Nonlinear Parametric Resonances in a Stay of the Iroise Cable-Stayed Bridge: Analytical Model and Experiments

2007 ◽  
Author(s):  
Olivier Boujard ◽  
Ste´phane Pernot ◽  
Alain Berlioz ◽  
Claude Lamarque
Keyword(s):  
Spectral Analysis ◽  
Analytical Model ◽  
Parametric Resonance ◽  
Resonance Mechanism ◽  
The Third ◽  
Cable Stayed Bridge ◽  
Parametric Resonances ◽  
Traffic Environment ◽  
Cable Stays ◽  
Bending Modes

Recent experimental campaigns led on the Iroise cable stayed bridge near Brest, France, revealed repeated vibratory events in some cable stays likely to provoke durability problems. A spectral analysis emphasized two regimes in which either the fundamental or the third cable mode were excited. Yet, wavelet scalograms of tests allowed to exhibit a global pylon mode excited by traffic environment through deck-cable-tower interaction and which again excites local cable modes by means of a nonlinear parametric resonance mechanism with vertical bending modes of the girder. Preliminary results are introduced as an attempt to explain such a scenario.

scholarly journals SHM System and a FEM Model-Based Force Analysis Assessment in Stay Cables

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1927
Author(s):  
Jan Biliszczuk ◽  
Paweł Hawryszków ◽  
Marco Teichgraeber
Keyword(s):  
Measured Data ◽  
The Finite Element Method ◽  
Force Analysis ◽  
Fem Model ◽  
Temperature Changes ◽  
The Third ◽  
Cable Stayed Bridge ◽  
Stay Cables ◽  
Durability Assessment ◽  
Cable Stays

The Rędziński Bridge in Wrocław is the biggest Polish concrete cable-stayed bridge. It is equipped with a large structural health monitoring (SHM) system which has been collecting the measured data since the bridge opening in the year 2011. This paper presents a comparison between the measured data and the finite element method (FEM) calculations, while taking into account 7 years of data collection and analyses. The first part of this paper concerns the SHM application. In the next part, which contains comparisons between forces in cables and temperature changes throughout the structure, the measured data are presented. The third part includes SHM-based calculations and simulations with a complex FEM model to check the measured data and to estimate future measurements. The last part contains a durability assessment calculation for the cable stays.

Analysis of Parametric Resonances in In-Plane Vibrations of Electrostrictive Hyperelastic Plates

2018 ◽  
Vol 13 (9) ◽  
Author(s):  
Astitva Tripathi ◽  
Anil K. Bajaj
Keyword(s):  
Electric Field ◽  
Parametric Resonance ◽  
Mechanical Response ◽  
Element Model ◽  
Mode Shapes ◽  
Principal Parametric Resonance ◽  
Parametric Resonances ◽  
Second Mode ◽  
Electrostrictive Polymer ◽  
Large Amplitude Vibrations

Electrostriction is a recent actuation mechanism which is being explored for a variety of new micro- and millimeter scale devices along with macroscale applications such as artificial muscles. The general characteristics of these materials and the nature of actuation lend itself to possible production of very rich nonlinear dynamic behavior. In this work, principal parametric resonance of the second mode in in-plane vibrations of appropriately designed electrostrictive plates is investigated. The plates are made of an electrostrictive polymer whose mechanical response can be approximated by Mooney Rivlin model, and the induced strain is assumed to have quadratic dependence on the applied electric field. A finite element model (FEM) formulation is used to develop mode shapes of the linearized structure whose lowest two natural frequencies are designed to be close to be in 1:2 ratio. Using these two structural modes and the complete Lagrangian, a nonlinear two-mode model of the electrostrictive plate structure is developed. Application of a harmonic electric field results in in-plane parametric oscillations. The nonlinear response of the structure is studied using averaging on the two-mode model. The structure exhibits 1:2 internal resonance and large amplitude vibrations through the route of parametric excitation. The principal parametric resonance of the second mode is investigated in detail, and the time response of the averaged system is also computed at few frequencies to demonstrate stability of branches. Some results for the case of principal parametric resonance of the first mode are also presented.

An Analytical Model for the Effective Dielectric Constant of a 0-3-0 Composite

2010 ◽  
Author(s):  
K. A. Cook-Chennault ◽  
S. Banerjee
Keyword(s):  
Dielectric Constant ◽  
Aspect Ratio ◽  
Analytical Model ◽  
Experimental Results ◽  
Effective Dielectric Constant ◽  
The Third ◽  
Third Phase ◽  
Three Phase ◽  
Phase 0 ◽  
Experimental Values

An analytical expression for prediction of the effective dielectric constant of a three phase 0-3-0 ferroelectric composite is presented. The analytical results are verified with the experimental results from Nan et al [1]. We extend the analytical model, so that the influence of the shape of the third phase inclusion, on the effective dielectric constant of the composite, can be investigated. The results indicate that the dielectric constant increases ∼7 times, when the aspect ratio of the conductive inclusion is increased from 1 (sphere) to 10 (spheroid). The analytical predictions compare favorably with the experimental values.

Modeling of Tuned Liquid Damper With Submerged Nets

1999 ◽  
Vol 121 (3) ◽  
pp. 334-343 ◽  
Author(s):  
S. Kaneko ◽  
M. Ishikawa
Keyword(s):  
Analytical Model ◽  
Wave Theory ◽  
Damping Factor ◽  
Tuned Liquid Damper ◽  
Liquid Motion ◽  
Tuned Mass Dampers ◽  
Dissipation Energy ◽  
Structure Interaction ◽  
Cable Stayed Bridge ◽  
Optimal Damping

An analytical model for describing the effectiveness of tuned liquid damper (TLD) with submerged nets for suppressing horizontal vibration of structures is proposed. Dissipation energy due to the liquid motion under sinusoidal excitation is calculated based on nonlinear shallow water wave theory. In particular, the effects of hydraulic resistance produced by nets installed in a tank on the performance of TLDs are examined. The results of dissipation energy theoretically obtained are confirmed by experiments. To show the effectiveness of the proposed analytical model for TLD-structure interaction problems, the case in which TLD with nets is installed on top of a pylon of a cable-stayed bridge is described and the calculated results are compared with the actual experimental data. In the calculation, it is shown that the optimal damping factor, as is the case for tuned mass dampers (TMD), can be produced by the nets, and the effectiveness of TLD with nets are demonstrated.

scholarly journals Novel Approaches to Smoothing and Comparing SELDI TOF Spectra

2005 ◽  
Vol 1 ◽  
pp. 117693510500100 ◽  
Author(s):  
Sreelatha Meleth ◽  
Isam-Eldin Eltoum ◽  
Liu Zhu ◽  
Denise Oelschlager ◽  
Chandrika Piyathilake ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Fourier Transforms ◽  
Area Under The Curve ◽  
Maximum Intensity ◽  
Data Sets ◽  
Intensity Level ◽  
Prominent Feature ◽  
Data Set ◽  
The Third ◽  
Novel Approaches

Background Most published literature using SELDI-TOF has used traditional techniques in Spectral Analysis such as Fourier transforms and wavelets for denoising. Most of these publications also compare spectra using their most prominent feature, ie, peaks or local maximums. Methods The maximum intensity value within each window of differentiable m/z values was used to represent the intensity level in that window. We also calculated the ‘Area under the Curve’ (AUC) spanned by each window. Results Keeping everything else constant, such as pre-processing of the data and the classifier used, the AUC performed much better as a metric of comparison than the peaks in two out of three data sets. In the third data set both metrics performed equivalently. Conclusions This study shows that the feature used to compare spectra can have an impact on the results of a study attempting to identify biomarkers using SELDI TOF data.

S190 – Voice Spectral Analysis After Surface Electrical Stimulation

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P139-P139 ◽  
Author(s):  
Edie Renee Hapner ◽  
Mary Gorham-Rowan ◽  
Richard J. Morris ◽  
Linda P Fowler
Keyword(s):  
Spectral Analysis ◽  
Electrical Stimulation ◽  
Direct Effect ◽  
Vocal Fold ◽  
Second Harmonic ◽  
The Third ◽  
Glottal Closure ◽  
Significant Difference ◽  
Study Participants ◽  
Spectral Tilt

Objectives The purpose of this study was to measure changes in vocal fold closure associated with surface electrical stimulation (VitalStim®). Methods 30 participants, 15 male and 15 female, ages 20–56 years, were included in the study. Participants underwent 1 hour of surface electrical stimulation, per guidelines reported in the VitalStim® manual. 3 trials of the vowel /ae/ were analyzed pre- and post-stimulation. Indirect estimates of glottal closure were obtained from the recorded vowels, as follows: 1) H1–H2: the amplitude of the first harmonic to the second harmonic (open quotient); 2) H1–A1: the ratio of the amplitude of the first harmonic to the amplitude of the first formant (glottal width); and 3) H1–A3: the ratio of the amplitude of the first harmonic to the amplitude of the third formant (spectral tilt). Results The direction and magnitude of change for all 3 parameters varied widely across participants. No significant difference occurred pre- vs. post-stimulation for any of the parameters. Conclusions VitalStim® did not systematically affect open quotient, glottal width, or spectral tilt. These results do not support the concept that VitalStim® has a direct effect upon vocal fold closure.

Parametric and Combination Resonances of a Pipe Conveying Pulsating Fluid

1975 ◽  
Vol 42 (4) ◽  
pp. 780-784 ◽  
Author(s):  
M. P. Paidoussis ◽  
C. Sundararajan
Keyword(s):  
Flow Velocity ◽  
Parametric Resonance ◽  
Mean Value ◽  
Pipe Conveying Fluid ◽  
Combination Resonance ◽  
Load Combination ◽  
Parametric Resonances ◽  
The Difference ◽  
Pulsating Fluid ◽  
Conveying Fluid

In this paper we consider the dynamics of a pipe conveying fluid, when the flow velocity is harmonically perturbed about a mean value. Two methods of analysis are presented; Bolotin’s method, which can only give the boundaries of regions of parametric resonance, and a numerical Floquet analysis, which gives also the boundaries of combination resonance. A number of calculations for cantilevered pipes show that, generally, combination resonance is less important than parametric resonance, except for flow velocities near the critical (where the system loses stability in steady flow); parametric resonances are selectively associated with only some of the modes of the system, and combination resonances involve only the difference of the eigenfrequencies. For pipes clamped at both ends the behavior of the system is similar to that of a column subjected to a pulsating load; combination resonances in this case involve the sum of the eigenfrequencies.

Islands and the Delimitation of the Continental Shelf: A Framework for Analysis

1977 ◽  
Vol 71 (4) ◽  
pp. 642-673 ◽  
Author(s):  
Donald E. Karl
Keyword(s):  
Continental Shelf ◽  
Analytical Model ◽  
Relative Size ◽  
Exclusive Economic Zone ◽  
Law Of The Sea ◽  
Relative Location ◽  
The Third ◽  
State Practice ◽  
Economic Zone ◽  
The Law

This article examines one of the recurring problems in the law of the sea—the treatment of islands in the delimitation of the continental shelf between opposite and adjacent states—in light of developments at the Third UN Conference on the Law of the Sea, in particular, the adoption of “equitable principles” as the standard for delimitation of the continental shelf and exclusive economic zone between adjacent and opposite states. On the assumption that the content of these equitable principles may be derived from contemporary state practice in maritime delimitations, this state practice is used as a basis for the construction of an analytical model of the continental shelf problem of islands. This model relies primarily on an island's relative location and secondarily on its relative size with respect to the delimiting states. It provides a framework for determining how an island should be treated in a given delimitation. Though the model is, out of necessity, based upon state practice in continental shelf delimitations, the premises underlying the model are not so limited and thus the general principles derived from this analysis will have an important bearing on the new problem of the delimitation of the exclusive economic zone.

Spectral Analysis and Characterization of a Membrane-Based Artificial Hair Cell Sensor

2014 ◽  
Author(s):  
Rodrigo Sarlo ◽  
Donald Leo ◽  
Pablo Tarazaga
Keyword(s):  
Spectral Analysis ◽  
Hair Cell ◽  
Vibration Amplitude ◽  
Bilayer Membrane ◽  
Torsional Stiffness ◽  
Sensor Output ◽  
Base Excitation ◽  
Array Sensing ◽  
Bending Modes

A fully hydrogel-supported, artificial hair cell (AHC) sensor based on bilayer membrane mechanotransduction is designed with sensitivity and versatility in mind. Thanks to fabrication improvements from previous generations, the sensor demonstrates peak current outputs in the nanoamp range and can clearly measure inputs as high as 2k Hz. Characterization of the AHC response to base excitation and air pulses show that membrane current oscillates with the first three bending modes of the hair. Output magnitudes reflect of vibrations near the base of the hair. A 2 DOF Rayleigh-Ritz approximation of the system dynamics yields estimates of 19 N/m and 0.0011 Nm/rad for the equivalent linear and torsional stiffness of the hair’s hydrogel base, although double modes suggest non-symmetry in the gel’s linear stiffness. The sensor output scales linearly with applied voltage (1.79 pA/V), avoiding a higher-order dependence on electrowetting effects. The free vibration amplitude of the sensor also increases in a linear fashion with applied airflow pressure (18.4 pA/psi). Based on these sensitivity characteristics, an array sensing strategy for these sensors is proposed.

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