Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 14 of 14 for “"rotor dynamics"”.
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Computer-aided design software for rotor dynamics analysis
… a critical speed map for a general flexible rotor in isotropic bearings has been developed. Rotordynamics theory related to this research work is studied including synchronous unbalance response, critical speed, gyroscopic effect, critical speed map, and stability. The method of solution is …
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Advanced analysis of rotor-bearing systems for stability and response
Rotor dynamics has become an integral part in the analysis and design of industrial turbo machinery. Rotor dynamics deals predominantly with the evaluation of the stability and damped critical speeds, and the response to an unbalance excitation, of turbomachinery. The majority of the industries …
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Evaluation of Alternate Bearing Designs in a High Speed Automotive Turbocharger
… found in automotive turbochargers. DyRoBeS rotor dynamics software was used to determine analytically damped natural frequencies for floating ring bearings, and also for six, eight, and ten axial groove fixed geometry bearings, under different speed and loading conditions. The resulting data …
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Mechanical design and validation of 1 MW permanent magnet synchronous machine (PMSM)
… Then the thesis mainly addresses analysis for rotor dynamics as well as fan performance. Design challenges are analyzed by analytical equations, numerical methods like finite element analysis and finally test results.
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Performance enhancements to Joint Army/Navy Rotorcraft Analysis and Design (JANRAD) software and Graphical User Interface (GUI)
The Joint Army/Navy Rotorcraft Analysis and Design (JANRAD) computer program was developed at the Naval Postgraduate School to perform performance, stability and control, and rotor dynamics analysis during preliminary helicopter design efforts. This thesis is the continuation of a previous work in …
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Foundations for the Coupled Inflow and Structural Dynamics of Multi-rotor Helicopters
… is expanded to calculate the coupled inflow and rotor dynamics of tandem rotor configurations. This establishes the foundation for a more complete multi-rotor, dynamic inflow model with finite-state methods. The derivation presented in this work is for the general case of two rotors in the same …
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Dynamic response of small turbine flowmeters in pulsating liquid flows
… CFD and extending the simulation to predict the rotor dynamics and, hence, the response of this meter to specified cases of pulsating flow. A theoretical model developed by Dijstelbergen (1966) assumes frictionless behaviour and that flow is perfectly guided by meter blading through the rotor and …
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Finite element based non-linear transient analysis of active magnetic bearing turbomachinery
… conditions, essential for the protection of AMB rotor, stator and other stationery seals along the shaft. The increase in the number of critical path machinery using AMB technology has focused awareness and necessity for proper design of these auxiliary bearings to avoid additional unwanted …
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Super High-speed Miniaturized Permanent Magnet Synchronous Motor
… parameters such as phase inductors, core losses, rotor eddy current loss, torque, and induced electromotive force (back-EMF) are also presented in detail in this dissertation. Some mechanical issues such as thermal analysis, bearing pre-load, rotor stress analysis, and rotor dynamics analysis are …
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Improved continuous-time higher harmonic control using H [infinity] methods
… space. This versatility is enabled by the main rotor, which also causes undesired harmonic vibration during operation. This unwanted vibration has a negative impact on the practicality of the helicopter and also increases its operational cost. Passive control techniques have been applied to …
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A Study of Methods for Improving the Dynamic Stability of High-Speed Turbochargers
… inside the bearings are usually causing the rotor to whirl in a limit cycle but may become large enough to cause permanent damages. Additionally, the lubrication oil may leak at higher rates through the seals into the engine or the exhaust emissions. This dissertation investigates methods for …
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Controlling radial waves through effective periodicity
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-12-01
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Effects of variations in controller gains on the dynamics of magnetic bearings
… be tuned for stable and safe operation of the rotor. The ultimate goal of this study is to determine the effects of changing controller gains on the behavior of the rotor during operation in its normal speed range with a known unbalance load. We also endeavor to confirm the model of the rotor …
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Propeller-Driven Rotor Twirl Phenomenon: Hover Performance, Dynamics, and Controls
Propeller-driven rotors use compact electric motors and propellers, mounted on the main rotor blade, to generate the mechanical torque needed to rotate the main rotor. The presented work details experiments and model developments in three major areas: hover performance, dynamics, and controls. The …