@article{9747,
  abstract     = {{Bei der Konstruktion von Maschinen ist es oftmals erforderlich, Schwingungen minimal zu halten. Um z.B. die Lebensdauer zu erhöhen, Material einzusparen oder den Geräuschpegel gering zu halten muss oft ein großer Aufwand zur Dämpfung von auftretenden Schwingungen betrieben werden. In vielen technischen Anwendungen werden Einzelteile miteinander verschraubt. Diese Fügestellen können gezielt und mit wenig Aufwand zur Schwingungsdämpfung herangezogen werden. Die Berechnung des dynamischen Verhaltens verschraubter Strukturen stellt immer noch eine Herausforderung dar. Es wurde eine Methode entwickelt, um den eingeschwungenen Zustand elastischer, miteinander verschraubter Körper mit rauen Fügestellen bei periodischer Anregung zu berechnen. Als Basis dienen Finite Elemente Modelle der einzelnen Teile, deren Freiheitsgrade durch modale Kondensation reduziert werden. Unter Anwendung des Verfahrens von Ritz und Galerkin wird eine Näherungslösung für den eingeschwungenen Zustand des nichtlinearen, gekoppelten Systems ermittelt. Abhängig von den Schraubenvorspannkräften sowie den bestimmenden Parametern der Kontaktflächen, Rautiefe und Reibungskoeffizient, kann die Systemantwort berechnet und optimiert werden. Um die Berechnungsmethode zu verifizieren wurden Experimente durchgeführt. Der Vergleich zwischen Messung und Rechnung zeigt eine gute Übereinstimmung. ({\copyright} 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)}},
  author       = {{Hölzl, Johannes Sebastian and Sextro, Walter}},
  issn         = {{1617-7061}},
  journal      = {{PAMM}},
  number       = {{1}},
  pages        = {{247--248}},
  publisher    = {{WILEY-VCH Verlag}},
  title        = {{{Reibungsdämpfung in ausgedehnten, verschraubten Fügestellen}}},
  doi          = {{10.1002/pamm.201010116}},
  volume       = {{10}},
  year         = {{2010}},
}

@article{9748,
  abstract     = {{For many technical applications it is necessary to avoid or to reduce vibrations. Factors benefiting from vibration reduction are for example the durability of the application, which is increased, as well as cost expenses and the level of noise, which are both decreased. Rough, bolted interfaces are common in most machines and can be used as damping devices with some effort. Perhaps in future such contact surfaces could be used as damping devices at the interfaces of an automotive engine or exhaust system. Nevertheless it is difficult to predict the effect of a change in contact interface parameters on the dynamic behavior of the entire mechanical system. Therefore a method for calculating the steady state behavior of elastic multi-body systems was developed. The basis of this method is a finite element model of each contacting unit. On each model a modal reduction is applied in order to reduce the degrees of freedom. The method of Ritz and Galerkin is used to calculate the frequency response functions of the reduced system including contact. This method allows the calculation of the steady-state behavior of elastic multi-body systems with rough, bolted contact interfaces, by taking the pre-stress of the bolts, the roughness and the friction coefficient of the contacting surfaces as parameters. In order to verify calculated results, a test stand was built. The comparison of calculated and experimental results showed a satisfying correlation.}},
  author       = {{ Hölzl, Johannes Sebastian and Sextro, Walter}},
  journal      = {{SAE International Journal of Passenger Cars- Mechanical Systems}},
  keywords     = {{Automotive}},
  pages        = {{929--935}},
  title        = {{{Simulation of the Dynamical Behavior of Elastic Multi-Body Systems with Bolted, Rough Contact Interfaces}}},
  doi          = {{10.4271/2010-01-1422}},
  year         = {{2010}},
}

@inproceedings{9753,
  abstract     = {{Piezoelektrische Trägheitsmotoren nutzen die Trägheit einer bewegten Masse, um diese in kleinen Schritten durch abwechselnde Haft- und Gleitphasen voranzutreiben. Eine Kernfrage bei der Entwicklung eines piezoelektrischen Trägheitsmotors ist, welches elektrische Ansteuersignal für das gewünschte Motorverhalten optimal ist. Das elektrische Signal führt zu einer Bewegung des piezoelektrischen Aktors und damit der Antriebsstange, die den reibschlüssigen Vortrieb bewirkt. Entsprechend wird diese Fragestellung in zwei Teilen untersucht: Anhand eines Starrkörpermodells werden zunächst Bewegungsverläufe für die Antriebsstange ermittelt, mit denen die maximale Geschwindigkeit erreicht wird. Dabei werden drei Antriebsmodi identifiziert. Mit allen kann eine höhere Geschwindigkeit als mit der heute häufig verwendeten Sägezahnanregung erreicht werden. Anschließend wird ein einfaches dynamisches Modell eines piezoelektrischen Aktors genutzt, um die notwendigen elektrischen Ansteuersignale für die verschiedenen Antriebsmodi zu bestimmen. Es zeigt sich, dass das gewählte einfache Modell hierzu nur bedingt geeignet ist.}},
  author       = {{Hunstig, Matthias and Hemsel, Tobias and Sextro, Walter}},
  booktitle    = {{7. Paderborner Workshop Entwurf mechatronischer Systeme}},
  editor       = {{Gausemeier, Jürgen and Rammig, Franz and Schäfer, Wilhelm and Trächtler, Ansgar}},
  issn         = {{0924-4247}},
  keywords     = {{Piezoelektrischer Trägheitsmotoren}},
  pages        = {{129--141}},
  publisher    = {{Heinz Nixdorf Institut, Universität Paderborn}},
  title        = {{{Anregungskonzepte und Modellierung piezoelektrischer Trägheitsmotoren}}},
  volume       = {{272}},
  year         = {{2010}},
}

@inproceedings{9754,
  abstract     = {{A model based design approach for improved piezoelectric inertia motors is presented. Three velocityoptimized movement patterns for the driving body have been derived. The influence of the motor parameters and the process of designing an application specific motor with maximum velocity are shown. A simple dynamic model of the piezoelectric actuator is used to calculate the voltage signal for achieving the desired movement pattern. Observed distortions of the optimum pattern, their influence on the motion of the driven body and different methods to reduce them are discussed.}},
  author       = {{Hunstig, Matthias and Hemsel, Tobias and Sextro, Walter}},
  booktitle    = {{ACTUATOR 2010 Conference Proceedings}},
  issn         = {{0924-4247}},
  pages        = {{657--661}},
  title        = {{{Improving the Performance of Piezoelectric Inertia Motors}}},
  year         = {{2010}},
}

@inproceedings{9760,
  abstract     = {{Self-optimizing systems are able to adapt their behavior autonomously according to their current self-determined objectives. Unforeseen influences could lead to dependability-critical behavior of the system. Methods are required which secure self-optimizing systems during operation. These methods to increase the dependability of the system should already be taken into consideration in the design process. This paper presents a guideline for the dependability-oriented design of self-optimizing systems, which integrates established classical methods like failure mode and effects analysis as well as methods based on self-optimization. On the one hand self-optimization is used to increase the dependability of the system by integrating objectives like safety, availability, and reliability to the objectives of the system. On the other hand methods are required to ensure the self-optimization itself. As basis for this guideline serves the principle solution of the system. The six phases of the guideline extend the design process and lead to an enhanced principle solution. Additionally, the guideline illustrates phases to implement and validate the self-optimizing system. The proposed guideline is applied to an innovative rail-bound vehicle, called RailCab, which is equipped with self-optimizing function modules.}},
  author       = {{Sondermann-Wölke, Christoph and Hemsel, Tobias and Sextro, Walter and Gausemeier, Jürgen and Pook, Sebastian}},
  booktitle    = {{Industrial Informatics (INDIN), 2010 8th IEEE International Conference on}},
  keywords     = {{RailCab, dependability-critical behavior, dependability-oriented design, failure mode, rail-bound vehicle, secure self-optimizing systems, self-optimizing function modules, optimisation, railways, self-adjusting systems}},
  pages        = {{739 --744}},
  title        = {{{Guideline for the dependability-oriented design of self-optimizing systems}}},
  doi          = {{10.1109/INDIN.2010.5549490}},
  year         = {{2010}},
}

@article{9761,
  abstract     = {{New mechatronic systems, called self-optimizing systems, are able to adapt their behavior according to environmental, user and system specific influences. Self-optimizing systems are complex and due to their non-deterministic behavior comprise hidden risks, which cannot be foreseen in the design phase of the system. Therefore, modifications of the ISO 17359 condition monitoring policy for being able to cope with this new kind of systems are presented. Besides avoiding critical situations evoked by self-optimization, the proposed concept uses self-optimization to increase the dependability of the system. This concept is applied to the active guidance module of an innovative rail-bound vehicle. First test drives provide information for the enhancement of the implementation of realtime switching to appropriate control strategies. The different control strategies are investigated in detail. It is illustrated that influences on the system like different track sections or the desired velocity of the RailCab effect the system and can lead to a higher amount of flange contacts, which indicate higher wear and thus a reduction of the availability of the system. Therefore, these influences should be minded within the condition monitoring policy. Consequently, this article presents the condition monitoring policy for self-optimizing function modules and its application to the active railway guidance module.}},
  author       = {{Sondermann-Wölke, Christoph and Sextro, Walter}},
  journal      = {{International Journal On Advances in Intelligent Systems}},
  keywords     = {{dependability, condition monitoring, selfoptimization, active railway guidance module}},
  number       = {{1 - 3}},
  pages        = {{65 -- 74}},
  title        = {{{Integration of Condition Monitoring in Self-optimizing Function Modules Applied to the Active Railway Guidance Module}}},
  volume       = {{3}},
  year         = {{2010}},
}

@inproceedings{9762,
  abstract     = {{Die erweiterten Möglichkeiten der Informationsverarbeitung mechatronischer Systeme erlauben es, mechatronische Systeme selbstoptimierend zu gestalten. Dabei bezieht sich die Selbstoptimierung auf die Fähigkeit des Systems, sich an die aktuelle Umfeldsituation anzupassen; wobei das System im Allgemeinen mehrere relevante Ziele verfolgt. Wurde eine Umfeldveränderung bemerkt, so müssen diese Ziele an die neue Situation angepasst und das resultierende Verhalten ausgewählt werden. In diesem Beitrag wird das selbstoptimierende Spurführungsmodul näher untersucht. Das Spurführungsmodul ist Bestandteil eines innovativen schienengebundenen Verkehrssystems, genannt RailCab, und dient zur Lenkung des einzelnen Fahrzeugs. Ziele des Spurführungsmoduls bestehen darin, die Verlässlichkeit des Spurführungsmoduls zu erhöhen sowie möglichst wenig Energie zu verbrauchen. Um kritische Systemzustände zu erkennen bzw. frühzeitig zu verhindern wird eine Vorgehensweise zur Einrichtung einer Zustandsüberwachung für selbstoptimierende Systeme beschrieben. Diese wird auf dem realen Versuchsträger im Maßstab 1:2,5 implementiert. Die Auswertung von Versuchsfahrten zeigt, dass gerade beim Auftreten eines Fehlers das Umschalten vom Ziel ''Energieverbrauch minimieren`` auf das Ziel ''Verlässlichkeit maximieren`` sinnvoll ist.}},
  author       = {{Sondermann-Wölke, Christoph and Sextro, Walter and Geisler, Jens and Trächtler, Ansgar}},
  booktitle    = {{Entwurf mechatronischer Systeme}},
  editor       = {{Gausemeier, Jürgen and Rammig, Frans Josef and Trächtler, Ansgar}},
  keywords     = {{Selbstoptimierung, Spurführungsmodul}},
  pages        = {{411 -- 420}},
  title        = {{{Experimentelle Untersuchung der Selbstoptimierung innerhalb des RailCab-Spurführungsmoduls}}},
  volume       = {{272}},
  year         = {{2010}},
}

@inproceedings{9763,
  abstract     = {{Recent advances in information processing enable new kinds of technical systems, called self-optimizing systems. These systems are able to adapt their objectives and their behavior according to the current situation and influences autonomously. This behavior adaptation is non-deterministic and hence self-optimization is a risk to the system, e.g. if the result of the self-optimization process does not match the suddenly changed situation. In contrary, self-optimization could be used to increase the dependability by pursuing objectives like reliability and availability. In our preceding publications we introduced the so called multi-level dependability concept to cope with this new kind of systems (cf. [6]). This concept comprises the monitoring of the system behavior, the classification of the current situation, and the selection of the appropriate measure, if reliability limits are exceeded. In this paper we present for the first time experimental results. The dependability concept is implemented in the self-optimizing active guidance system of a railway vehicle. The test drives illustrate clearly that the proposed concept is able to cope with, e.g., sensor failures, and is able to increase the reliability and availability of the active guidance module.}},
  author       = {{Sondermann-Wölke, Christoph and Geisler, Jens and Sextro, Walter}},
  booktitle    = {{Reliability and Maintainability Symposium (RAMS), 2010 Proceedings - Annual}},
  issn         = {{0149-144X}},
  keywords     = {{availability, dependability concept, multilevel dependability concept, railway vehicle, reliability, self optimizing active guidance system, self optimizing railway guidance system, situation classification, system behavior monitoring, optimal control, railways, reliability theory, self-adjusting systems}},
  pages        = {{1 --6}},
  title        = {{{Increasing the reliability of a self-optimizing railway guidance system}}},
  doi          = {{10.1109/RAMS.2010.5448080}},
  year         = {{2010}},
}

@article{9764,
  author       = {{Tomberger, Christoph and Dietmaier, Peter and Martin, Rosenberger and Sextro, Walter and Six, Klaus}},
  issn         = {{0043-1648}},
  journal      = {{ZEVrail}},
  pages        = {{127--135}},
  title        = {{{Einfluss von Oberflächenrauheit, fluiden Zwischenschichten und Kontakttemperaturen auf den Kraftschluss zwischen Rad und Schiene}}},
  volume       = {{134}},
  year         = {{2010}},
}

@inproceedings{9742,
  abstract     = {{New mechatronic systems, called self-optimizing systems, are able to adapt their behavior according to environmental, user and system specific influences. Self-optimizing systems are complex and due to their non-deterministic behavior comprise hidden risks, which cannot be foreseen in the design phase of the system. Therefore, this paper presents modifications of the current condition monitoring policy, to be able to cope with this new kind of systems. Beside avoiding critical situations evoked by self-optimization, the proposed concept uses self-optimization to increase the dependability of the system. In this case, the concept is applied to the active guidance module of an innovative rail-bound vehicle.}},
  author       = {{Sondermann-Wölke, Christoph and Sextro, Walter}},
  booktitle    = {{Future Computing, Service Computation, Cognitive, Adaptive, Content, Patterns, 2009. COMPUTATIONWORLD '09. Computation World:}},
  keywords     = {{condition monitoring, mechatronic systems, rail bound vehicle, rail guidance module, self-optimization, self-optimizing function modules, condition monitoring, mechatronics, railway rolling stock, self-adjusting systems}},
  pages        = {{15 --20}},
  title        = {{{Towards the Integration of Condition Monitoring in Self-Optimizing Function Modules}}},
  doi          = {{10.1109/ComputationWorld.2009.47}},
  year         = {{2009}},
}

@inproceedings{9560,
  author       = {{Tonchev, Anton and Hirschberg, Wolfgang and Sextro, Walter and Major, Zoltan and Neges, Josef}},
  booktitle    = {{27. Internationales Mju-Symposium/Bremsen-Fachtagung}},
  number       = {{657}},
  pages        = {{29 -- 49}},
  publisher    = {{VDI Verlag GmbH}},
  title        = {{{Modellierung der Hysterese- und Adhäsionseffekte zwischen Bremsbelag und Bremsscheibe}}},
  year         = {{2007}},
}

@inproceedings{9561,
  author       = {{Tonchev, Anton and Hirschberg, Wolfgang and Sextro, Walter and Major, Zoltan and Neges, Josef}},
  booktitle    = {{27. Internationales Mju-Symposium/Bremsen-Fachtagung}},
  number       = {{657}},
  pages        = {{144--163}},
  publisher    = {{VDI Verlag GmbH}},
  title        = {{{Modelling of Hysteresis and Adhesion Effects between Brake Pad and Disc}}},
  year         = {{2007}},
}

@inproceedings{9563,
  author       = {{Genzo, Alexander and Sextro, Walter and Panning, Lars}},
  booktitle    = {{VDI-Berichte}},
  pages        = {{147--161}},
  publisher    = {{VDI Verlag GmbH}},
  title        = {{{Schwingungsverhalten elastischer Körper mit nichtlinearen Kopplungen in ausgedehnten Reibkontakten}}},
  volume       = {{2022}},
  year         = {{2007}},
}

@article{9567,
  abstract     = {{Numerical predictions of the forced vibration of a disk assembly including frictional effects between the shrouds are presented concerning engineering needs for the blade design process. Assuming a tuned disk 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 nonlinear 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{\^a}30deg) between the circumferential direction and the normal vector to the contact surface.}},
  author       = {{Szwedowicz, J and Visser, R and Sextro, Walter and Masserey, P. A}},
  issn         = {{0889-504X}},
  journal      = {{Journal of Turbomachinery}},
  number       = {{1}},
  pages        = {{011002--011002}},
  title        = {{{On Nonlinear Forced Vibration of Shrouded Turbine Blades}}},
  volume       = {{130}},
  year         = {{2007}},
}

@inproceedings{9535,
  author       = {{Genzo, Alexander and Sextro, Walter}},
  booktitle    = {{Proceedings of ISMA - International conference on noise and vibration engineering}},
  keywords     = {{Noise, Vibration engineering}},
  pages        = {{51--52}},
  title        = {{{Dynamic Behaviour of Elastic Bodies Coupled by Extended Friction Contacts}}},
  year         = {{2006}},
}

@inbook{9536,
  abstract     = {{This paper presents a model for unsteady longitudinal slippage of a loaded rubber wheel. The aim of modelling was to calculate the dynamical contact behavior in a numerical efficient way. Further on, simulation results are compared to experimental data.}},
  author       = {{Gutzeit, F and Sextro, Walter and Kröger, Matthias}},
  booktitle    = {{Analysis and Simulation of Contact Problems}},
  editor       = {{Wriggers, Peter and Nackenhorst, Udo}},
  isbn         = {{978-3-540-31760-9}},
  pages        = {{261--270}},
  publisher    = {{Springer Berlin Heidelberg}},
  title        = {{{Unsteady rolling contact of rubber wheels}}},
  doi          = {{10.1007/3-540-31761-9_29}},
  volume       = {{27}},
  year         = {{2006}},
}

@inproceedings{9542,
  author       = {{Hofmeisterro, Adolf and Sextro, Walter and Röschel, Otto}},
  booktitle    = {{Proceedings of EUCOMES, the first European Conference on Mechanism Science}},
  pages        = {{1--12}},
  title        = {{{Error-Workspace Analysis of Plane Mechanisms}}},
  year         = {{2006}},
}

@inbook{9551,
  abstract     = {{Friction occurs in the contact between tyre and road. The friction of rubber material on dry surfaces is dominated by hysteresis and adhesion effects. Hysterisis friction is characterised by the energy dissipation within the visco-elastic material, which is caused by its deformation while passing the surface roughness. Hysteresis effects are modelled by an extended linear visco-elastic material with several Maxwell elements. The development of a model in the time domain allows to consider nonlinear effects. Additionally temperature effects are taken into account based on the WLF-transformation. Adhesion forces originate from molecular bindings between the contact partners. This effect is simulated by applying a modified model of Achenbach on real surfaces. The temperature distribution within the friction contact region is investigated experimentally as well. Furthermore global stick-slip vibrations of a rubber block element are investigated using a global contact model. Numerical results are compared with experiments performed on a tribometer test rig.}},
  author       = {{Sextro, Walter and Moldenhauer, Patrick and Wangenheim, M and Lindner, Markus and Kröger, Matthias}},
  booktitle    = {{Analysis and Simulation of Contact Problems}},
  editor       = {{Wriggers, Peter and Nackenhorst, Udo}},
  isbn         = {{978-3-540-31760-9}},
  pages        = {{243--252}},
  publisher    = {{Springer Berlin Heidelberg}},
  title        = {{{Contact behaviour of a sliding rubber element}}},
  doi          = {{10.1007/3-540-31761-9_27}},
  volume       = {{27}},
  year         = {{2006}},
}

@article{9266,
  abstract     = {{The present paper deals with the forced vibration analysis of a test structure. The test structure consists of two parts, an upper and a lower half pipe, joint in two bolted flanges which represent the extended friction contacts. Depending on the clamping loads different normal pressure distributions can be established in the contact interfaces. Since the test structure is loaded with a harmonic external force relative displacements occur in the contact interface. This leads to microslip effects affecting the dynamic behaviour. The experimental validation of the calculation method accounting for these effects is shown by comparing measured and calculated frequency response functions (FRF). ({\^A}{\copyright} 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)}},
  author       = {{Genzo, Alexander and Sextro, Walter and Popp, Karl}},
  issn         = {{1617-7061}},
  journal      = {{PAMM}},
  number       = {{1}},
  pages        = {{91--92}},
  publisher    = {{WILEY-VCH Verlag}},
  title        = {{{Analysis of the Forced Vibration of Two Bolted Half-Pipes with Extended Friction Contacts}}},
  doi          = {{10.1002/pamm.200510026}},
  volume       = {{5}},
  year         = {{2005}},
}

@article{9526,
  abstract     = {{The present paper deals with the forced vibration analysis of a test structure. The test structure consists of two parts, an upper and a lower half pipe, joint in two bolted flanges which represent the extended friction contacts. Depending on the clamping loads different normal pressure distributions can be established in the contact interfaces. Since the test structure is loaded with a harmonic external force relative displacements occur in the contact interface. This leads to microslip effects affecting the dynamic behaviour. The experimental validation of the calculation method accounting for these effects is shown by comparing measured and calculated frequency response functions (FRF). ({\^A}{\copyright} 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)}},
  author       = {{Genzo, Alexander and Sextro, Walter and Popp, Karl}},
  issn         = {{1617-7061}},
  journal      = {{PAMM}},
  number       = {{1}},
  pages        = {{91--92}},
  publisher    = {{WILEY-VCH Verlag}},
  title        = {{{Analysis of the Forced Vibration of Two Bolted Half-Pipes with Extended Friction Contacts}}},
  doi          = {{10.1002/pamm.200510026}},
  volume       = {{5}},
  year         = {{2005}},
}