@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{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 <Werkstoff>},
  language  = {en}
}
@inproceedings{Staat2003,
  author    = {Staat, Manfred},
  title     = {Design by Analysis of Pressure Components by non-linear Optimization},
  year      = {2003},
  abstract  = {This paper presents the direct route to Design by Analysis (DBA) of the new European pressure vessel standard in the language of limit and shakedown analysis (LISA). This approach leads to an optimization problem. Its solution with Finite Element Analysis is demonstrated for some examples from the DBA-Manual. One observation from the examples is, that the optimisation approach gives reliable and close lower bound solutions leading to simple and optimised design decision.},
  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}
}
@inproceedings{ButenwegKuhlmannLopezetal.2003,
  author    = {Butenweg, Christoph and Kuhlmann, Winfried and Lopez, M. and Fernandez, S.},
  title     = {Seismic vulnerability assessment of the Aachen Cathedral based on measurements and numerical simulations},
  series = {International Conference on Earthquake Engineering to mark 40 years from Catastrophic 1963 Skopje Earthquake, Skopje 2003},
  booktitle = {International Conference on Earthquake Engineering to mark 40 years from Catastrophic 1963 Skopje Earthquake, Skopje 2003},
  organization    = {International conference in earthquake engineering to mark 40 years from catastrophic 1963 Skopje earthquake <2003, Skopje>},
  pages     = {1 -- 8},
  year      = {2003},
  language  = {en}
}
@inproceedings{KraftMeyerNagl2002,
  author    = {Kraft, Bodo and Meyer, Oliver and Nagl, Manfred},
  title     = {Graph technology support for conceptual design in civil engineering},
  isbn      = {3-18-318004-9},
  year      = {2002},
  abstract  = {In: Advances in intelligent computing in engineering : proceedings of the 9.International EG-ICE Workshop ; Darmstadt, (01 - 03 August) 2002 / Martina Schnellenbach-Held ... (eds.) . - D{\"u}sseldorf: VDI-Verl., 2002 .- Fortschritt-Berichte VDI, Reihe 4, Bauingenieurwesen ; 180 ; S. 1-35 The paper describes a novel way to support conceptual design in civil engineering. The designer uses semantical tools guaranteeing certain internal structures of the design result but also the fulfillment of various constraints. Two different approaches and corresponding tools are discussed: (a) Visually specified tools with automatic code generation to determine a design structure as well as fixing various constraints a design has to obey. These tools are also valuable for design knowledge specialist. (b) Extensions of existing CAD tools to provide semantical knowledge to be used by an architect. It is sketched how these different tools can be combined in the future. The main part of the paper discusses the concepts and realization of two prototypes following the two above approaches. The paper especially discusses that specific graphs and the specification of their structure are useful for both tool realization projects.},
  subject      = {CAD},
  language  = {en}
}
@inproceedings{StaatHeitzer2002,
  author    = {Staat, Manfred and Heitzer, Michael},
  title     = {The restricted influence of kinematic hardening on shakedown loads},
  year      = {2002},
  abstract  = {Structural design analyses are conducted with the aim of verifying the exclusion of ratcheting. To this end it is important to make a clear distinction between the shakedown range and the ratcheting range. In cyclic plasticity more sophisticated hardening models have been suggested in order to model the strain evolution observed in ratcheting experiments. The hardening models used in shakedown analysis are comparatively simple. It is shown that shakedown analysis can make quite stable predictions of admissible load ranges despite the simplicity of the underlying hardening models. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis. Both give identical or similar shakedown ranges. Structural shakedown analyses show that the loading may have a more pronounced effect than the hardening model.},
  subject      = {Biomedizinische Technik},
  language  = {en}
}
@inproceedings{DarvenizaFlisowskiKernetal.2002,
  author    = {Darveniza, M. and Flisowski, Z. and Kern, Alexander and Landers, E.-U. and LoPiparo, G. and Mazzetti, C. and Rousseau, A. and Sherlock, J.},
  title     = {Application problems of the probabilistic approach to the assessment of risk for structures and services},
  year      = {2002},
  abstract  = {The paper deals with the development of the probabilistic approach to the assessment of risk due to lightning. Sources of damage, types of damage and types of loss are defined and, accordingly, the procedure for risk analysis and the way of assessment of different risk components is proposed. The way to evaluate the influence of different protection measures (lightning protection system; shielding of structure, cables and equipment; routing of internal wiring; surge protective device) in reducing such probabilities is considered. The paper has been prepared within the framework of the activity of IEC TC81-WG9/CLC TC81-WG4 directed to prepare the draft IEC 62305-2 Risk Management, in cooperation with the Secretary of IEC/CLC TC81.},
  language  = {en}
}
@inproceedings{KernKrichel2002,
  author    = {Kern, Alexander and Krichel, Frank},
  title     = {Considerations about the lightning protection system of mains independent renewable energy hybrid-systems - practical experiences},
  year      = {2002},
  abstract  = {In the paper a lightning protection design concept for renewable energy hybrid-systems without power mains connection is described. Based on a risk analysis protection measures against direct strikes and overvoltages are shown in an overview. The design concept is realized exemplarily for the hybrid-system VATALI on the Greek island Crete. VATALI, not lightning protected at that time, was a victim of a lightning strike in the year 2000 causing destructions and damages of some mechanical and electrical components with costs of approx. 60.000 €. 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.},
  language  = {en}
}
@inproceedings{ZischankHeidlerKernetal.2002,
  author    = {Zischank, Wolfgang J. and Heidler, Fridolin and Kern, Alexander and Metwally, I. A. and Wiesinger, J. and Seevers, M.},
  title     = {Laboratory simulation of direct lightning strokes to a modelled building - measurement of magnetic fields and induced voltages},
  year      = {2002},
  abstract  = {In IEC 61312-2 equations for the assessment of the magnetic fields inside structures due to a direct lightning strike are given. These equations are based on computer simulations for shields consisting of a single-layer steel grid of a given mesh width. Real constructions, however, contain at least two layers of reinforcement steel grids. The objective of this study was to experimentally determine the additional shielding effectiveness of a second reinforcement layer compared to a single-layer grid. To this end, simulated structures were set up in the high current laboratory. The structures consisted of cubic cages of 2 m side length with one or with two reinforcement grids, respectively. The structures were exposed to direct lightning currents representing the variety of anticipated lightning current waveforms. The magnetic fields and their derivatives at several positions inside the structure as well as the voltage between "floor" and "roof" in the center were determined for different current injection points. From these data the improvement of the shielding caused by a second reinforcement layer is derived.},
  language  = {en}
}
@inproceedings{DielmannPeters2002,
  author    = {Dielmann, Klaus-Peter and Peters, Bernhard},
  title     = {Micro Turbine Using Different Gases and Liquid Fuels},
  year      = {2002},
  abstract  = {Micro turbine using different gases and liquid fuels},
  subject      = {Gasturbine},
  language  = {en}
}
@inproceedings{ChudobaButenwegKuhlmann2002,
  author    = {Chudoba, Rostislav and Butenweg, Christoph and Kuhlmann, Wolfram},
  title     = {Technical information system for collaborative material research},
  series = {Sixth International Conference on Computational Structures Technology : [Prague, Czech Republic, 4 - 6 September 2002]},
  booktitle = {Sixth International Conference on Computational Structures Technology : [Prague, Czech Republic, 4 - 6 September 2002]},
  organization    = {International Conference on Computational Structures Technology <6, 2002, Prag>},
  pages     = {1 -- 11},
  year      = {2002},
  language  = {en}
}
@inproceedings{KernKrichelMueller2001,
  author    = {Kern, Alexander and Krichel, Frank and M{\"u}ller, Klaus-Peter},
  title     = {Lightning protection design of a renewable energy hybrid-system without power mains connection},
  year      = {2001},
  abstract  = {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.},
  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{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 <Werkstoff>},
  language  = {en}
}
@inproceedings{Mertens2000,
  author    = {Mertens, Josef},
  title     = {Laminar leading edges: manufacturing, contamination, and operational aspects - results from the German RaWid programme},
  year      = {2000},
  abstract  = {RaWid was the German national technology programme on transonic aerodynamics and supporting technologies, lasting from 1995 to 1998. One of the main topics was laminar wing development. Besides aerodynamic design work, many operational aspects were investigated. A manufacturing concept was developed to be applied to operational laminar wings and empennages. It was built in a large scale manufacturing demonstrator with the aerodynamic shape of a 1,5 m section of the A320 fin nose. Tolerances in shape and roughness fulfilled all requirements. The construction can easily be adapted to varying stiffness and strength requirements. Weight and manufacturing costs are comparable to common nose designs. The mock-up to be designed in ALTTA is based on this manufacturing principle. Another critical point is contamination of suction surfaces. Several tests were performed to investigate perforated titanium suction surfaces at realistic operational conditions: - a one year flight test with a suction plate in the stagnation area of the Airbus "Beluga" - a one year test of several suction plates in a ground test near the airport - a one year test of a working suction ground test installation at all weather conditions. No critical results were found. There is no long term suction degradation visible. Icing conditions and ground de-icing fluids used on airports did not pose severe problems. Some problems detected require only respection of weak design constraints.},
  subject      = {Laminare Str{\"o}mung},
  language  = {en}
}
@inproceedings{HeitzerStaat2000,
  author    = {Heitzer, M. and Staat, Manfred},
  title     = {Direct FEM approach to design-by-analysis of pressurized components},
  year      = {2000},
  abstract  = {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},
  subject      = {Finite-Elemente-Methode},
  language  = {en}
}
@inproceedings{ZischankKernFrentzeletal.2000,
  author    = {Zischank, Wolfgang J. and Kern, Alexander and Frentzel, Ralf and Heidler, Fridolin and Seevers, M.},
  title     = {Assessment of the lightning transient coupling to control cables interconnecting structures in large industrial facilities and power plants},
  year      = {2000},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{StaatHeitzer2000,
  author    = {Staat, Manfred and Heitzer, Michael},
  title     = {Direct static FEM approach to limit and shakedown analysis},
  year      = {2000},
  abstract  = {Safety and reliability of structures may be assessed indirectly by stress distributions. Limit and shakedown theorems are simplified but exact methods of plasticity that provide safety factors directly in the loading space. These theorems may be used for a direct definition of the limit state function for failure by plastic collapse or by inadaptation. In a FEM formulation the limit state function is obtained from a nonlinear optimization problem. This direct approach reduces considerably the necessary knowledge of uncertain technological input data, the computing time, and the numerical error. Moreover, the direct way leads to highly effective and precise reliability analyses. The theorems are implemented into a general purpose FEM program in a way capable of large-scale analysis.},
  subject      = {Einspielen <Werkstoff>},
  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}
}