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 20 of 66 for “"vibration modes"”.
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Flow Analysis of Vibration Modes in Turbocharger Turbines
… The flow analysis is carried out for the rotor vibration modes corresponding to a set of natural frequencies lower than but close to the frequency associated with the upper end of the turbine operation range. The core computational method is the Space–Time Variational Multiscale (ST-VMS) method. …
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Characterization of in-phase and out-of-phase vibration modes of secondary structures attached to a primary structure by experimentation and finite element analysis
Ground vibration testing (GVT), is one of the most critical testing procedures for airplane certification. With proper GVT, analysts can determine the stiffness distribution, natural frequencies, mode shapes, and structural damping of each component, all of which are needed to perform flutter and …
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Model reduction of a set of elastic, nested gimbals by component mode selection criteria and static correction modes
… employs mode ranking criteria to select modes which influence the dynamics of the problem the most. The second involves the use of static correction modes along with vibration modes to simulate the dynamics of this nested gimbal model. A model of the structure is described in terms of a …
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On the free vibration behavior of cylindrical shell structures
… as cylindrical shell structures. The study of vibrations of cylindrical shells is an important aspect in the successful applications of the cylindrical shells. The free vibration characteristics of a submarine hull have an important influence on the noise signature of the submarine. That makes …
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Test and analysis methods for resolving fan/motor vibration problems in air-conditioning units
… and Analysis Methods for Resolving Fan/Motor Vibration Problems in Air-Conditioning Units. The objective is to develop the basic analytical models and experimental procedures that can be used to find the vibration modes associated with fan impeller, motor and motor mount in air-conditioning …
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Vibrações de cascas cilíndricas delgadas contendo fluido
… which result from a strong coupling among the vibration modes, are presented herein. Emphasis is given to the used experimental techniques and obtained test results which have corroborated recently reported theoretical results [6,7] on the fluid-thin shell interactive problem. Through out the …
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Seismic performance, design and placement of multiple tuned mass dampers in building applications
… reasons is that both the fundamental and higher vibration modes may play important roles in the seismic responses of building structures while the conventional single TMD tuned to the fundamental mode has little effect on the responses of higher modes.</p> <p>In this study, a multiple tuned mass …
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An analytical and experimental investigation of the longitudinal vibrational response of an empty and unpressurized Agena-B vehicle
… and analytical study of the longitudinal vibrational response of a modified Agena-B vehicle. The empty, unpressurized vehicle was excited with sinusoidal loads and the response was measured through a frequency range including the first two classical longitudinal. modes of the structure. …
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Effect of modal truncation on derivatives of closed-loop damping ratios in structural control
… actuators. Reduced models based on the natural modes of the structure are formed and derivatives of the damping ratios of the closed-loop eigenvalues are calculated. As expected, the convergence of the derivatives of the damping ratios with increasing number of modes is slower than the …
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A Hybrid Adaptive and Robust Control Methodology With Application to Active Vibration Isolation
… of new approaches to achieve broad-band active vibration isolation with electrohydraulic actuation. Two new methods, the velocity-tracking approach and the position-tracking approach, are proposed and implemented in a custom-built multiple degree-of-freedom active vibration isolation testbed. …
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Análise dinâmica de placas sandwich comprimidas simplesmente apoiadas
… lt was also plotted a curve connecting the vibration modes with the critical loads. Through this curve it was possible to find out the smallest value for the critical load.
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Instructional shake table for demonstrations in structural dynamics
… demonstrated by use of wavelets for extracting vibration modes of the structure and their damping.
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Beitrag zur Auslegung von Industrieanlagen auf seismische Belastungen
… and stiffness centres, the influence of higher vibration modes and the numeric modelling of existing structures. As it is a displacement based design procedure it directly provides maximum expected relative displacements for the design of deformation-sensitive secondary structures like pipes and …
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Dynamics of High-Speed Planetary Gears with a Deformable Ring
… ring deformations, natural frequencies, vibration modes, parametric instabilities, and nonlinear dynamics of high-speed planetary gears with an elastically deformable ring gear and equally-spaced planets. An analytical dynamic model is developed with rigid sun, carrier, and planets …
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Diagnostic test and analytical methods for resolving fan/motor vibration problems in air-conditioning units
… (nonzero) hub mobility; In this project, the vibration modes of a fan with three cambered blades were investigated. Experimental and Finite Element Analysis (FEA) was performed on the fan blade and the fan-motor unit. The project compared the results obtained from the FEA and experimental …
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Novel Auxiliary Fixture System to Enhance Milled Thin-Walled Parts Quality
… the high flexibility of thin-walled workpieces, vibrations are a common problem when milling thin-walled workpieces. Vibrations lead to poor surface finish and reduced machining efficiency. Employing multi-pin fixtures to increase the damping and stiffness of the vibration modes of the workpieces …
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Piezoelectric Transformer Characterization and Application of Electronic Ballast
… both of which work in longitudinal or transverse vibration mode. These actuators and transducers are both made of piezoelectric elements, which are composed of electrode plates and piezoelectric ceramic materials. Instead of the magnetic field coupling between the primary and secondary windings in …
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Lateral vibration of a beam carrying a concentrated mass at the mid-point, including the effect of rotatory inertia
… solution has been obtained for the lateral vibrations of a simply supported beam with constant cross-section carrying a concentrated mass at the mid-point of span. The elementary beam theory including the rotatory inertia of the beam is utilized. The frequency equation involves the product …
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Análise modal operacional de uma bomba centrífuga submersa utilizando a decomposição melhorada no domínio da frequência
… is, the natural frequencies, damping rates and vibration modes of an ESP installed in a mock well through operational and impact tests. The operational modal analysis method employed was the Enhanced Frequency Domain Decomposition (EFDD). The same method was used to identify the modal parameters …
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