TY - CHAP A1 - Staat, Manfred A1 - Heitzer, Michael T1 - Limit and shakedown analysis for plastic design N2 - Limit and shakedown theorems are exact theories of classical plasticity for the direct computation of safety factors or of the load carrying capacity under constant and varying loads. Simple versions of limit and shakedown analysis are the basis of all design codes for pressure vessels and pipings. Using Finite Element Methods more realistic modeling can be used for a more rational design. The methods can be extended to yield optimum plastic design. In this paper we present a first implementation in FE of limit and shakedown analyses for perfectly plastic material. Limit and shakedown analyses are done of a pipe–junction and a interaction diagram is calculated. The results are in good correspondence with the analytic solution we give in the appendix. KW - Einspielen KW - Traglast KW - Finite-Elemente-Methode KW - Traglastanalyse KW - Einspielanalyse KW - FEM KW - limit analysis KW - shakedown analysis Y1 - 1997 ER - TY - CHAP A1 - Staat, Manfred A1 - Tran, Thanh Ngoc A1 - Pham, Phu Tinh T1 - Limit and shakedown reliability analysis by nonlinear programming N2 - 7th International Conference on Reliability of Materials and Structures (RELMAS 2008). June 17 - 20, 2008 ; Saint Petersburg, Russia. pp 354-358. Reprint with corrections in red Introduction Analysis of advanced structures working under extreme heavy loading such as nuclear power plants and piping system should take into account the randomness of loading, geometrical and material parameters. The existing reliability are restricted mostly to the elastic working regime, e.g. allowable local stresses. Development of the limit and shakedown reliability-based analysis and design methods, exploiting potential of the shakedown working regime, is highly needed. In this paper the application of a new algorithm of probabilistic limit and shakedown analysis for shell structures is presented, in which the loading and strength of the material as well as the thickness of the shell are considered as random variables. The reliability analysis problems may be efficiently solved by using a system combining the available FE codes, a deterministic limit and shakedown analysis, and the First and Second Order Reliability Methods (FORM/SORM). Non-linear sensitivity analyses are obtained directly from the solution of the deterministic problem without extra computational costs. KW - Finite-Elemente-Methode KW - Limit analysis KW - Shakedown analysis Y1 - 2008 ER - TY - CHAP A1 - Kern, Alexander A1 - Krichel, Frank A1 - Müller, Klaus-Peter T1 - Lightning protection design of a renewable energy hybrid-system without power mains connection N2 - In the year 2000 a direct lightning strike to the hybridsystem without power mains connection VATALI on the Greek island Crete results in the destruction and damage of some mechanical and electrical components. The hybrid-system VATALI was not lightning protected at that time. The hardware damage costs are approx. 60,000 €. The exposed site of the hybrid-system on top of a mountain was and still is the reason for a high risk of lightning strikes. Also in the future further lightning strikes have to be taken into consideration. In the paper a fundamental lightning protection design concept for renewable energy hybrid-systems without power mains connection and protection measures against direct strikes and overvoltages are shown in detail. The design concept was realized exemplarily for the hybrid-system VATALI. The hardware costs for the protection measures were about 15,000 €. About 50% of the costs are due to protection measures against direct strikes, 50% are due to overvoltage protection. Future extensions, new installations, or modifications have to be included into the lightning protection design concept of the hybrid-system. KW - Blitzschutz KW - Erneuerbare Energien KW - Hybridsystem KW - Lightning protection KW - Renewable energy KW - hybrid-system Y1 - 2001 ER - TY - CHAP A1 - Zischank, Wolfgang J. A1 - Kern, Alexander A1 - Frentzel, Ralf A1 - Heidler, Fridolin A1 - Seevers, M. T1 - Assessment of the lightning transient coupling to control cables interconnecting structures in large industrial facilities and power plants N2 - Large industrial facilities and power plants often require a huge number fo information and control cables between the differnet structures. These I&C-cables can be routed in reinforced concrete cable ducts or in isolated buried cable runs. KTA 2206 is the German lightning protection standard for nuclear power plants. During the last several years considerable effort has been made to revise this standard. Despite the well established principles and design guidelines for the construction of the lightning protection system, this standard puts special emphasis on the coupling of transient overvoltages to I&C-cables. KW - Blitzschutz KW - Elektromagnetische Kopplung KW - Überspannung KW - Kraftwerke KW - Industrieanlagen KW - Lightning KW - current distribution KW - electromagnetic coupling KW - overvoltages Y1 - 2000 ER - TY - CHAP A1 - Fredebeul-Krein, Markus T1 - Time for revision: The regulation of Germany's next generation networks in the light of new economic and technological challenges on telecom markets : Presentation for the 18th Biennial conference of the International Telecommunications Society, June 24–27, 2008 Montreal, Canada N2 - On 1st January 1998, the German telecom market was fully liberalised. Since then genuine competition between market participants has developed, based on a comprehensive legal and regulatory framework that provides for safeguards against unfair competition and market power by Deutsche Telekom. Today, about 10 years after the liberalisation of the telecommunications sector a revision of this regulatory approach has become necessary because at least on three dimensions the situation is quite different from the one 10 years ago: First, with numerous established alternative operators in the market monopolies have been successfully challenged and competition introduced. Second, not only is Cable TV becoming in large parts of Germany a viable alternative for the provision of broadband services but also mobile services are becoming increasingly a substitute for fixed services. Last but not least there are important technological changes under way, requiring huge investments in infrastructure upgrades for next generation networks. In the light of these new developments the question is to which extent the current regulatory approach of severe ex-ante regulatory intervention is still appropriate. Is any part of the network of the former incumbent still a bottleneck? A more light handed regulatory approach might be the right response to this new situation. The paper is organised as follows: The first section will briefly examine the economic rationale for regulating network access. Based on the assumption that regulation is always necessary when bottlenecks exist regulatory principles for an efficient network access regime will be derived. The second section compares the situation of the German market in early 1998 with the one of today. Thereby three dimensions will be considered: the degree of competition, the potential for substitution and technological developments. The third section will define some requirements for the future regulation of telecom markets. Proposals will be elaborated how to ensure competitive telecom markets in the light of new economic and technological challenges. KW - Telekommunikationsmarkt KW - Telekommunikationsmarkt Y1 - 2008 ER - TY - CHAP A1 - Fredebeul-Krein, Markus A1 - Haunert, Martina T1 - Assessing the effectiveness of price cap regimes for the regulation of fixed telephony markets: has it been successful in achieving competition? : preliminary draft / by Markus Fredebeul-Krein and Martina Haunert. 19th European Regional ITS Conference of the International Telecommunications Society, September 17–19, 2008 Rome, Italy N2 - 1. Introduction 2. Tariff regulation, rebalancing and price caps 3. Price cap regimes in selected European countries 4. Has price cap regulation been successful? 5. Regulatory implications for other countries KW - Telekommunikationsmarkt KW - Telekommunikationsmarkt Y1 - 2008 ER - TY - CHAP A1 - Fredebeul-Krein, Markus T1 - Developing competitive broadband markets: Lessons learnt from German and European regulatory approaches on broad-band access N2 - A key feature of future broadband markets will be diversity of access technologies, meaning that numerous technologies will be exploited for broadband communication. Various factors will affect the success of these future broadband markets, the regulatory policy being one amongst others. So far, a coherent regulatory approach does not exist as to broadband markets. First results of policies so far suggest that less sector-specific regulation is likely to occur. Instead, regulators must ensure that access to networks and services of potentially dominant providers in a relevant broadband market will satisfy requirements for openness and non-discrimination. In this environment the future challenge of regulationg broadband markets will be to set the right incentives for investment into new infrastructures. This paper examines whether there is a need for the regulation of future broadband access markets an if yes, what is the appropriate regulatory tool to do so. Thereby the focus is on the analysis of European broadband markets and the regulatory approaches applied. The first section provides a description of the characteristics of future broadband markets. The second section discusses possible bottlenecks on broadband markets an their regulatory implications. The third section will examine regulatory issues concerning access to broadband networks in more detail. This will be done by comparing the regulatory approaches of European countries and the results in terms of bradband penetration. The final section will give key recommendations for a regulatory strategy on brandband access markets. KW - Telekommunikationsmarkt KW - Telekommunikationsmarkt Y1 - 2006 N1 - paper presented at 16th Biennial conference of the International Telecommunications Society. Information Communication Technology: Opportunities and Challenges for Telecommunications. June 12-16, 2006 Beijing, China. ER - TY - CHAP A1 - Staat, Manfred A1 - Ballmann, J. T1 - Fundamental aspects of numerical methods for the propagation of multi-dimensional nonlinear waves in solids T2 - Nonlinear hyperbolic equations : theory, computations methods, and applications ; proceedings of the 2nd International Conference on Nonlinear Hyperbolic Problems, Aachen N2 - The nonlinear scalar constitutive equations of gases lead to a change in sound speed from point to point as would be found in linear inhomogeneous (and time dependent) media. The nonlinear tensor constitutive equations of solids introduce the additional local effect of solution dependent anisotropy. The speed of a wave passing through a point changes with propagation direction and its rays are inclined to the front. It is an open question whether the widely used operator splitting techniques achieve a dimensional splitting with physically reasonable results for these multi-dimensional problems. May be this is the main reason why the theoretical and numerical investigations of multi-dimensional wave propagation in nonlinear solids are so far behind gas dynamics. We hope to promote the subject a little by a discussion of some fundamental aspects of the solution of the equations of nonlinear elastodynamics. We use methods of characteristics because they only integrate mathematically exact equations which have a direct physical interpretation. KW - Nichtlineare Welle KW - Nichtlineare Gleichung KW - Festkörper KW - Elastodynamik KW - Multi-dimensional wave propagation KW - nonlinear solids KW - nonlinear tensor constitutive equation Y1 - 1989 SP - 574 EP - 588 ER - TY - CHAP A1 - Merten, Sabine A1 - Conrad, Thorsten A1 - Kämper, Klaus-Peter A1 - Picard, Antoni A1 - Schütze, Andreas T1 - Virtual Technology Labs - an efficient tool for the preparation of hands-on-MEMS-courses in training foundries N2 - Hands-on-training in high technology areas is usually limited due to the high cost for lab infrastructure and equipment. One specific example is the field of MEMS, where investment and upkeep of clean rooms with microtechnology equipment is either financed by production or R&D projects greatly reducing the availability for education purposes. For efficient hands-on-courses a MEMS training foundry, currently used jointly by six higher education institutions, was established at FH Kaiserslautern. In a typical one week course, students manufacture a micromachined pressure sensor including all lithography, thin film and packaging steps. This compact and yet complete program is only possible because participants learn to use the different complex machines in advance via a Virtual Training Lab (VTL). In this paper we present the concept of the MEMS training foundry and the VTL preparation together with results from a scientific evaluation of the VTL over the last three years. KW - Virtuelles Laboratorium KW - Virtuelles Labor KW - Hand-on-training KW - Virtual Technology Lab KW - MEMS ; education and training foundry Y1 - 2006 ER - TY - CHAP A1 - Weßling, Matthias T1 - Leadership Perspectives: Research Findings, Theories, Practical Experiences N2 - Leadership Perspectives: Research Findings, Theories, Practical Experiences: Results of Leadership Research and exemplarily application cases show the perspectives and consequences for leadership practice and the following requirements for executives in future. N2 - Leadership Perspectives: Research Findings, Theories, Practical Experiences: Bisherige Ergebnisse der betriebswirtschaftlichen Führungsforschung und exemplarische Anwendungsbeispiele der Führungspraxis, sowie die Schlußfolgerungen für die Perspektiven der betrieblichen Mitarbeiterführung sowie die sich daraus ergebenden Anforderungen an zukünftige Führungskräfte. KW - Leadership KW - Führung KW - Führungsansätze KW - Leadership KW - Self-Leadership KW - Leadership Approaches KW - Skill Assessment KW - Leadership Theories Y1 - 2007 ER - TY - CHAP A1 - Weßling, Matthias T1 - Motivation and Leadership - The Reiss-Profile of the 16 Basic Desires: Research results and managerial applications N2 - Recent Results of the scientific Reiss-Profile (16 basic desires) due to the concept of Prof. Dr. Steven Reiss (State University Ohio, U.S.A.), supplemented by the comparative analysis of empirical motivational profiles of european executives of various companies. N2 - Neuere Forschungsergebnisse des wissenschaftlichen Reiss-Profils der 16 Lebensmotive nach Prof. Dr. Steven Reiss (State University Ohio, U.S.A.) und die Möglichkeiten und Grenzen ihrer Umsetzung in der betrieblichen Führungspraxis unter Integration der vergleichenden Analyse und Interpretation empirisch erhobener Motivprofile einzelner europäischer Führungskräfte. KW - Motivation KW - Leadership KW - Motivation KW - Führung KW - Motivation KW - Leadership Y1 - 2007 ER - TY - CHAP A1 - Weßling, Matthias T1 - Provocative Communication in Coaching and Leadership: scientific research and managerial applications of the Provocative Communication Style N2 - Concept, scientific research and managerial applications of Provocative Coaching, according to the „Provocative Therapy“ of Prof. Dr. Frank Farrelly (University of Wisconsin, U.S.A) in terms of an application of the Provocative Communication Style in specific situations of practical leadership, especially in the role of a coach for their subordinates. N2 - Konzept, Forschungsergebnisse und Tools der sogenannten „Provocative Therapy“ nach Prof. Dr. Frank Farrelly (University of Wisconsin, U.S.A) und ihre Anwendung als provokativer Kommunikationsstil einer Führungskraft in spezifischen Situationen der betrieblichen Führungspraxis in der Rolle eines Coaches. KW - Kommunikation KW - Coaching KW - Führung KW - Kommunikation KW - Coaching KW - Führung KW - Provokativer Stil KW - Provocative Coaching KW - Leadership KW - Communication KW - Provocative Style Y1 - 2007 ER - TY - GEN A1 - Kämper, Klaus-Peter T1 - Lecture notes Sensors and Actuators N2 - Kennwortgeschützter Zugang nur für Studierende bei Prof. Dr. Klaus-Peter Kämper. Wintersemester 2007/2008. Version vom 30.08.2007. 472 Seiten (pdf-Format) N2 - Password necessarily. Access only for Students by Prof. Dr. Klaus-Peter Kämper. Winter semester 2007/2008. Version 2007-08-30. 472 pages (pdf) Contents 1. Introduction 2. Introduction to Sensors 3. Introduction to Microfabrication 4. Pressure Sensors 5. Acceleration Sensors 6. Angular Rate Sensors 7. Position Sensors 8. Flow Sensors 9. Piezoelectric Actuators 10. Magnetostrictive Actuators 11. Actuators based on Shape Memory Alloys 12. Actuators based on Electrorheological Fluids 13. Actuators based on Magnetorheological Fluids KW - Sensor KW - Aktor KW - Sensoren KW - Aktoren KW - Sensores KW - Actuators KW - Microfabrication Y1 - 2007 ER - TY - CHAP A1 - Tran, Thanh Ngoc A1 - Staat, Manfred A1 - Kreißig, R. T1 - Calculation of load carrying capacity of shell structures with elasto-plastic material by direct methods N2 - Proceedings of the International Conference on Material Theory and Nonlinear Dynamics. MatDyn. Hanoi, Vietnam, Sept. 24-26, 2007, 8 p. In this paper, a method is introduced to determine the limit load of general shells using the finite element method. The method is based on an upper bound limit and shakedown analysis with elastic-perfectly plastic material model. A non-linear constrained optimisation problem is solved by using Newton’s method in conjunction with a penalty method and the Lagrangean dual method. Numerical investigation of a pipe bend subjected to bending moments proves the effectiveness of the algorithm. KW - Finite-Elemente-Methode Y1 - 2007 ER - TY - CHAP A1 - Fredebeul-Krein, Markus T1 - 10 years of liberalised telecom markets in Germany: Assessing the degree of competition on the markets for voice telephony N2 - Market data for the German telecom market shows that Deutsche Telekom as the former incumbent is constantly loosing shares on all arkets for voice telephony: the market for local calls, the market for long-distance calls and the market for international calls. At the same time prices decline steadily with the latest trend being that operators offer voice services free of charge, the costs of which are covered by a monthly subscription charge. Against this background the paper examines the state of policy and regulatory reform in the telecommunications sector in Germany almost 10 years after the liberalisation of the fixed telecommunications market. Thereby the focus is on the analysis of the competitive conditions that have been established on the German market for voice telephony services. If these retail markets are competitive, there might be a need to remove remaining regulatory provisions. In the new environment of converging markets the future challenge of regulating fixed telecom markets might be to ensure that access to the network and/or services of a potentially dominant provider in a relevant market will satisfy requirements for openness and non-discrimination. KW - Telekommunikationsmarkt KW - Telekommunikationsmarkt Y1 - 2007 N1 - paper presented at 18th European Regional ITS Conference of the International Telecommunications Society, September 2-4, 2007 Istanbul, Turkey ER - TY - CHAP A1 - Tran, Thanh Ngoc A1 - Staat, Manfred A1 - Kreißig, R. T1 - Finite element shakedown and limit reliability analysis of thin shells N2 - A procedure for the evaluation of the failure probability of elastic-plastic thin shell structures is presented. The procedure involves a deterministic limit and shakedown analysis for each probabilistic iteration which is based on the kinematical approach and the use the exact Ilyushin yield surface. Based on a direct definition of the limit state function, the non-linear problems may be efficiently solved by using the First and Second Order Reliabiblity Methods (Form/SORM). This direct approach reduces considerably the necessary knowledge of uncertain technological input data, computing costs and the numerical error. In: Computational plasticity / ed. by Eugenio Onate. Dordrecht: Springer 2007. VII, 265 S. (Computational Methods in Applied Sciences ; 7) (COMPLAS IX. Part 1 . International Center for Numerical Methods in Engineering (CIMNE)). ISBN 978-1-402-06576-7 S. 186-189 KW - Finite-Elemente-Methode KW - Limit analysis KW - shakedown analysis KW - Exact Ilyushin yield surface KW - Random variable KW - First Order Reliabiblity Method Y1 - 2007 ER - TY - CHAP A1 - Heitzer, M. A1 - Staat, Manfred T1 - Direct FEM approach to design-by-analysis of pressurized components N2 - Abstracts of the ACHEMA 2000 - International Meeting on Chemical Engineering, Environmental Protection and Biotechnology, May 22 - 27, 2000. Frankfurt am Main. Achema 2000 : special edition / Linde. [Ed.: Linde AG. Red.: Volker R. Leski]. - Wiesbaden : Linde AG, 2000. - 56 p. : Ill., . - pp: 79 - 81 N2 - Abstracts der ACHEMA 2000 - International Meeting on Chemical Engineering, Environmental Protection and Biotechnology, May 22 - 27, 2000. Frankfurt am Main. KW - Finite-Elemente-Methode KW - Finite-Elemente-Methode KW - limit analysis KW - shakedown analysis Y1 - 2000 ER - TY - JOUR A1 - Staat, Manfred T1 - Direct FEM Limit and Shakedown Analysis with Uncertain Data N2 - 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. KW - Finite-Elemente-Methode KW - Einspielen KW - FEM KW - Einspielanalyse KW - shakedown KW - limit load KW - reliability analysis KW - FEM KW - direct method Y1 - 2000 ER - TY - JOUR A1 - Vu, Duc-Khoi A1 - Staat, Manfred T1 - An algorithm for shakedown analysis of structure with temperature dependent yield stress N2 - 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. KW - Einspielen KW - Temperaturabhängigkeit KW - Fließgrenze KW - Shakedown KW - shakedown analysis KW - yield stress Y1 - 2004 ER - TY - JOUR A1 - Kühn, Raoul-Roman A1 - Haugner, Werner A1 - Staat, Manfred A1 - Sponagel, Stefan T1 - A Two Phase Mixture Model based on Bone Observation N2 - 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. KW - Knochen KW - Knochenbildung KW - Knochenchirugie KW - Strukturanalyse KW - Schwammknochen KW - Knochendichte KW - Wolffsches Gesetz KW - bone structure KW - bone density KW - Wolff's Law KW - cancellous bone Y1 - 2004 ER -