Modal parameter identification using the log decrement method and band-pass filters

Liao, Yabin; Wells, Valana L.

doi:10.1016/j.jsv.2011.05.017

Cited by 40 publications

(14 citation statements)

References 6 publications

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“…In this system, vibration amplitude exponentially decays over time and the natural log of amplitudes of any two successive peaks is defined as the logarithmic decrement or log decrement. Logarithmic decrement (δ) 28 can be calculated by where A 0 and A are the maximum amplitude of the first and n th cycle, respectively. Damping ratio (ξ) can be obtained by the substitution of equation (1) into the following …”

Section: Resultsmentioning

confidence: 99%

The effects of S-glass fiber hybridization on vibration-damping behavior of intraply woven carbon/aramid hybrid composites for different lay-up configurations

Bulut

Alsaadi

Erkliğ

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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In this study, the vibration and damping characteristics of the hybrid composites reinforced with plain woven S-glass and intraply woven carbon/Kevlar fiber fabrics are investigated. Vibration tests on the samples have been conducted only for measuring the first mode of natural frequency with application of experimental modal analysis procedures. Symmetric and asymmetric layering structures have been prepared for the hybrid composite configurations in order to study the stacking sequence effects. Damping ratios have been evaluated from the logarithmic decrement method by using acceleration–time envelope curves. Results have shown that position and percentage of the fibers in the composites are the most effective parameters for natural frequency and damping characteristics of hybrid samples, and some samples have shown the synergistic effects leading to a significant enhancement in damping and natural frequency.

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Section: Resultsmentioning

confidence: 99%

The effects of S-glass fiber hybridization on vibration-damping behavior of intraply woven carbon/aramid hybrid composites for different lay-up configurations

Bulut

Alsaadi

Erkliğ

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…This oscillation was observed at 11 MHz and the damping ratio of the power loop was determined to be approximately 0.025 by the log-decrement method [14], [15]. To mitigate this oscillation, a simple RC snubber (4.7 nF metal film capacitor in series with a 10 Ω resistor) was placed across the bus very close to the module terminals.…”

Section: Gate-drive Circuit and Management Of Power Circuit Natumentioning

confidence: 99%

Evaluation of 1.2 kV, 100A SiC modules for high-frequency, high-temperature applications

Lemmon

Graves

Gafford

2015

2015 IEEE Applied Power Electronics Conference and Exposition (APEC)

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Cumulative advances in substrate quality and device manufacturing yields over the past few years have paved the way for the commercial introduction of Silicon Carbide (SiC) power modules capable of supporting applications in the 10-20 kW load class and beyond. This paper investigates the suitability of one such module for high-frequency operation at elevated temperatures by leveraging a high-peak-current gate-drive circuit and careful management of parasitic-induced oscillations. Clamped-inductive load experiments have been carried out at elevated temperatures, and the results compared to published results for similar-scale prototype modules.This work demonstrates achievement of very fast slew rates and switching times; the resulting switching losses are 50-70% lower than figures reported in the literature for modules of this scale.

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“…All frequency bands of the broadband spectra of the free vibrational decay have different decay rates. Itis not possible to calculate just one valid damping ratio [21], especially if one wants to calculate the AT, which is the case in this investigation. In this case, one can use band-pass filters to determine each specific damping ratio.…”

Section: Introductionmentioning

confidence: 99%

Damping of post-impact vibrations

et al. 2019

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Impacts of solid bodies on rigid plates produce loud noise and strong vibrations. During this impact, flexural waves travel circularly outwards from the point of impact. These waves are used to determine the properties of the impacting body. For accurate location and momentum measurements, it is necessary that the set of flexural waves pass acceleration sensors just once without being disturbed by reflections. Different plate designs are tested with the aim to evaluate the shape, which offers the best damping properties against strong single impact. The investigations showed that the damping properties of the plates are significantly better with a star-shaped design, which is equipped with a damping layer. The novelty presented here is that the damping properties are significantly increased using a star-shaped plate with specially power law formed and damped edges. The work offers a solution to get significant better damping properties and a better signal for impact investigations. The results demonstrate that it is a promising approach for an impact detection system, which could be equally applicable to acoustic damping applications.

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Modal parameter identification using the log decrement method and band-pass filters

Cited by 40 publications

References 6 publications

The effects of S-glass fiber hybridization on vibration-damping behavior of intraply woven carbon/aramid hybrid composites for different lay-up configurations

The effects of S-glass fiber hybridization on vibration-damping behavior of intraply woven carbon/aramid hybrid composites for different lay-up configurations

Evaluation of 1.2 kV, 100A SiC modules for high-frequency, high-temperature applications

Damping of post-impact vibrations

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