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Showing 1 to 20 of 21 for “"Parametric Excitation"”.
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Parametric Excitation of a DWSC
Parametric excitation of the DWSC (Deep Water Stable Craneship) is studied in this thesis. It occurs for a system without any external forcing, when one of the coefficients in the equation of motion (EOM) modeling the system varies with time. Parametric instability might be triggered for certain …
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Nonlinear oscillations under multifrequency parametric excitation
… equations containing a multifrequency parametric excitation and weak quadratic and cubic nonlinearities is investigated. The method of multiple scales is used to carry out a general analysis, and three resonance conditions are considered in detail. First, the case in which the sum of …
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Harmonic generation and parametric excitation in a beam-plasma system
… by wave-wave and wave-particle interactions and parametric excitation of plasma and ion-acoustic waves by a beam-plasma instability are studied, theoretically and experimentally, in a cold beam-plasma system. The dispersion relations for plasma and ion-acoustic waves are calculated. Coupling …
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Nonlinear oscillations of self-excited systems under multifrequency parametric excitation
… with weak nonlinearities and multifrequency parametric excitation is investigated in this study. The method of multiple scales is used to analyze the system under four different resonances relating parametric excitation frequencies with the natural frequencies. In the first case, the …
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Parameter Identification of Nonlinear Systems Using Perturbation Methods and Higher-Order Statistics
A parametric identification procedure is proposed that combines the method of multiple scales and higher-order statistics to efficiently and accurately model nonlinear systems. A theoretical background for the method of multiple scales and higher-order statistics is given. Validation of the …
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Material and Damping Characterization of Discretized Adhesive Tapes in Cantilever Beams undergoing Free and Forced Vibration
… beams with damping layers subjected to parametric excitation. Comparison of the response amplitude of the parametrically excited beam was performed for different discretization lengths, and system identification of the nonlinear parameters was carried out. The effects of large …
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Modeling and Analysis of a Cantilever Beam Tip Mass System
… beam with tip mass system subjected to different excitation and exploit the nonlinear behavior to perform sensitivity analysis and propose a parameter identification scheme for nonlinear piezoelectric coefficients. First, the distributed parameter governing equations taking into consideration the …
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Structural Identification and Buffet Alleviation of Twin-Tailed Fighter Aircraft
… vibrations of the tails due to either principal parametric or external excitations. To understand the dynamical characteristics of the twin-tails, the model is excited parametrically. For the same excitation amplitude and frequency, five different responses are observed depending on the initial …
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The Winch-Bot : a cable-suspended, under-actuated robot utilizing parametric self-excitation
… by swinging the load dynamically based on parametric self-excitation. The generated trajectories can be used for a variety of tasks, from moving material to cyclic inspection of surfaces. The basic principle and design concept of the Winch-Bot are first described, followed by dynamic …
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The nonlinear evolution of secondary instabilities in boundary layers
… portion. The basic flow portion acts as a parametric excitation for the secondary wave. The interaction portion then captures the resonance effects of the secondary back onto the primary. A perturbation method is also used for the secondary and interaction components. The results obtained …
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An analytical study and computer analysis of three-dimensional, steady-state vibration of multishaft geared-rotor systems
… with special attention to the significance of parametric excitation due to the gear mesh.
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Theoretical and Experimental Study of a Continuous Hydrodynamically-Enhanced Separation System Paradigm
… system is used as a base flow to investigate how parametric excitation can lead to chaotic segregation. The first part of this project focuses on how the three-dimensional velocity field in SHV is reconstructed for the first time from coarse Magnetic Resonance Imaging (MRI) data. A novel …
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A numerical investigation of the global stability of ship roll: invariant manifolds, Melnikov's method, and transient basins
A parametrically forced, single-degree-of-freedom equation modelling ship roll is investigated through the numerical study of invariant manifolds, Melnikov's method, and transient basins. The calculation of the manifolds is facilitated through the development of a sophisticated algorithm for …
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The response of multidegree-of-freedom systems with quadratic and cubic nonlinearities subjected to parametric and external excitations
… under simultaneous sinusoidal external and parametric excitations is investigated. Quadratic and cubic nonlinearities are present in the governing equations. A general perturbation analysis, the Method of Multiple Scales (MMS), is performed for numerous resonance frequencies. Emphasis is …
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Stability of nonlinear oscillatory systems with application to ship dynamics
… composed of the amplitude and frequency of the excitation. The behavior of a softening Duffing oscillator is analyzed under external and parametric excitation. The dynamics of a ship rolling in waves is also considered and three types of excitations are treated: external, parametric, and a …
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Semi-Analytical Model to Study Vibrations of High-Speed, Rotating Axisymmetric Bodies Coupled to Other Rotating/ Stationary Structures
… modes. Time-varying coupling elements act as parametric excitation in the system. Large strain energy in the coupling elements lead to large parametric instability regions. The analytical closed-form expression of the parametric instability bandwidth obtained using a perturbation method …
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Mechanics of Flapping Flight: Analytical Formulations of Unsteady Aerodynamics, Kinematic Optimization, Flight Dynamics and Control
… and the effects of the aerodynamic-induced parametric excitation are assessed. Finally, tools combining geometric control theory and averaging are used to derive analytic expressions for the textit{Symmetric Products}, which are vector fields that directly affect the acceleration of the …
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Techniques for Controlling Structural Vibrations
… to either primary external or principal parametric resonances. Guided by results of previous investigations into the nonlinear dynamics of single- and multi-degree-of-freedom structures, we design mechatronic systems of sensors, actuators, and electronic devices and implement nonlinear …
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Parametric vibration of composite beams with integrated shape memory alloy elements
This research is concerned with parametric vibration in composite beam structures with shape memory alloy elements. As a precursor to this investigation, a flexible steel beam of rectangular uniform cross-section is considered with a lumped end mass under a parametric excitation. A single frequency …
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Nonlinear System Identification of Physical Parameters for Damage Prognosis and Localization in Structures
… signature is the structure's response to forced excitation. The realization of such a goal would help in advancing structural health monitoring procedures using interrogative system identification techniques and determine sensitivities of physical parameters to damage. Additionally, …
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