepasst wurden. Ein weiterer Punkt der Forschungsaktivitäten stellte die Entwicklung der Maschinentechnik zur Herstellung von Verstärkungstextilien dar. Am Institut für Textiltechnik (ITA) der RWTH Aachen University wurde in Zusammenarbeit mit Industriepartnern ein Maschinenkonzept entwickelt und umgesetzt, das die Herstellung von 3D-Abstandsgewirken mit einer freien Gestaltung der Deckflächen mit marktrelevanten Produktionsgeschwindigkeiten ermöglicht. Zur gezielten Einstellung der Wirkfadenspannung wurde ein Regelungssystem konzipiert und technisch umgesetzt, mit dem eine reproduzierbare Fertigung von textilen Verstärkungsstrukturen möglich wird.

The task performed in this assignment is to improve the reliability of Norden Machinery ABs product family. This is to be done by examining and replacing the belt used to stop the spreading of tubes from ingoing shipping crate to the infeed of the machine. The way that this was approached was by testing different candidates on a spectrum of their rigidity to find if a flexible or more rigid belt would perform better than the current context of the system. The testing was conducted for a period of 4 weeks and results were gathered by examining damages to the belts by the use of microscope. After the damage had been analyzed the conclusion was drawn that flexible alternatives seems to perform the task better than their rigid counterparts however more work is needed in the fields regarding the fastening and operation of the machine to use the best suited candidates derived from this test, the monolithic belt FMT-02TXCT-U1.

This thesis presents an extension to Hyperledger Fabric, a private blockchain system, allowing historic transactions to be pruned without peer coordination. The feature is facilitated via pruning predicate functions, provided along any smart contracts a given system is desired to host. An evaluation of the extension demonstrates its impact, in terms of memory saved, for a specific asset delivery use case. It is concluded that the gains of pruning historic transactions from blockchain systems could yield significantly reduced storage requirements for some categories of applications, especially such with low transaction interdependency. It is also suggested that the deterministic consensus algorithms used by Hyperledger Fabric makes the transaction histories it may maintain not strictly required, meaning that the particular set of transactions that must survive pruning depend on what properties a blockchain is expected to maintain.

Grâce à leur géométrie spécifique, faite d’une superposition de couches unidirectionnelles de fibres continues, liées par des coutures plus ou moins complexes, les renforts NCF (Non-Crimp Fabric) possèdent une combinaison de propriétés intéressantes. Ces propriétés permettent l'utilisation de procédés de production tels que le procédé RTM (Resin Transfer Moulding) et permettent l’utilisation des caractéristiques de rigidité élevée des fibres dans la pièce finale. Ainsi, ces renforts trouvent des applications dans différents secteurs de l'industrie des composites et notamment en aéronautique. Les couches, formées de fibres parallèles juxtaposées, sont liées par différents types de coutures. Ce lien conduit à des propriétés différentes de celles observées sur un renfort tissé où les mèches de chaîne et de trame sont liées par entrelacement. Par conséquent, la cinématique de déformation des renforts NCF secs lors de la mise en forme peut être différente. Dans ce travail de recherche, nous menons d'abord une étude expérimentale sur les mécanismes de déformation se produisant lors de tests élémentaires et lors d’une expérience d’emboutissage. Plusieurs renforts NCF et un renfort interlock sont étudiés. Ensuite, nous introduisons un nouveau modèle pour la simulation de la mise en forme du renfort de composite NCF sec. Cette approche implique l’utilisation d’éléments finis lagrangien semi-discrets pour représenter les couches et d’éléments de barres pour représenter les coutures. Ce modèle nécessite un algorithme de contact spécifique pour gérer la relation entre les éléments finis. Une loi de frottement de Coulomb avec seuil de glissement est utilisée. Enfin, le modèle est validé par l’intermédiaire de l’essai de bias test puis la mise en forme sur un hémisphère est simulée et comparée à l'expérience. / Due to their specific geometry, made of overlapping layers of unidirectional plies of continuous fibres, linked by more or less complex stitching, non-crimp fabric (NCF) reinforcements have advantageous combination of properties. These properties enable the use of process in production such as RTM process and allow the full use of stiffness characteristics of the fibres in the final part. Thus, these reinforcements find applications in different areas of composites industry. The plies of juxtaposed parallel fibres are bound by a tricot or a chain stitching with a lead. This link leads to different properties of the NCF compared to those of a woven reinforcement where the warp and weft yarns are linked by the interweaving. Therefore, deformation kinematics of dry NCF reinforcements might be different. In this research work, we first carry out an experimental study on deformation mechanisms occurring during elementary tests and a drawing experiment. Several non-crimp fabrics and an interlock fabric are studied. Then, we introduce a new model for the simulation of the dry composite reinforcement preforming. This approach involves a semi discrete Lagrangian finite element to represent the plies and a truss element to represent the stitching. This model requires a specific contact algorithm to handle the relation between the finite elements. A Coulomb law with a friction threshold is used. Finally, the model is validated using the bias extension test and the preforming on a hemisphere is simulated and compared to the experiment.

The master thesis deals with mechanical design of device used for stretching and fixing filtration fabric on plastics frames segments for disc filtration device. The thesis was solved in cooperation with IN-EKO Team company that deals with development and manufacturing of filter units. Solution is connected to already ended project FR-T13/699 (end of the year 2013). At the beginning is described the field of filtration devices in broader context with description of the overall functionality these devices and description of used elements in final design. Opening text is followed by concretization of task list and descriptions of concepts variants which are based on FEM analysis of behavior of stretched filtration fabric. The best concept is processed in detail as mechanical design along with pneumatic and PLC control design. Critical part of the design is stretching clamp which was experimentally verified by using experimental clamp in combination with testing machine. The whole design is developed for mass production of disc segments for disc filter which is projected in to the level of the automation.

As the threat of supply-chain attacks grows, the need for techniques to protect software integrity likewise increases. The concept of reproducible builds is one such protection. By ensuring that a package can be rebuilt in the exact same way every time, reproducible builds allow users to notice when a package has changed even though its source code stays the same. Thus, the knowledge of which packages are reproducible and therefore easier to trust is a crucial part of this protection mechanism. Current strategies for validating and distributing this information rely on the work of a small number of individual entities with limited coordination in-between them, leading to user confusion because of the lack of a central authority. This work describes a protocol for decentralized coordination and validation of package reproducibility based on hidden votes to limit collusion and a reward scheme to ensure collaboration. The protocol uses the Hyperledger Fabric blockchain as supporting infrastructure, gaining the benefits of high availability, integrity of results and decision traceability from its decentralized nature. To test the protocol, a formal specification was written in TLA+ and validated through model checking. The results showed that, at least for the tested networks, the protocol produces valid results and enforces collaboration between users. Next steps for the project would be to build a functional prototype of the system to test its performance characteristics as well as studying the system actor assumptions made in the protocol design. / Likt hotet från leveranskedjeattacker har ökat, ökar även behoven av skyddstekniker för att säkerställa riktigheten hos mjukvara. Ett sådant typ av skydd ges av reproducerbara byggen. Om ett mjukvarupaket kan byggas exakt likadant varje gång så möjliggör det för användare att upptäcka om paketet har förändrats trots att dess källkod inte har gjort det. Att kunna veta vilka paket som är reproducerbara och därmed lättar att lita på är således en central del i denna skyddsmekanism. Nuvarande strategier för validering och distribution av sådan information bygger på arbete från ett fåtal individer och organisationer med begränsad koordinering däremellan. Detta leder till förvirring för användare på grund av bristen av en central tillitspunkt eller auktoritet. Detta arbete beskriver ett protokoll för decentralizerad koordinering och validering av paketreproducerbarhet baserat på hemliga röster för att begränsa otillåtet samarbete och ett belöningssystem för att motivera önskat samarbete. Protokollet använder blockkedjan Hyperledger Fabric som grund, med fördelarna av att få hög tillgänglighet, resultatsriktighet och spårbara beslut. En formel specifikation skrevs i TLA+ för att testa protokollet och validerades med modeltestning. Testresultatet för de testade nätverkskonfigurationerna visade att protokollet genererar valida resultat och garanterar samarbete mellan användare. De nästa stegen i projektet skulle vara att bygga en funktionell prototyp av systemet för att testa dess prestanda såväl som att studera de antaganden protokollet är designat runt.

Fabric Reinforced Cementitious Matrix (FRCM) composites utilize a mineral mortar matrix as a substitute for epoxy resin that is used for Fibre Reinforced Polymer (FRP). This eliminates issues associated with the low thermal compatibility of FRP with concrete, susceptibility to UV radiation, and sensitivity to high temperatures in which organic polymers undergo vitrification. This study discussed the effect of varying parameters like the number of Carbon-FRCM (C-FRCM) layers (1, 2 and 3 layers), different anchorage configurations (non-anchored, spike anchor, wrap anchor and mechanical anchor), bond length (300 or 200 mm), and the fabric type (unidirectional and bidirectional) on the direct shear behaviour of C-FRCM composites bonded to a concrete substrate, especially the fibre-matrix bond which is the most common debonding interface of FRCM composites. Calibrated models of the bond – slip behaviour are provided based on the fabric type and number of fabric layers. The results indicate that the anchor type and the overall composite thickness are the main factors that control the failure mode of the composite. All properly anchored specimens using spike and wrap anchors failed due to fabric rupture. Moreover, a considerable number of the non-anchored specimens failed due to composite-substrate debonding, although premature fabric rupture was frequently observed. Furthermore, specimens with bidirectional fabric demonstrated shallower penetration of the strain into the composite which may be due to the horizontal fabric strands providing some anchorage for the longitudinal strands. They also exhibited slip initiation at a higher stress compared to unidirectional specimens. In addition, slip initiation stress of unidirectional specimens decreased with more fabric layers which may indicate that the additional layers have a lower bond efficiency. For the same reason, specimens with three layers of fabric generally experienced deeper strain penetration into the composite than one-layered or two-layered specimens regardless of the anchor type. The results also indicate that the use of bidirectional fabric and anchorage systems decreases the strain penetration into the composite and correspondingly, the effective length is shortened. Surface strain measurements captured using digital image correlation generally did not match the internal fabric strain values obtained from strain gauges.

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Blockchain seems to be the hot new innovation that brings disruption to many different industries in the form of decentralization. Groups of peers can finally organize and work together without a central actor having an authority over the transactions that occur. Other than decentralization, due to the distributed and cryptographic nature of the data, the system also enjoys resilience, immutability and safety. In this thesis, we are leveraging permissioned blockchain technology to take steps towards a trustless service level agreement (SLA) management system where both service providers and customers lack the power to tamper with the contracts and their outcomes. The thesis yields a systematic literature review on the state-of-the-art within SLA management and relevant blockchain technology, a proof-of-concept working with Ericssons decentralized edge service marketplace, Nubo, and finally asimulation which evaluates how the proof-of-concept performs in terms of throughput and latency under different network loads. The simulation shows that the network works as expected, until 70 transactions per second (TPS) are reached, at which point the network is limited by throughput. / Blockchain ser ut att vara den nya teknologin som leder till stora förändringar i olika industrier i form av decentralisering. En grupp av noder kan till slut organisera sig och arbeta tillsammmans utan en central figur som styr och har kontroll över arbetet. Utöver decentralisering ger blockchain också fördelen av uthållighet, oföränderlighet och säkerhet till systemet tack vare sin kryptografiska grund. I den här studien utnyttjar vi privat blockchainteknologi för att ta steg mot en decentraliserad service level agreement (SLA) platform, där både tjänsteleverantörer och konsumenter saknar makten att manipulera kontrakt och dess resultat. Studien ger en systematisk literaturstudie på state-of-the-art inom SLA och relevant blockchain teknologi, ett bevis på koncept som fungerar tillsammans med Ericssons decentraliserade Nubo Service Marknad, och till slut en simulation som undersöker hur systemet reagerar i form av genomströmmning och responstid under olika nätverksbelastningar. Undersökningen visar att nätverket fungerar som förväntat upp till 70 transaktioner per sekund, då nätverket begränsas av genomströmning och köer bildas.

The underlying motives of the research undertaken here are twofold: to obtain a deeper understanding of the dewatering mechanisms at the forming section of a papermaking machine and to develop numerical models that describe the flow through forming fabrics. More comprehensive knowledge of dewatering in the forming section allows suggestions to be made for improvements that reduce the amount of energy used in the process without affecting the quality of the end product.   The objective of this thesis is to answer the following questions: How and why does rewetting occur at the high vacuum suction boxes? How does the structure of the forming fabric affect dewatering at the forming section? Is it possible to create accurate numerical models for forming fabrics, and can these be used to predict the dewatering behaviour of new types of fabrics?   Laboratory and pilot studies simulating high vacuum suction boxes were performed together with numerical modelling of the flow of air and water through both the forming fabric and the paper sheet.   The conclusion drawn from the pilot study is that rewetting significantly lowers the dryness of the paper sheet exiting the suction boxes. The phenomenon is extremely rapid and is most likely driven by capillary forces. The high speed at which this rewetting occurs makes it difficult to impede by placing the suction boxes closer to the couch pick-up: the solution is more likely to be the use of new and improved designs of the forming fabric. The structure of the forming fabric has been shown to affect the dewatering rate at certain conditions of vacuum dewatering, and can possibly be connected partly to the fact that fibres penetrate the surface of the fabric to varying degrees and partly to the flow resistance of the different fabric structures. Numerical models of high accuracy can be constructed and used to predetermine how new fabric designs would affect dewatering at the forming section.   This thesis quantifies aspects of dewatering such as rewetting and the influence of the forming fabric. Understanding these dewatering aspects further provides for the potential enhancement of energy efficiency in the forming section, and thereby the entire papermaking process. The forming fabric can play an important role in improving energy efficiency: rewetting after the high vacuum suction boxes occurs more rapidly than was previously known, so its design might be the only possible way of impeding it. The forming fabric can also improve the rate of dewatering: it is therefore likely that its design will be important in the next stage of developing energy efficiency and thereby play a part in achieving a more sustainable future. / This thesis quantifies aspects of dewatering such as rewetting and the influence of the forming fabric. Understanding these dewatering aspects further provides for the potential enhancement of energy efficiency in the forming section, and thereby the entire papermaking process. The forming fabric can play an important role in improving energy efficiency: rewetting after the high vacuum suction boxes occurs more rapidly than was previously known, so its design might be the only possible way of impeding it. The forming fabric can also improve the rate of dewatering: it is therefore likely that its design will be important in the next stage of developing energy efficiency and thereby play a part in achieving a more sustainable future.