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 61 for “"Damping Ratio"”.
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Investigating Various Modal Analysis Extraction Techniques to Estimate Damping Ratio
… to certain characteristics. In this thesis the Rational Fraction Polynomial (RFP) Method, the Prony or Complex Exponential Method (CEM), the Ibrahim Time Domain (ITD) Method, and Hilbert Envelope Method are used to evaluate how the accuracy of the damping ratio is affected with respect to …
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Uncertainties in the Estimation of the Shear-Wave Velocity and the Small-Strain Damping Ratio from Surface Wave Analysis
L'abstract è presente nell'allegato / the abstract is in the attachment
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The effect of stiffness and mass on the dynamic response of wood floors
… load, and boundary conditions on the floor vibrational performance. Three main parameters used to describe the vibration are resonant frequency, damping ratio, and root mean square (RMS) acceleration. The results showed that COV of joist MOE affected the fundamental frequency, and had no …
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Investigating the Dynamic Soil Behaviour of Cape Flat Sands Under Earthquake Cyclic Loading
… dynamic properties, such as shear modulus and damping ratio. Therefore, this necessitates an inclusive methodology to consider and incorporate the degree of saturation in seismic analyses to ensure that seismic designs are not overly conservative based on local soil conditions. In Cape Town, …
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Sulla progettazione in zona sismica di strutture dotate di dissipatori fluido-viscosi: proposta di una metodologia
… this way it is possible to define an equivalent damping ratio and the problem becomes linear; the solution of the equivalent problem is well-known. In the following section two techniques of linearization, proposed by some authors in literature, are described: the first technique is based on the …
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Influence of soil parameters on the motion of rocking walls
… these uncertainties is the effect of radiation damping on the motion of the system. Existing estimations for the radiation damping use an equivalent damping ratio, which was actually derived for a rocking block that is not connected to any structure. The formula for this equivalent damping ratio …
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Fixed order controller design via linear programming
… problem. Natural frequencies and minimum damping ratio are the design parameters of the developed controller design process. The design parameters are insightful since damping ratio and frequencies are closely related to time domain specifications. The interval polynomial search algorithm …
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Impact Mechanics Of A Lap Joint: A Theoretical-Based Parametric Study
… six influential parameters are studied: damping ratio, contact stiffness, position of intermediate springs, gaps, excitation amplitude and beam height. For all parameters, the system response was highly controlled by modes with two contacting springs. Regarding damping, increasing damping …
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Effect of ground motion frequency on non-structural seismic damage
The need for economic consideration in structural design triggered the emergence of performance-based design to minimize material waste while achieving better performance. The displacement measurements of structures are significant to structural damage evaluation, and most seismic design methods …
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Dynamic response of 3D printed beams with damping layers
… on the dynamic response of 3D printed beams with damping layers. More precisely, natural frequency and damping ratio will be analysed in order to find the optimal location of the damping layers. For this experiment, three methods are used, one with an accelerometer, one with a high speed camera …
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The control of flexible structure vibrations using a cantilevered adaptive truss
… tools for the control of flexible structure vibrations using a cantilevered adaptive truss. A specific six-actuator, octahedral-octahedral truss effects the control of different flexible structures. These structures could represent space structures or robotic manipulators or a variety of other …
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Liquid Slosh Analysis Using Smoothed Particle Hydrodynamics
… Simulated sloshing liquid frequency and damping ratio data for 1g cases has been compared to existing experiments for both spherical and prismatic container geometries. The 0g case has been studied to determine what further modifications would be required to obtain realistic simulations …
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Influence of some particle characteristics on the small strain response of granular materials
… Gmax, shear modulus degradation G/Gmax, and damping ratio. These are also important parameters in the design of foundations where only small deformation takes place. A review of the literature suggests that shear modulus and damping ratio at small strain are significantly influenced by void …
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Effects of oversized particles on the dynamic properties of sand specimens evaluated by resonant column testing
… particles on the shear modulus (G) and material damping ratio (D) of a uniform sand were evaluated in the linear (γ ≤ 0.001%) and nonlinear (γ > 0.001%) ranges of shear strain with combined resonant column and torsional shear (RCTS) equipment. The sand used in this investigation is a uniform sand …
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Dynamic Testing of a Full-Scale Pile Cap with Dense Silty Sand Backfill
… was observed to be non-linear with a concentration of pressure near the bottom of the pile cap. Rankine, Coulomb, and log-spiral earth pressure theories underestimated the passive earth pressure from the backfill by at least 30%. The natural frequency of the pile cap increased with increasing …
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The effects of cutouts in joists on the vibrational response of wood floors
… joist types were used to evaluate the vibrational response of wood floors with and without cutouts in the joists. Each floor was also subjected to different boundary conditions and imposed load during the evaluation. Two types of tests were performed on the floors, a free vibration test …
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Estudo do comportamento dinâmico de plataforma offshore do tipo T.L.P. para águas profundas através de modelo reduzido hidroelástico
… techniques. The obtained results from free vibration tests and the action of regular waves on the model are also shown. Among the available experimental results, those related to the damping ratio, inertia and drag coefficients should be highlited. It should be noted for the model under wave …
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Análise da resposta dinâmica de um modelo em escala reduzida de plataforma offshore do tipo T.L.P.
… Among the experimental results, those related to damping ratio, inertia and drag coefficients should be highlighted. Tests were performed to verify the contribution of the deck mass distribution for the model natural periods. The experimental time responses from tests under impacts and under wave …
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A modal analysis method for a lumped parameter model of a dynamic fluid system
… introduces terms such as the natural frequency, damping ratio and the frequency response function. For the analysis of more complex mechanical systems the topic of modal analysis is introduced. Proceeding in a manner analogous to that of the review of the mechanical system, the lumped parameter …
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An analytical investigation of aircraft handling qualities
… are developed on aircraft frequency and damping ratio for "good" longitudinal short-period control. The lateral phugoid mode is also investigated and the conclusion reached is that this mode cannot be controlled in a manner resulting in "good" pilot ratings. Comparison of the results …
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