TY - JOUR A1 - Kumari, Vandana A1 - Harirchian, Ehsan A1 - Lahmer, Tom A1 - Rasulzade, Shahla T1 - Evaluation of Machine Learning and Web-Based Process for Damage Score Estimation of Existing Buildings JF - Buildings N2 - The seismic vulnerability assessment of existing reinforced concrete (RC) buildings is a significant source of disaster mitigation plans and rescue services. Different countries evolved various Rapid Visual Screening (RVS) techniques and methodologies to deal with the devastating consequences of earthquakes on the structural characteristics of buildings and human casualties. Artificial intelligence (AI) methods, such as machine learning (ML) algorithm-based methods, are increasingly used in various scientific and technical applications. The investigation toward using these techniques in civil engineering applications has shown encouraging results and reduced human intervention, including uncertainties and biased judgment. In this study, several known non-parametric algorithms are investigated toward RVS using a dataset employing different earthquakes. Moreover, the methodology encourages the possibility of examining the buildings’ vulnerability based on the factors related to the buildings’ importance and exposure. In addition, a web-based application built on Django is introduced. The interface is designed with the idea to ease the seismic vulnerability investigation in real-time. The concept was validated using two case studies, and the achieved results showed the proposed approach’s potential efficiency KW - Maschinelles Lernen KW - rapid assessment KW - Machine learning KW - Vulnerability assessment KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220509-46387 UR - https://www.mdpi.com/2075-5309/12/5/578 VL - 2022 IS - Volume 12, issue 5, article 578 SP - 1 EP - 23 PB - MDPI CY - Basel ER - TY - JOUR A1 - Artus, Mathias A1 - Koch, Christian T1 - State of the art in damage information modeling for RC bridges – A literature review JF - Advanced Engineering Informatics N2 - In Germany, bridges have an average age of 40 years. A bridge consumes between 0.4% and 2% of its construction cost per year over its entire life cycle. This means that up to 80% of the construction cost are additionally needed for operation, inspection, maintenance, and destruction. Current practices rely either on paperbased inspections or on abstract specialist software. Every application in the inspection and maintenance sector uses its own data model for structures, inspections, defects, and maintenance. Due to this, data and properties have to be transferred manually, otherwise a converter is necessary for every data exchange between two applications. To overcome this issue, an adequate model standard for inspections, damage, and maintenance is necessary. Modern 3D models may serve as a single source of truth, which has been suggested in the Building Information Modeling (BIM) concept. Further, these models offer a clear visualization of the built infrastructure, and improve not only the planning and construction phases, but also the operation phase of construction projects. BIM is established mostly in the Architecture, Engineering, and Construction (AEC) sector to plan and construct new buildings. Currently, BIM does not cover the whole life cycle of a building, especially not inspection and maintenance. Creating damage models needs the building model first, because a defect is dependent on the building component, its properties and material. Hence, a building information model is necessary to obtain meaningful conclusions from damage information. This paper analyzes the requirements, which arise from practice, and the research that has been done in modeling damage and related information for bridges. With a look at damage categories and use cases related to inspection and maintenance, scientific literature is discussed and synthesized. Finally, research gaps and needs are identified and discussed. KW - Building Information Modeling KW - Brücke KW - Inspektion KW - Literaturrecherche KW - Datenmodell Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220506-46390 UR - https://www.sciencedirect.com/science/article/abs/pii/S1474034620301427?via%3Dihub VL - 2020 IS - volume 46, article 101171 SP - 1 EP - 16 PB - Elsevier Science CY - Amsterdam ER - TY - JOUR A1 - Simon-Ritz, Frank T1 - Zwischen Residenzkultur und Bratwursttradition: Thüringer UNESCO-Initiativen JF - Palmbaum: Literarisches Journal aus Thüringen N2 - Der Essay, der in H. 1/2022 des "Palmbaum: literarisches Journal aus Thüringen" erschienen ist, beschäftigt sich mit dem Begriff des "kulturellen Erbes", der verschiedenen UNESCO-Programmen zugrundeliegt. KW - Kultur KW - UNESCO Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220413-46282 VL - 2022 IS - Heft 1 PB - Quartus Verlag CY - Bucha bei Jena ER - TY - JOUR A1 - Artus, Mathias A1 - Alabassy, Mohamed Said Helmy A1 - Koch, Christian T1 - A BIM Based Framework for Damage Segmentation, Modeling, and Visualization Using IFC JF - Applied Sciences N2 - Paper-based data acquisition and manual transfer between incompatible software or data formats during inspections of bridges, as done currently, are time-consuming, error-prone, cumbersome, and lead to information loss. A fully digitized workflow using open data formats would reduce data loss, efforts, and the costs of future inspections. On the one hand, existing studies proposed methods to automatize data acquisition and visualization for inspections. These studies lack an open standard to make the gathered data available for other processes. On the other hand, several studies discuss data structures for exchanging damage information among different stakeholders. However, those studies do not cover the process of automatic data acquisition and transfer. This study focuses on a framework that incorporates automatic damage data acquisition, transfer, and a damage information model for data exchange. This enables inspectors to use damage data for subsequent analyses and simulations. The proposed framework shows the potentials for a comprehensive damage information model and related (semi-)automatic data acquisition and processing. KW - Building Information Modeling KW - Brücke KW - Inspektion KW - Maschinelles Lernen KW - Bildverarbeitung KW - Building Information Modeling KW - Bridge KW - Inspection KW - Damage Segmentation KW - Machine Learning KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220314-46059 UR - https://www.mdpi.com/2076-3417/12/6/2772 VL - 2022 IS - volume 12, issue 6, article 2772 SP - 1 EP - 24 PB - MDPI CY - Basel ER - TY - JOUR A1 - Zhang, Yongzheng A1 - Ren, Huilong T1 - Implicit implementation of the nonlocal operator method: an open source code JF - Engineering with computers N2 - In this paper, we present an open-source code for the first-order and higher-order nonlocal operator method (NOM) including a detailed description of the implementation. The NOM is based on so-called support, dual-support, nonlocal operators, and an operate energy functional ensuring stability. The nonlocal operator is a generalization of the conventional differential operators. Combined with the method of weighed residuals and variational principles, NOM establishes the residual and tangent stiffness matrix of operate energy functional through some simple matrix without the need of shape functions as in other classical computational methods such as FEM. NOM only requires the definition of the energy drastically simplifying its implementation. The implementation in this paper is focused on linear elastic solids for sake of conciseness through the NOM can handle more complex nonlinear problems. The NOM can be very flexible and efficient to solve partial differential equations (PDEs), it’s also quite easy for readers to use the NOM and extend it to solve other complicated physical phenomena described by one or a set of PDEs. Finally, we present some classical benchmark problems including the classical cantilever beam and plate-with-a-hole problem, and we also make an extension of this method to solve complicated problems including phase-field fracture modeling and gradient elasticity material. KW - Strukturmechanik KW - Nonlocal operator method KW - Operator energy functional KW - Implicit KW - Dual-support KW - Variational principle KW - Taylor series expansion KW - Stiffness matrix Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220216-45930 UR - https://link.springer.com/article/10.1007/s00366-021-01537-x VL - 2022 SP - 1 EP - 35 PB - Springer CY - London ER - TY - JOUR A1 - Mehling, Simon A1 - Schnabel, Tobias A1 - Londong, Jörg T1 - Photocatalytic ozonation in an immersion rotary body reactor for the removal of micro-pollutants from the effluent of wastewater treatment plants JF - Water Science & Technology N2 - Carrier-bound titanium dioxide catalysts were used in a photocatalytic ozonation reactor for the degradation of micro-pollutants in real wastewater. A photocatalytic immersion rotary body reactor with a 36-cm disk diameter was used, and was irradiated using UV-A light-emitting diodes. The rotating disks were covered with catalysts based on stainless steel grids coated with titanium dioxide. The dosing of ozone was carried out through the liquid phase via an external enrichment and a supply system transverse to the flow direction. The influence of irradiation power and ozone dose on the degradation rate for photocatalytic ozonation was investigated. In addition, the performance of the individual processes photocatalysis and ozonation were studied. The degradation kinetics of the parent compounds were determined using liquid chromatography tandem mass spectrometry. First-order kinetics were determined for photocatalysis and photocatalytic ozonation. A maximum reaction rate of the reactor was determined, which could be achieved by both photocatalysis and photocatalytic ozonation. At a dosage of 0.4 mg /mg DOC, the maximum reaction rate could be achieved using 75% of the irradiation power used for sole photocatalysis, allowing increases in the energetic efficiency of photocatalytic wastewater treatment processes. The process of photocatalytic ozonation is suitable to remove a wide spectrum of micro-pollutants from wastewater. KW - Abwasserreinigung KW - Fotokatalyse KW - Mikroverunreinigungen KW - anthropogenic micro-pollutants KW - photocatalysis KW - photocatalytic ozonation KW - wastewater treatment KW - titan dioxide Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220209-45865 UR - https://iwaponline.com/wst/article/85/1/535/85800/Photocatalytic-ozonation-in-an-immersion-rotary VL - 2022 IS - volume 85, issue 1 SP - 535 EP - 548 PB - IWA Publishing CY - London ER - TY - JOUR A1 - Zhang, Yongzheng T1 - Nonlocal dynamic Kirchhoff plate formulation based on nonlocal operator method JF - Engineering with Computers N2 - In this study, we propose a nonlocal operator method (NOM) for the dynamic analysis of (thin) Kirchhoff plates. The nonlocal Hessian operator is derived based on a second-order Taylor series expansion. The NOM does not require any shape functions and associated derivatives as ’classical’ approaches such as FEM, drastically facilitating the implementation. Furthermore, NOM is higher order continuous, which is exploited for thin plate analysis that requires C1 continuity. The nonlocal dynamic governing formulation and operator energy functional for Kirchhoff plates are derived from a variational principle. The Verlet-velocity algorithm is used for the time discretization. After confirming the accuracy of the nonlocal Hessian operator, several numerical examples are simulated by the nonlocal dynamic Kirchhoff plate formulation. KW - Angewandte Mathematik KW - nonlocal operator method KW - nonlocal Hessian operator KW - operator energy functional KW - dual-support KW - variational principle Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220209-45849 UR - https://link.springer.com/article/10.1007/s00366-021-01587-1 VL - 2022 SP - 1 EP - 35 PB - Springer CY - London ER - TY - JOUR A1 - Rabczuk, Timon A1 - Guo, Hongwei A1 - Zhuang, Xiaoying A1 - Chen, Pengwan A1 - Alajlan, Naif T1 - Stochastic deep collocation method based on neural architecture search and transfer learning for heterogeneous porous media JF - Engineering with Computers N2 - We present a stochastic deep collocation method (DCM) based on neural architecture search (NAS) and transfer learning for heterogeneous porous media. We first carry out a sensitivity analysis to determine the key hyper-parameters of the network to reduce the search space and subsequently employ hyper-parameter optimization to finally obtain the parameter values. The presented NAS based DCM also saves the weights and biases of the most favorable architectures, which is then used in the fine-tuning process. We also employ transfer learning techniques to drastically reduce the computational cost. The presented DCM is then applied to the stochastic analysis of heterogeneous porous material. Therefore, a three dimensional stochastic flow model is built providing a benchmark to the simulation of groundwater flow in highly heterogeneous aquifers. The performance of the presented NAS based DCM is verified in different dimensions using the method of manufactured solutions. We show that it significantly outperforms finite difference methods in both accuracy and computational cost. KW - Maschinelles Lernen KW - Neuronales Lernen KW - Fehlerabschätzung KW - deep learning KW - neural architecture search KW - randomized spectral representation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220209-45835 UR - https://link.springer.com/article/10.1007/s00366-021-01586-2 VL - 2022 SP - 1 EP - 26 PB - Springer CY - London ER - TY - JOUR A1 - Legatiuk, Anastasiia A1 - Gürlebeck, Klaus A1 - Hommel, Angela T1 - Estimates for the discrete fundamental solution of the discrete Laplace operator on a rectangular lattice JF - Mathematical Methods in the Applied Sciences N2 - This paper presents numerical analysis of the discrete fundamental solution of the discrete Laplace operator on a rectangular lattice. Additionally, to provide estimates in interior and exterior domains, two different regularisations of the discrete fundamental solution are considered. Estimates for the absolute difference and lp-estimates are constructed for both regularisations. Thus, this work extends the classical results in the discrete potential theory to the case of a rectangular lattice and serves as a basis for future convergence analysis of the method of discrete potentials on rectangular lattices. KW - diskrete Fourier-Transformation KW - Laplace-Operator KW - discrete fourier transform KW - discrete fundamental solution KW - laplace operator KW - rectangular lattice Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220209-45829 UR - https://onlinelibrary.wiley.com/doi/full/10.1002/mma.7747 VL - 2021 SP - 1 EP - 23 PB - Wiley CY - Chichester ER - TY - JOUR A1 - Becher, Lia A1 - Gena, Amayu Wakoya A1 - Alsaad, Hayder A1 - Richter, Bernhard A1 - Spahn, Claudia A1 - Völker, Conrad T1 - The spread of breathing air from wind instruments and singers using schlieren techniques JF - Indoor Air N2 - The spread of breathing air when playing wind instruments and singing was investigated and visualized using two methods: (1) schlieren imaging with a schlieren mirror and (2) background-oriented schlieren (BOS). These methods visualize airflow by visualizing density gradients in transparent media. The playing of professional woodwind and brass instrument players, as well as professional classical trained singers were investigated to estimate the spread distances of the breathing air. For a better comparison and consistent measurement series, a single high note, a single low note, and an extract of a musical piece were investigated. Additionally, anemometry was used to determine the velocity of the spreading breathing air and the extent to which it was quantifiable. The results showed that the ejected airflow from the examined instruments and singers did not exceed a spreading range of 1.2 m into the room. However, differences in the various instruments have to be considered to assess properly the spread of the breathing air. The findings discussed below help to estimate the risk of cross-infection for wind instrument players and singers and to develop efficacious safety precautions, which is essential during critical health periods such as the current COVID-19 pandemic. KW - Covid-19 KW - Pandemie KW - Blasinstrument KW - Gesang KW - Schlierenmethode KW - airborne infection KW - background-oriented schlieren KW - schlieren imaging Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220209-45817 UR - https://onlinelibrary.wiley.com/doi/full/10.1111/ina.12869 VL - 2021 IS - volume 31, issue 6 SP - 1798 EP - 1814 PB - Wiley Blackwell CY - Oxford ER - TY - JOUR A1 - Buschow, Christopher A1 - Suhr, Maike A1 - Serger, Hauke T1 - Media Work as Field Advancement: The Case of Science Media Center Germany JF - Media and Communication N2 - In the wake of the news industry’s digitization, novel organizations that differ considerably from traditional media firms in terms of their functional roles and organizational practices of media work are emerging. One new type is the field repair organization, which is characterized by supporting high‐quality media work to compensate for the deficits (such as those which come from cost savings and layoffs) which have become apparent in legacy media today. From a practice‐theoretical research perspective and based on semi‐structured interviews, virtual field observations, and document analysis, we have conducted a single case study on Science Media Center Germany (SMC), a unique non‐profit news start‐up launched in 2016 in Cologne, Germany. Our findings show that, in addition to field repair activities, SMC aims to facilitate progress and innovation in the field, which we refer to as field advancement. This helps to uncover emerging needs and anticipates problems before they intensify or even occur, proactively providing products and tools for future journalism. This article contributes to our understanding of novel media organizations with distinct functions in the news industry, allowing for advancements in theory on media work and the organization of journalism in times of digital upheaval. KW - Journalismus KW - Digitalisierung KW - Online-Medien KW - digital journalism KW - field repair organization KW - news media start-up KW - media work KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220125-45709 UR - https://www.cogitatiopress.com/mediaandcommunication/article/view/4454 VL - 2022 IS - Volume 10, issue 1 SP - 99 EP - 109 PB - Cogitatio Press CY - Lisbon ER - TY - JOUR A1 - Kraus, Matthias A1 - Crişan, Nicolae-Andrei A1 - Wittor, Björn T1 - Stability Study of Cantilever-Beams – Numerical Analysis and Analytical Calculation (LTB) JF - ce/papers N2 - According to Eurocode, the computation of bending strength for steel cantilever beams is a straightforward process. The approach is based on an Ayrton-Perry formula adaptation of buckling curves for steel members in compression, which involves the computation of an elastic critical buckling load for considering the instability. NCCI documents offer a simplified formula to determine the critical bending moment for cantilevers beams with symmetric cross-section. Besides the NCCI recommendations, other approaches, e.g. research literature or Finite-Element-Analysis, may be employed to determine critical buckling loads. However, in certain cases they render different results. Present paper summarizes and compares the abovementioned analytical and numerical approaches for determining critical loads and it exemplarily analyses corresponding cantilever beam capacities using numerical approaches based on plastic zones theory (GMNIA). KW - Träger KW - Stahl KW - Biegefestigkeit KW - Finite-Elemente-Methode KW - Stahlträger KW - Knicklast KW - Freiträgerkapazität KW - Eurocode Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220112-45637 UR - https://onlinelibrary.wiley.com/doi/full/10.1002/cepa.1539 VL - 2021 IS - Volume 4, issue 2-4 SP - 2199 EP - 2206 PB - Ernst & Sohn, a Wiley brand CY - Berlin ER - TY - JOUR A1 - Ibanez, Stalin A1 - Kraus, Matthias T1 - A Numerical Approach for Plastic Cross Cross-Sectional Analyses of Steel Members JF - ce/papers N2 - Global structural analyses in civil engineering are usually performed considering linear-elastic material behavior. However, for steel structures, a certain degree of plasticization depending on the member classification may be considered. Corresponding plastic analyses taking material nonlinearities into account are effectively realized using numerical methods. Frequently applied finite elements of two and three-dimensional models evaluate the plasticity at defined nodes using a yield surface, i.e. by a yield condition, hardening rule, and flow rule. Corresponding calculations are connected to a large numerical as well as time-consuming effort and they do not rely on the theoretical background of beam theory, to which the regulations of standards mainly correspond. For that reason, methods using beam elements (one-dimensional) combined with cross-sectional analyses are commonly applied for steel members in terms of plastic zones theories. In these approaches, plasticization is in general assessed by means of axial stress only. In this paper, more precise numerical representation of the combined stress states, i.e. axial and shear stresses, is presented and results of the proposed approach are validated and discussed. KW - Stahlkonstruktion KW - Plastizität KW - Strukturanalyse KW - Stahlbauteil KW - Axialspannung KW - Finite-Elemente-Methode Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220112-45622 UR - https://onlinelibrary.wiley.com/doi/full/10.1002/cepa.1527 VL - 2021 IS - Volume 4, issue 2-4 SP - 2098 EP - 2106 PB - Ernst & Sohn, a Wiley brand CY - Berlin ER - TY - JOUR A1 - Mullis, Daniel A1 - Schipper, Sebastian T1 - Die postdemokratische Stadt zwischen Politisierung und Kontinuität. Oder ist die Stadt jemals demokratisch gewesen? JF - sub\urban. Zeitschrift für Kritische Stadtforschung N2 - In der kritischen Stadtforschung wird die These der postdemokratischen Stadt aktuell immer wieder aufgegriffen und dabei eng mit Prozessen der Neoliberalisierung verknüpft. Ausgehend von einer kritischen Diskussion der konzeptionellen Zugänge bei Colin Crouch und Jacques Rancière geht der Beitrag anhand der Geschichte der kommunalen Selbstverwaltung in Frankfurt am Main dem Gehalt der beiden Begriffsbestimmungen in der konkreten historischen Analyse nach. Verwiesen wird dabei auf die unterschiedliche Analysetiefe der beiden Konzepte. Entgegen der bei Crouch vorherrschenden Annahme, dass es vor der neoliberalen Stadt eine demokratische Form städtischen Regierens gegeben hat, wird unter Rückbezug auf die Argumentation Rancières zur Demokratie betont, dass der Fordismus keinesfalls als egalitärer, inklusiver oder demokratischer charakterisiert werden kann. Vielmehr vertreten wir die These, dass die fordistische Stadt zwar aus anderen Gründen, aber vom Grundsatz her nicht weniger postdemokratisch gewesen ist als die neoliberale der Gegenwart und dass die demokratischen Momente am ehesten in den Brüchen und Spalten der sozialen Konflikte der 1970er und 1980er Jahre gefunden werden können. KW - Stadtplanung KW - Demokratie KW - Neoliberalismus KW - Frankfurt am Main KW - Postdemokratie KW - soziale Kämpfe Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220112-45600 UR - https://zeitschrift-suburban.de/sys/index.php/suburban/article/view/97 VL - 2013 IS - Band 1, Heft 2 SP - 79 EP - 100 PB - sub\urban e.V. CY - Berlin ER - TY - JOUR A1 - Birkholz, Marie Luise T1 - Mächtiger Boden. Essay über den Versuch, einen Staatsapparat zu erlaufen JF - sub\urban. Zeitschrift für Kritische Stadtforschung N2 - Der Text folgt in essayistischer Form einem Spaziergang durch das politische Zentrum Brasílias in Brasilien. Die Konzentration liegt auf der Gestaltung des Bodens. Wie ist die Planhauptstadt „vom Reißbrett“ in der Horizontalen gestaltet? Wie sehen repräsentative Plätze einer Stadt aus, die vor allem für Autos gebaut worden ist? Der forschende Blick liegt auf dem erlebten Ist-Zustand und wird assoziativ mit Ergebnissen der Forschungsarbeit aus Deutschland reflektiert. „Mächtiger Boden“ entstand als Satellit zur aktuellen Forschung der Autorin im Rahmen eines Aufenthalts in Brasilien. KW - Brasilia KW - Stadtplanung KW - Brasilia KW - Stadtgestaltung KW - Bodengestaltung KW - Spaziergang KW - politische Repräsentation Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220112-45591 UR - https://zeitschrift-suburban.de/sys/index.php/suburban/article/view/200 VL - 2015 IS - Band 3, Heft 2 SP - 141 EP - 154 PB - ub\urban e.V. CY - Berlin ER - TY - JOUR A1 - Schmidt, Albrecht A1 - Lahmer, Tom T1 - Efficient domain decomposition based reliability analysis for polymorphic uncertain material parameters JF - Proceedings in Applied Mathematics & Mechanics N2 - Realistic uncertainty description incorporating aleatoric and epistemic uncertainties can be described within the framework of polymorphic uncertainty, which is computationally demanding. Utilizing a domain decomposition approach for random field based uncertainty models the proposed level-based sampling method can reduce these computational costs significantly and shows good agreement with a standard sampling technique. While 2-level configurations tend to get unstable with decreasing sampling density 3-level setups show encouraging results for the investigated reliability analysis of a structural unit square. KW - Polymorphie KW - Stoffeigenschaft KW - Stochastik KW - polymorphe Unschärfemodellierung KW - Materialverhalten KW - hybride Werkstoffe Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220112-45563 UR - https://onlinelibrary.wiley.com/doi/full/10.1002/pamm.202100014 VL - 2021 IS - Volume 21, issue 1 SP - 1 EP - 4 PB - Wiley-VHC CY - Weinheim ER - TY - JOUR A1 - Kraus, Matthias A1 - Klaus, Martin A1 - Wittor, Björn T1 - Experimental Analyses on the Resistance of Tapped Blind Holes JF - ce/papers N2 - Bolted connections are commonly used in steel construction. The load-bearing behavior of bolt fittings has extensively been studied in various research activities and the bearing capacity of bolted connections can be assessed well by standard regulations for practical applications. With regard to tensile loading, the nut does not have strong influence on resistances, since the failure occurs in the bolts due to higher material strengths of the nuts. In some applications, so-called “blind holes” are used to connect plated components. In a manner of speaking, the nut is replaced by the “outer” plate with a prefabricated hole and thread, in which the bolt can be screwed and tightened. In such connections, the limit load capacity cannot solely be assessed by the bolt resistance, since the threaded hole in the base material has strong influence on the structural behavior. In this context, the available screw-in depth of the blind hole is of fundamental importance. The German National Annex of EN 1993-1-8 provides information on a necessary depth in order to transfer the full tensile capacity of the bolt. However, some connections do not allow to fabricate such depths. In these cases, the capacity of the connection is unclear and not specified. In this paper, first experiments on corresponding connections with different screw-in depths are presented and compared to limit load capacities according to the standard. KW - Gewinde KW - Bolzen KW - threat KW - bolt KW - tapped blind holes Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220112-45553 UR - https://onlinelibrary.wiley.com/doi/10.1002/cepa.1273 VL - 2021 IS - Volume 4, issue 2-4 SP - 141 EP - 147 PB - Ernst & Sohn, a Wiley brand CY - Berlin ER - TY - JOUR A1 - Meiabadi, Mohammad Saleh A1 - Moradi, Mahmoud A1 - Karamimoghadam, Mojtaba A1 - Ardabili, Sina A1 - Bodaghi, Mahdi A1 - Shokri, Manouchehr A1 - Mosavi, Amir Hosein T1 - Modeling the Producibility of 3D Printing in Polylactic Acid Using Artificial Neural Networks and Fused Filament Fabrication JF - polymers N2 - Polylactic acid (PLA) is a highly applicable material that is used in 3D printers due to some significant features such as its deformation property and affordable cost. For improvement of the end-use quality, it is of significant importance to enhance the quality of fused filament fabrication (FFF)-printed objects in PLA. The purpose of this investigation was to boost toughness and to reduce the production cost of the FFF-printed tensile test samples with the desired part thickness. To remove the need for numerous and idle printing samples, the response surface method (RSM) was used. Statistical analysis was performed to deal with this concern by considering extruder temperature (ET), infill percentage (IP), and layer thickness (LT) as controlled factors. The artificial intelligence method of artificial neural network (ANN) and ANN-genetic algorithm (ANN-GA) were further developed to estimate the toughness, part thickness, and production-cost-dependent variables. Results were evaluated by correlation coefficient and RMSE values. According to the modeling results, ANN-GA as a hybrid machine learning (ML) technique could enhance the accuracy of modeling by about 7.5, 11.5, and 4.5% for toughness, part thickness, and production cost, respectively, in comparison with those for the single ANN method. On the other hand, the optimization results confirm that the optimized specimen is cost-effective and able to comparatively undergo deformation, which enables the usability of printed PLA objects. KW - 3D-Druck KW - Polymere KW - Maschinelles Lernen KW - 3D printing KW - machine learning KW - fused filament fabrication KW - OA-Publikationsfonds2021 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220110-45518 UR - https://www.mdpi.com/2073-4360/13/19/3219 VL - 2021 IS - Volume 13, issue 19, article 3219 SP - 1 EP - 21 PB - MDPI CY - Basel ER - TY - JOUR A1 - Alsaad, Hayder A1 - Hartmann, Maria A1 - Völker, Conrad T1 - Hygrothermal simulation data of a living wall system for decentralized greywater treatment JF - Data in Brief N2 - This dataset presents the numerical analysis of the heat and moisture transport through a facade equipped with a living wall system designated for greywater treatment. While such greening systems provide many environmental benefits, they involve pumping large quantities of water onto the wall assembly, which can increase the risk of moisture in the wall as well as impaired energetic performance due to increased thermal conductivity with increased moisture content in the building materials. This dataset was acquired through numerical simulation using the coupling of two simulation tools, namely Envi-Met and Delphin. This coupling was used to include the complex role the plants play in shaping the near-wall environmental parameters in the hygrothermal simulations. Four different wall assemblies were investigated, each assembly was assessed twice: with and without the living wall. The presented data include the input and output parameters of the simulations, which were presented in the co-submitted article [1]. KW - Kupplung KW - Feuchteleitung KW - Heat transport KW - Moisture transport KW - Living wall KW - Wärmeübertragung KW - coupling KW - ENVI-Met KW - Delphin KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220106-45483 UR - https://www.sciencedirect.com/science/article/pii/S2352340921010167?via%3Dihub VL - 2022 IS - volume 40, article 107741 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kleiner, Florian A1 - Rößler, Christiane A1 - Vogt, Franziska A1 - Osburg, Andrea A1 - Ludwig, Horst-Michael T1 - Reconstruction of calcium silicate hydrates using multiple 2D and 3D imaging techniques: Light microscopy, μ-CT, SEM, FIB-nT combined with EDX JF - Journal of Microscopy N2 - This study demonstrates the application and combination of multiple imaging techniques [light microscopy, micro-X-ray computer tomography (μ-CT), scanning electron microscopy (SEM) and focussed ion beam – nano-tomography (FIB-nT)] to the analysis of the microstructure of hydrated alite across multiple scales. However, by comparing findings with mercury intrusion porosimetry (MIP), it becomes obvious that the imaged 3D volumes and 2D images do not sufficiently overlap at certain scales to allow a continuous quantification of the pore size distribution (PSD). This can be overcome by improving the resolution and increasing the measured volume. Furthermore, results show that the fibrous morphology of calcium-silicate-hydrates (C-S-H) phases is preserved during FIB-nT. This is a requirement for characterisation of nano-scale porosity. Finally, it was proven that the combination of FIB-nT with energy-dispersive X-ray spectroscopy (EDX) data facilitates the phase segmentation of a 11 × 11 × 7.7 μm3 volume of hydrated alite. KW - Zementklinker KW - Bildsegmentierung KW - Rasterelektronenmikroskopie KW - Computertomographie KW - tomography KW - focussed ion beam KW - cement microstructure KW - micro-CT Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220106-45458 UR - https://onlinelibrary.wiley.com/doi/10.1111/jmi.13081 VL - 2021 SP - 1 EP - 6 PB - John Wiley & Sons Ltd CY - Oxford ER -