@inproceedings{KuehhornGolze, author = {K{\"u}hhorn, Arnold and Golze, Mark}, title = {An Improved Sandwich Theory for a Better Prediction of the Wrinkling Phenomenon}, series = {Proceedings of the Fifth World Congress on Computational Mechanics, Vienna, Austria, July 7 - 12, 2002, held at Vienna University of Technology}, booktitle = {Proceedings of the Fifth World Congress on Computational Mechanics, Vienna, Austria, July 7 - 12, 2002, held at Vienna University of Technology}, address = {Vienna}, isbn = {3-9501554-0-6}, abstract = {An advanced design of sandwichstructures does not only require the knowledge of the global stress- and deformation behavior, but also the knowledge of the local effects, such as load singularities and the loss of stability caused by the short wave wrinkling of one (bending) or both (pressure) sandwich skins.Based on the nonlinear theory for sandwich shells with seven kinematic degrees of freedom, introduced from K{\"u}hhorn and Schoop an improved theory for plane sandwich shells with eight degrees of freedom will be presented, enabling a much better representation of the sandwich core behavior.Due to consideration of quadratic core thickness and linear core shear strain as well as longitudinal core deformation an improved prediction of the wrinkling behavior is succeeded even for thick cores and thin skins.The kinematic quantities as well as the nonlinear-differential equations and the simplified equations of first order theory resulting from them are given.Finally applying the well known classical problems of stability loaded by pressure and bending, the efficiency of this 8 DOF-theory ist demonstrated. A comparison with a detailed finite element (plain strain) calculation shows the high quality of these results.The presented sandwich theory characterized by eight degrees of freedom enables the calculation of nearly all essential sandwich phenomena even for thick cores.}, language = {en} } @inproceedings{KuehhornGolze, author = {K{\"u}hhorn, Arnold and Golze, Mark}, title = {Thickness flexible theory with generalized core warping for plane sandwich-structures}, abstract = {An advanced design of sandwichstructures does not only require the knowledge of the global stress- and deformation behavior, but also the knowledge of the local effects, such as load singularities and the loss of stability caused by the short wave wrinkling of one (bending) or both (pressure) sandwich skins.Based on the nonlinear theory for sandwich shells with seven kinematic degrees of freedom, introduced from K{\"u}hhorn and Schoop an improved theory for plane sandwich shells with eight degrees of freedom (position vector r, director d, and intensity factors az1, az2 for including core flexibility) will be presented, enabling a much better representation of the sandwich core behavior.Due to consideration of quadratic core thickness and linear core shear strain as well as longitudinal core deformation an improved prediction of the wrinkling behavior is succeeded even for thick cores and thin skins.The kinematic quantities as well as the nonlinear-differential equations achieved from the principle of virtual work and the simplified equations of first order theory resulting from them are given.Finally applying the well known classical problems of stability loaded by pressure and bending, the efficiency of this 8 DOF-theory is demonstrated. A comparison with a detailed finite element (plain strain) calculation shows the high quality of these results.The presented sandwich theory characterized by eight kinematic degrees of freedom is valid for arbitrary displacements, rotations and moderat strains enables the calculation of nearly all essential sandwich phenomena even for thick cores.}, language = {en} } @inproceedings{GolzeKuehhorn, author = {Golze, Mark and K{\"u}hhorn, Arnold}, title = {CFK-/GFK-Auslegung am Beispiel eines Modellfl{\"u}gels}, series = {Tagungsband, 14. deutschsprachiges ABAQUS Anwendertreffen, 23. - 24. September 2002 in Wiesbaden}, booktitle = {Tagungsband, 14. deutschsprachiges ABAQUS Anwendertreffen, 23. - 24. September 2002 in Wiesbaden}, publisher = {ABACOM Software GmbH}, address = {Aachen}, abstract = {{\"O}konomische und {\"o}kologische Bed{\"u}rfnisse verlangen von modernen Konstruktionen sowohl eine hochintegrative Bauweise als auch eine massive Gewichtseinsparung. Dies f{\"u}hrt zu neuen Leichtbaukonstruktionen mit einem stetig zunehmenden Anteil an Faserverbundl{\"o}sungen. Die hierbei er{\"o}ffnete M{\"o}glichkeit, kraftfluß- und beanspruchungsgerecht auszulegen, erschließt sich erst vollst{\"a}ndig durch die sichere Anwendung moderner FE-Programme wie beispielsweise ABAQUS. Nutzt man dar{\"u}ber hinaus die M{\"o}glichkeit der flexiblen Script-Programmierung, so lassen sich wirkungsvolle Effizienzsteigerungen durch die gezielte Erstellung spezifischer Eingabemen{\"u}s und Ausgaberoutinen erreichen. Dieser Beitrag veranschaulicht an Hand eines ausgef{\"u}hrten und getesteten CFK-Modellfl{\"u}gels unter Biegebeanspruchung, die Vorgehensweise bei Verwendung von ABAQUS und der Script-Sprache Python.}, language = {de} } @article{KuehhornKlaukeGolze, author = {K{\"u}hhorn, Arnold and Klauke, Thomas and Golze, Mark}, title = {Simulation und Verifikation der sukzessiven Bruchabfolge eines CFK-Bauteils mittels neuartiger Bruchkriterien}, language = {de} } @article{KuehhornBeirowKlaukeetal., author = {K{\"u}hhorn, Arnold and Beirow, Bernd and Klauke, Thomas and Golze, Mark}, title = {Simulation der Mistuningeffekte von Hochdruckverdichter-Schaufelscheiben zur Bestimmung kritischer Schwingungen in Flugtriebwerken}, language = {de} } @inproceedings{BeirowKuehhornGolzeetal., author = {Beirow, Bernd and K{\"u}hhorn, Arnold and Golze, Mark and Klauke, Thomas}, title = {Strukturdynamische Untersuchungen an Hochdruckverdichterschaufelscheiben unter Ber{\"u}cksichtigung von Mistuningeffekten}, series = {Modalanalyse und Identifikation, Verfahren und Anwendungen bei dynamischen Systemen, Tagung Wiesloch, 25. und 26. Mai 2004}, booktitle = {Modalanalyse und Identifikation, Verfahren und Anwendungen bei dynamischen Systemen, Tagung Wiesloch, 25. und 26. Mai 2004}, publisher = {VDI-Verlag}, address = {D{\"u}sseldorf}, isbn = {3-18-091825-X}, pages = {351 -- 372}, language = {de} } @misc{KuehhornBeirowSchrapeetal., author = {K{\"u}hhorn, Arnold and Beirow, Bernd and Schrape, Sven and Golze, Mark and Kn{\"o}pke, Martin}, title = {Simulation fluidged{\"a}mpfter Strukturschwingungen mittels partitionierter Fluid-Struktur-Kopplung}, series = {Forum der Forschung}, volume = {9}, journal = {Forum der Forschung}, number = {18}, issn = {0947-6989}, pages = {79 -- 86}, language = {de} } @misc{deSilvaKuehhornGolze, author = {de Silva, Tina and K{\"u}hhorn, Arnold and Golze, Mark}, title = {Homogenization of thin structured sheet metals by using FEM}, series = {Proceedings in applied mathematics and mechanics : PAMM}, volume = {12}, journal = {Proceedings in applied mathematics and mechanics : PAMM}, number = {1}, doi = {10.1002/pamm.201210104}, pages = {227 -- 228}, language = {en} } @misc{BeirowGolzePopig, author = {Beirow, Bernd and Golze, Mark and Popig, Frederik}, title = {Vibration Reduction of a Steam Turbine Wheel by Means of Intentional Mistuning}, series = {Advances in Mechanism Design III : Proceedings of TMM 2020}, journal = {Advances in Mechanism Design III : Proceedings of TMM 2020}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-83593-4}, issn = {2211-0984}, doi = {10.1007/978-3-030-83594-1_8}, pages = {73 -- 82}, abstract = {A last stage steam turbine wheel is analyzed with the objective to alleviate the flutter susceptibility by employing intentional mistuning (IM). In particular, the operation at nominal speed under part-load conditions may cause unfavorable flow conditions facilitating flow separation. In consequence, negative aerodynamic damping ratios occur for the first bending mode family in some circumstances. Employing intended alternate mistuning of adequate magnitude has proved to be a promising measure to stabilize rotors in terms of avoiding self-excited vibration phenomena. From the manufacturing point of view, this two-blade design is advantageous as well and hence, chosen here as a first measure to attenuate flutter susceptibility. Two prototypes of bladed disks series have been made, which are exhibiting small but unavoidable deviations from the design intention due to manufacturing. The real blade alone frequencies have been identified within foregoing experimental investigations. Numerical modal analyses carried out for the prototypes as manufactured finally reveal that there is an additional positive contribution of random mistuning in terms of further enhancing the least aerodynamic damping ratio. Another promising and robust IM pattern is found by using generic algorithms to optimize the least aerodynamic damping ratio yielding stable conditions at any time as well. Moreover, it shows that IM combined with random mistuning also mitigates the maximum forced response at part-speed conditions.}, language = {en} } @inproceedings{BeirowKuehhornGolzeetal., author = {Beirow, Bernd and K{\"u}hhorn, Arnold and Golze, Mark and Klauke, Thomas}, title = {Experimentelle Untersuchungen des strukturdynamischen Verhaltens von Hochdruckverdichterschaufeln in Integralbauweise (Blisks) mittels Laser-Doppler-Vibrometrie}, language = {de} }