TY - JOUR A1 - Staat, Manfred T1 - Shakedown and ratchetting under tension-torsion loadings: analysis and experiments N2 - 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. KW - Einspielen KW - Einspielen KW - Ratchetting KW - Zug-Druck Belastung KW - shakedown KW - ratchetting KW - tension–torsion loading Y1 - 2003 ER - TY - CHAP A1 - Staat, Manfred T1 - Design by Analysis of Pressure Components by non-linear Optimization N2 - 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. KW - Analytischer Zulaessigkeitsnachweis KW - FEM KW - Einspiel-Analyse KW - design-by-analysis KW - finite element analysis KW - limit and shakedown analysis Y1 - 2003 ER - TY - JOUR A1 - Kämper, Klaus-Peter A1 - Picard, Antoni A1 - Brill, Manfred A1 - Cassel, Detlev A1 - Jentsch, Andreas A1 - Merten, Sabine A1 - Rollwa, Markus T1 - The Virtual Clean Room - a new tool in teaching MST process technologies N2 - 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. KW - Virtuelle Maschine KW - VM KW - Mikrosystemtechnik KW - MST KW - virtual clean room Y1 - 2003 ER - TY - JOUR A1 - Seibler, Jost A1 - Zevnik, Branko A1 - Küter-Luks, Birgit A1 - Andreas, Susanne A1 - Kern, Heidrun A1 - Hennek, Thomas A1 - Rode, Anja A1 - Heimann, Cornelia A1 - Faust, Nicole A1 - Kauselmann, Gunther A1 - Schoor, Michael A1 - Jaenisch, Rudolf A1 - Rajewsky, Klaus A1 - Kühn, Ralf A1 - Schwenk, Frieder T1 - Rapid generation of inducible mouse mutants JF - Nucleic Acids Research Y1 - 2003 U6 - http://dx.doi.org/10.1093/nar/gng012 SN - 1362-4962 VL - 33 IS - 4 SP - e12 ER - TY - CHAP A1 - Chudoba, Rostislav A1 - Butenweg, Christoph A1 - Pfeiffer, Frank T1 - Textile reinforced concrete. Part I: Process model for collaborative research and development T2 - Digital proceedings / IKM 2003, proceedings 16th International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering [Elektronische Ressource : 10. - 12. Juni 2003, Weimar] / Bauhaus-Universität Weimar. Ed.: K. Gürlebeck; L. Hempel; C. Könke Y1 - 2003 SP - 1 EP - 8 PB - IKM CY - Weimar ER - TY - CHAP A1 - Konrad, M. A1 - Chudoba, Rostislav A1 - Butenweg, Christoph A1 - Bruckermann, O. T1 - Textile reinforced concrete. Part II: Multi-level modeling concept T2 - Digital proceedings / IKM 2003, proceedings 16th International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering [Elektronische Ressource : 10. - 12. Juni 2003, Weimar] / Bauhaus-Universität Weimar. Ed.: K. Gürlebeck; L. Hempel; C. Könke Y1 - 2003 SP - 1 EP - 11 PB - IKM CY - Weimar ER - TY - CHAP A1 - Butenweg, Christoph A1 - Kuhlmann, Winfried A1 - Lopez, M. A1 - Fernandez, S. T1 - Seismic vulnerability assessment of the Aachen Cathedral based on measurements and numerical simulations T2 - International Conference on Earthquake Engineering to mark 40 years from Catastrophic 1963 Skopje Earthquake, Skopje 2003 Y1 - 2003 SP - 1 EP - 8 ER - TY - CHAP A1 - Staat, Manfred A1 - Heitzer, Michael ED - Staat, Manfred ED - Heitzer, Michael T1 - Probabilistic limit and shakedown problems T2 - Numerical methods for limit and shakedown analysis. Deterministic and probabilistic problems Y1 - 2003 SN - 3-00-010001-6 N1 - NIC Series VL - 15 SP - 217 EP - 268 PB - John von Neumann Institute for Computing (NIC) CY - Jülich ER - TY - JOUR A1 - Kearney, D. A1 - Herrmann, Ulf A1 - Nava, P. A1 - Kelly, B. A1 - Mahoney, R. A1 - Pacheco, J. A1 - Cable, R. A1 - Potrovitza, N. A1 - Blake, D. A1 - Price, H. T1 - Assessment of a Molten Salt Heat Transfer Fluid in a Parabolic Trough Solar Field JF - Journal of Solar Energy Engineering Y1 - 2003 U6 - http://dx.doi.org/10.1115/1.1565087 SN - 1528-8986 VL - 125 IS - 2 SP - 170 EP - 176 ER - TY - BOOK A1 - Staat, Manfred A1 - Heitzer, Michael T1 - Numerical methods for limit and shakedown analysis. Deterministic and probabilistic problems. Y1 - 2003 SN - 3-00-010001-6 N1 - NIC Series Vol. 15 / Ed. by Staat, M; Heitzer, M. PB - John von Neumann Institute for Computing (NIC) CY - Jülich ER - TY - CHAP A1 - Seboldt, Wolfgang A1 - Dachwald, Bernd T1 - Solar sails for near-term advanced scientific deep space missions T2 - Proceedings of the 8th International Workshop on Combustion and Propulsion N2 - Solar sails are propelled in space by reflecting solar photons off large mirroring surfaces, thereby transforming the momentum of the photons into a propulsive force. This innovative concept for low-thrust space propulsion works without any propellant and thus provides a wide range of opportunities for highenergy low-cost missions. Offering an efficient way of propulsion, solar sailcraft could close a gap in transportation options for highly demanding exploration missions within our solar system and even beyond. On December 17th, 1999, a significant step was made towards the realization of this technology: a lightweight solar sail structure with an area of 20 m × 20 m was successfully deployed on ground in a large facility at the German Aerospace Center (DLR) at Cologne. The deployment from a package of 60 cm × 60 cm × 65 cm with a total mass of less than 35 kg was achieved using four extremely light-weight carbon fiber reinforced plastics (CFRP) booms with a specific mass of 100 g/m. The paper briefly reviews the basic principles of solar sails as well as the technical concept and its realization in the ground demonstration experiment, performed in close cooperation between DLR and ESA. Next possible steps are outlined. They could comprise the in-orbit demonstration of the sail deployment on the upper stage of a low-cost rocket and the verification of the propulsion concept by an autonomous and free flying solar sail in the frame of a scientific mission. It is expected that the present design could be extended to sail sizes of about (40 m)2 up to even (70 m)2 without significant mass penalty. With these areas, the maximum achievable thrust at 1 AU would range between 10 and 40 mN – comparable to some electric thrusters. Such prototype sails with a mass between 50 and 150 kg plus a micro-spacecraft of 50 to 250 kg would have a maximum acceleration in the order of 0.1 mm/s2 at 1 AU, corresponding to a maximum ∆V-capability of about 3 km/s per year. Two near/medium-term mission examples to a near-Earth asteroid (NEA) will be discussed: a rendezvous mission and a sample return mission. KW - solar sail KW - low-thrust KW - near-Earth asteroid KW - sample return KW - solar system Y1 - 2003 N1 - Proceedings of the 8th International Workshop on Combustion and Propulsion. Pozzuoli, Italy, 16 - 21 June 2002. ER -