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The behaviour of infilled reinforced concrete frames under horizontal load has been widely investigated, both experimentally and numerically. Since experimental tests represent large investments, numerical simulations offer an efficient approach for a more comprehensive analysis. When RC frames with masonry infill walls are subjected to horizontal loading, their behaviour is highly non-linear after a certain limit, which makes their analysis quite difficult. The non-linear behaviour results from the complex inelastic material properties of the concrete, infill wall and conditions at the wall-frame interface. In order to investigate this non-linear behaviour in detail, a finite element model using a micro modelling approach is developed, which is able to predict the complex non-linear behaviour resulting from the different materials and their interaction. Concrete and bricks are represented by a non-linear material model, while each reinforcement bar is represented as an individual part installed in the concrete part and behaving elasto-plastically. Each brick is modelled individually and connected taking into account the non-linearity of a brick mortar interface. The same approach is followed using two finite element software packages and the results are compared with the experimental results. The numerical models show a good agreement with the experiments in predicting the overall behaviour, but also very good matching for strength capacity and drift. The results emphasize the quality and the valuable contribution of the numerical models for use in parametric studies, which are needed for the derivation of design recommendations for infilled frame structures.
Eine seismische Anregung verursacht in einem Flüssigkeitstank einen kombinierten Spannungszustand, was zu einem Stabilitätsversagen der häufig sehr dünnwandigen Konstruktionen führen kann. Für die Durchführung von Stabilitätsnachweisen stehen verschiedene Verfahren zur Verfügung. Üblicherweise werden aus Gründen der Einfachheit spannungsbasierte Verfahren angewendet. Diese sind für Einheitslastfälle experimentell abgesichert, wobei eine Übertragung auf kombinierte Spannungszustände wie im Erdbebenfall nur begrenzt möglich ist. Alternativ kann ein globales, numerisches Konzept, das LBA/MNA-Verfahren, angewendet werden. Das Verfahren kombiniert eine materiell nichtlineare Berechnung (MNA) mit einer linearen Beulanalyse (LBA) und erfasst die Interaktion verschiedener gleichzeitig auftretender Beanspruchungen implizit im Nachweis. Dieser Beitrag demonstriert die Anwendung der Verfahren am Beispiel verschiedener Tankgeometrien mit Höhe/Radius-Verhältnissen zwischen 1 ≤ H/R ≤ 2 und Radius/Tankwand-Verhältnissen zwischen 500 ≤ R/t ≤ 1000 und diskutiert zusätzlich die Defizite der spannungsbasierten Nachweisverfahren.
This paper describes the procedure on the evaluation of the masonry chapter for the next generation of Eurocode 8, the European Standard for earthquake-resistant design. In CEN, TC 250/SC8, working group WG 1 has been established to support the subcommittee on the topic of masonry on both design of new structures (EN1998-1) and assessment of existing structures (EN1998-3). The aim is to elaborate suggestions for amendments which fit the current state of the art in masonry and earthquake-resistant design. Focus will be on modelling, simplified methods, linear-analysis (q-values, overstrength-values), nonlinear procedures, out-of-plane design as well as on clearer definition of limit states. Beside these, topics related to general material properties, reinforced masonry, confined masonry, mixed structures and non-structural infills will be covered too. This paper presents the preliminary work and results up to the submission date.
Future engineers are increasingly confronted with the so-called Megatrends which are the big social challenges society has to cope with. These Megatrends, such as “Silver Society”, “Globalization”, “Mobility” and “Female Shift” require an application-oriented perspective on Diversity especially in the engineering field. Therefore, it is necessary to enable future engineers not only to look at the technical perspectives of a problem, but also to be able to see the related questions within societies they are developing their artefacts for. The aim of teaching engineering should be to prepare engineers for these requirements and to draw attention to the diverse needs in a globalized world.
Bringing together technical knowledge and social competences which go beyond a mere training of the so-called “soft skills”, is a new approach followed at RWTH Aachen University, one of the leading technical universities in Germany. RWTH Aachen University has established the bridging professorship “Gender and Diversity in Engineering” (GDI) which educates engineers with an interdisciplinary approach to expand engineering limits. In the frame of a sustainable teaching concept the research group under the leadership of Prof. Carmen Leicht-Scholten has developed an approach which imparts a supplication-specific Gender and Diversity expertise to engineers. In workshops students gain theoretical knowledge about Gender and Diversity and learn how to transfer their knowledge in their special field of study and later work. To substantiate this, the course participants have to solve case studies from real life. The cases which are developed in collaboration with non-profit organizations and enterprises from economy rise the students to challenges which are inspired by professional life. Evaluation shows the success of this approach as well as an increasing demand for such teaching formats.
Simulating the electromagnetic‐thermal treatment of thin aluminium layers for adhesion improvement
(2015)
A composite layer material used in packaging industry is made from joining layers of different materials using an adhesive. An important processing step in the production of aluminium-containing composites is the surface treatment and consequent coating of adhesive material on the aluminium surface. To increase adhesion strength between aluminium layer and the adhesive material, the foil is heat treated. For efficient heating, induction heating was considered as state-of-the-art treatment process. Due to the complexity of the heating process and the unpredictable nature of the heating source, the control of the process is not yet optimised. In this work, a finite element analysis of the process was established and various process parameters were studied. The process was simplified and modelled in 3D. The numerical model contains an air domain, an aluminium layer and a copper coil fitted with a magnetic field concentrating material. The effect of changing the speed of the aluminium foil (or rolling speed) was studied with the change of the coil current. Statistical analysis was used for generating a general control equation of coil current with changing rolling speed.
Lately there has been an increasing concern about uranium toxicity in some districts of Punjab State located in the North Western part of India after the publication of a report (Blaurock-Busch et al. 2010) which showed that the concentration of uranium in hair and urine of children suffering from physical deformities, neurological and mental disorder from Malwa region (Fig. 1) of Punjab State was manifold higher than the reference ranges. A train which connects the affected region with the nearby city of Bikaner which has a Cancer Hospital has been nicknamed as Cancer Express due to the frenzy generated on account of uranium related toxicity.
Globale Stabilitätsanalysen zylindrischer, seismisch belasteter Tanks auf numerischer Grundlage
(2015)
Laut Zukunftsinstitut (2010) stellt die Individualisierung eine langfristige und nachhaltige Veränderung dar, die die gesamte Gesellschaft (den einzelnen Menschen, Unternehmen, den Staat) betrifft und Auswirkungen auf nahezu alle Lebensbereiche (z. B. Arbeit, Wohnen, Partnerschaft) hat. Die Individualisierung beschreibt dabei die Entwicklung hin zur Fokussierung persönlicher Interessen und Lebensentscheidungen der einzelnen Person (Kunze, Individualisierung, 2011). Der Grund für diese Entwicklung sind laut Kunze (Individualisierung, 2011) Treiber wie steigendes Vermögen, Bildung und Mobilität, was die einzelne Person unabhängiger von größeren Gemeinschaften macht und mehr Freiheit zur Selbstverwirklichung bietet. Als eine Konsequenz daraus werden Wertevorstellungen nicht mehr einfach hingenommen, sondern für die eigene Person überprüft und individualisiert (Kunze, Individualisierung, 2011). So wies Beck bereits 1996 darauf hin, dass Individualisierung meint „erstens die Auflösung und zweitens die Ablösung industriegesellschaftlicher Lebensformen durch andere, in denen die Einzelnen ihre Biographie selbst herstellen, inszenieren, zusammenflickschustern müssen“ (Beck, Die Erfindung des Politischen, 1996, S. 150).
Ausblick: Der individualitätsbezogene Diversity Management-Ansatz als Antwort auf Individualisierung
(2015)
Der Megatrend Individualisierung fordert von Unternehmen, ihre Strategien und Prozessabläufe bei zunehmender Globalisierung grundlegend zu überdenken. Während Strategien und Prozessabläufe im Unternehmen Standards unterliegen, entwickelt sich unsere Gesellschaft immer stärker zu einem individuumszentrierten System, in dem es gilt, Werte und Lebensstile der Individuen zu berücksichtigen und derart wertzuschätzen, dass Mitarbeitende motiviert und mit hoher Bindung an das Unternehmen die anstehenden Leistungen für das Unternehmen erbringen. Im Konzept DiM sind Standardisierung und Individualisierung keine gegensätzlichen Aspekte, da bei DiM neben der Betrachtung des betriebswirtschaftlichen Nutzens dieses Konzepts für Unternehmen die Wertschätzung des Individuums als genuines Merkmal betont wird.
Within the framework of the project a genderand diversity-oriented teaching evaluation and modern, media-supported blended learning approaches were used in order to achieve the intended goals. First research results of the literature and status quo analysis were already implemented and tested in newly designed teaching approaches, for example in a multidisciplinary introductory lecture of civil engineering at RWTH Aachen University.
Heat production in the windings of the stators of electric machines under stationary condition
(2014)
In electric machines due to high currents and resistive losses (joule heating) heat is produced. To avoid damages by overheating the design of effective cooling systems is required. Therefore the knowledge of heat sources and heat transfer processes is necessary. The purpose of this paper is to illustrate a good and effective calculation method for the temperature analysis based on homogenization techniques. These methods have been applied for the stator windings in a slot of an electric machine consisting of copper wires and resin. The key quantity here is an effective thermal conductivity, which characterizes the heterogeneous wire resin-arrangement inside the stator slot. To illustrate the applicability of the method, the analysis of a simplified, homogenized model is compared with the detailed analysis of temperature behavior inside a slot of an electric machine according to the heat generation. We considered here only the stationary situation. The achieved numerical results are accurate and show that the applied homogenization technique works in practice. Finally the results of simulations for the two cases, the original model of the slot and the homogenized model chosen for the slot (unit cell), are compared to experimental results.
Following earlier studies, we present forward and inverse simulations of heat and fluid transport of the upper crust using a local 3-D model of the Kola area. We provide best estimates for palaeotemperatures and permeabilities, their errors and their dependencies. Our results allow discriminating between the two mentioned processes to a certain extent, partly resolving the non-uniqueness of the problem. We find clear indications for a significant contribution of advective heat transport, which, in turn, imply only slightly lower ground surface temperatures during the last glacial maximum relative to the present value. These findings are consistent with the general background knowledge of (i) the fracture zones and the corresponding fluid movements in the bedrock and (ii) the glacial history of the Kola area.
This paper describes two courses on
simulation methods for graduate students:
“Simulation Methods” and “Simulation and
Optimization in Virtual Engineering” The
courses were planned to teach young engineers
how to work with simulation software as well as
to understand the necessary mathematical background.
As simulation software COMSOL is
used. The main philosophy was to combine
theory and praxis in a way that motivates the
students. In addition “soft skills” should be
improved. This was achieved by project work as
final examination. As underlying didactical principle
the ideas of Bloom’s revised taxonomy
were followed. The paper basically focusses on
educational aspects, e.g. how to structure the
course, plan the exercises, organize the project
work and include practical COMSOL examples.
The 2nd edition of the lightning risk management
standard (IEC 62305-2) considers structures, which may
endanger environment. In these cases, the loss is not limited to
the structure itself, which is valid for usual structures. In the past
(Edition 1) this danger was simply taken into account by a special
hazard factor, multiplying the existing risk for the structure with
a number. Now, in the edition 2, we add to the risk for the
structure itself a “second risk” due to the losses outside the
structure. The losses outside can be treated independently from
what occurs inside. This is a major advantage to analyze the risk
for sensitive structures, like chemical plants, nuclear plants, or
structures containing explosives, etc. In this paper, the existing
procedure given by the European version EN 62305-2 Ed.2 is
further developed and applied to a few structures.
Risk management for structures with a risk of explosion should be considered very carefully when performing a risk analysis according to IEC 62305-2. In contrast to the 2006 edition of the standard, the 2010 edition describes the topic “Structures with a risk of explosion” in more detail. Moreover, in Germany separate procedures and parameters are defined for the risk analysis of structures with a risk of explosion (Supplement 3 of the German DIN EN 62305-2 standard). This paper describes the contents and the relevant calculations of this Supplement 3, together with a numerical example.
Am 1. Oktober 2013 ist das auf drei Jahre angelegte EU-Forschungsprojekt INSYSME – Innovative Systeme für erdbebentaugliche Ausfachungswände aus Ziegelmauerwerk in Stahlbetonrahmentragwerken – gestartet. Unter der Koordination der Universität Padua beteiligen sich 16 Partner aus sechs europäischen Ländern (Deutschland, Griechenland, Italien, Portugal, Rumänien, Türkei). Als deutsche Partner nehmen die Arbeitsgemeinschaft Mauerziegel aus Bonn, die Universität Kassel sowie das Ingenieurbüro SDA-engineering GmbH aus Herzogenrath, teil. Ziel der deutschen Partner ist die Entwicklung von innovativen Ausfachungssystemen aus monolithischem wärmedämmenden Ziegelmauerwerk, mit denen nicht nur eine erhöhte Erdbebensicherheit, sondern auch die sichere Erfüllung der steigenden Anforderungen aus Windbeanspruchungen gewährleistet werden können. Die Forschungsergebnisse sollen vom Partner SDA-engineering GmbH in die bereits seit einigen Jahren verfügbare Softwarelösung MINEA [1] integriert werden. Weitere Informationen stehen auf den Websites des Projektes [2] zur Verfügung. Im vorliegenden Beitrag werden nach einer kurzen thematischen Einführung die Ergebnisse von Tastversuchen an senkrecht zur Ebene belasteten Ausfachungswänden aus Planziegelmauerwerk vorgestellt. Im Anschluss wird das geplante Arbeitsprogramm der deutschen Partner im Projekt INSYSME beschrieben.
Die Erdbeben in Albstadt 1978 (Magnitude 5,7), Roermond 1992 (Magnitude 5,9) oder in Waldkirch 2004 (Magnitude 5,1) haben verdeutlicht, dass die erdbebensichere Auslegung von Mauerwerksbauten auch in Deutschland von großer Bedeutung ist. Bereits im Jahr 1981 wurde die DIN 4149 (1981) “Bauten in deutschen Erdbebengebieten – Lastannahmen, Bemessung und Ausführung üblicher Hochbauten“ eingeführt, in der aber für Mauerwerksbauten nur wenige Anforderungen gestellt wurden. Diese Norm wurde durch den NABau-Arbeitsausschuss “Erdbeben; Sonderfragen“ des Deutschen Instituts für Normung e.V. (DIN) auf Grundlage des Eurocode 8 (2004) vollständig überarbeitet und durch die DIN 4149 (2005) abgelöst, die umfangreiche Regelungen für die seismische Auslegung von Mauerwerksbauten enthält. Mittlerweile liegen die DIN EN 1998-1 (2010) und der Nationale Anhang DIN EN 1998-1/NA (2011) vor, die nach Einarbeitung der Ergebnisse der durchgeführten Anwendungserprobung bauaufsichtlich eingeführt und die DIN 4149 (2005) ersetzen werden. Der folgende Beitrag gibt einen Überblick über die seismische Berechnung und Bemessung von Mauerwerksbauten nach dem europäischen Regelwerk und illustriert deren Anwendung an einem baupraktischen Beispiel.