TY - THES A1 - Danckwerth, Julia T1 - Strategien der Sichtbarkeit und Sichtbarmachung von ‚Wearable Enhancement‘ im Bereich Smart Health N2 - Die vorliegende Forschungsarbeit befasst sich mit der Entwicklung und Gestaltung von körpernahen, tragbaren Artefakten für den digitalisierten Gesundheitsbereich. Unter dem entwickelten Begriff des Wearable Enhancements werden die verschiedenen Termini aus smarten Textilien, Fashion Technologies, Wearable Technologies sowie elektronischen Textilien zusammengefasst und zwei zentrale Forschungsfragen untersucht. Wie kann Wearable Enhancement im Bereich Smart Health ethisch, sozial und ökologisch entwickelt und gestaltet werden? Inwiefern können textile Schnittstellen die Wahrnehmung und die Wahrnehmbarkeit des Körpers verändern? Mit der ersten Forschungsfrage sollen vorrangig Ansätze und Strategien der Sichtbarkeit für die Entwicklung und Gestaltung diskutiert werden, welche Aussagen für die Designpraxis, den Gestaltungs- und Designforschungsprozess sowie die Designlösungen selbst generieren sollen. Die zweite Forschungsfrage zielt darauf, Formen der Sichtbarmachung von sowie für Wearable Enhancement zu untersuchen. Anhand von drei konkreten Fallstudien werden wesentliche Aspekte der Rezeption, Perzeption, Konstruktion, Konfiguration und Konzeption von soziotechnischen Artefakten zur Funktionssteigerung des menschlichen Körpers untersucht und verschiedene Formen der Sichtbarkeit und Sichtbarmachung entwickelt. In der Arbeit wird ein dual-angelegter transdisziplinärer Designforschungsansatz entwickelt und praktiziert, welcher sowohl die menschlichen Bedürfnisse der Nutzer*innen als auch die Weiterentwicklung von Technologien berücksichtigt. Auf dieser Grundlage wird versucht Anregungen für ein zukunftsfähiges und zugleich verantwortungsorientiertes Design zu geben. KW - Design KW - Wearable Computing KW - Künstlerische Forschung KW - Digital Health KW - Smart Health KW - Smart Textiles KW - Designforschung KW - Wearable Technology Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220202-45768 ER - TY - THES A1 - Pacheco Alvim, Sarah T1 - Falsa Seringueira: Rubber Trees and the Materiality of the Unseen N2 - The theme of this project is the colonial history of the natural rubber industry. It focuses on two species of tropical plants: Ficus elastica and Hevea brasiliensis. Geographically their native habitat is very distant from each other, but they connect by European influence through the exploitation of latex. The many forms and outcomes from this work manifest the attempt of the artist to create an association between a common household plant, the origin of its name, and the source of rubber. As a ghostly connective tissue, the latex surrounds reconstructed history, old prints, live plants, and drawings, accepting the material's capacity to both erase and preserve the past. KW - Kautschuk KW - Gummi KW - Kolonialismus KW - Kunst KW - Geschichte KW - art installation KW - colonialism KW - history KW - natural latex KW - rubber industry Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230105-48467 ER - TY - THES A1 - López Zermeño, Jorge Alberto T1 - Isogeometric and CAD-based methods for shape and topology optimization: Sensitivity analysis, Bézier elements and phase-field approaches N2 - The Finite Element Method (FEM) is widely used in engineering for solving Partial Differential Equations (PDEs) over complex geometries. To this end, it is required to provide the FEM software with a geometric model that is typically constructed in a Computer-Aided Design (CAD) software. However, FEM and CAD use different approaches for the mathematical description of the geometry. Thus, it is required to generate a mesh, which is suitable for FEM, based on the CAD model. Nonetheless, this procedure is not a trivial task and it can be time consuming. This issue becomes more significant for solving shape and topology optimization problems, which consist in evolving the geometry iteratively. Therefore, the computational cost associated to the mesh generation process is increased exponentially for this type of applications. The main goal of this work is to investigate the integration of CAD and CAE in shape and topology optimization. To this end, numerical tools that close the gap between design and analysis are presented. The specific objectives of this work are listed below: • Automatize the sensitivity analysis in an isogeometric framework for applications in shape optimization. Applications for linear elasticity are considered. • A methodology is developed for providing a direct link between the CAD model and the analysis mesh. In consequence, the sensitivity analysis can be performed in terms of the design variables located in the design model. • The last objective is to develop an isogeometric method for shape and topological optimization. This method should take advantage of using Non-Uniform Rational B-Splines (NURBS) with higher continuity as basis functions. Isogeometric Analysis (IGA) is a framework designed to integrate the design and analysis in engineering problems. The fundamental idea of IGA is to use the same basis functions for modeling the geometry, usually NURBS, for the approximation of the solution fields. The advantage of integrating design and analysis is two-fold. First, the analysis stage is more accurate since the system of PDEs is not solved using an approximated geometry, but the exact CAD model. Moreover, providing a direct link between the design and analysis discretizations makes possible the implementation of efficient sensitivity analysis methods. Second, the computational time is significantly reduced because the mesh generation process can be avoided. Sensitivity analysis is essential for solving optimization problems when gradient-based optimization algorithms are employed. Automatic differentiation can compute exact gradients, automatically by tracking the algebraic operations performed on the design variables. For the automation of the sensitivity analysis, an isogeometric framework is used. Here, the analysis mesh is obtained after carrying out successive refinements, while retaining the coarse geometry for the domain design. An automatic differentiation (AD) toolbox is used to perform the sensitivity analysis. The AD toolbox takes the code for computing the objective and constraint functions as input. Then, using a source code transformation approach, it outputs a code for computing the objective and constraint functions, and their sensitivities as well. The sensitivities obtained from the sensitivity propagation method are compared with analytical sensitivities, which are computed using a full isogeometric approach. The computational efficiency of AD is comparable to that of analytical sensitivities. However, the memory requirements are larger for AD. Therefore, AD is preferable if the memory requirements are satisfied. Automatic sensitivity analysis demonstrates its practicality since it simplifies the work of engineers and designers. Complex geometries with sharp edges and/or holes cannot easily be described with NURBS. One solution is the use of unstructured meshes. Simplex-elements (triangles and tetrahedra for two and three dimensions respectively) are particularly useful since they can automatically parameterize a wide variety of domains. In this regard, unstructured Bézier elements, commonly used in CAD, can be employed for the exact modelling of CAD boundary representations. In two dimensions, the domain enclosed by NURBS curves is parameterized with Bézier triangles. To describe exactly the boundary of a two-dimensional CAD model, the continuity of a NURBS boundary representation is reduced to C^0. Then, the control points are used to generate a triangulation such that the boundary of the domain is identical to the initial CAD boundary representation. Thus, a direct link between the design and analysis discretizations is provided and the sensitivities can be propagated to the design domain. In three dimensions, the initial CAD boundary representation is given as a collection of NURBS surfaces that enclose a volume. Using a mesh generator (Gmsh), a tetrahedral mesh is obtained. The original surface is reconstructed by modifying the location of the control points of the tetrahedral mesh using Bézier tetrahedral elements and a point inversion algorithm. This method offers the possibility of computing the sensitivity analysis using the analysis mesh. Then, the sensitivities can be propagated into the design discretization. To reuse the mesh originally generated, a moving Bézier tetrahedral mesh approach was implemented. A gradient-based optimization algorithm is employed together with a sensitivity propagation procedure for the shape optimization cases. The proposed shape optimization approaches are used to solve some standard benchmark problems in structural mechanics. The results obtained show that the proposed approach can compute accurate gradients and evolve the geometry towards optimal solutions. In three dimensions, the moving mesh approach results in faster convergence in terms of computational time and avoids remeshing at each optimization step. For considering topological changes in a CAD-based framework, an isogeometric phase-field based shape and topology optimization is developed. In this case, the diffuse interface of a phase-field variable over a design domain implicitly describes the boundaries of the geometry. The design variables are the local values of the phase-field variable. The descent direction to minimize the objective function is found by using the sensitivities of the objective function with respect to the design variables. The evolution of the phase-field is determined by solving the time dependent Allen-Cahn equation. Especially for topology optimization problems that require C^1 continuity, such as for flexoelectric structures, the isogeometric phase field method is of great advantage. NURBS can achieve the desired continuity more efficiently than the traditional employed functions. The robustness of the method is demonstrated when applied to different geometries, boundary conditions, and material configurations. The applications illustrate that compared to piezoelectricity, the electrical performance of flexoelectric microbeams is larger under bending. In contrast, the electrical power for a structure under compression becomes larger with piezoelectricity. T3 - ISM-Bericht // Institut für Strukturmechanik, Bauhaus-Universität Weimar - 2022,4 KW - CAD KW - Gestaltoptimierung KW - Topologieoptimierung KW - Isogeometrische Analyse KW - Finite-Elemente-Methode KW - Computer-Aided Design KW - Shape Optimization KW - Topology Optimization KW - Isogeometric Analysis KW - Finite Element Method Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220831-47102 ER - TY - THES A1 - Mojahedin, Arvin T1 - Analysis of Functionally Graded Porous Materials Using Deep Energy Method and Analytical Solution N2 - Porous materials are an emerging branch of engineering materials that are composed of two elements: One element is a solid (matrix), and the other element is either liquid or gas. Pores can be distributed within the solid matrix of porous materials with different shapes and sizes. In addition, porous materials are lightweight, and flexible, and have higher resistance to crack propagation and specific thermal, mechanical, and magnetic properties. These properties are necessary for manufacturing engineering structures such as beams and other engineering structures. These materials are widely used in solid mechanics and are considered a good replacement for classical materials by many researchers recently. Producing lightweight materials has been developed because of the possibility of exploiting the properties of these materials. Various types of porous material are generated naturally or artificially for a specific application such as bones and foams. Like functionally graded materials, pore distribution patterns can be uniform or non-uniform. Biot’s theory is a well-developed theory to study the behavior of poroelastic materials which investigates the interaction between fluid and solid phases of a fluid-saturated porous medium. Functionally graded porous materials (FGPM) are widely used in modern industries, such as aerospace, automotive, and biomechanics. These advanced materials have some specific properties compared to materials with a classic structure. They are extremely light, while they have specific strength in mechanical and high-temperature environments. FGPMs are characterized by a gradual variation of material parameters over the volume. Although these materials can be made naturally, it is possible to design and manufacture them for a specific application. Therefore, many studies have been done to analyze the mechanical and thermal properties of FGPM structures, especially beams. Biot was the pioneer in formulating the linear elasticity and thermoelasticity equations of porous material. Since then, Biot's formulation has been developed in continuum mechanics which is named poroelasticity. There are obstacles to analyzing the behavior of these materials accurately like the shape of the pores, the distribution of pores in the material, and the behavior of the fluid (or gas) that saturated pores. Indeed, most of the engineering structures made of FGPM have nonlinear governing equations. Therefore, it is difficult to study engineering structures by solving these complicated equations. The main purpose of this dissertation is to analyze porous materials in engineering structures. For this purpose, the complex equations of porous materials have been simplified and applied to engineering problems so that the effect of all parameters of porous materials on the behavior of engineering structure has been investigated. The effect of important parameters of porous materials on beam behavior including pores compressibility, porosity distribution, thermal expansion of fluid within pores, the interaction of stresses between pores and material matrix due to temperature increase, effects of pore size, material thickness, and saturated pores with fluid and unsaturated conditions are investigated. Two methods, the deep energy method, and the exact solution have been used to reduce the problem hypotheses, increase accuracy, increase processing speed, and apply these in engineering structures. In both methods, they are analyzed nonlinear and complex equations of porous materials. To increase the accuracy of analysis and study of the effect of shear forces, Timoshenko and Reddy's beam theories have been used. Also, neural networks such as residual and fully connected networks are designed to have high accuracy and less processing time than other computational methods. T3 - ISM-Bericht // Institut für Strukturmechanik, Bauhaus-Universität Weimar - 2022,12 KW - Poröser Stoff KW - Analytische Lösung KW - Porous Materials KW - Deep Energy Method KW - Analytical Solution KW - Functionally Graded Materials Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20221220-48674 ER - TY - JOUR A1 - Hahlbrock, David A1 - Braun, Michael A1 - Heidel, Robin A1 - Lemmen, Patrik A1 - Boumann, Roland A1 - Bruckmann, Tobias A1 - Schramm, Dieter A1 - Helm, Volker A1 - Willmann, Jan T1 - Cable Robotic 3D-printing: additive manufacturing on the construction site JF - Construction Robotics N2 - This paper outlines an important step in characterizing a novel field of robotic construction research where a cable-driven parallel robot is used to extrude cementitious material in three-dimensional space, and thus offering a comprehensive new approach to computational design and construction, and to robotic fabrication at larger scales. Developed by the Faculty of Art and Design at Bauhaus-University Weimar (Germany), the faculty of Architecture at the University of Applied Sciences Dortmund (Germany) and the Chair of Mechatronics at the University of Duisburg-Essen (Germany), this approach offers unique advantages over existing additive manufacturing methods: the system is easily transportable and scalable, it does not require additional formwork or scaffolding, and it offers digital integration and informational oversight across the entire design and building process. This paper considers 1) key research components of cable robotic 3D-printing (such as computational design, material exploration, and robotic control), and 2) the integration of these parameters into a unified design and building process. The demonstration of the approach at full-scale is of particular concern. KW - Robotik KW - Automation KW - 3D-Printing KW - Cable-driven parallel robots Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230124-48791 UR - https://link.springer.com/article/10.1007/s41693-022-00082-3 VL - 2022 SP - 1 EP - 14 PB - Springer International Publishing CY - Cham ER - TY - JOUR A1 - Coenen, Ekkehard T1 - Communicative Action, Objectifications, and the Triad of Violence JF - Human Studies N2 - This article aims to develop a social theory of violence that emphasizes the role of the third party as well as the communication between the involved subjects. For this Teresa Koloma Beck’s essay ‘The Eye of the Beholder: Violence as a Social Process’ is taken as a starting point, which adopts a social-constructivist perspective. On the one hand, the basic concepts and the benefits of this approach are presented. On the other hand, social-theoretical problems of this approach are revealed. These deficits are counteracted by expanding Koloma Beck’s approach with a communicative-constructivist framework. Thus, the role of communicative action and the ‘objectification of violence’ is emphasized. These aspects impact the perception, judgement and (de-)legitimation of violence phenomena and the emergence of a ‘knowledge of violence’. Communicative actions and objectifications form a key to understanding violent interactions and the link between the micro and macro levels. Finally, the methodological consequences for the research of violence and Communicative Constructivism are discussed. Furthermore, possible research fields are outlined, which open up by looking at communicative action and the objectifications within the ‘triads of violence’. KW - Gewalt KW - Soziologie KW - violence KW - social theory KW - communicative action KW - triad of violence Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230124-48828 UR - https://link.springer.com/article/10.1007/s10746-022-09639-1 VL - 2022 IS - 45 (2022) SP - 447 EP - 468 PB - Springer Science + Business Media B.V CY - Dordrecht ER - TY - JOUR A1 - Stadler, Max T1 - Gründerzeit. Hightech und Alternativen der Wissenschaft in West-Berlin JF - NTM Zeitschrift für Geschichte der Wissenschaften, Technik und Medizin N2 - Zu den diversen Unternehmungen sozialbewegter „Gegenwissenschaft“, die um 1980 auf der Bildfläche der BRD erschienen, zählte der 1982 gegründete Berliner Wissenschaftsladen e. V., kurz WILAB – eine Art „alternatives“ Spin-off der Technischen Universität Berlin. Der vorliegende Beitrag situiert die Ausgründung des „Ladens“ im Kontext zeitgenössischer Fortschritte der (regionalen) Forschungs- und Technologiepolitik. Gezeigt wird, wie der deindustrialisierenden Inselstadt, qua „innovationspolitischer“ Gegensteuerung, dabei sogar eine gewisse Vorreiterrolle zukam: über die Stadtgrenzen hinaus sichtbare Neuerungen wie die Gründermesse BIG TECH oder das 1983 eröffnete Berliner Innovations- und Gründerzentrum (BIG), der erste „Incubator“ [sic] der BRD, etwa gingen auf das Konto der 1977/78 lancierten Technologie-Transferstelle der TU Berlin, TU-transfer. Anders gesagt: tendenziell bekam man es hier nun mit Verhältnissen zu tun, die immer weniger mit den Träumen einer „kritischen“, nicht-fremdbestimmten (Gegen‑)Wissenschaft kompatibel waren. Latent konträr zur historiographischen Prominenz des wissenschaftskritischen Zeitgeists fristeten „alternativen“ Zielsetzungen verpflichtete Unternehmungen wie „WILAB“ ein relativ marginalisiertes Nischendasein. Dennoch wirft das am WILAB verfolgte, so gesehen wenig aussichtsreiche Anliegen, eine andere, nämlich „humanere“ Informationstechnologie in die Wege zu leiten, ein instruktives Licht auf die Aufbrüche „unternehmerischer“ Wissenschaft in der BRD um 1980. KW - Berlin KW - Wissenschaftspolitik KW - Gegenwissenschaft KW - Gegenwissen KW - Informatik KW - Strukturkrise Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230124-48800 UR - https://link.springer.com/article/10.1007/s00048-022-00352-9 VL - 2022 IS - 30 (2022) SP - 599 EP - 632 PB - Basel CY - Birkhäuser ER - TY - CHAP A1 - Dokhanchi, Najmeh Sadat ED - Arnold, Jörg T1 - Acoustic travel time tomography: Applicability of an array of directional sound sources N2 - The technique of Acoustic travel-time TOMography (ATOM) allows for measuring the distribution of air temperatures throughout the entire room based on the determined sound-travel-times of early reflections, currently up to second order reflections. The number of detected early reflections in the room impulse response (RIR) which stands for the desired sound paths inside the room, has a significant impact on the resolution of reconstructed temperatures. This study investigates the possibility of utilizing an array of directional sound sources for ATOM measurements instead of a single omnidirectional loudspeaker used in the previous studies [1–3]. The developed measurement setup consists of two directional sound sources placed near the edge of the floor in the climate chamber of the Bauhaus-University Weimar and one omnidirectional receiver at center of the room near the ceiling. In order to compensate for the reduced number of sound paths when using directional sound sources, it is proposed to take high-energy early reflections up to third order into account. For this purpose, the simulated travel times up to third-order image sources were implemented in the image source model (ISM) algorithm, by which these early reflections can be detected effectively for air temperature reconstructions. To minimize the uncertainties of travel-times estimation due to the positioning of the sound transducers inside the room, measurements were conducted to determine the exact emitting point of the utilized sound source i.e. its acoustic center (AC). For these measurements, three types of excitation signals (MLS, linear and logarithmic chirp signals) with various frequency ranges were used considering that the acoustic center of a sound source is a frequency dependent parameter [4]. Furthermore, measurements were conducted to determine an optimum excitation signal based on the given condition of the ATOM measurement set-up which defines an optimum method for the RIR estimation correspondingly. Finally, the uncertainty of the measuring system utilizing an array of directional sound sources was analyzed. KW - Bauphysik KW - Akustische Laufzeit-Tomographie KW - Acoustic Travel-Time Tomography KW - Bauklimatik Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220622-46589 UR - https://www.dega-akustik.de/publikationen/online-proceedings N1 - This conference paper has been submitted to the DAGA 2022. Thus, the original paper first is published in the "Fortschritte der Akustik - DAGA 2022" ER - TY - THES A1 - Argañaraz, Cecilia Magdalena T1 - Tiempos imaginados y espacios áridos: controversias en torno al agua en el Valle de Catamarca (siglos XIX-XX) N2 - The thesis addresses journalistic, administrative and judicial historical documentation to analyze the links between aridity and geographical imaginaries in the province of Catamarca (Argentina), from a historical point of view. The research aims to contribute to the understanding of the "non-hegemonic" versions of Modernity, its territoriality and the productions of geographic imaginaries that they involve. To provide a broad purpose, it raises as an object of study the ways in which "modern" practices, actors, links, discourses and expectations about the territory are mobilized when they are located in a space in "other" water conditions. those that are intended to "civilize" it. The general objective of the research is to analyze time-space controversies around water in the city and valley of Catamarca towards 19th and 20th centuries. The specific objectives derived are a) analyzing how various actors are related to waters behavior - in other words, the local water regime – in Catamarca and the meanings built around it. b) to analyze the controversies about the place of Catamarca and its water regime in the local and national geographic imaginary. c) analyze controversies in which the relationships between actors and materialities involved in modernization projects are put into discussion. These concerns by the experience of the actors and by the historical-spatial imagination of the territory, combined, led to the construction of an interdisciplinary methodology based on tools from anthropology, sociology, geography and history. KW - Anthologie KW - Geschichte KW - Umweltforschung KW - Stadtforschung KW - ANTROPOLOGÍA KW - HISTORIA KW - ECOLOGÍA POLÍTICA KW - ESTUDIOS URBANOS KW - HISTORIA AMBIENTAL KW - Anthology KW - History KW - Political ecology KW - urban studies KW - Environmental studies Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220803-46817 ER - TY - THES A1 - Miller, Martin T1 - BIM-basierte Digitalisierung von Bestandsgebäuden aus Sicht des FM am Beispiel von Heizungsanlagen N2 - Das Ziel der Arbeit ist, für das Facility Management relevante Informationen für die mit Building Information Modeling basierende Erstellung von Bestandsgebäuden am Beispiel einer Hei- zungsanlage zu definieren. Darauf basierend sind die notwendigen Arbeitsschritte der Objek- taufnahme abgeleitet. Für die Definition der Arbeitsschritte wurden das grundlegende Vorge- hen bei einer Objektaufnahme sowie die gesetzlichen Gegebenheiten für den Betrieb einer Heizungsanlage dargelegt. Darüber hinaus sind in der vorliegenden Ausarbeitung die Vorteile und Herausforderungen hinsichtlich des Zusammenspiels von Building Information Modeling und Facility Management analysiert. Die definierten Arbeitsschritte sind anhand eines Beispiel- projektes angewendet worden. Im Rahmen des Beispielprojekts sind die entscheidenden Be- triebsdaten je Anlagenteil in Form von Informationsanforderungen nach DIN 17412 definiert. Das Gebäudemodell ist durch Parameter mit den für das Facility Management relevanten In- formationen ergänzt. Die Resultate des Beispielprojektes sind mit aussagekräftigen Schnitten, Plänen sowie 3-D-Visualisierungen dargestellt. Abschließend sind die Ergebnisse in Bezug auf das FM validiert. Aus den Arbeitsschritten und Ergebnissen ist eine Leitlinie erstellt worden für den Digitalisierungsprozess von Bestandsgebäuden für das Facility Management. KW - Facility Management KW - BIM Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220623-46616 ER - TY - THES A1 - Drescher, Marcel T1 - Open Innovation in KMU - Eine empirische Analyse der offenen Innovationsaktivitäten im Kontext der Entrepreneurial Orientation N2 - Open Innovation in kleinen und mittleren Unternehmen (KMU) hat sich stark ausdifferenziert. Dabei zeigt die Empirie, dass KMU unterschiedliche Wege in der offenen Entwicklung von Innovationen begehen. Um die bestehende Literatur zu erweitern, wurden mit dieser Dissertation die Ziele verfolgt 1) offene Innovationsaktivitäten in KMU aus einer Prozessperspektive aufzudecken und genau zu beschreiben und 2) zu erklären, warum sich die Öffnung von Innovationsprozessen in KMU unterscheidet. Dafür wurde auf eine multiple Fallstudienanalyse zurückgegriffen. Untersuchungsobjekte waren kleine etablierte High-Tech Unternehmen aus den neuen Bundesländern. Die Ergebnisse zeigen sechs Prozessmodelle der offenen Innovationsentwicklung, beschrieben als Open Innovation Muster. Deskriptionen dieser Muster unter Berücksichtigung von formenden Innovationsaktivitäten, ausgetauschtem Wissen, beteiligten externen Akteuren und Gründen für und gegen Open Innovation vermitteln ein über den bisherigen Forschungsstand hinausgehendes Verständnis von Open Innovation in KMU. Zudem zeigen die Ergebnisse, dass die Entrepreneurial Orientation erklärt, warum KMU bei der Ausgestaltung von offenen Innovationsprozessen unterschiedlich vorgehen. In der Dissertation wird detailliert dargelegt, welche Open Innovation Muster sich anhand der Entrepreneurial Orientation von KMU (nicht-entrepreneurial bis entrepreneurial) zeigen. Die Ergebnisse liefern sowohl wissenschaftliche Implikationen, als auch Handlungsempfehlungen für die Unternehmenspraxis. KW - Open Innovation KW - Innovationsmanagement KW - Entrepreneurship KW - Klein- und Mittelbetrieb KW - KMU KW - Entrepreneurial Orientation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20230314-49463 ER - TY - CHAP A1 - Kiesel, Gerd A1 - Engels, Merit A1 - Völker, Conrad ED - Kornadt, Oliver ED - Carrigan, Svenja ED - Hofmann, Markus ED - Völker, Conrad T1 - Energetische Transformation im ländlichen Raum – Aufbau eines prozessorientierten Entwicklungs- und Moderationsmodells T2 - Schriftenreihe des Fachgebiets Bauphysik/Energetische Gebäudeoptimierung N2 - Kleine Kommunen im ländlichen Raum sind aufgrund ihrer oft eingeschränkten personellen und finanziellen Kapazitäten bisher eher sporadisch in den Themenfeldern Energieeffizienz und Erneuerbare Energien aktiv. Immer wieder stellt sich daher Frage, wie die Klimaschutzstrategien des Bundes und der Länder dort mit dem verfügbaren Personal kostengünstig realisierbar sind. Vor diesem Hintergrund wird ein Werkzeug entwickelt, mit dessen Hilfe der aktive Einstieg in diese Thematik mit geringen Aufwand und überwiegend barrierefrei möglich ist. Der Aufbau eines prozessorientierten Entwicklungs- und Moderationsmodells zur Erprobung und Umsetzung bezahlbarer Handlungsoptionen für Energieeinsparungen und effizienten Energieeinsatz im überwiegend ländlichen geprägten Raum ist der Schwerpunkt der Softwarelösung. Kommunen werden mit deren Hilfe in die Lage versetzt, in die notwendigen Prozesse der Energie- und Wärmewende einzusteigen. Dabei soll der modulare Aufbau die regulären Schritte notwendiger (integrierter) Planungsprozesse nicht vollständig ersetzen. Vielmehr können innerhalb der Online-Anwendung - überwiegend automatisiert - konkrete Maßnahmenvorschläge erstellt werden, die ein solides Fundament der künftigen energetischen Entwicklung der Kommunen darstellen. Für eine gezielte Validierung der Ergebnisse und der Ableitung potentieller Maßnahmen werden für die Erprobung Modellkommunen in Thüringen, Bayern und Hessen als Reallabore einbezogen. Das Tool steht bisher zunächst nur den beteiligten Modellkommunen zur Verfügung. Die entwickelte Softwarelösung soll künftig Schritt für Schritt allen interessierten Kommunen mit diversen Hilfsmitteln und einer Vielzahl anderer praktischer Bestandteile zur Verfügung gestellt werden. KW - Modellierung KW - Kommune KW - Energiewende KW - Transformation KW - ländlicher Raum Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220617-46566 SN - 978-3-95974-176-7 SN - 2363-8206 PB - Eigenverlag Technische Universität Kaiserslautern CY - Kaiserslautern ER - TY - JOUR A1 - Artus, Mathias A1 - Koch, Christian T1 - Object-Oriented Damage Information Modeling Concepts and Implementation for Bridge Inspection JF - Journal of Computing in Civil Engineering N2 - Bridges are designed to last for more than 50 years and consume up to 50% of their life-cycle costs during their operation phase. Several inspections and assessment actions are executed during this period. Bridge and damage information must be gathered, digitized, and exchanged between different stakeholders. Currently, the inspection and assessment practices rely on paper-based data collection and exchange, which is time-consuming and error-prone, and leads to loss of information. Storing and exchanging damage and building information in a digital format may lower costs and errors during inspection and assessment and support future needs, for example, immediate simulations regarding performance assessment, automated maintenance planning, and mixed reality inspections. This study focused on the concept for modeling damage information to support bridge reviews and structural analysis. Starting from the definition of multiple use cases and related requirements, the data model for damage information is defined independently from the subsequent implementation. In the next step, the implementation via an established standard is explained. Functional tests aim to identify problems in the concept and implementation. To show the capability of the final model, two example use cases are illustrated: the inspection review of the entire bridge and a finite-element analysis of a single component. Main results are the definition of necessary damage data, an object-oriented damage model, which supports multiple use cases, and the implementation of the model in a standard. Furthermore, the tests have shown that the standard is suitable to deliver damage information; however, several software programs lack proper implementation of the standard. KW - Building Information Modeling KW - Brücke KW - Inspektion KW - Produktdaten KW - Objektorientierung KW - Building Information Modeling KW - Bridge KW - Inspection KW - Damage Information Modeling KW - Damage Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220826-47087 UR - https://ascelibrary.org/doi/10.1061/%28ASCE%29CP.1943-5487.0001030 VL - 2022 IS - Volume 36, issue 6 SP - 1 EP - 21 ER - TY - THES A1 - Riechert, Christin T1 - Hydratation und Eigenschaften von Gips-Zement-Puzzolan-Bindemitteln mit alumosilikatischen Puzzolanen N2 - Reine Calciumsulfatbindemittel weisen eine hohe Löslichkeit auf. Feuchteinwirkung führt zudem zu starken Festigkeitsverlusten. Aus diesem Grund werden diese Bindemittel ausschließlich für Baustoffe und -produkte im Innenbereich ohne permanenten Feuchtebeanspruchung eingesetzt. Eine Möglichkeit, die Feuchtebeständigkeit zu erhöhen, ist die Beimischung puzzolanischer und zementärer Komponenten. Diese Mischsysteme werden Gips-Zement-Puzzolan-Bindemittel (kurz: GZPB) genannt. Mischungen aus Calciumsulfaten und Portlandzementen allein sind aufgrund der treibenden Ettringitbildung nicht raumbeständig. Durch die Zugabe von puzzolanischen Stoffen können aber Bedingungen im hydratisierenden System geschaffen werden, welche eine rissfreie Erhärtung ermöglichen. Hierfür ist eine exakte Rezeptierung der GZPB notwendig, um die GZPB-typischen, ettringitbedingten Dehnungen zeitlich zu begrenzen. Insbesondere bei alumosilikatischen Puzzolanen treten während der Hydratation gegenüber rein silikatischen Puzzolanen deutlich höhere Expansionen auf, wodurch die Gefahr einer potenziellen Rissbildung steigt. Für die Erstellung geeigneter GZPB-Zusammensetzungen bedarf es daher einer Methodik, um raumbeständig erhärtende Systeme sicher von destruktiven Mischungen unterscheiden zu können. Sowohl für die Rezeptierung als auch für die Anwendung der GZPB existieren in Deutschland keinerlei Normen. Darüber hinaus sind die Hydratationsvorgänge sowie die entstehenden Produkte nicht konsistent beschrieben. Auch auf die Besonderheiten der GZPB mit alumosilikatischen Puzzolanen wird in der Literatur nur unzureichend eingegangen. Ziel war es daher, ein grundlegendes Verständnis der Hydratation sowie eine sichere Methodik zur Rezeptierung raumbeständig und rissfrei erhärtender GZPB, insbesondere in Hinblick auf die Verwendung alumosilikatischer Puzzolane, zu erarbeiten. Darüber hinaus sollte systematisch der Einfluss der Einzelkomponenten auf Hydratation und Eigenschaften dieser Bindemittelsysteme untersucht werden. Dies soll ermöglichen, die GZPB für ein breites Anwendungsspektrum als Bindemittel zu etablieren, und somit vorteilhafte Eigenschaften der Calciumsulfate (geringe Schwindneigung, geringe CO2-Emission etc.) mit der Leistungs-fähigkeit von Zementen (Wasserbeständigkeit, Festigkeit, Dauerhaftigkeit etc.) zu verbinden. Als Ausgangsstoffe der Untersuchungen zu den GZPB wurden Stuckgips und Alpha-Halbhydrat als Calciumsulfatbindemittel in unterschiedlichen Anteilen im GZPB verwendet. Die Puzzolan-Zement-Verhältnisse wurden ebenfalls variiert. Als Puzzolan kam für den Großteil der Untersuchungen ein alumosilikatisches Metakaolin zum Einsatz. Als kalkspendende Komponente diente ein reiner Portlandzement. Das Untersuchungsprogramm gliederte sich in 4 Teile. Zuerst wurde anhand von CaO- und pH-Wert-Messungen in Suspensionen sowie dem Längenänderungsverhalten von Bindemittelleimen verschiedener Zusammensetzungen eine Vorauswahl geeigneter GZPB-Rezepturen ermittelt. Danach erfolgten, ebenfalls an Bindemittelleimen, Untersuchungen zu den Eigenschaften der als geeignet eingeschätzten GZPB-Mischungen. Hierzu zählten Langzeitbetrachtungen zur rissfreien Erhärtung bei unterschiedlichen Umgebungsbedingungen sowie die Festigkeitsentwicklung im trockenen und feuchten Zustand. Im nächsten Schritt wurde anhand zweier exemplarischer GZPB-Zusammensetzungen (mit silikatischen und alumosilikatischen Puzzolan) die prinzipiell mögliche Phasenzusammensetzung unter Variation des Puzzolan-Zement-Verhältnisses (P/Z-Verhältnis) und des Calciumsulfatanteils im thermodynamischen Gleichgewichtszustand berechnet. Hier wurde im Besonderen auf Unterschiede der silikatischen und alumosilikatischen Puzzolane eingegangen. Im letzten Teil der Untersuchungen wurden die Hydratationskinetik der GZPB sowie die Gefügeentwicklung näher betrachtet. Hierfür wurden die Porenlösungen chemisch analysiert und Sättigungsindizes berechnet, sowie elektronenmikropische, porosimetrische und röntgenografische Untersuchungen durchgeführt. Abschließend wurden die Ergebnisse gesamtheitlich interpretiert, da die Ergebnisse der einzelnen Untersuchungsprogramme miteinander in Wechselwirkung stehen. Als hauptsächliche Hydratationsprodukte wurden Calciumsulfat-Dihydrat, Ettringit und C-(A)-S-H-Phasen ermittelt, deren Anteile im GZPB neben dem Calciumsulfatanteil und dem Puzzolan-Zement-Verhältnis auch deutlich vom Wasserangebot und der Gefügeentwicklung abhängen. Bei Verwendung von alumosilikatischen Puzzolans kommt es wahrscheinlich zur teilweisen Substitution des Siliciums durch Aluminium in den C-S-H-Phasen. Dies erscheint aufgrund des Nachweises der für diese Phasen typischen, folienartigen Morphologie wahrscheinlich. Portlandit wurde in raumbeständigen GZPB-Systemen nur zu sehr frühen Zeitpunkten in geringen Mengen gefunden. In den Untersuchungen konnte ein Teil der in der Literatur beschriebenen, prinzipiellen Hydratationsabläufe bestätigt werden. Bei Verwendung von Halbhydrat als Calciumsulfatkomponente entsteht zuerst Dihydrat und bildet die Primärstruktur der GZPB. In dieses existierende Grundgefüge kristallisieren dann das Ettringit und die C-(A)-S-H-Phasen. In den GZPB sorgen entgegen der Beschreibungen in der Literatur nicht ausschließlich die C-(A)-S-H-Phasen zur Verbesserung der Feuchtebeständigkeit und der Erhöhung des Festigkeitsniveaus, sondern auch das Ettringit. Beide Phasen überwachsen im zeitlichen Verlauf der Hydratation die Dihydratkristalle in der Matrix und hüllen diese – je nach Calciumsulfatanteil im GZPB – teilweise oder vollständig ein. Diese Umhüllung sowie die starke Gefügeverdichtung durch die C-(A)-S-H-Phasen und das Ettringit bedingen, dass ein lösender Angriff durch Wasser erschwert oder gar verhindert wird. Gleichzeitig wird die Gleitfähigkeit an den Kontaktstellen der Dihydratkristalle verringert. Eine rissfreie und raumbeständige Erhärtung ist für die gefahrlose Anwendung eines GZPB-Systems essentiell. Hierfür ist die Kinetik der Ettringitbildung von elementarer Bedeutung. Die gebildete Ettringitmenge spielt nur eine untergeordnete Rolle. Selbst ausgeprägte, ettringitbedingte Dehnungen und hohe sich bildende Mengen führen zu frühen Zeitpunkten, wenn die Dihydratkristalle noch leicht gegeneinander verschiebbar sind, zu keinen Schäden. Bleibt die Übersättigung bezüglich Ettringit und somit auch der Kristallisationsdruck allerdings über einen langen Zeitraum hoch, genügen bereits geringe Ettringitmengen, um das sich stetig verfestigende Gefüge stark zu schädigen. Die für die raumbeständige Erhärtung der GZPB notwendige, schnelle Abnahme der Ettringitübersättigung wird hauptsächlich durch die Reaktivität des Puzzolans beeinflusst. Die puzzolanische Reaktion führt zur Bindung des aus dem Zement stammenden Calciumhydroxid durch die Bildung von C-(A)-S-H-Phasen und Ettringit. Hierdurch sinkt die Calcium- und Hydroxidionenkonzentration in der Porenlösung im Verlauf der Hydratation, wodurch auch die Übersättigung bezüglich Ettringit abnimmt. Je höher die Reaktivität des Puzzolans ist, desto schneller sinkt der Sättigungsindex des Ettringits und somit auch der Kristallisationsdruck. Nach Unterschreiten eines noch näher zu klärendem Grenzwert der Übersättigung stagnieren die Dehnungen. Das Ettringit kristallisiert bzw. wächst nun bevorzugt in den Poren ohne eine weitere, äußere Volumenzunahme zu verursachen. Um eine schadensfreie Erhärtung des GZPB zu gewährleisten, muss gerade in der frühen Phase der Hydratation ein ausreichendes Wasserangebot gewährleistet werden, so dass die Ettringitbildung möglichst vollständig ablaufen kann. Andernfalls kann es bei einer Wiederbefeuchtung zur Reaktivierung der Ettringitbildung kommen, was im eingebauten Zustand Schäden verursachen kann. Die Gewährleistung eines ausreichenden Wasserangebots ist im GZPB-System nicht unproblematisch. In Abhängigkeit der GZPB-Zusammensetzung können sich große Ettringitmengen bilden, die einen sehr hohen Wasserbedarf aufweisen. Deshalb kann es, je nach verwendeten Wasser-Bindemittel-Wert, im Bindemittelleim zu einem Wassermangel kommen, welcher die weitere Hydratation verlangsamt bzw. komplett verhindert. Zudem können GZPB-Systeme teils sehr dichte Gefüge ausbilden, wodurch der Wassertransport zum Reaktionsort des Ettringits zusätzlich behindert wird. Die Konzeption raumbeständiger GZPB-Systeme muss anhand mehrerer aufeinander aufbauender Untersuchungen erfolgen. Zur Vorauswahl geeigneter Puzzolan-Zementverhältnisse eignen sich die Messungen der CaO-Konzentration und des pH-Wertes in Suspensionen. Als alleinige Beurteilungsgrundlage reicht dies allerdings nicht aus. Zusätzlich muss das Längenänderungs-verhalten beurteilt werden. Raumbeständige Mischungen mit alumosilikatischen Puzzolanen zeigen zu frühen Zeitpunkten starke Dehnungen, welche dann abrupt stagnieren. Stetige – auch geringe – Dehnungen weisen auf eine destruktive Zusammensetzung hin. Mit diesem mehrstufigen Vorgehen können raumbeständige, stabile GZPB-Systeme konzipiert werden, so dass die Zielstellung der Arbeit erreicht wurde und ein sicherer praktischer Einsatz dieser Bindemittelart gewährleistet werden kann.   KW - Gips KW - Zement KW - Hydratation KW - Gips-Zement-Puzzolan-Bindemittel KW - Hydratation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220825-47076 SN - 978-3-00-073003-0 ER - TY - THES A1 - Carvalho Daher, Cesar Felipe T1 - Horoskopos: a virtual planetarium for astrology N2 - This report details the development of Horoskopos, a virtual planetarium for astrology. This project was an attempt to develop a learning tool for studying astrological concepts as connected to observational astronomy. The premise that astrology and observational astronomy were once inseparable from each other in ancient times guided the conceptualization of this tool as an interactive planetarium. The main references were existing software and applications for visualization in astrology and astronomy. Professional astrology teachers were consulted in order to understand better the state of astrological teaching and learning, as well as existing tools and practice. Horoskopos was built using the Unity3D development interface, which is based on the C# programming language. It also relied on the Swiss Ephemeris coding interface from Astrodienst. The development process was experimental and many of the needed skills were developed as needed. Usability tests were performed as new features were added to the interface. The final version of Horoskopos is fully usable, with many interactive visualization features and a defined visual identity. It was validated together with professional astrologers for its effectiveness in concept and visualization. KW - Mediendesign KW - Astrologie KW - Astronomie KW - Planetarium KW - Information design KW - Interaction design KW - Astrology KW - Observational astronomy Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220930-47181 ER - TY - THES A1 - Malik, Irfan T1 - An adaptive contact formulation for Isogeometric Finite Element Analysis N2 - Numerical simulation of physical phenomena, like electro-magnetics, structural and fluid mechanics is essential for the cost- and time-efficient development of mechanical products at high quality. It allows to investigate the behavior of a product or a system far before the first prototype of a product is manufactured. This thesis addresses the simulation of contact mechanics. Mechanical contacts appear in nearly every product of mechanical engineering. Gearboxes, roller bearings, valves and pumps are only some examples. Simulating these systems not only for the maximal/minimal stresses and strains but for the stress-distribution in case of tribo-contacts is a challenging task from a numerical point of view. Classical procedures like the Finite Element Method suffer from the nonsmooth representation of contact surfaces with discrete Lagrange elements. On the one hand, an error due to the approximate description of the surface is introduced. On the other hand it is difficult to attain a robust contact search because surface normals can not be described in a unique form at element edges. This thesis introduces therefore a novel approach, the adaptive isogeometric contact formulation based on polynomial Splines over hierarchical T-meshes (PHT-Splines), for the approximate solution of the non-linear contact problem. It provides a more accurate, robust and efficient solution compared to conventional methods. During the development of this method the focus was laid on the solution of static contact problems without friction in 2D and 3D in which the structures undergo small deformations. The mathematical description of the problem entails a system of partial differential equations and boundary conditions which model the linear elastic behaviour of continua. Additionally, it comprises side conditions, the Karush-Kuhn-Tuckerconditions, to prevent the contacting structures from non-physical penetration. The mathematical model must be transformed into its integral form for approximation of the solution. Employing a penalty method, contact constraints are incorporated by adding the resulting equations in weak form to the overall set of equations. For an efficient space discretization of the bulk and especially the contact boundary of the structures, the principle of Isogeometric Analysis (IGA) is applied. Isogeometric Finite Element Methods provide several advantages over conventional Finite Element discretization. Surface approximation with Non-Uniform Rational B-Splines (NURBS) allow a robust numerical solution of the contact problem with high accuracy in terms of an exact geometry description including the surface smoothness. The numerical evaluation of the contact integral is challenging due to generally non-conforming meshes of the contacting structures. In this work the highly accurate Mortar Method is applied in the isogeometric setting for the evaluation of contact contributions. This leads to an algebraic system of equations that is linearized and solved in sequential steps. This procedure is known as the Newton Raphson Method. Based on numerical examples, the advantages of the isogeometric approach with classical refinement strategies, like the p- and h-refinement, are shown and the influence of relevant algorithmic parameters on the approximate solution of the contact problem is verified. One drawback of the Spline approximations of stresses though is that they lack accuracy at the contact edge where the structures change their boundary from contact to no contact and where the solution features a kink. The approximation with smooth Spline functions yields numerical artefacts in the form of non-physical oscillations. This property of the numerical solution is not only a drawback for the simulation of e.g. tribological contacts, it also influences the convergence properties of iterative solution procedures negatively. Hence, the NURBS discretized geometries are transformed to Polynomial Splines over Hierarchical T-meshes (PHT-Splines), for the local refinement along contact edges to reduce the artefact of pressure oscillations. NURBS have a tensor product structure which does not allow to refine only certain parts of the geometrical domain while leaving other parts unchanged. Due to the Bézier Extraction, lying behind the transformation from NURBS to PHT-Splines, the connected mesh structure is broken up into separate elements. This allows an efficient local refinement along the contact edge. Before single elements are refined in a hierarchical form with cross-insertion, existing basis functions must be modified or eliminated. This process of truncation assures local and global linear independence of the refined basis which is needed for a unique approximate solution. The contact boundary is a priori unknown. Local refinement along the contact edge, especially for 3D problems, is for this reason not straight forward. In this work the use of an a posteriori error estimation procedure, the Super Convergent Recovery Solution Based Error Estimation Scheme, together with the Dörfler Marking Method is suggested for the spatial search of the contact edge. Numerical examples show that the developed method improves the quality of solutions along the contact edge significantly compared to NURBS based approximate solutions. Also, the error in maximum contact pressures, which correlates with the pressure artefacts, is minimized by the adaptive local refinement. In a final step the practicability of the developed solution algorithm is verified by an industrial application: The highly loaded mechanical contact between roller and cam in the drive train of a high-pressure fuel pump is considered. KW - Isogeometrische Analyse KW - Elementanalyse KW - Isogeometric Analysis KW - Error estimation KW - adaptive contact KW - Finite Element Analysis KW - Computational contact mechanics Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220324-46129 ER - TY - BOOK ED - Zorn, Josephine T1 - Ausgründung aus der Universität - Ein praktischer Leitfaden für Wissenschaftler*innen N2 - Ob MP3-Player, Elektro-Jet oder Hochgeschwindigkeits-Röntgendetektor – hinter erfolgreichen Produkten stehen wissenschaftliche Erfindungen und Wissenschaftler*innen, die ihre Technologien kommerzialisiert haben. Auch Ihre Forschungsergebnisse könnten Potenzial für eine Ausgründung bieten. Doch vor dem Wechsel aus der Universität in die Selbstständigkeit stehen viele Fragen: Welche Marktchancen ergeben sich für meine Technologie? Welche Kompetenzen benötige ich in meinem Gründungsteam? Wie entwickle ich ein tragfähiges Geschäftsmodell? Und nicht zuletzt: Welche Förderprogramme und Finanzierungsoptionen gibt es für forschungsbasierte Ausgründungen? Das Workbook der Gründerwerkstatt neudeli möchte Ihnen als Wissenschaftler*in Unterstützung bei der Beantwortung dieser und vieler weiterer Fragen geben. Liebevoll gestaltet durch die parzelle34 bietet das Workbook den geeigneten Einstieg zum Thema »Ausgründung aus der Wissenschaft«, gibt Ihnen erste Informationen sowie weiterführende Beratungsangebote an die Hand und animiert mit interaktiven Elementen dazu, direkt durchzustarten! KW - Wissenschaft KW - Forschung KW - Unternehmensgründung KW - Entrepreneurship Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220311-46048 UR - https://www.uni-weimar.de/de/medien/institute/neudeli/incubator/workbook-fuer-wissenschaftlerinnen/ ER - TY - JOUR A1 - Patzelt, Max A1 - Erfurt, Doreen A1 - Ludwig, Horst-Michael T1 - Quantification of cracks in concrete thin sections considering current methods of image analysis JF - Journal of Microscopy N2 - Image analysis is used in this work to quantify cracks in concrete thin sections via modern image processing. Thin sections were impregnated with a yellow epoxy resin, to increase the contrast between voids and other phases of the concrete. By the means of different steps of pre-processing, machine learning and python scripts, cracks can be quantified in an area of up to 40 cm2. As a result, the crack area, lengths and widths were estimated automatically within a single workflow. Crack patterns caused by freeze-thaw damages were investigated. To compare the inner degradation of the investigated thin sections, the crack density was used. Cracks in the thin sections were measured manually in two different ways for validation of the automatic determined results. On the one hand, the presented work shows that the width of cracks can be determined pixelwise, thus providing the plot of a width distribution. On the other hand, the automatically measured crack length differs in comparison to the manually measured ones. KW - Beton KW - Rissbildung KW - Bildanalyse KW - Maschinelles Lernen KW - Mikroskopie KW - concrete KW - crack KW - degradation KW - transmitted light microscopy Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220811-46754 UR - https://onlinelibrary.wiley.com/doi/full/10.1111/jmi.13091 VL - 2022 IS - Volume 286, Issue 2 SP - 154 EP - 159 ER - TY - THES A1 - Shaaban Mohamed, Ahmed Mostafa T1 - Isogeometric boundary element analysis and structural shape optimization for Helmholtz acoustic problems N2 - In this thesis, a new approach is developed for applications of shape optimization on the time harmonic wave propagation (Helmholtz equation) for acoustic problems. This approach is introduced for different dimensional problems: 2D, 3D axi-symmetric and fully 3D problems. The boundary element method (BEM) is coupled with the isogeometric analysis (IGA) forming the so-called (IGABEM) which speeds up meshing and gives higher accuracy in comparison with standard BEM. BEM is superior for handling unbounded domains by modeling only the inner boundaries and avoiding the truncation error, present in the finite element method (FEM) since BEM solutions satisfy the Sommerfeld radiation condition automatically. Moreover, BEM reduces the space dimension by one from a volumetric three-dimensional problem to a surface two-dimensional problem, or from a surface two-dimensional problem to a perimeter one-dimensional problem. Non-uniform rational B-splines basis functions (NURBS) are used in an isogeometric setting to describe both the CAD geometries and the physical fields. IGABEM is coupled with one of the gradient-free optimization methods, the Particle Swarm Optimization (PSO) for structural shape optimization problems. PSO is a straightforward method since it does not require any sensitivity analysis but it has some trade-offs with regard to the computational cost. Coupling IGA with optimization problems enables the NURBS basis functions to represent the three models: shape design, analysis and optimization models, by a definition of a set of control points to be the control variables and the optimization parameters as well which enables an easy transition between the three models. Acoustic shape optimization for various frequencies in different mediums is performed with PSO and the results are compared with the benchmark solutions from the literature for different dimensional problems proving the efficiency of the proposed approach with the following remarks: - In 2D problems, two BEM methods are used: the conventional isogeometric boundary element method (IGABEM) and the eXtended IGABEM (XIBEM) enriched with the partition-of-unity expansion using a set of plane waves, where the results are generally in good agreement with the linterature with some computation advantage to XIBEM which allows coarser meshes. -In 3D axi-symmetric problems, the three-dimensional problem is simplified in BEM from a surface integral to a combination of two 1D integrals. The first is the line integral similar to a two-dimensional BEM problem. The second integral is performed over the angle of revolution. The discretization is applied only to the former integration. This leads to significant computational savings and, consequently, better treatment for higher frequencies over the full three-dimensional models. - In fully 3D problems, a detailed comparison between two BEM methods: the conventional boundary integral equation (CBIE) and Burton-Miller (BM) is provided including the computational cost. The proposed models are enhanced with a modified collocation scheme with offsets to Greville abscissae to avoid placing collocation points at the corners. Placing collocation points on smooth surface enables accurate evaluation of normals for BM formulation in addition to straightforward prediction of jump-terms and avoids singularities in $\mathcal{O} (1/r)$ integrals eliminating the need for polar integration. Furthermore, no additional special treatment is required for the hyper-singular integral while collocating on highly distorted elements, such as those containing sphere poles. The obtained results indicate that, CBIE with PSO is a feasible alternative (except for a small number of fictitious frequencies) which is easier to implement. Furthermore, BM presents an outstanding treatment of the complicated geometry of mufflers with internal extended inlet/outlet tube as an interior 3D Helmholtz acoustic problem instead of using mixed or dual BEM. T3 - ISM-Bericht // Institut für Strukturmechanik, Bauhaus-Universität Weimar - 2022,6 KW - Randelemente-Methode KW - Isogeometrische Analyse KW - Gestaltoptimierung KW - Boundary Element Method KW - Isogeometric Analysis KW - Helmholtz Acoustic Problems KW - Shape Optimization Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220816-47030 ER - TY - THES A1 - Cicek, Burhan T1 - Revisiting vernacular technique: Engineering a low environmental impact earth stabilisation method N2 - The major drawbacks of earth as a construction material — such as its low water stability and moderate strength — have led mankind to stabilize earth. Different civilizations developed vernacular techniques mainly focussing on lime, pozzolan or gypsum stabilization. Recently, cement has become the most commonly used additive in earth stabilization as it improves the strength and durability of plain earth. Also, it is a familiar and globally available construction material. However, using cement as an additive reduces the environmental advantages of earth and run counter to global targets regarding the reduction of CO2 emissions. Alternatives to cement stabilization are currently neither efficient enough to reduce its environmental impact nor allow the possibility of obtaining better results than those of cement. As such, this thesis deals with the rediscovery of a reverse engineering approach for a low environmental impact earth stabilization technique, aiming to replace cement in earth stabilization. The first step in the method consists in a comprehensive review of earth stabilization with regards to earthen building standards and soil classification, which allows us to identify the research gap. The review showed that there is great potential in using other additives which result in similar improvements as those achieved by cement. However, the studies that have been conducted so far either use expansive soils, which are not suitable for earth constructions or artificial pozzolans that indirectly contribute to CO2 emissions. This is the main research gap. The key concept for the development in the second step of the method is to combine vernacular additives to both improve the strength and durability of plain earth and to reduce the CO2 emissions. Various earth-mixtures were prepared and both development and performance tests were done to investigate the performance of this technique. The laboratory analyses on mix-design have proven a high durability and the results show a remarkable increase in strength performance. Furthermore, a significant reduction in CO2 emissions in comparison to cement stabilization could be shown. The third step of the method discusses the results drawn from the experimental programme. In addition, the potential of the new earth mixture with regards to its usability in the field of building construction and architectural design is further elaborated on. The method used in this study is the first of its kind that allows investors to avoid the very time-consuming processes such as finding a suitable source for soil excavation and soil classification. The developed mixture has significant workability and suitability for production of stabilized earthen panels — the very first of its kind. Such a panel is practically feasible, reasonable, and could be integrated into earthen building standards in general and in particular to DIN 18948, which is related to earthen boards and published in 2018. KW - Lehm KW - Stabilisierung KW - Lehmbau KW - Kalk KW - Gips Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220803-46989 ER -