TY - CHAP A1 - Ballmann, J. A1 - Raatschen, Hans-Jürgen A1 - Staat, Manfred T1 - High stress intensities in focussing zones of waves N2 - The propagation of mechanical waves in plates of isotropic elastic material is investigated. After a short introduction to the understanding of focussing of stress waves in a plate with a curved boundary the method of characteristics is applied to a plate of hyperelastic material. Using this method the propagation of acceleration waves is discussed. Based on this a numerical difference scheme is developed for solving initial-boundary-value problems and applied to two examples: propagation of a point disturbance in a homogeneously finitely strained non-linear elastic plate and geometrical focussing in al linear elastic plate. KW - Technische Mechanik KW - Wellen KW - mechanical waves Y1 - 1985 U6 - http://dx.doi.org/10.1016/B978-0-444-42520-1.50015-3 ER - TY - JOUR A1 - Staat, Manfred A1 - Ballmann, J. T1 - Computation of impacts on elastic solids by methods of bicharacteristics JF - Computational Mechanics '88 : theory and applications ; proceedings of the International Conference on Computational Engineering Science April 10-14, 1988, Atlanta, GA, USA ; vol. 2 N2 - Shock waves, explosions, impacts or cavitation bubble collapses may generate stress waves in solids causing cracks or unexpected dammage due to focussing, physical nonlinearity or interaction with existing cracks. There is a growing interest in wave propagation, which poses many novel problems to experimentalists and theorists. KW - Bicharakteristikenverfahren KW - Elastizität KW - elastic solids KW - bicharacteristics Y1 - 1988 SP - 1719 EP - 1722 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 - 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 - JOUR A1 - Bogoyavlenskiy, A. P. A1 - Digel, Ilya A1 - Berezin, V. E. T1 - Assessment of dot-blot ELISA sensitivity on membrane sorbent using various peroxidase substrates N2 - The sensitivity of the peroxidase reaction in dot-blot ELISA significantly depends on the substrate. The highest sensitivity is observed using benzidine and diamine- phenol combinations as the substrates due to the reaction of the coupled oxidation (NADI) KW - Enzyme-linked immunosorbent assay KW - Peroxidase KW - ELISA KW - phenols KW - naphtols KW - aromatic amines Y1 - 1997 ER - TY - JOUR A1 - Staat, Manfred A1 - Heitzer, M. T1 - Limit and Shakedown Analysis Using a General Purpose Finite Element Code JF - Proceedings of NAFEMS World Congress '97 on Design, Simulation & Optimisation : reliability & applicability of computational methods ; Stuttgart, Germany, 9 - 11 April 1997 Y1 - 1997 SN - 1-87437-620-4 SP - 522 EP - 533 PB - NAFEMS CY - Glasgow ER - TY - CHAP A1 - Burgazzi, L. A1 - Fiorini, F. A1 - De Magistris, W. (u.a.) A1 - Lensa, W. von A1 - Staat, Manfred A1 - Altes, J. T1 - Reliability Assessment of Passive Safety Systems T2 - Proceedings of the 6th International Conference on Nuclear Engineering : ICONE : May 10 - 14, 1998, San Diego, Calif. Y1 - 1998 N1 - CD-ROM PB - American Society of Mechanical Engineers CY - New York ER - TY - CHAP A1 - Mertens, Josef T1 - Laminar leading edges: manufacturing, contamination, and operational aspects - results from the German RaWid programme N2 - 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. KW - Laminare Strömung KW - Ansaugsystem KW - Profilumströmung KW - Laminarprofil KW - RaWid KW - hybrid laminar flow KW - suction systems KW - suction structure KW - contamination KW - operational aspects Y1 - 2000 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 - 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 -