TY - JOUR A1 - Sponagel, Stefan A1 - Akbay, U. A1 - Becker, E. A1 - Krozer, S. T1 - Instability of slow viscometric flow JF - Mechanics Research Communications. 7 (1980), H. 4 Y1 - 1980 SN - 0093-6413 SP - 199 EP - 204 ER - TY - JOUR A1 - Sponagel, Stefan A1 - Adbay, U. A1 - Becker, E. A1 - Krozer, S. T1 - A possible cause of viscoelastic turbulence JF - Rheology : proceedings of the 8th International Congress of Rheology, held in Naples, Italy, September 1 - 5, 1980 / Hrsg. von Giovanni Astarita, Vol. 2 Y1 - 1980 SN - 0-306-40465-6 SP - 79 EP - 84 PB - Plenum Pr. CY - New York ER - 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 - Sponagel, Stefan A1 - Akbay, U. A1 - Becker, E. T1 - Instability of plane Couette flow of viscoelastic liquids JF - Journal of non-Newtonian fluid mechanics. 18 (1985), H. 2 Y1 - 1985 SN - 0377-0257 SP - 123 EP - 141 ER - TY - JOUR A1 - Artmann, Gerhard T1 - A microscopic photometric method for measuring erythrocyte deformability. Artmann, Gerhard Michael JF - Clinical Hemorheology. 6 (1986) Y1 - 1986 SN - 0271-5198 SP - 617 EP - 627 ER - TY - JOUR A1 - Artmann, Gerhard A1 - Schmid-Schönbein, H. T1 - The microscope-photometrical-monolayer-technique- a new principle for analyzing the distribution of rheological responses in pathological and experimentally modified red cell populations. Artmann, Gerhard Michael; Schmid-Schönbein, H. JF - Microcirculation, an update : proceedings of the Fourth World Congress for Microcirculation, Tokyo, Japan, July 26-30, 1987 Y1 - 1987 SN - 0444809511 N1 - World Congress for Microcirculation (4, 1987, Tokyo;); International congress series ; 755 SP - 475 EP - 477 PB - Excerpta Medica CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Sponagel, Stefan A1 - Kilthau, G. A1 - Spies, K. H. T1 - Sealing mechanism of lip seals JF - Eleventh 11th International Conference on Fluid Sealing : proceedings of the 11th Internat. Conference on Fluid Sealing, held at Cannes, France 8 - 10 April, 1987 / organised and sponsored by BHRA, the Fluid Engineering Centre. Ed. B. S. Nau Y1 - 1987 SN - 3-540-51383-3 N1 - International Conference on Fluid Sealing <11, 1987, Cannes> SP - 748 EP - 772 PB - Elsevier CY - London 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 - JOUR A1 - Staat, Manfred A1 - Ballmann, J. T1 - Wave Propagation and Focussing in Plates JF - Impact loading and dynamic behaviour of materials : Papers presented at the International Conference on Impact Loading and Dynamic Behaviour of Materials, Vol. 2 / Chiem, C. Y.; Kunze, L. (u.a.) [eds] Y1 - 1988 PB - DGM Informationsges. CY - Oberursel ER - TY - JOUR A1 - Artmann, Gerhard A1 - Schmid-Schönbein, H. A1 - Grebe, R. A1 - Teitel, P. [u.a.] T1 - Restoration of Microsieve Filterability of Human Red Cells After Exposure to Hyperosmolarity and Lactazidosis: Effect of Vinpocetine. Schmid-Schönbein, H.; Grebe, R.; Teitel, P.; Artmann, Gerhard Michael, Eschweiler, H.; Schröder, Susanne JF - Drug Development Research. 14 (1988), H. 3-4 Y1 - 1988 SN - 1098-2299 N1 - Abstracts frei unter: SP - 205 EP - 211 ER - TY - JOUR A1 - Artmann, Gerhard A1 - Schmid-Schönbein, H. A1 - Schröder, Susanne A1 - Grebe, R. [u.a.] T1 - Influence of Moxaverine-HCL on Membrane Curvature and Microsieve Filterability of Red Cells after Exposure to Hyperosmolarity and Lactacidosis. Schmid-Schönbein, H.; Schröder, Susanne; Grebe, R.; Artmann, Gerhard Michael, Eschweiler, H; Teitel, P. JF - Arzneimittelforschung. 38 (1988), H. 5 Y1 - 1988 SN - 0004-4172 SP - 710 EP - 716 ER - TY - JOUR A1 - Artmann, Gerhard A1 - Grebe, R. A1 - Homrighausen, A. A1 - Wolff, H. A1 - [u.a.], T1 - Response of normal and diabetic erythrocytes to membrane deformation by chemical and mechanical forces. Artmann, Gerhard Michael; Grebe, R.; Homrighausen, A.; Wolff, H.; Teitel, P.; Schmid-Schönbein, H. JF - 12. Jahrestagung der Gesellschaft für Mikrozirkulation Y1 - 1988 SP - 196 EP - 200 PB - Karger [u.a.] CY - Basel [u.a.] ER - TY - PAT A1 - Sponagel, Stefan A1 - Graf, Günter A1 - Groß, Heinz T1 - Method for manufacturing a sealing ring : United States Patent 4,861,536 ; date of patent: Aug. 12, 1989 / assignee: Firma Carl Freudenberg. Inventors: Gunter Graf ; Heinz Gross ; Stefan Sponagel Y1 - 1989 N1 - Barcode: US004861536A ; Volltext über Datenbank: http://www.google.com/patents PB - [United States Patent and Trademark Office] CY - [Alexandria, VA] ER - TY - PAT A1 - Sponagel, Stefan A1 - Graf, Günter A1 - Groß, Heinz T1 - Method for the manufacture of a sealing ring with a sealing lip having hydrodynamically acting return elements : United States Patent 4,850,097 ; date of patent: Jul. 25, 1989 / assignee: Firma Carl Freudenberg. Inventors: Gunter Graf ; Heinz Gross ; Stefan Sponagel Y1 - 1989 N1 - Barcode: US004850097A ; Volltext über Datenbank: http://www.google.com/patents PB - [United States Patent and Trademark Office] CY - [Alexandria, VA] 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 -