Results 261 to 270 of about 4,853 (302)

Computational prediction of modal damping ratios in thin-walled structures

Journal of Sound and Vibration, 2014
Abstract Modal analysis in finite element packages gives natural frequencies and mode shapes, but not modal damping values. Given a constitutive relation for specific material dissipation, volume integrals of the per cycle dissipation can be used to estimate the modal damping. Here, we adopt a well known power law model for such specific dissipation.
Prasun Jana, Anindya Chatterjee
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Modal damping ratio analysis of dynamical system with non-stationary responses

Applied Ocean Research, 2016
Abstract During the long term monitoring of the structure, the damping ratio reflects the characteristics of the structure from perspective of energy loss, and its changes can reflect the structural damages to some extent. But in the structural modal analysis based on the prototype measurement, the damping ratio identification results are difficult ...
Da Tang, Ran Ju, Qianjin Yue, Shisheng Wang   +3 more
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Empirical Modeling of Modal Damping Ratio of Impact-Damped Flexible Beams by GEP

Arabian Journal for Science and Engineering, 2017
In this paper, the empirical models for predicting the modal damping ratio ( $$\xi )$$ of impact-damped flexible beams (IDFB) via gene expression programming (GEP) are proposed. The experimental data used in
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Modal truncation, Ritz vectors, and derivatives of closed-loop damping ratios

Journal of Guidance, Control, and Dynamics, 1991
The effect of modal truncation on the damping ratio and their derivatives with respect to an added mass is investigated for a simply supported, multispan beam with a linear quadratic Gaussian control system. It is found that both the damping ratios and derivatives converge slowly, but the derivatives converge more slowly than the damping ratios ...
Chris A. Sandridge, Raphael T. Haftka
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Equivalent modal damping ratios for non-classically damped hybrid steel concrete buildings with transitional storey

Structural Engineering and Mechanics, 2014
Over the past years, hybrid building systems, consisting of reinforced concrete frames in bottom and steel frames in top are used as a cost-effective alternative to traditional structural steel or reinforced concrete constructions. Dynamic analysis of hybrid structures is usually a complex procedure due to various dynamic characteristics of each part ...
Abbas Sivandi-Pour, Mohsen Gerami, Daryush Khodayarnezhad   +2 more
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Frequencies and damping ratios of bridges through Operational Modal Analysis using smartphones

Construction and Building Materials, 2018
Abstract Seismic Force Assessment in structural design of bridges requires a good estimation of the fundamental period. Estimated periods, using current methodologies in seismic provisions, are approximations that may significantly differ from the real periods.
Sebastián Castellanos-Toro, Mario Marmolejo, Johannio Marulanda, Alejandro Cruz, Peter Thomson   +4 more
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Seismic design of plane steel braced frames using equivalent modal damping ratios

Soil Dynamics and Earthquake Engineering, 2020
Abstract A force-based seismic design method for eccentrically braced and buckling-restrained braced plane steel frames is proposed. The method makes use of equivalent modal damping ratios that play the role of the behavior (strength reduction) factor.
Nicos A. Kalapodis, George A. Papagiannopoulos   +1 more
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The derivation of modal damping ratios from complex-plane response plots

Journal of Sound and Vibration, 1973
Theoretically derived Kennedy-Pancu type plots for two-degree-of-freedom systems are evaluated to assess the likely accuracy of the determination of natural frequencies and damping ratios from empirical plots. Within the region in which an amplitude/frequency plot alone is inadequate, it is shown that there is a much more restricted region (an ...
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Theoretical Determination of Modal Damping Ratio of Sloshing Using a Variational Method

Journal of Pressure Vessel Technology, 2011
This paper investigates a variational method for theoretically determining the first damping ratio of sloshing in cylindrical and arbitrary axisymmetric tanks. In this method, a virtual work expression for the viscous terms in the Navier–Stokes equations is transformed into the first-mode damping term, thereby extending Hamilton’s principle for ...
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Identification of natural frequencies and modal damping ratios from response data

The Journal of the Acoustical Society of America, 1976
Response data are processed in the frequency domain to determine natural frequencies and modal damping ratios of a multidegree-of-freedom system. The excitation can be either deterministic or a random function of time. When the time history of the excitation is now known, the method requires its power spectral density to be flat. An iterative scheme is
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