@inproceedings{8941,
  abstract     = {{Numerical predictions of the forced vibration of a disc assembly including frictional effects between the shrouds are presented concerning engineering needs for the blade design process. Assuming a tuned disc assembly, numerical static, free and then forced vibration analyses of a shrouded turbine blade measured in the spin pit are performed systematically. For the excitation forces of an air jet evaluated from the fairly linear behavior of the experimental blade resonance peaks, the reliability of the proposed approach is validated through the very close agreement of the computed and measured resonant peaks. These resonant peaks demonstrate either a fairly linear behavior or a non-linear one like the jump effect of blade resonance amplitudes, or elastic impacts between the shrouds. Also, the damping performance for different contact configurations between the shrouds is numerically analyzed. These numerical results indicate that the shrouds generate higher frictional damping for small angles (0--30 deg) between the circumferential direction and the normal vector to the contact surface. Copyright {\copyright} 2003 by ASME}},
  author       = {{Szwedowicz, J and Sextro, Walter and Visser, R and Masserey, P.A}},
  booktitle    = {{ASME Turbo Expo 2003, collocated with the 2003 International Joint Power Generation Conference}},
  isbn         = {{0-7918-3687-8}},
  keywords     = {{Turbine blades, Vibration}},
  number       = {{GT2003-38808}},
  title        = {{{On forced vibration of shrouded turbine blades}}},
  doi          = {{doi:10.1115/GT2003-38808}},
  year         = {{2003}},
}

@inproceedings{8928,
  author       = {{Panning, Lars and Sextro, Walter and Popp, Karl}},
  booktitle    = {{Proceedings of ASME TURBO Expo, Power for Land, Sea, and Air}},
  number       = {{GT- 2002-30429}},
  title        = {{{Optimization of the Contact Geometry between Turbine Blades and Underplatform Dampers with respect to Friction Damping}}},
  year         = {{2002}},
}

@inproceedings{8929,
  author       = {{Panning, Lars and Sextro, Walter and Popp, Karl}},
  booktitle    = {{Proceedings of the 9th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC}},
  title        = {{{Spatial dynamics of tuned and mistuned bladed disks with cylindrical and wedge-shaped friction dampers}}},
  year         = {{2002}},
}

@inproceedings{8931,
  author       = {{Sextro, Walter and Panning, Lars and Götting, Florian}},
  booktitle    = {{Proceedings of ASME TURBO Expo, Power for Land, Sea, and Air}},
  number       = {{GT- 2002-30427}},
  title        = {{{Fast Calculation of the Statistics of the Forced Response of Mistuned Bladed Disk Assemblies with Friction Contacts}}},
  year         = {{2002}},
}

@inproceedings{8932,
  author       = {{Sextro, Walter and Popp, Karl}},
  booktitle    = {{Forschungsvereinigung Verbrennungskraftmaschinen (FW) - lnformationstagung Turbinen}},
  number       = {{518}},
  pages        = {{157--183}},
  title        = {{{Optimierung des Schwingungsverhaltens elastischer Strukturen mit Reibfugen}}},
  year         = {{2002}},
}

@inproceedings{8921,
  author       = {{Panning, Lars and Sextro, Walter and Popp, Karl}},
  booktitle    = {{Schwingungen in rotierenden Maschinen VI SIRM, Referate der Tagung in Wien}},
  editor       = {{Irretier, H and Nordmann, R and Springer, H}},
  pages        = {{297--306}},
  publisher    = {{Vieweg-Verlag}},
  title        = {{{Schwingungsanalyse verstimmter Schaufelkränze mit Reibelementen}}},
  year         = {{2001}},
}

@article{8922,
  author       = {{Sextro, Walter}},
  journal      = {{Zeitschrift für angewandte Mathematik und Mechanik (ZAMM)}},
  pages        = {{225--226}},
  title        = {{{Heat and Wear Generation for Rolling Contacts}}},
  volume       = {{81}},
  year         = {{2001}},
}

@inproceedings{8923,
  author       = {{Sextro, Walter}},
  booktitle    = {{ASME Design Engineering Technical Conferences}},
  number       = {{DETC2001/VIB-21512}},
  pages        = {{1--12}},
  title        = {{{Development and Experimental Validation of a Point Contact Model for Dynamical Problems with Friction}}},
  year         = {{2001}},
}

@article{8924,
  abstract     = {{In forced systems with cyclic symmetry localization can occur due toparameter uncertainties. Often, Monte-Carlo simulations are used to findregions, where the system response is sensitive to parameteruncertainties. These simulations require a large computation time.Therefore, an approximate method to calculate the envelopes of thefrequency response functions is developed in this paper. An example of anonlinear system with cyclic symmetry is a bladed disk assembly withfriction dampers. Friction dampers can be installed underneath the bladeplatforms of turbine blades. Due to dry friction and the relative motionbetween blades and dampers, energy is dissipated, which results in areduction of blade vibration amplitudes. By optimizing the mass of thefriction dampers, the best damping effects are obtained, which lead toan increase in the reliability of the turbine. In this paper, thecalculated response of a mistuned bladed disk assembly with frictiondampers is discussed. An approximate method is developed to calculatethe envelopes of the corresponding frequency response function forstatistically varying eigenfrequencies of the blades. Regions wherelocalization can occur with a high probability, are calculated by thismethod.}},
  author       = {{Sextro, Walter and Popp, Karl and Krzyzynski, Tomasz}},
  issn         = {{0924-090X}},
  journal      = {{Nonlinear Dynamics}},
  keywords     = {{bladed disk assembly, mistuning, sensitivity, localization}},
  number       = {{1-3}},
  pages        = {{207--220}},
  publisher    = {{Kluwer Academic Publishers}},
  title        = {{{Localization in Nonlinear Mistuned Systems with Cyclic Symmetry}}},
  doi          = {{10.1023/A:1012915002568}},
  volume       = {{25}},
  year         = {{2001}},
}

@article{8918,
  abstract     = {{The paper deals with cyclic periodic structures modelling bladed disk assemblies of blades with friction elements for vibration damping. These elements placed between adjacent blades reduce the vibration amplitudes by means of dry friction resulting from centrifugal forces acting on the elements and relative displacements of the blades. However, the application of these friction elements results in an additional dynamical coupling which together with mistuning of some system parameters (e.g., blade eigenfrequency or contact parameters) may cause localization of vibration. In the present paper a linear approximation of such a system is investigated. The structure composed of cyclic periodic cells modelled each as a clamped-free beam interacting with each other by means of viscoelastic elements of complex stiffness is applied for dynamic system analysis. In case of free vibrations as well as in case of steady-state dynamic response to a harmonic pressure field, a perfect periodic structure and the structures with periodically mistuned parameters (blade eigenfrequencies and contact parameters) are studied. Some regularities in the dynamic response of the systems with mistuning have been noticed. Despite the fact that only a linear approximation has been used, the results and conclusions can be applied for models which describe the blade interaction in a nonlinear way.}},
  author       = {{Krzyzynski, Tomasz and Popp, Karl and Sextro, Walter}},
  issn         = {{0960-0779}},
  journal      = {{Chaos, Solitons \& Fractals}},
  number       = {{10}},
  pages        = {{1597 -- 1609}},
  title        = {{{On some regularities in dynamic response of cyclic periodic structures}}},
  doi          = {{10.1016/S0960-0779(99)00080-6}},
  volume       = {{11}},
  year         = {{2000}},
}

@inproceedings{8919,
  abstract     = {{the vibration amplitudes of bladed disk assemblies can be reduced significantly by means of friction damping devices such as shrouds, damping wires and interblade Friction dampers. in practice, interblade Friction dampers are applied in rotating arrangements with various geometries showing curved or flat surfaces like so-called wedge-shaped dampers. this paper is focusing on a computation method to predict the dynamical behaviour of turbine blades with Friction dampers including both, curved and wedge-shaped dampers with hertzian and non-herutian contact conditions, respectively. the presented computation method uses a 3d contact model to calculate the contact forces, including normal and tangential stiffnesses, roughness and microslip effects. the relative displacements in the contact area can be expressed by means of 6 dof of the blade platforms and 6 rigid body dof of the damper including translational and rotational displacements. the relative displacement of the Friction damper with respect to the adjacent blades can be derived from the contact kinematics of the blade-damper-blade system and the equations of motion of the Friction damper. thus, the model can be applied to investigate spatial motions of the bladed disk assembly including bending and torsional vibrations. a comparison of different Friction damper designs with respect to an optimal damper geometry and damper mass is presented. the advantages and disadvantages of each design will be discussed. experimental results are shown to validate the developed computation method.}},
  author       = {{Panning, Lars and Sextro, Walter and Popp, Karl}},
  booktitle    = {{International Gas Turbine \& Aeroengine Congress \& Exhibition, ASME}},
  pages        = {{1--8}},
  title        = {{{Optimization of Interblade Friction Damper}}},
  year         = {{2000}},
}

@inproceedings{8920,
  author       = {{Sextro, Walter}},
  booktitle    = {{International Gas Turbine \& Aeroengine Congress \& Exhibition, ASME}},
  pages        = {{1--8}},
  title        = {{{The Calculation of the Forced Response of Shrouded Blades with Friction Contacts and Its Experimental Verification}}},
  year         = {{2000}},
}

@inproceedings{8909,
  author       = {{Popp, Karl and Sextro, Walter}},
  booktitle    = {{Forschungsvereinigung Verbrennungskraftmaschinen (FW) -lnformationstagung Turbinen}},
  number       = {{504}},
  pages        = {{21--38}},
  title        = {{{Schwingungsanalyse von vorgespannten Schaufeln mit Deckplatten im Schaufelkranz}}},
  year         = {{1999}},
}

@inproceedings{8910,
  author       = {{Sextro, Walter}},
  booktitle    = {{International conference on computational methods in contact mechanics}},
  pages        = {{181--190}},
  title        = {{{Experimental verification of a non-Hertzian contact model}}},
  year         = {{1999}},
}

@inproceedings{8911,
  author       = {{Sextro, Walter}},
  booktitle    = {{ASME Design Engineering Technical Conferences}},
  number       = {{DETC99/VIB-8180}},
  pages        = {{1--10}},
  title        = {{{Forced Vibration of Elastic Structures with Friction Contacts}}},
  year         = {{1999}},
}

@article{8912,
  author       = {{Sextro, Walter and Popp, Karl}},
  journal      = {{Zeitschrift für angewandte Mathematik und Mechanik (ZAMM)}},
  pages        = {{311--312}},
  title        = {{{Ein ebenes Reibkontaktmodell zur Berechnung von Schaufelschwingungen mit Reibelementen}}},
  volume       = {{79}},
  year         = {{1999}},
}

@inproceedings{8913,
  author       = {{Sextro, Walter and Popp, Karl}},
  booktitle    = {{Forschungsvereinigung Verbrennungskraftmaschinen (FW)}},
  number       = {{686}},
  pages        = {{56}},
  title        = {{{Schwingungsanalyse von vorgespannten Schaufeln mit Deckplatten im Schaufelkranz}}},
  year         = {{1999}},
}

@inproceedings{8907,
  author       = {{Sextro, Walter and Popp, Karl and Wolter, I}},
  booktitle    = {{International Congress on Combustion Engines, Proceedings of the 22nd CIMAC}},
  pages        = {{257--270}},
  title        = {{{Vibrational Behaviour of Tuned and Detuned Bladed Disks with Friction Dampers}}},
  volume       = {{1}},
  year         = {{1998}},
}

@inproceedings{8908,
  author       = {{Sextro, Walter and Popp, Karl and Wolter, I}},
  booktitle    = {{The 7th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, Proceedings of ISROMAC-7}},
  pages        = {{621--630}},
  title        = {{{Three-Dimensional Vibration of Bladed Disk Assemblies with Friction Dampers}}},
  volume       = {{B}},
  year         = {{1998}},
}

@inproceedings{8902,
  author       = {{Popp, Karl and Sextro, Walter}},
  booktitle    = {{Forschungsvereinigung Verbrennungskraftmaschinen (FW) -lnformationstagung Turbinen}},
  number       = {{496}},
  pages        = {{131--142}},
  title        = {{{Schwingungsverhalten von verstimmten Beschaufelungen mit Reibelementen}}},
  year         = {{1997}},
}