Universitätsbibliothek
Weimar Open Access

Die Dissertation umfasst eine vertiefende Untersuchung der denkmalpflegerischen Erfassung von Siedlungen und Wohnanlagen als eine der wichtigsten und umfangreichsten Bautypologien der 1950er bis 1980er Jahre in Westeuropa. Die Beschäftigung mit Bauten der 1950er bis 1980er Jahre führt bei Denkmalpflegern, Architekten, Bewohnern und Politikern immer wieder zu Überlegungen, ob diese besondere Erfassungs- und Erhaltungsstrategien erfordern. Dabei wirft die Typologie des Siedlungsbaus besondere Fragen auf, da sie neben architektonischen Aspekten auch städtebauliche, landschaftsplanerische und sozialwissenschaftliche Bedeutungsebenen umfasst. Nicht zuletzt sind Siedlungen der 1950er bis 1980er Jahre aus denkmalpflegerischer Sicht häufig stark gefährdet. Obwohl die meisten Siedlungen noch nicht ausreichend kunsthistorisch gewürdigt und erfasst sind, unterliegen sie einem hohen Veränderungsdruck. Die teilweise enorme städtebauliche Dimension und Monofunktionalität der Anlagen, die häufig aufgrund von seriellen Bautypen und vorfabrizierten Elementen gleichförmige architektonische Gestaltung und eine Vernachlässigung im Bauunterhalt erschweren den Zugang zu dieser Baugattung. Gewandelte Wohnbedürfnisse sowie bauphysikalische, energietechnische oder ästhetische Maßnahmen führen zur Veränderung der noch relativ jungen Bausubstanz. Zudem weisen Siedlungen der Nachkriegszeit aufgrund ihrer teilweise sehr großzügigen Freiraumstruktur ein großes Potential zur Nachverdichtung auf. Die Auswahl der in dieser Arbeit untersuchten Länder und Siedlungen ergab sich aus der Auswertung einer europaweiten Befragung von Denkmalämtern sowie anschließend geführten Gesprächen mit Fachleuten. Die untersuchten 20 Siedlungen und Wohnanlagen repräsentieren verschiedene Länder (Deutschland, Österreich, Schweiz, Frankreich, Niederlande, England) sowie Bauepochen und Siedlungstypologien, die von der Einfamilienhaussiedlung über Siedlungen mit gemischter Bautypologie hin zur Großsiedlung reichen. Anhand der unterschiedlichen Fallbeispiele wird aufgezeigt, inwiefern die jeweiligen Länder, Bauepochen beziehungsweise Siedlungstypologien Einfluss auf die denkmalpflegerischen Erfassungsstrategien haben. Zusammenfassend lässt sich resümieren, dass die Gesetzesgrundlagen und Denkmalkriterien für eine denkmalpflegerische Erfassung von Bauten der 1950er bis 1980er Jahre in den meisten Ländern konstant bleiben, während sich in den Bereichen Zeitpunkt, Auswahl und Einbindung der Öffentlichkeit eine Modifizierung oder zumindest eine Reflektion der bisherigen Strukturen abzeichnet. Sinnvoll und wünschenswert erscheint darüber hinaus ein verstärkter Austausch der Denkmalpflege über die nationalen Grenzen hinweg und ein gegenseitiges Lernen voneinander.

In der vorliegenden Arbeit „Speaking from Somewhere: Der Audio-Walk als künstlerische Praxis und Methode“ wird der Audio-Walk auf theoretischer und praktischer Basis untersucht. Der erste Teil widmet sich dem Audio-Walk als künstlerisches Format. Darin wird analysiert, wie dieses aufgebaut ist und welche Komponenten wie zusammenwirken, damit sich die Darbietung – und die dafür charakteristisch intensive Wirkung – entfalten kann. Im zweiten Teil wird der Audio-Walk als experimentelle mobile Methode für die künstlerische Forschung betrachtet. Im Zentrum steht dabei die Frage, wie sich das künstlerische Format nutzen lässt, um spezifische Fragestellungen an einen ausgewählten Personenkreis zu adressieren, der sich währenddessen in einer inszenierten Situation befindet. Der Schwerpunkt liegt dabei auf Audio-Walk-Experimenten, die mit dieser Absicht entwickelt wurden. Als Fallbeispiel für die Methode dient dabei die Zusammenarbeit mit einer Gruppe kürzlich nach Deutschland migrierter Frauen.

Zum Begriff Illustration scheint ein Missverhältnis zwischen wissenschaftlicher Rezeption und praktischem Gegenstand vorzuliegen. Traditionell bezeichnet der Begriff Illustration ein Bild, das einen textlich vorangestellten Inhalt noch einmal visuell wiederholt und auf diesem Weg in einem Abbild verdoppelt. Traditionelle Illustration benennt also ein sekundäres, explizit von einem anderen Inhalt abhängiges Bild, das auch weggelassen werden könnte, ohne das Inhalt verloren geht. Genutzt wird dieser traditionelle Illustrationsbegriff heute unter anderem in den Forschungsfeldern der Kunstgeschichte, der Bildwissenschaften und der Literatur­wissenschaften. Aus der Perpektive der Praxis birgt der traditionelle Illustrationsbegriff ein grundsätzliches Problem in sich. Er versucht, mit einer statischen Definition ein äußerst lebendiges visuelles Phänomen unserer heutigen Zeit zu beschreiben. Professionelle Berufszeichner, die sogenannten Illustratorinnen und Illustratoren, kreieren heute Werke, die mit dem traditionellen Illustrations­begriff nicht mehr beschreibbar sind. Mehr noch, der traditionelle Illustrationsbegriff macht blind für diese Entwicklungen, die sich deshalb außerhalb des wissenschaft­lichen Diskurses abspielen. Die vorliegende Arbeit möchte deshalb einen Blick auf den Zustand zeitgenössischer literarischer Buch­illustration werfen, um den Begriff der Illustration in seiner aktuellen Unschärfe zu präzisieren, zu erweitern und somit zu aktualisieren.

The underlying goal of this work is to reduce the uncertainty related to thermally induced stress prediction. This is accomplished by considering use of non-linear material behavior, notably path dependent thermal hysteresis behavior in the elastic properties. Primary novel factors of this work center on two aspects. 1. Broad material characterization and mechanistic material understanding, giving insight into why this class of material behaves in characteristic manners. 2. Development and implementation of a thermal hysteresis material model and its use to determine impact on overall macroscopic stress predictions. Results highlight microcracking evolution and behavior as the dominant mechanism for material property complexity in this class of materials. Additionally, it was found that for the cases studied, thermal hysteresis behavior impacts relevant peak stress predictions of a heavy-duty diesel particulate filter undergoing a drop-to-idle regeneration by less than ~15% for all conditions tested. It is also found that path independent heating curves may be utilized for a linear solution assumption to simplify analysis. This work brings forth a newly conceived concept of a 3 state, 4 path, thermally induced microcrack evolution process; demonstrates experimental behavior that is consistent with the proposed mechanisms, develops a mathematical framework that describes the process and quantifies the impact in a real world application space.

Bei einem marktüblichen Calciumsulfat-Fließestrich wurden in der Praxis schädigende Volu-menexpansionen festgestellt. Diese sind ein Resultat aus dem Zusammenwirken des einge-setzten Bindemittel-Compounds und einer kritischen Gesteinskörnung. Das Ziel dieser Arbeit ist es, ein Calciumsulfat-Bindemittelsystem zu konfektionieren, welches in der Lage ist, die im Mörtel festgestellten Volumenexpansionen zu unterbinden. Es sollen verschiedene Bindemittel- und Additivzusammensetzungen untersucht werden, welche in Verbindung mit der kritischen Gesteinskörnung die Herstellung eines volumenstabilen Fließestrichs ermöglichen. Dazu soll folgende Fragestellung beantwortet werden: Welche Ursachen hat die Volumenzunahme und wie ist diese zu minimieren bzw. unterbinden? Dabei werden unterschiedliche Bindemittelrezepturen aus α-Halbhydrat, Thermoanhydrit und Naturanhydrit, sowie verschiedene Additivzusammensetzungen hergestellt und untersucht. Durch Längenänderungsmessungen in der Schwindrinne werden die Einflüsse der Binde-mittel, der Additivzusammensetzungen und der Wasser/Bindemittel-Werte auf das Län-genänderungsverhalten untersucht. Mittels Variation der einzelnen Compound-Bestandteile kann festgestellt werden, dass der Stabilisierer die Längenänderung negativ beeinflusst. Dieser bindet freies Wasser, welches für eine Reaktion zwischen Bindemittel und Gesteins-körnung im plastischen Zustand nicht mehr zur Verfügung steht. Diese Reaktion kann folglich erst im erhärteten Zustand ablaufen und verursacht die schädigende Volumenexpansion. Abschließend wurde ein Bindemittel-Compound konfektioniert, welcher ohne Zusatz von Stabilisierern in Zusammenhang mit der kritischen Gesteinskörnung volumenstabil ist und keine Schäden auslöst.

Due to an increased need for hydro-electricity, water storage, and flood protection, it is assumed that a series of new dams will be built throughout the world. Comparing existing design methodologies for arch-type dams, model-based shape optimization can effectively reduce construction costs and leverage the properties of construction materials. To apply the means of shape optimization, suitable variables need to be chosen to formulate the objective function, which is the volume of the arch dam here. In order to increase the consistency with practical conditions, a great number of geometrical and behavioral constraints are included in the mathematical model. An optimization method, namely Genetic Algorithm is adopted which allows a global search. Traditional optimization techniques are realized based on a deterministic approach, which means that the material properties and loading conditions are assumed to be fixed values. As a result, the real-world structures that are optimized by these approaches suffer from uncertainties that one needs to be aware of. Hence, in any optimization process for arch dams, it is nec- essary to find a methodology that is capable of considering the influences of uncertainties and generating a solution which is robust enough against the uncertainties. The focus of this thesis is the formulation and the numerical method for the optimization of the arch dam under the uncertainties. The two main models, the probabilistic model, and non-probabilistic models are intro- duced and discussed. Classic procedures of probabilistic approaches un- der uncertainties, such as RDO (robust design optimization) and RBDO (reliability-based design optimization), are in general computationally ex- pensive and rely on estimates of the system’s response variance and fail- ure probabilities. Instead, the robust optimization (RO) method which is based on the non-probabilistic model, will not follow a full probabilistic approach but works with pre-defined confidence levels. This leads to a bi-level optimization program where the volume of the dam is optimized under the worst combination of the uncertain parameters. By this, robust and reliable designs are obtained and the result is independent of any as- sumptions on stochastic properties of the random variables in the model. The optimization of an arch-type dam is realized here by a robust optimiza- tion method under load uncertainty, where hydraulic and thermal loads are considered. The load uncertainty is modeled as an ellipsoidal expression. Comparing with any traditional deterministic optimization (DO) method, which only concerns the minimum objective value and offers a solution candidate close to limit-states, the RO method provides a robust solution against uncertainties. All the above mentioned methods are applied to the optimization of the arch dam to compare with the optimal design with DO methods. The re- sults are compared and analyzed to discuss the advantages and drawbacks of each method. In order to reduce the computational cost, a ranking strategy and an ap- proximation model are further involved to do a preliminary screening. By means of these, the robust design can generate an improved arch dam structure which ensures both safety and serviceability during its lifetime.

Since the Industrial Revolution in the 1700s, the high emission of gaseous wastes into the atmosphere from the usage of fossil fuels has caused a general increase in temperatures globally. To combat the environmental imbalance, there is an increase in the demand for renewable energy sources. Dams play a major role in the generation of “green" energy. However, these structures require frequent and strict monitoring to ensure safe and efficient operation. To tackle the challenges faced in the application of convention dam monitoring techniques, this work proposes the inverse analysis of numerical models to identify damaged regions in the dam. Using a dynamic coupled hydro-mechanical Extended Finite Element Method (XFEM) model and a global optimization strategy, damage (crack) in the dam is identified. By employing seismic waves to probe the dam structure, a more detailed information on the distribution of heterogeneous materials and damaged regions are obtained by the application of the Full Waveform Inversion (FWI) method. The FWI is based on a local optimization strategy and thus it is highly dependent on the starting model. A variety of data acquisition setups are investigated, and an optimal setup is proposed. The effect of different starting models and noise in the measured data on the damage identification is considered. Combining the non-dependence of a starting model of the global optimization strategy based dynamic coupled hydro-mechanical XFEM method and the detailed output of the local optimization strategy based FWI method, an enhanced Full Waveform Inversion is proposed for the structural analysis of dams.

Die niederländische Architekturmoderne wird seit den 1980er Jahren nahezu durchgehend baulich rezipiert. Bisher unternommene uneinheitliche Kategorisierungen dieser Bauten als "Neo-Moderne" oder "Neu-Amsterdamer- Schule" werden dem komplexen Sachverhalt oftmals nicht in ausreichendem Maße gerecht. Die Arbeit soll daher einen Beitrag zum besseren Verständnis der Rezeption des Neuen Bauens und der Amsterdamer Schule leisten. Anhand vier ausgewählter jüngerer Wohnungsbauten in den Niederlanden untersucht sie konkret das Verhältnis zu den städtebaulichen, typologischen und formal- gestalterischen Vorbildern aus den 1920er und 1930er Jahren. Welche Gründe waren ausschlaggebend für die Wahl bestimmter Vorbilder? Auf welche Wohnanlagen greifen sie konkret zurück und mithilfe welcher Verfahren tun sie dies? Inwiefern unterscheidet sich die Vorgehensweise der ArchitektInnen von denen des Neuen Bauens oder der Amsterdamer Schule? Das Resümee offenbart eine große Vielfalt an Rezeptionstechniken von zumeist mehreren historischen Vorbildern und damit die Schwierigkeit, das vorliegende Phänomen zu deuten. Vor allem aber scheint die Moderne mit ihrem Paradigma der Originalität von einem erneuten eklektischen Ansatz in der Architektur überholt worden zu sein. In ihrem methodischen Ansatz verbindet die Thesis formal-gestalterische Analysen mit theoretischen Reflexionen und behandelt mit dem Thema der Referenzen eine zentrale Praxis im Entwurfsprozess von ArchitektInnen.

The task-based view of web search implies that retrieval should take the user perspective into account. Going beyond merely retrieving the most relevant result set for the current query, the retrieval system should aim to surface results that are actually useful to the task that motivated the query. This dissertation explores how retrieval systems can better understand and support their users’ tasks from three main angles: First, we study and quantify search engine user behavior during complex writing tasks, and how task success and behavior are associated in such settings. Second, we investigate search engine queries formulated as questions, and explore patterns in a large query log that may help search engines to better support this increasingly prevalent interaction pattern. Third, we propose a novel approach to reranking the search result lists produced by web search engines, taking into account retrieval axioms that formally specify properties of a good ranking.

Diese Arbeit beschäftigt sich mit der Nutzung von Worteinbettungen in der automatischen Analyse von argumentativen Texten. Die Arbeit diskutiert wichtige Einstellungen des Einbettungsverfahren sowie diverse Anwendungsmethoden der eingebetteten Wortvektoren für drei Aufgaben der automatischen argumentativen Analyse: Textsegmentierung, Argumentativitäts-Klassifikation und Relationenfindung. Meine Experimente auf zwei Standard-Argumentationsdatensätzen zeigen die folgenden Haupterkenntnisse: Bei der Textsegmentierung konnten keine Verbesserungen erzielt werden, während in der Argumentativitäts-Klassifikation und der Relationenfindung sich kleine Erfolge gezeigt haben und weitere bestimmte Forschungsthesen bewahrheitet werden konnten. In der Diskussion wird darauf eingegangen, warum bei der einfachen Worteinbettung in der argumentativen Analyse sich kaum nutzbare Ergebnisse erzielen lassen konnten, diese sich aber in Zukunft durch erweiterte Worteinbettungsverfahren verbessern können.

Die internationale Jazzforschung hat sich in den vergangenen Jahrzehnten zahlreiche neue Fragestellungen und Forschungsansätze erschlossen. So sind etwa die globalen Dimensionen des Jazz, die Rolle von Frauen im Jazz oder seine mannigfaltigen kulturellen Bedeutungen in Geschichte und Gegenwart ins Zentrum der Forschung gerückt. Die dreizehn Beiträge des Tagungsbandes widmen sich Themen, Methoden und Desideraten der gegenwärtigen wissenschaftlichen Auseinandersetzung mit dem Jazz. Zudem werden Perspektiven des künstlerischen Forschens im Jazz und der Ausbildung von Jazzmusikern und -forschern diskutiert.

Am Beispiel der Elektrifizierung zweier Großstädte an der Westküste Südamerikas zeigt die Arbeit den globalen Einfluss deutscher Industrie- und Finanzakteure auf technische, städtebauliche und gesellschaftlich-kulturelle Entwicklungen zur Blütezeit des europäischen Imperialismus auf. Damit werden die Regionalgeschichten der chilenischen Hauptstadtregion und der Elektropolis Berlin zu einer Globalgeschichte miteinander verknüpft. Ein Hauptaugenmerk der Analyse liegt dabei auf den weltweiten Akteursnetzwerken und Machtverhältnissen sowie dem kulturellen Erbe und seiner gegenwärtigen Interpretation.

Wireless sensor networks have attracted great attention for applications in structural health monitoring due to their ease of use, flexibility of deployment, and cost-effectiveness. This paper presents a software framework for WiFi-based wireless sensor networks composed of low-cost mass market single-board computers. A number of specific system-level software components were developed to enable robust data acquisition, data processing, sensor network communication, and timing with a focus on structural health monitoring (SHM) applications. The framework was validated on Raspberry Pi computers, and its performance was studied in detail. The paper presents several characteristics of the measurement quality such as sampling accuracy and time synchronization and discusses the specific limitations of the system. The implementation includes a complementary smartphone application that is utilized for data acquisition, visualization, and analysis. A prototypical implementation further demonstrates the feasibility of integrating smartphones as data acquisition nodes into the network, utilizing their internal sensors. The measurement system was employed in several monitoring campaigns, three of which are documented in detail. The suitability of the system is evaluated based on comparisons of target quantities with reference measurements. The results indicate that the presented system can robustly achieve a measurement performance commensurate with that required in many typical SHM tasks such as modal identification. As such, it represents a cost-effective alternative to more traditional monitoring solutions.

Brazilian battlers’ housing discusses the self-production of dwellings in the circumstances of the socioeconomic rise of the so-called Brazilian new middle class, occurred on the first decade of the years 2000. Battlers are a precarious working class of about 100 million people, who have used their recently increased purchase power to informally solve their private housing demands, planning, building and renovating their homes themselves, with limited technical knowledge and almost no access to formal technicians as for example architects. The result is a mode of housing production, which spreads over the territory in micro-local self-initiatives and informal social practices of construction and management. With the support of a controversial manpower, this practice presents all sorts of technical complications, but at the same time expedient ways of affordability and creative spatial solutions for ordinary constructive problems. Such initiatives have consolidated Brazilian informal settlements and peripheral subdivisions, attending a demand poorly responded by the government. This research recognises the benefits of the self-production, but questions the conditions under which it happens and asks if it really collaborates for a true social rise of those who are engaged in it. With an empirical and qualitative approach and taking dwelling construction processes leaded by battlers as main information sources, the academic work responds if and how the socioeconomic rise of the Brazilian battlers has exactly affected the self-production of dwellings. For that, battlers’ self-production of dwellings is analysed and discussed in five main aspects: 1) acquisition of land and real state, 2) building overtime, 3) space and creative power, 4) technical complications and building materials and 5) manpower and know-how.

Acoustic travel-time tomography (ATOM) determines the distribution of the temperature in a propagation medium by measuring the travel-time of acoustic signals between transmitters and receivers. To employ ATOM for indoor climate measurements, the impulse responses have been measured in the climate chamber lab of the Bauhaus-University Weimar and compared with the theoretical results of its image source model (ISM). A challenging task is distinguishing the reflections of interest in the reflectogram when the sound rays have similar travel-times. This paper presents a numerical method to address this problem by finding optimal positions of transmitter and receiver, since they have a direct impact on the distribution of travel times. These optimal positions have the minimum number of simultaneous arrival time within a threshold level. Moreover, for the tomographic reconstruction, when some of the voxels remain empty of sound-rays, it leads to inaccurate determination of the air temperature within those voxels. Based on the presented numerical method, the number of empty tomographic voxels are minimized to ensure the best sound-ray coverage of the room. Subsequently, a spatial temperature distribution is estimated by simultaneous iterative reconstruction technique (SIRT). The experimental set-up in the climate chamber verifies the simulation results.

Der vorliegende Beitrag beschreibt die Problematik bei der Prognose verkehrsbedingter Schadstoff-Immissionen. Im Mittelpunkt steht die Entwicklung und der Aufbau einer Simulationsumgebung zur Evaluation von umweltorientierten Verkehrsmanagement-Strategien. Die Simulationsumgebung wird über die drei Felder Verkehr, Emission, Immission entwickelt und findet zunächst Anwendung in der Evaluation verkehrlicher Maßnahmen für die Friedberger Landstraße in Frankfurt am Main.

The vibration control of the tall building during earthquake excitations is a challenging task due to their complex seismic behavior. This paper investigates the optimum placement and properties of the Tuned Mass Dampers (TMDs) in tall buildings, which are employed to control the vibrations during earthquakes. An algorithm was developed to spend a limited mass either in a single TMD or in multiple TMDs and distribute them optimally over the height of the building. The Non-dominated Sorting Genetic Algorithm (NSGA – II) method was improved by adding multi-variant genetic operators and utilized to simultaneously study the optimum design parameters of the TMDs and the optimum placement. The results showed that under earthquake excitations with noticeable amplitude in higher modes, distributing TMDs over the height of the building is more effective in mitigating the vibrations compared to the use of a single TMD system. From the optimization, it was observed that the locations of the TMDs were related to the stories corresponding to the maximum modal displacements in the lower modes and the stories corresponding to the maximum modal displacements in the modes which were highly activated by the earthquake excitations. It was also noted that the frequency content of the earthquake has significant influence on the optimum location of the TMDs.

This study aims to develop an approach to couple a computational fluid dynamics (CFD) solver to the University of California, Berkeley (UCB) thermal comfort model to accurately evaluate thermal comfort. The coupling was made using an iterative JavaScript to automatically transfer data for each individual segment of the human body back and forth between the CFD solver and the UCB model until reaching convergence defined by a stopping criterion. The location from which data are transferred to the UCB model was determined using a new approach based on the temperature difference between subsequent points on the temperature profile curve in the vicinity of the body surface. This approach was used because the microclimate surrounding the human body differs in thickness depending on the body segment and the surrounding environment. To accurately simulate the thermal environment, the numerical model was validated beforehand using experimental data collected in a climate chamber equipped with a thermal manikin. Furthermore, an example of the practical implementations of this coupling is reported in this paper through radiant floor cooling simulation cases, in which overall and local thermal sensation and comfort were investigated using the coupled UCB model.

Landwirtschaftliche Biogasanlagen leisten mit ca. 9.300 Anlagen und einem Anteil von 5,3% an der Stromerzeugung, einen Beitrag zur Erzeugung Erneuer-barer Energien in Deutschland. Die Optimierung dieser Anlagen fördert die nachhaltige Bereitstellung von Strom, Wärme und BioErdgas. Das Ergebnis dieser Forschungsarbeit ist die Entwicklung eines mehrmethodi-schen Bewertungsansatzes zur Beschreibung der Qualität der Eingangs-substrate als Teil einer ganzheitlichen Prozessoptimierung. Dies gelingt durch die kombinierte Nutzung klassischer Analysesätze, der Nutzung organolepti-scher Parameter – der humansensorischen Sinnenprüfung – und der Integration von prozess- und substratspezifischem Erfahrungswissen. Anhand von halbtechnischen Versuchen werden Korrelationen und Kausalitäten zwi-schen chemisch-physikalischen, biologischen, organoleptischen und erfahrungsbezogenen Parametern erforscht. Die Entwicklung einer Fallbasis mit Hilfe des Fallbasierten Schließens, einer Form Künstlicher Intelligenz, zeigt das Entwicklungs- und Integrationspotenzial der Automatisierung auf, insbesondere auch im Hinblick auf neue Ansätze z.B. Industrie 4.0. Erste Lösungen zur Bewältigung der identifizierten Herausforderungen der mehrmethodischen Prozessbewertung werden vorgestellt. Abschließend wird ein Ausblick auf den weiteren Forschungsbedarf gegeben und die Übertragbarkeit des mehrmethodischen Bewertungsansatzes auf andere Anwendungsfelder z.B. Bioabfallbehandlung, Kläranlagen angeregt.

Identification of flaws in structures is a critical element in the management of maintenance and quality assurance processes in engineering. Nondestructive testing (NDT) techniques based on a wide range of physical principles have been developed and are used in common practice for structural health monitoring. However, basic NDT techniques are usually limited in their ability to provide the accurate information on locations, dimensions and shapes of flaws. One alternative to extract additional information from the results of NDT is to append it with a computational model that provides detailed analysis of the physical process involved and enables the accurate identification of the flaw parameters. The aim here is to develop the strategies to uniquely identify cracks in two-dimensional 2D) structures under dynamic loadings. A local NDT technique combined eXtended Finite Element Method (XFEM) with dynamic loading in order to identify the cracks in the structures quickly and accurately is developed in this dissertation. The Newmark-b time integration method with Rayleigh damping is used for the time integration. We apply Nelder-Mead (NM)and Quasi-Newton (QN) methods for identifying the crack tip in plate. The inverse problem is solved iteratively, in which XFEM is used for solving the forward problem in each iteration. For a timeharmonic excitation with a single frequency and a short-duration signal measured along part of the external boundary, the crack is detected through the solution of an inverse time-dependent problem. Compared to the static load, we show that the dynamic loads are more effective for crack detection problems. Moreover, we tested different dynamic loads and find that NM method works more efficient under the harmonic load than the pounding load while the QN method achieves almost the same results for both load types. A global strategy, Multilevel Coordinate Search (MCS) with XFEM (XFEM-MCS) methodology under the dynamic electric load, to detect multiple cracks in 2D piezoelectric plates is proposed in this dissertation. The Newmark-b method is employed for the time integration and in each iteration the forward problem is solved by XFEM for various cracks. The objective functional is minimized by using a global search algorithm MCS. The test problems show that the XFEM-MCS algorithm under the dynamic electric load can be effectively employed for multiple cracks detection in piezoelectric materials, and it proves to be robust in identifying defects in piezoelectric structures. Fiber-reinforced composites (FRCs) are extensively applied in practical engineering since they have high stiffness and strength. Experiments reveal a so-called interphase zone, i.e. the space between the outside interface of the fiber and the inside interface of the matrix. The interphase strength between the fiber and the matrix strongly affects the mechanical properties as a result of the large ratio of interface/volume. For the purpose of understanding the mechanical properties of FRCs with functionally graded interphase (FGI), a closed-form expression of the interface strength between a fiber and a matrix is obtained in this dissertation using a continuum modeling approach according to the ver derWaals (vdW) forces. Based on the interatomic potential, we develop a new modified nonlinear cohesive law, which is applied to study the interface delamination of FRCs with FGI under different loadings. The analytical solutions show that the delamination behavior strongly depends on the interphase thickness, the fiber radius, the Young’s moduli and Poisson’s ratios of the fiber and the matrix. Thermal conductivity is the property of a material to conduct heat. With the development and deep research of 2D materials, especially graphene and molybdenum disulfide (MoS2), the thermal conductivity of 2D materials attracts wide attentions. The thermal conductivity of graphene nanoribbons (GNRs) is found to appear a tendency of decreasing under tensile strain by classical molecular dynamics (MD) simulations. Hence, the strain effects of graphene can play a key role in the continuous tunability and applicability of its thermal conductivity property at nanoscale, and the dissipation of thermal conductivity is an obstacle for the applications of thermal management. Up to now, the thermal conductivity of graphene under shear deformation has not been investigated yet. From a practical point of view, good thermal managements of GNRs have significantly potential applications of future GNR-based thermal nanodevices, which can greatly improve performances of the nanosized devices due to heat dissipations. Meanwhile, graphene is a thin membrane structure, it is also important to understand the wrinkling behavior under shear deformation. MoS2 exists in the stable semiconducting 1H phase (1H-MoS2) while the metallic 1T phase (1T-MoS2) is unstable at ambient conditions. As it’s well known that much attention has been focused on studying the nonlinear optical properties of the 1H-MoS2. In a very recent research, the 1T-type monolayer crystals of TMDCs, MX2 (MoS2, WS2 ...) was reported having an intrinsic in-plane negative Poisson’s ratio. Luckily, nearly at the same time, unprecedented long-term (>3months) air stability of the 1T-MoS2 can be achieved by using the donor lithium hydride (LiH). Therefore, it’s very important to study the thermal conductivity of 1T-MoS2. The thermal conductivity of graphene under shear strain is systematically studied in this dissertation by MD simulations. The results show that, in contrast to the dramatic decrease of thermal conductivity of graphene under uniaxial tensile, the thermal conductivity of graphene is not sensitive to the shear strain, and the thermal conductivity decreases only 12-16%. The wrinkle evolves when the shear strain is around 5%-10%, but the thermal conductivity barely changes. The thermal conductivities of single-layer 1H-MoS2(1H-SLMoS2) and single-layer 1T-MoS2 (1T-SLMoS2) with different sample sizes, temperatures and strain rates have been studied systematically in this dissertation. We find that the thermal conductivities of 1H-SLMoS2 and 1T-SLMoS2 in both the armchair and the zigzag directions increase with the increasing of the sample length, while the increase of the width of the sample has minor effect on the thermal conductions of these two structures. The thermal conductivity of 1HSLMoS2 is smaller than that of 1T-SLMoS2 under size effect. Furthermore, the temperature effect results show that the thermal conductivities of both 1H-SLMoS2 and 1T-SLMoS2 decrease with the increasing of the temperature. The thermal conductivities of 1HSLMoS2 and 1T-SLMoS2 are nearly the same (difference <6%) in both of the chiral orientations under corresponding temperatures, especially in the armchair direction (difference <2.8%). Moreover, we find that the strain effects on the thermal conductivity of 1HSLMoS2 and 1T-SLMoS2 are different. More specifically, the thermal conductivity decreases with the increasing tensile strain rate for 1T-SLMoS2, while fluctuates with the growth of the strain for 1HSLMoS2. Finally, we find that the thermal conductivity of same sized 1H-SLMoS2 is similar with that of the strained 1H-SLMoS2 structure.

Modern image detection techniques such as micro computer tomography (μCT), magnetic resonance imaging (MRI) and scanning electron microscopy (SEM) provide us with high resolution images of the microstructure of materials in a non-invasive and convenient way. They form the basis for the geometrical models of high-resolution analysis, so called image-based analysis. However especially in 3D, discretizations of these models reach easily the size of 100 Mill. degrees of freedoms and require extensive hardware resources in terms of main memory and computing power to solve the numerical model. Consequently, the focus of this work is to combine and adapt numerical solution methods to reduce the memory demand first and then the computation time and therewith enable an execution of the image-based analysis on modern computer desktops. Hence, the numerical model is a straightforward grid discretization of the voxel-based (pixels with a third dimension) geometry which omits the boundary detection algorithms and allows reduced storage of the finite element data structure and a matrix-free solution algorithm. This in turn reduce the effort of almost all applied grid-based solution techniques and results in memory efficient and numerically stable algorithms for the microstructural models. Two variants of the matrix-free algorithm are presented. The efficient iterative solution method of conjugate gradients is used with matrix-free applicable preconditioners such as the Jacobi and the especially suited multigrid method. The jagged material boundaries of the voxel-based mesh are smoothed through embedded boundary elements which contain different material information at the integration point and are integrated sub-cell wise though without additional boundary detection. The efficiency of the matrix-free methods can be retained.

The capitalization of ‘certified’ sustainable building sector will be investigated over the power theory of value approach of Jonathan Nitzan and Shimshon Bichler. The study will be initiated by questioning why the environment problems are one of the first items on the agenda and by sharing the ideas of scholars who approaches the subject skeptically, because the predominant literature underlying the necessity and prominence of the topic is already well-known and adapted by the majority. Over the theory developed by Nitzan and Bichler, the concepts of capitalization, strategic sabotage, power, legitimacy, and obedience will be discussed. The hypothesis of “the absentee owners of the construction sector, holding the whip hand and capitalizing the ecology, control the growth and the creativity of green building production and make it carbon-dependent, in order to increase their profit margin” will be questioned. To strengthen the arguments in the hypothesis, the factors, the institutional arrangements, value measurement methods, which affect directly the net present value, will be investigated both in corporation and in building scale in detail, because net present value/ capitalization is asserted as the most important criteria by Nitzan and Bichler to make the investment decisions in the capitalist economic system. To trace the implications of power and the strategic sabotage that power caused, as the empirical dimension of this dissertation, an interface exploring the correlational ties between the climate responsive architecture and the ever changing political, economical, and social contexts and building economics praxis by decades will be developed and the expert interviews will be conducted with the design teams and the appraisers.

Für eine Abschätzung des Heizwärmebedarfs von Gebäuden und Quartieren können thermisch-energetische Simulationen eingesetzt werden. Grundlage dieser Simulationen sind geometrische und physikalische Gebäudemodelle. Die Erstellung des geometrischen Modells erfolgt in der Regel auf Basis von Bauplänen oder Vor-Ort-Begehungen, was mit einem großen Recherche- und Modellierungsaufwand verbunden ist. Spätere bauliche Veränderungen des Gebäudes müssen häufig manuell in das Modell eingearbeitet werden, was den Arbeitsaufwand zusätzlich erhöht. Das physikalische Modell stellt die Menge an Parametern und Randbedingungen dar, welche durch Materialeigenschaften, Lage und Umgebungs-einflüsse gegeben sind. Die Verknüpfung beider Modelle wird innerhalb der entsprechenden Simulations-software realisiert und ist meist nicht in andere Softwareprodukte überführbar. Mithilfe des Building Information Modeling (BIM) können Simulationsdaten sowohl konsistent gespeichert als auch über Schnittstellen mit entsprechenden Anwendungen ausgetauscht werden. Hierfür wird eine Methode vorgestellt, die thermisch-energetische Simulationen auf Basis des standardisierten Übergabe-formats Industry Foundation Classes (IFC) inklusive anschließender Auswertungen ermöglicht. Dabei werden geometrische und physikalische Parameter direkt aus einem über den gesamten Lebenszyklus aktuellen Gebäudemodell extrahiert und an die Simulation übergeben. Dies beschleunigt den Simulations-prozess hinsichtlich der Gebäudemodellierung und nach späteren baulichen Veränderungen. Die erarbeite-te Methode beruht hierbei auf einfachen Modellierungskonventionen bei der Erstellung des Bauwerksinformationsmodells und stellt eine vollständige Übertragbarkeit der Eingangs- und Ausgangswerte sicher. Thermal building simulation based on BIM-models. Thermal energetic simulations are used for the estimation of the heating demand of buildings and districts. These simulations are based on building models containing geometrical and physical information. The creation of geometrical models is usually based on existing construction plans or in situ assessments which demand a comparatively big effort of investigation and modeling. Alterations, which are later applied to the structure, request manual changes of the related model, which increases the effort additionally. The physical model represents the total amount of parameters and boundary conditions that are influenced by material properties, location and environmental influences on the building. The link between both models is realized within the correspondent simulation soft-ware and is usually not transferable to other software products. By Applying Building Information Modeling (BIM) simulation data is stored consistently and an exchange to other software is enabled. Therefore, a method which allows a thermal energetic simulation based on the exchange format Industry Foundation Classes (IFC) including an evaluation is presented. All geometrical and physical information are extracted directly from the building model that is kept up-to-date during its life cycle and transferred to the simulation. This accelerates the simulation process regarding the geometrical modeling and adjustments after later changes of the building. The developed method is based on simple conventions for the creation of the building model and ensures a complete transfer of all simulation data.

In the field of engineering, surrogate models are commonly used for approximating the behavior of a physical phenomenon in order to reduce the computational costs. Generally, a surrogate model is created based on a set of training data, where a typical method for the statistical design is the Latin hypercube sampling (LHS). Even though a space filling distribution of the training data is reached, the sampling process takes no information on the underlying behavior of the physical phenomenon into account and new data cannot be sampled in the same distribution if the approximation quality is not sufficient. Therefore, in this study we present a novel adaptive sampling method based on a specific surrogate model, the least-squares support vector regresson. The adaptive sampling method generates training data based on the uncertainty in local prognosis capabilities of the surrogate model - areas of higher uncertainty require more sample data. The approach offers a cost efficient calculation due to the properties of the least-squares support vector regression. The opportunities of the adaptive sampling method are proven in comparison with the LHS on different analytical examples. Furthermore, the adaptive sampling method is applied to the calculation of global sensitivity values according to Sobol, where it shows faster convergence than the LHS method. With the applications in this paper it is shown that the presented adaptive sampling method improves the estimation of global sensitivity values, hence reducing the overall computational costs visibly.

Polymer-modified cement concrete (PCC) is a heterogeneous building material with a hierarchically organized microstructure. Therefore, continuum micromechanics-based multiscale models represent a promising method to estimate the mechanical properties. By means of a bottom-up approach, homogenized properties at the macroscopic scale are derived considering microstructural characteristics. The extension of existing multiscale models for the application to PCC is the main objective of this work. For that, cross-scale experimental studies are required. Both macroscopic and microscopic mechanical tests are performed to characterize the elastic and viscoelastic properties of different PCC. The comparison between experiment and model prediction illustrates the success of the modeling approach.