Thesis (M.S.)--Mississippi State University. Department of Mechanical Engineering. / Title from title screen. Includes bibliographical references.

Misalignment in turbomachinery has been commonly known to produce twotimes- running-speed (2N) response. This project aimed to investigate the source of the 2N vibration response seen in misaligned vibrating machinery by simulating misalignment through a coupling. Three flexible disc-pack couplings (4-bolt, 6-bolt, and 8-bolt coupling) were modeled, and parallel and angular misalignments were simulated using a finite element program. The stiffness terms obtained from the coupling simulations had 1N, 2N, and 3N harmonic components. The 4-bolt coupling had large 1N reaction components under angular and parallel misalignment. The 6-bolt coupling model only had a 1N reaction component under angular misalignment, and both cases of parallel misalignment showed a strong 2N reaction component, larger than both the 1N and 3N components. The 8-bolt coupling model under angular misalignment produced large 1N reaction components. Under parallel misalignment, it produced 1N, 2N, and 3N components that were similar in magnitude. All the couplings behaved linearly in the range studied. A simple model predicted that the 2N frequency seen in the response is caused by the harmonic (1N) term in the stiffness. The amplitude of the 2N component in the response depends on the amplitude of the 1N term in the stiffness compared to the average value of the stiffness and the frequency ratio. The rotordynamic response of a parallel and angular misaligned system was completed in XLTRC2. When the frequency ratio was 0.5, the system response with the 4-bolt and 6-bolt coupling had a synchronous 1N component that was much larger than the 2N component. The response did not have a 2N component when the 8-bolt coupling was used but the response did have a 1.6N component that was considerably larger than the 1N component. When the frequency ratio was 2, the system response with the 4-bolt and 6-bolt coupling had a synchronous 1N component and a relatively small ½ frequency component. The response with the 8-bolt coupling had a 0.4N component that was larger than the 1N component. A 5-tilting pad journal bearing was also tested to better understand its behavior under misalignment because some experts attribute the 2N response to the nonlinear forces produced by bearings with high unit loads. The response of the 5-tilting pad bearing did not produce any 2N components while the bearing was subjected to unit loads of up to 34.5 bars.

Die vorliegende Arbeit befasst sich mit dem Betriebsverhalten und den Auslegungsrichtlinien für ein hochtemperaturfähiges Übertragungselement aus Stahl für elastischen Klauenkupplungen. Im Grundlagenkapitel wurden hierfür zunächst aus den Eigenschaften und Auslegungsvorschriften handelsüblicher Klauenkupplungen wichtige Kenngrößen und Kennwerte bestimmt und relevante Aspekte der Tribologie und der Federtechnologie beleuchtet. Mittels FEM wird die Spannungsverteilung und das Verformungsverhalten des Übertragungselements bei Drehmomentbelastung untersucht und anhand einer Parameterstudie der Einfluss verschiedener Konstruktionsparameter analysiert. Zusätzlich werden Berechnungen und Simulationen zur Dämpfung und zur Betriebsfestigkeit durchgeführt. Die gewonnenen Erkenntnisse wurden anschließend durch experimentelle Untersuchungen mit statischer und dynamischer Belastung sowie durch Lebensdauerversuche und Betriebslastenversuche verifiziert und ergänzt. Hierbei wurden zu Vergleichszwecken auch handelsübliche Übertragungselemente aus TPE untersucht. Auf Basis der Untersuchungsergebnisse wurden anschließend Richtlinien für die Auslegung und den Betrieb des Übertragungselements abgeleitet. / The present work deals with the operating behaviour and the selection guidelines for a new high-temperature steel transmission element for elastic jaw couplings. In the state oft the art chapter, important parameters and characteristic values were first determined from the properties and selection specifications of commercially available claw couplings and relevant aspects of tribology and spring technology were highlighted. FEM is used to investigate the stress distribution and the deformation behaviour of the transmission element under torque loading and to analyse the influence of various design parameters. In addition, calculations and simulations for damping and fatigue strength are carried out. The knowledge gained was then verified and supplemented by experimental investigations with static and dynamic loads as well as by service life tests and operating load tests. For comparison purposes, commercially available transmission elements made of TPE were also investigated. Based on the test results, guidelines were then derived for the selection and operation of the new transmission element.