@article{DickWagnerRoeth2005, author = {Dick, Angela and Wagner, Manfred and R{\"o}th, Thilo}, title = {Capro Automotive Group FH Aachen}, year = {2005}, abstract = {Design- und Karosseriebaustudenten der FH Aachen entwickeln gemeinsam mit externen Fachleuten unter Einsatz virtueller Entwicklungswerkzeuge ein Konzept f{\"u}r einen Sportwagen}, subject = {Karosseriebau}, language = {de} } @article{MatheisRoethWagner2005, author = {Matheis, Anton and R{\"o}th, Thilo and Wagner, Manfred}, title = {Studentenprojekt "Capro" - eine virtuelle Sportwagenstudie "Vision 2015"}, year = {2005}, abstract = {Design- und Karosseriebaustudenten der FH Aachen entwickeln gemeinsam mit externen Fachleuten unter Einsatz virtueller Entwicklungswerkzeuge ein Konzept f{\"u}r einen Sportwagen}, subject = {Karosseriebau}, language = {de} } @article{BaroudWuBohneretal.2003, author = {Baroud, G. and Wu, J.Z. and Bohner, M and Sponagel, Stefan and Steffen, T.}, title = {How to determine the permeability for cement infiltration into osteoporotic cancellous bone}, series = {Medical Engineering \& Physics. 25 (2003), H. 4}, journal = {Medical Engineering \& Physics. 25 (2003), H. 4}, issn = {1350-4533}, pages = {283 -- 288}, year = {2003}, abstract = {Cement augmentation is an emerging surgical procedure in which bone cement is used to infiltrate and reinforce osteoporotic vertebrae. Although this infiltration procedure has been widely applied, it is performed empirically and little is known about the flow characteristics of cement during the injection process. We present a theoretical and experimental approach to investigate the intertrabecular bone permeability during the infiltration procedure. The cement permeability was considered to be dependent on time, bone porosity, and cement viscosity in our analysis. In order to determine the time-dependent permeability, ten cancellous bone cores were harvested from osteoporotic vertebrae, infiltrated with acrylic cement at a constant flow rate, and the pressure drop across the cores during the infiltration was measured. The viscosity dependence of the permeability was determined based on published experimental data. The theoretical model for the permeability as a function of bone porosity and time was then fit to the testing data. Our findings suggest that the intertrabecular bone permeability depends strongly on time. For instance, the initial permeability (60.89 mm4/N.s) reduced to approximately 63\% of its original value within 18 seconds. This study is the first to analyze cement flow through osteoporotic bone. The theoretical and experimental models provided in this paper are generic. Thus, they can be used to systematically study and optimize the infiltration process for clinical practice.}, subject = {Osteoporose}, language = {en} } @article{KuehnHaugnerStaatetal.2004, author = {K{\"u}hn, Raoul-Roman and Haugner, Werner and Staat, Manfred and Sponagel, Stefan}, title = {A Two Phase Mixture Model based on Bone Observation}, year = {2004}, abstract = {An optimization method is developed to describe the mechanical behaviour of the human cancellous bone. The method is based on a mixture theory. A careful observation of the behaviour of the bone material leads to the hypothesis that the bone density is controlled by the principal stress trajectories (Wolff's law). The basic idea of the developed method is the coupling of a scalar value via an eigenvalue problem to the principal stress trajectories. On the one hand this theory will permit a prediction of the reaction of the biological bone structure after the implantation of a prosthesis, on the other hand it may be useful in engineering optimization problems. An analytical example shows its efficiency.}, subject = {Knochen}, language = {en} } @article{VuStaat2004, author = {Vu, Duc-Khoi and Staat, Manfred}, title = {An algorithm for shakedown analysis of structure with temperature dependent yield stress}, year = {2004}, abstract = {This work is an attempt to answer the question: How to use convex programming in shakedown analysis of structures made of materials with temperature-dependent properties. Based on recently established shakedown theorems and formulations, a dual relationship between upper and lower bounds of the shakedown limit load is found, an algorithmfor shakedown analysis is proposed. While the original problem is neither convex nor concave, the algorithm presented here has the advantage of employing convex programming tools.}, subject = {Einspielen }, language = {en} } @article{Staat2000, author = {Staat, Manfred}, title = {Direct FEM Limit and Shakedown Analysis with Uncertain Data}, year = {2000}, abstract = {The structural reliability with respect to plastic collapse or to inadaptation is formulated on the basis of the lower bound limit and shakedown theorems. A direct definition of the limit state function is achieved which permits the use of the highly effective first order reliability methods (FORM) is achieved. The theorems are implemented into a general purpose FEM program in a way capable of large-scale analysis. The limit state function and its gradient are obtained from a mathematical optimization problem. This direct approach reduces considerably the necessary knowledge of uncertain technological input data, the computing time, and the numerical error, leading to highly effective and precise reliability analyses.}, subject = {Finite-Elemente-Methode}, language = {en} } @article{KaemperPicardBrilletal.2003, author = {K{\"a}mper, Klaus-Peter and Picard, Antoni and Brill, Manfred and Cassel, Detlev and Jentsch, Andreas and Merten, Sabine and Rollwa, Markus}, title = {The Virtual Clean Room - a new tool in teaching MST process technologies}, year = {2003}, abstract = {The Virtual Clean Room - a new tool in teaching MST process technologies University education in high-technology fields like MST is not complete without intensive laboratory sessions. Students cannot fully grasp the complexity and the special problems related to the manufacturing of microsystems without a thorough hands-on experience in a MST clean room.}, subject = {Virtuelle Maschine}, language = {en} } @article{PicardBrillCasseletal.2002, author = {Picard, Antoni and Brill, Manfred and Cassel, Detlev and Jentsch, Andreas and Rollwa, Markus and K{\"a}mper, Klaus-Peter and Merten, Sabine}, title = {Neue Medien f{\"u}r die praktische MST-Ausbildung}, organization = {FH-Kaiserslautern}, year = {2002}, abstract = {Im Studiengang Mikrosystemtechnik des Fachhochschulstandortes Zweibr{\"u}cken werden zwei neue moderne Anlagen f{\"u}r die Herstellung von mikrotechnischen Komponenten in Betrieb genommen: Ein Oxidationsofen f{\"u}r Herstellung d{\"u}nner Oxidschichten auf Silizium-Einkristallen und eine Belichtungsapparatur f{\"u}r die Fotolithografie - das Besondere an diesen Anlagen: Sie existieren nur virtuell, d.h. als Animationen in einer Computerwelt.}, subject = {Mikrosystemtechnik}, language = {de} } @article{Fabo2003, author = {Fabo, Sabine}, title = {Das Museum lebt? Der Diskurs der Vernetzung im virtuellen Kunstraum}, series = {Zeitenblicke}, volume = {2(2003)}, journal = {Zeitenblicke}, number = {1}, year = {2003}, abstract = {Kunstwerke sowie ihre Pr{\"a}sentation und Vermittlung werden zunehmend von digitalen Technologien unterst{\"u}tzt. Virtuelle Ausstellungen, Internet-Projekte und komplexe Datenarchive stellen das Kunstwerk in einen medialen Kontext, der weit {\"u}ber das Moment einer technischen Reproduzierbarkeit hinausgeht. Das allgegenw{\"a}rtige Konzept der Vernetzung dynamisiert Kunst, ihre Rezipienten und Ausstellungsorte. Die Beziehungen zwischen diesen Feldern werden mit Hilfe physiologischer Metaphern definiert und visualisiert. Fr{\"u}here Speicher und Archive geraten in einen prozessualen Sog, in dem alles fluktuiert, sich kurzweilig verkn{\"u}pft, aufl{\"o}st und in permanente Dialoge mit seiner Umgebung tritt - das virtuelle Museum ger{\"a}t in aktuellen Standortbestimmungen in die definitorische N{\"a}he des K{\"u}nstlichen Lebens.}, subject = {Elektronische Kunst}, language = {de} } @article{Staat2001, author = {Staat, Manfred}, title = {LISA - a European project for FEM-based limit and shakedown analysis}, year = {2001}, abstract = {The load-carrying capacity or the safety against plastic limit states are the central questions in the design of structures and passive components in the apparatus engineering. A precise answer is most simply given by limit and shakedown analysis. These methods can be based on static and kinematic theorems for lower and upper bound analysis. Both may be formulated as optimization problems for finite element discretizations of structures. The problems of large-scale analysis and the extension towards realistic material modelling will be solved in a European research project. Limit and shakedown analyses are briefly demonstrated with illustrative examples.}, subject = {Einspielen }, language = {en} } @article{Staat2000, author = {Staat, Manfred}, title = {Basis Reduction for the Shakedown Problem for Bounded Kinematic Hardening Material}, year = {2000}, abstract = {Limit and shakedown analysis are effective methods for assessing the load carrying capacity of a given structure. The elasto-plastic behavior of the structure subjected to loads varying in a given load domain is characterized by the shakedown load factor, defined as the maximum factor which satisfies the sufficient conditions stated in the corresponding static shakedown theorem. The finite element dicretization of the problem may lead to very large convex optimization. For the effective solution a basis reduction method has been developed that makes use of the special problem structure for perfectly plastic material. The paper proposes a modified basis reduction method for direct application to the two-surface plasticity model of bounded kinematic hardening material. The considered numerical examples show an enlargement of the load carrying capacity due to bounded hardening.}, subject = {Finite-Elemente-Methode}, language = {en} } @article{Staat2003, author = {Staat, Manfred}, title = {Shakedown and ratchetting under tension-torsion loadings: analysis and experiments}, year = {2003}, abstract = {Structural design analyses are conducted with the aim of verifying the exclusion of ratchetting. To this end it is important to make a clear distinction between the shakedown range and the ratchetting range. The performed experiment comprised a hollow tension specimen which was subjected to alternating axial forces, superimposed with constant moments. First, a series of uniaxial tests has been carried out in order to calibrate a bounded kinematic hardening rule. The load parameters have been selected on the basis of previous shakedown analyses with the PERMAS code using a kinematic hardening material model. It is shown that this shakedown analysis gives reasonable agreement between the experimental and the numerical results. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis.}, subject = {Einspielen }, language = {en} } @article{Staat2005, author = {Staat, Manfred}, title = {Direct finite element route for design-by-analysis of pressure components}, year = {2005}, abstract = {In the new European standard for unfired pressure vessels, EN 13445-3, there are two approaches for carrying out a Design-by-Analysis that cover both the stress categorization method (Annex C) and the direct route method (Annex B) for a check against global plastic deformation and against progressive plastic deformation. This paper presents the direct route in the language of limit and shakedown analysis. This approach leads to an optimization problem. Its solution with Finite Element Analysis is demonstrated for mechanical and thermal actions. One observation from the examples is that the so-called 3f (3Sm) criterion fails to be a reliable check against progressive plastic deformation. Precise conditions are given, which greatly restrict the applicability of the 3f criterion.}, subject = {Einspielen }, language = {en} } @article{Staat2005, author = {Staat, Manfred}, title = {Local and global collapse pressure of longitudinally flawed pipes and cylindrical vessels}, year = {2005}, abstract = {Limit loads can be calculated with the finite element method (FEM) for any component, defect geometry, and loading. FEM suggests that published long crack limit formulae for axial defects under-estimate the burst pressure for internal surface defects in thick pipes while limit loads are not conservative for deep cracks and for pressure loaded crack-faces. Very deep cracks have a residual strength, which is modelled by a global collapse load. These observations are combined to derive new analytical local and global collapse loads. The global collapse loads are close to FEM limit analyses for all crack dimensions.}, subject = {Finite-Elemente-Methode}, language = {en} } @article{Staat2001, author = {Staat, Manfred}, title = {Cyclic plastic deformation tests to verify FEM-based shakedown analyses}, year = {2001}, abstract = {Fatigue analyses are conducted with the aim of verifying that thermal ratcheting is limited. To this end it is important to make a clear distintion between the shakedown range and the ratcheting range (continuing deformation). As part of an EU-supported research project, experiments were carried out using a 4-bar model. The experiment comprised a water-cooled internal tube, and three insulated heatable outer test bars. The system was subjected to alternating axial forces, superimposed with alternating temperatures at the outer bars. The test parameters were partly selected on the basis of previous shakedown analyses. During the test, temperatures and strains were measured as a function of time. The loads and the resulting stresses were confirmed on an ongoing basis during performance of the test, and after it. Different material models were applied for this incremental elasto-plastic analysis using the ANSYS program. The results of the simulation are used to verify the FEM-based shakedown analysis.}, subject = {Materialerm{\"u}dung}, language = {en} } @article{Staat2004, author = {Staat, Manfred}, title = {Plastic collapse analysis of longitudinally flawed pipes and vessels}, year = {2004}, abstract = {Improved collapse loads of thick-walled, crack containing pipes and vessels are suggested. Very deep cracks have a residual strength which is better modelled by a global limit load. In all burst tests, the ductility of pressure vessel steels was sufficiently high whereby the burst pressure could be predicted by limit analysis with no need to apply fracture mechanics. The relative prognosis error increases however, for long and deep defects due to uncertainties of geometry and strength data.}, subject = {Druckbeh{\"a}lter}, language = {en} } @article{SchermutzkiKluss2004, author = {Schermutzki, Margret and Kluß, Stefan}, title = {Kontaktstunden oder workload? Die Vergabe von ECTS credits}, year = {2004}, abstract = {Informationen dar{\"u}ber, wie die Arbeitsbelastung (workload) der Studierenden ermittelt werden kann}, subject = {Bologna-Prozess}, language = {de} } @article{Heger2004, author = {Heger, Michael}, title = {Konzept hochschuldidaktischer Aktionsforschung am Beispiel INGMEDIA}, year = {2004}, abstract = {"INGMEDIA: Entwicklung und Evaluation interaktiver, multimedialer Lernsoftware f{\"u}r technische und physikalische Praktika in Ingenieurstudieng{\"a}ngen". So lautet der Titel des vom bmb+f im F{\"o}rderprogramm "Neue Medien in der Hochschullehre" unterst{\"u}tzten Verbundprojekts. [...] Im vorliegenden Beitrag wird {\"u}ber das Evaluationskonzept von INGMEDIA berichtet. Es handelt sich hierbei um einen im E-Learning-Bereich bisher kaum vertretenen Ansatz hochschuldidaktischer Aktionsforschung. Der Beitrag betont entsprechend des kevih - Tagungskonzepts (T{\"u}bingen 11./12.3.03) die besonderen hochschuldidaktischen Zielrichtungen, fokussiert also klar auf der konzeptionellen Ebene. Die Umsetzung und Evaluationsergebnisse zu INGMEDIA werden nach Projektabschluss an anderer Stelle ver{\"o}ffentlicht.}, language = {de} } @article{HegerKock2004, author = {Heger, Michael and Kock, Winfried}, title = {INGMEDIA, blended learning im Laborpraktikum. Ein hochschuldidaktisches Projekt}, year = {2004}, abstract = {Laborpraktika bieten Studierenden besondere Lernm{\"o}glichkeiten. Sie erleben im Praktikum mit Kopf (kognitiv), Herz (affektiv) und Hand (motorisch) Zusammenh{\"a}nge und Zusammenarbeit. Durch die multimediale Vorbereitung und Unterst{\"u}tzung der Laborpraktika mit INGMEDIA k{\"o}nnen diese Lernvorteile intensiver genutzt werden. Vielf{\"a}ltige und differenzierte Kontextangebote bieten individuelle Lerneinstiegsm{\"o}glichkeiten und aktivieren zu Selbstgesteuertem Lernen. Durch die Verbesserung von Vorwissen und Motivation er{\"o}ffnen scih Lehrenden und Lernenden neue Freir{\"a}ume bei der Gestaltung der Pr{\"a}senzveranstaltung. Durch hochschuldidaktische Aktionsforschung beim Einsatz im Lehrbetrieb wird die weitere Entwicklung von Software und Pr{\"a}senzveranstaltung prozesshaft begleitet.}, language = {de} } @article{Kern2003, author = {Kern, Alexander}, title = {Risikomanagement f{\"u}r den Blitzschutz - Absch{\"a}tzung des Blitzschadensrisikos nach der neuen Vornorm VDE V 0185 Teil 2 : 2002}, year = {2003}, abstract = {Ein vorausschauendes Risikomanagement beinhaltet, Risiken zu kalkulieren. Es liefert Entscheidungsgrundlagen, um diese Risiken zu begrenzen und es macht transparent,welche Risiken sinnvoll {\"u}ber Versicherungen abgedeckt werden sollten. Bei Unternehmen, die mit umfangreichen elektronischenEinrichtungen produzieren oder Dienstleistungen erbringen (und das sind heutzutage wohl die meisten), muss auch das Risiko durch Blitzeinwirkungen besondere Ber{\"u}cksichtigung finden. Dabei ist zu beachten, dass der Schaden aufgrund der Nichtverf{\"u}gbarkeit der elektronischen Einrichtungen und damit derProduktion bzw. der Dienstleistung und ggf. der Verlust von Daten den Hardwareschaden an der betroffenen Anlage oft bei weitem {\"u}bersteigt.}, language = {de} } @article{KernKrichel2003, author = {Kern, Alexander and Krichel, Frank}, title = {{\"U}berlegungen zum Blitzschutzkonzept f{\"u}r regenerative Energieanlagen}, year = {2003}, abstract = {Dem Blitzschutz von Anlagen der regenerativen Energien kommt in Zukunft eine steigende Bedeutung zu. Dabei ist es notwendig zu ber{\"u}cksichtigen, dass die Schutzmaßnahmen technisch/wirtschaftlich ausgewogen sind. Erbauer, Besitzer oder Benutzer von netzautarken Hybridanlagen haben zu entscheiden, ob die Anlage einen Schutz braucht oder nicht. Um diese Entscheidung zu f{\"a}llen, ist eine Risikoanalyse als erster Schritt sinnvoll. Diese muss dabei die f{\"u}r die Hybridanlage relevanten Schadenarten und spezifischen Parameter, Werte und Randbedingungen mit einbeziehen. Dazu ist die Hilfe eines Blitzschutzexperten sehr hilfreich.}, subject = {Alternative Energiequelle}, language = {de} }